Why did the USA have to go and protect all those enemies of saddam hussein?
If the millions of victims that Saddam murdered aren't a reason without some manner of paperwork or legal justification there's always the Convention on the Prevention and Punishment of the Crime of Genocide. All 147 signatories are obliged to act to prevent genocide, and failing that to act to punish those who have committed it. So, by 1990 already, 147 countries around the world were obliged to go and protect those 'enemies' of Saddam Hussein. The world failed to do what they signed on for though, as they later did in Rwanda, and the next time Saddam committed another genocide, and finally when somebody did act folks like you come out defending the genocidal dictator. All the worse, defending him in the name of his people(aka victims).
So your argument is that the US is better than Saddam, which considering what has happened is actually debatable. By very convincing.
My argument is more that nearly 3 decades of brutal repression, sectarian warfare and genocide at the hands of Saddam might have played a larger formative role in the Iraqis troubles than the much shorter lived, incompetent, American occupation.
Ahem, shit brain. We could have just left it all alone.
Ignoring problems doesn't always make them better.
Like when Saddam was left in power after the Iran-Iraq war, he went on to commit a genocide because he was left alone. He then went on to invade Kuwait, because he was left alone. He then was pushed out of Kuwait, but otherwise left in power, he then committed another genocide because he was left free to.
You noticing a trend?
It's folks like you willing to ignore everyone else's suffering that Bill Clinton catered to during the Rwandan genocide. He played it exactly your way, even going as far as to actively fight to prevent any action being taken to intervene. There comes a point where actively failing to save people when you have the capacity to do so is itself immoral.
Was it worth 5000 dead soldiers to prevent that for-sure? I dunno, whadda you think?
You seem to be forgetting the ~1 million civilian dead.
Okay, it's hard to estimate, I'll give you 500k. And helping ISIS grow in the subsequent power vacuum. And some torture.
What is the exchange rate of American lives to everyone else's lives?
How many dead from Saddam's war against Iran? How about his genocide of the Kurds? How about his war against Kuwait? How about his genocide of the Shia Iraqis? How many people did Saddam kill beyond that just for suspicions of disloyalty in his decades of rule?
If you can't already answer those questions you can't pretend to appreciate the cost of inaction on Saddam's regime. You think ISIS didn't equally find it's roots from the brutal dictatorships of guys like Saddam and Assad? Do you honestly believe that prior to Saddam's removal by American forces the region was free of sectarian hatred, violence and massacres? Step 1 through 20 of dictator class is divide and conquer, and Assad and Saddam made an extreme practice of deliberately fomenting and encouraging sectarian hatreds to make it all the easier to divide and conquer those under them.
But yeah, the troubles in Iraq and Syria today are all the result of American intervention and nothing else...
How about the numerous reports indicating that the CIAs reports were completely wrong.
They had a single expatriate source that had serious credibility problems bit the directive was go at all costs. So it was ignored.
Cheney would go on talk shows claiming that leaks in the media confirmed the Govs position. When the Gov had been the original leaker.
I believe one of the most prominent voices you are talking about is former Iraqi weapons inspector Scott Ritter. He very vehemently opposed the Iraq invasion and has been on of the leading voices in discussing how awful the intelligence was and obvious it was before hand that there were no WMD's in Iraq.
Regrettably for him and other revisionists his comments and those like him sang a different tune before the war. Ritter was quoted shortly before the war cautioning against it because Saddam would use his WMD's to defend Baghdad. This was a commonly made argument against the war, where if Saddam has nothing to lose, we can be sure he will deploy his chemical weapon arsenal: As I testified to the U.S. Senate in 1998, Iraq has the indigenous capability right now to reconstitute a chemical weapons program within a matter of weeks. And my concern is if we continue to push for military action against Iraq, and once the writing becomes clear on the wall -- and believe me, if Saddam Hussein doesn't understand that President Bush is dead serious about going to war against him now, I don't know when he'll be -- when he'll recognize that. But at some point, I believe that Iraq will seek to reconstitute militarized nerve agent that will be used in defense of Baghdad. And I think the Iraqi government's efforts to acquire significant stockpiles of atropine are an indication that this is the direction that Saddam Hussein is heading.
Now, does anyone have a link to those charts which show the models continue to run much hotter than the real climate? The IPCC's Fifth Assessment has it for you in Figure 11.9. They graph the instrumental record against an ensemble of 42 models and the instrumental consistently falls on the lowest end of the error margins for the predicted warming. IE, the very, very coldest models are the closest to matching the instrumental record.
Now, that is working from a short term prediction, which isn't where we expect the models to really start showing their promise, but the IPCC saw fit to print it regardless. You can compare the IPCC's first assessment from back in the 1990's, if you want a longer term prediction to compare against. The trouble is the IPCC back then hard referenced their predictions to the year 1975. Practice since then is to show anomaly against something like a 10 year average, so you don't cherry pick a particularly hot/cold year as your initial reference. IF you do use 1975 as the reference for the IPCC FAR predictions from 1990 though their predictions that come closest to the last 25 years are the ones using a CO2 sensitivity of 1.5C.
So you have to look at the overlap with the instrumental record for 1850 onwards to get an idea of how much the proxies under- or over-estimate warming. Looking at the EIV line at 1850, it's about 0.2C under the instrumental temperature at that time, so one could assume it might under-estimate temperatures by 0.2C.
I think see our misunderstanding now. I'm not talking about any corrections for over/under estimation. I have no desire to treat the proxy reconstructions as absolutely accurate plus a blind +/- correction for if they are too cold/hot. That'd be stupid and if you ever thought I in any way advised that we can agree to reject it as stupid.
The uncertainty I'm talking about is the strength and precision of the signal temperature leaves in proxy records for us to extract. The actual problem the researchers themselves are working at. That signal can fluctuate in as many ways as the proxy's themselves can have varied responses to temperatures and other factors. If precipitation AND temperature combine to impact tree rings, which we know is the case, the signal we extract has imprecision in it that we are working around that has no static +/- adjustment we can make to accommodate that. That's why the large variety of complex statistical analysis methods are being thrown at the problem to try and sort the signal from the noise.
Fig.2 shows proxy reconstructions for 20th century temperatures, which allows us more overlap with the instrumental record and thus a better idea of proxy bias, but if anything Fig.2 C/D shows the EIV proxies over-estimating temperatures, so that doesn't help your case.
Again, Fig 2 is NOT meant to illustrate some over/under absolute adjustment factor that should be applied to the proxies. As I've repeated numerous times, he is being upfront about the well-known bias the proxy methods(particularly CPS) has in reflecting recent warming. It isn't an absolute the proxies underestimate the entire instrumental record, but rather if calibrated with data prior to 1950, they systematically underestimate the warming after 1950. Mann includes Fig 2 to be upfront about this, and to show that although not entirely gone, the EIV method greatly reduces this bias. Given this particular paper is Mann introducing the EIV method as being superior he felt it important to point out it's greater ability to overcome this known systematic bias.
If that's true (it's unclear to me) - if the Fig.3 results have been re-calibrated to the instrumental record - then none of the proxy temperatures gets even slightly close to recent temperatures. I can't find the exact quote now myself either, I might be remembering it from Mann's earlier papers and just assuming the same here. You can suggestively tell though because the Fig 2 reconstructions don't match well with Fig 3, presumably because they are a calibration test using only data prior to 1950 for calibrating.
So if I am to understand you correctly, your sole point is that the Northern Hemisphere proxy reconstructions by themselves do not show any higher temperatures than those during medieval times (because they cut off early and don't even try to include current temperatures). You don't consider the instrumental record to be pertinent to this point.
You say that like it's crazy. The anomalous nature of temperature since 1900 only exists when we take data from different sources and compare them to one another. That's a relevant point to observe. Particularly so when the degree of skill in the proxies are an active area of research. Doubly so when the older methods of reconstruction are WELL KNOWN to systematically underestimate recent warming whenever we do calibration testing.
I'm curious why you feel you can interpret his data better than he can, since he clearly disagrees with you. Are you assuming that he is ignoring this bias himself, despite him describing it clearly in his graphs and his results? Did you factor in any of his mentioned caveats, such as the "divergence problem" of recently-declining tree-ring sensitivity (accounted for in Fig.2 B)?
I'm sorry, but I'm not interpreting anything when I observe that Fig 3 shows the Had and CRU instrumental records hitting 0.8C by 2000 and NONE of the reconstructed lines sitting higher than 0.2C. Nor am I interpreting anything in observing that the EIV reconstruction exceeds 0.2C multiple times historically. That is a statement of fact about the graph.
Here's the extent of my own 'interpretation' of Mann's graph. Imagine that the HAD and CRU(red and grey) lines are removed from the graph. The reconstructions you are left with show the temp since 1900AD rising, but still lower than 1400, 1000, 800 and close to 600 and 400.
Yes, I too looked at the data, and unless you're just slapping an arbitrarily-large boost onto the proxy data, I don't see anywhere that it supports your own conclusion. E.g. the CPS Land proxy slightly overestimates the instrumental record (in the period of overlap of Fig.3),
The under estimation problem SHOULDN'T exist in Fig 3. As Mann stated, the systematic underestimation was when calibrated to early years and then projected onto later years. In Fig 3 the calibration will have been to the entire instrumental record. My observation above though stands, the reconstructions since 1900 ARE NOT higher than the reconstructions themselves back in 1400, 1000, 800.
. The EIV proxies barely overlap the instrumental record at all, but you could perhaps assume about a 0.2C underestimation where they do (though this is not well supported by Fig.2 C/D)
No, assuming an understimation in Fig 3 would be wrong, As noted above that only occurred for early calibration and Fig 3 was not calibrated that way. The early calibration was for separate validation testing as Mann performed for Fig 2. As for Fig 2 c/d supporting a bias with the EIV method, Mann had this to say: Interestingly, the problem is greatly diminished (although not absent—particularly in the older networks where a decline is observed after 1980) with the EIV method, whether or not tree-ring data are used
It seems to me that you're taking an out-of-context quote about finding a bias, making an unsupported assumption as to how big that bias must be, then reinterpreting his conclusion to suit yourself
At the risk of repeating myself beyond all reason, I'm assuming NOTHING about the size of any bias. I am observing the fact that the reconstructions themselves as the represent the warming since 1900 do NOT show unrivalled temperatures, but instead reflect a current warming that was matched by the reconstructions multiple times earlier. It is only when including the instrumental record that the comparison becomes anomalous. That is a statement of fact with no interpretation, bias or nuance involved. My sole reason for noting the early calibration late verification bias observed by Mann was that it is a suggestive explanation for this difference between reconstructed and instrumental. The observation stands regardless.
Higher resolution reconstructions by groups like Mann... show temperatures matching the current day within the last 2k years
Mann says otherwise, right in the first paragraph of the study you linked to (emphasis mine):
Our results extend previous conclusions that recent Northern Hemisphere surface temperature increases are likely anomalous in a long-term context. Recent warmth appears anomalous for at least the past 1,300 years whether or not tree-ring data are used. If tree-ring data are used, the conclusion can be extended to at least the past 1,700 years, but with additional strong caveats. The reconstructed amplitude of change over past centuries is greater than hitherto reported, with somewhat greater Medieval warmth in the Northern Hemisphere, albeit still not reaching recent levels.
Your reading his summary and not his data, and that matters. The recent warmth as recorded by thermometers is anomalous compared with the proxy reconstruction over the last 2000 years. As I noted in the post you replied to, Mann equally noted that the proxy reconstruction of 1950 onward has a systematic bias in the underestimation of recent warming. AKA, the warming since 1950 is anomalous against the proxy reconstruction since 1950 as well.
So, if you look at Mann's data in the linked article you can see that the proxy reconstruction for 2000AD is no warmer than 1400AD, 1000AD, 800AD, and very close around 400AD. It is only the instrumental record that is much higher.
Proxy data might give a rough idea of the temperature of a century, but is it precise enough to show climate change within a century? And why would we use that when we have much more reliable measurements for the last century?
You do realise that by asking 'why would we use that' is the same as asking why the researchers that built the reconstruction in question should have ever bothered doing so. You are burying your head in the sand as badly as those denying man can affect the climate at all.
The importance of reconstruction covering the instrumental record is to give context to our current warming. We know the planet has been warming for the last century because of our CO2 emissions. Putting that into a context of how normal or abnormal that trend is historically helps us understand the scope of the problem we are creating. Halting the proxy record when the instrumental record begins limits that understanding. The best test of the sensitivity of the proxy sources to current change is to run compare the proxies over the current century as well and compare the result to the instrumental record. The only efforts to that affect I've seen have been in the calibration phase of proxy reconstructions and they have shown a systematic underestimation of recent warming. Identifying the degree of that bias MATTERS to more accurately understanding things.
Are you saying you would prefer a study based on measurements from 1000 years ago? Digital thermometers were so precise back then.
Nope, never said anything stupid like that. Let me repeat myself:...before leaping up and declaring human industrial era began at 1900, also note that the SOURCE OF DATA changed at 1900 too.
Rather than suggesting a stupid impossibility to the problem of disparate data sets from 1900 onward. Maybe a REAL answer like extending the proxy data forward AFTER 1900 and looking at what THAT shows. Other researchers like Michael Mann, famous for the original hockey stick kick off, have done similar test as part of testing their calibration of their reconstructions against the instrumental record. Here's a quote: in the case of the early calibration/late validation CPS reconstruction with the full screened network (Fig. 2A), we observed evidence for a systematic bias in the underestimation of recent warming..
He went on later to note a new and improved statistical method(EIV) tested out in the same paper was much LESS prone to this problem. It also, incidentally, showed much greater range in historic temperatures as well, matching the current temperatures 2 or 3 times over the last 2k years.
Specifically the part where it notes that the trend from 1900 onwards is graphing the instrumental record, while the period before 1900 is from their proxy reconstruction.
They can graph the trend based on a proxy measurement of observations discovered on stone tablets for all I care. What's important is not the source of the measurement (despite what the anti AGW crowd like to claim) but rather the accuracy and repeatability.
Amen on the accuracy. The original article has the graph data available here.
The overall reconstructions show about a 0.4 to 0.5C change in temperature with an error margin +/- 0.2C, so an error margin that's nearly as large as the signal. And that's just for the statistical uncertainty, not any other unaccounted for factors. When the comparison between that and an instrumental record differ, it's a bit less shocking and perhaps that difference in precision is a factor and not solely human activity starting in 1900.
The math of climate change is fairly straightforward. CO2 and methane in the atmosphere cause more heat to be trapped in the atmosphere and oceans. There's a certain amount of carbon that was stored underground over millions of years in the form of oil and coal. That carbon was slowly extracted from the atmosphere by plants over the course of 500 million years and stored underground. During that time, the planet's temperature went up and down for various reasons 1) Earth's orbit and distance from the sun 2) volcanic activity releasing CO2 3) aerosols reflecting light back into space 4) the reflectivity of the surface of the earth from accumulation of snow or melting of snow during those other changes 5) sudden die off or surge of plant life 6) other reasons.
The rate of change for temperature and CO2 levels during all of those changes was gradual, with the changes taking place over thousands or millions of years. When CO2 was released in previous times, it was gradual. What's different about the current climate is that humans have raised the CO2 levels in the atmosphere by 140% in 200 years (280ppm to 400pm). That rate is way faster than any natural change in the history of the planet. That rate is what is so significant about human caused release of CO2 into the atmosphere. There are simply no natural factors to compare the methodical migration of carbon from the ground into the atmosphere.
So, yes this is significant.
Quick, tell the climate modelling teams how easy the problem is, they've been mistakenly making it much more complicated than required...
Let's try an analogy. We're stuck in a bathtub over top a fire. The water's kind of warm, we aren't freezing and we aren't so hot we need to get out. Simple math does tell us that putting more fuel into the fire beneath us will make things warmer. Same goes for more CO2 in our atmosphere, we equally know that will make things warmer. The more important question is how much warmer will it make things, and that is NOT a simple question. Now we need to know how much fuel are we adding, how far is that fuel from the tub, is the fire space beneath enclosed, how much fuel is left, what kind of fuel, how fast does it burn, how much water in the tub, what material is the tub made of, how dense is it, what's it shape and how is it attached to anything around it.
The bathtub analogy is trivial compared to the interactions of all the molecules that compose our planet's surface, oceans and atmosphere. Assessing the degree and speed of warming MATTERS and it's not anywhere as trivially easy as you imply.
That's not undermining, questioning or denying anything, it's a restating of the words of the author's themselves.
Then why did you say anything at all?
it's pretty blasted important not to leave that out when analyzing an abrupt change in trend exactly coinciding with a change in data source.
Which you just said isn't a problem because you are not undermining, questioning, or denying anything. So again, why did you say anything at all?
Sorry, I was already worried about sounding condescending by adding the detail I was, but it seems required.
The proxy reconstruction data is the best reconstruction that the researchers were able to produce. It's sensitivity to short term trends is uncertain, we only know so much and have limited data to work with. Within that context, the 100 years of instrumental data is a short term trend. Higher resolution reconstructions by groups like Mann(the original hockey stick author) show temperatures matching the current day within the last 2k years(look for his most recent EIV research if you wish).
In fact, Mann even notes that: in the case of the early calibration/late validation CPS reconstruction with the full screened network (Fig. 2A), we observed evidence for a systematic bias in the underestimation of recent warming.. Meaning that if they calibrate their reconstruction to the instrumental record prior to 1950, the proxies systematically underestimate recent warming since 1950. This is not listed as proof positive proxies miss current warming, but it is suggestive.
I put the notice of a distinction because so do the author's of these papers! It's not mentioned just for interest, but because it is important to the integrity of the graphed data. When comparing disparate data sets you need to take into account their different error margins, precision and uncertainty. The precision and uncertainty on the proxy construction is grossly larger than that from thermometer measurements. Accurately assessing the uncertainty and errors in the proxy estimates is an active area of research. I'm not decrying or reject it. I'm stating that because it's still on going it is wrong to jump ahead and simply assume it isn't contributing to the change in trend between the two data sets. Doubly so when work within the field, as noted by Mann, gives indications that could very well be the case.
Yup, we can't trust any reckoning of temperatures before the "instrumental" temperature record.
Oh wait, they've moved the instrument due to construction on campus and now the temperatures need to be adjusted! OMG IT'S NOT RAW DATA!!!!eleven!!!11!!1!
Now here comes satellite measurements! We can't trust any numbers before 1980-ish! Oh noes! We can't know anything about anything!
Upside to not knowing anything about anything: when Florida sinks, can we just pretend it never existed?
The flames from all the straw men makes it hard to hear you.
Nowhere did I call into question any of the data sets. I provided a link to the actual journal article no less so anyone could fact check. What I DID point out is that we have two data sets on the graph, one that is the proxy record and one for the instrumental. That's not undermining, questioning or denying anything, it's a restating of the words of the author's themselves.
The reconstructed data is going to have different accuracy, precision and sensitivity than the instrumental record. The authors of course did their best to account for that. None the less, it's pretty blasted important not to leave that out when analyzing an abrupt change in trend exactly coinciding with a change in data source.
From the IPCC's first assessment report from 25 years ago we were supposed to hit this point by 2010. Look for the graph in chapter 1 where CO2 concentrations are graphed for various scenarios. The scenario with human emissions increasing every year by 2% hits 400ppm in 2010.
On the whole, that's not a terrible estimation though given the limits folks were working under back then. Doesn't sound as scary though in the papers to declare that we are about 6 years behind early estimates of when we'd hit this point...
Just going to note that here's what this means in terms of how the global average temperatures have been changing, and how rapidly so compared to the past:
Here's a link to the actual paper the xkcd graph is derived from.
Before drawing conclusions from the graph trend starting at the year 1900, read the journal article more closely. Specifically the part where it notes that the trend from 1900 onwards is graphing the instrumental record, while the period before 1900 is from their proxy reconstruction. As in, before leaping up and declaring human industrial era began at 1900, also note that the SOURCE OF DATA changed at 1900 too.
The fact that the argument keeps changing should tell anyone everything they need to know.
Not to mention we're still in a cold period.
And the notion that there's some global temperature that climate is "supposed to be' is patently unscientific and ignorant of history.
The data shows we SHOULD be in a cold phase but the Earth has been warming rapidly compared to the last 10,000 years. The last time the average temperature rose 1c rapidly it took 900 years. Since the Industrial Revolution( roughly 1850s) the average temperature has risen a bit over 1C.
You can insist that given the great complexity of the Earth's ecosystem, scientists could not possibly know what will happen. They can theorize about weather change and some are right and some are wrong. But there is no doubt that the average temperature is rising and some areas close to the equator will start to be come uninhabitable in 20-30 years.
You've noted, in different words, that the trend since around 1900 is unprecedented in the entire time frame of the temperature reconstruction, last 20k years or more. You are absolutely correct, the journal article re-confirms that the graph trend from 1900 onward is unlike anything in the 20,000 years prior in the entire dataset.
If you read closer though, there is another potential explanation beyond human CO2 emissions that must also be accounted for. If you check the article, you will find that the data set from 1900 backwards is a DIFFERENT data set than the one graphed from 1900 forwards. The data graphed prior to 1900 is reconstructed from proxy sources, the data graphed after 1900 is the instrumental record.
When temperatures averaged over 100+ years, it's tough to average the tail end last 100 years well so using the instrumental record isn't wrong. Drawing conclusions SOLELY on the divergence that happens at 1900 though is to say the least, nuanced. Plainly, the most important and probable factor that must first be thoroughly ruled out is that the change in data sets is having an impact. There's a possibility that thermometers measure temperature more accurately than proxy records that are statistically analyzed and averaged over hundreds or thousands of years.
Your concern about measurement tech would be more significant if there was a step change in the data when there was a step change in the measurement tech.
The step change doesn't exist because the instrumental record is what the entire reconstruction is calibrated against. The alignment to 1900 isn't happening spontaneously, but by design. You can check out the details in Marcott's paper here, and more detailed methodology in the supplementary notes.
Climate science is entirely falsifiable - it just hasn't been falsified despite all the fortunes spent on trying to do so. Nobody has yet managed to do a real experiment that showed CO2 NOT acting as a greenhouse gas (that would falsify it). Nobody has yet found a single shred of evidence that disproves the theory - while there are thousands of independent sources of evidence that all support it, and nobody has yet come up with a better explanation for the observations than that offered by climate change theory. Any of these things would: 1) Falsify the theory 2) Win you a nobel prize 3) Guarantee you tenure and an endless supply of grant money for the rest of your life at any academic institution of your choosing.
Basically EVERY incentive is to disprove climate change.
The failure of those trying to actually falsify something does not imply it is not falsifiable. It implies the theory is almost certainly correct.
At this stage, the most single most tested scientific theory in the history of science is so unlikely to be false - that we will almost certainly never see it replaced, modified and gradually improved - yes, replaced probably not. At least not for the next several centuries. Because at this point the only thing that could do so is an observation that actually does not fit the theory. It took 500 years for technology to give us a measuring device that could pick up the things that didn't quite follow Newton, and I'd say it will take about twice that long before something fundamentally alters climate science.
If you set the bar at CO2 causing warming, humans raising CO2 levels and things getting warmer, you are right about those being well established. We aren't gonna upset or falsify that anytime soon.
News flash, policy and behaviour changes aren't really driven by any of those points. What's the severity of the future we face is the question. On that we have two examples below: 1.The IPCC worst case scenario, with 95% confidence levels cited sea level rise relative to today of no more than 3ft by 2100 2.Adam Fenech, a Nobel Prize-winning climate scientist and the director of the Climate Research Lab at the University of Prince Edward Island:"A lot of the most recent science is telling us it could rise as much as three metres during that time," says Fenech. "Probably in about 50 years, with a three-metre increase, we'd probably lose about half the island under water completely."
So we have a Nobel winning committee declaring no more than 3 feet in 100 years, and a Nodel winning research director predicting 3 metres in 50 years. One of these are gonna be falsified, and the scope of difference in their predictions makes an outrageous difference to what our responses should be.
downvoted as over rated, with zero votes with a post that consists virtually nothing more than 2 statements of fact backed with a link to an external quote of a highly credentialed scientist. Thanks for the reminder why I so rarely bother posting anything here anymore.
Here's Adam Fenech, a Nobel Prize-winning climate scientist and the director of the Climate Research Lab at the University of Prince Edward Island:"A lot of the most recent science is telling us it could rise as much as three metres during that time," says Fenech. "Probably in about 50 years, with a three-metre increase, we'd probably lose about half the island under water completely."
That's a claim being made TODAY, by a well credentialed leader of a climate research lab. I'm thinking that's not gonna pan out, the IPCC vehemently agrees.
The point is that a lot of the gloom and doom forecasts being used to push policy changes are CONTRARY to the IPCC projections, and are still coming from 'scientists'. Guys like Hansen aren't much better and get a lot of press.
XKCD produced this graph http://xkcd.com/1732/ to shows how temperature has changed over the last 22,000 years
xkcd is great, but the data he referenced follows the infamous "hide the decline" trick. The 'trick' is nothing more than using the instrumental temperature record to fill in gaps or quality in data. For the proxy records cited going back 20k years, the accuracy and precision over the last 100 is poor and the authors themselves state as much. Thus, to complete the data set through to today the instrumental record is included from 1900 onwards.
Nothing really wrong with that. The only caveat is in how you interpret the graph. If you look at the graph and observe that there is an unprecedented trend set off at 1900, the beginning of the industrial era you have to be careful. The unprecedented trend ALSO coincides with a change in methodology and data source in the graph. Ruling out how sensitive the proxy data is to short term spikes like today is vitally important to interpreting that part of the graph well, and we're still working that.
That rather depends on what temperature readings you choose to use in the last 100 years;-). But, everyone loves a graph that goes up at the end, whatever that might happen to mean.
Is there a data set for global temperatures for the last 100 years that doesn't show a sharp rise at the end? Is there one that would have continued the rather prosaic rate of change displayed in the rest of the XKCD comic?
You are missing the point. The data trend of the last 100 years on the graph coincides not just with the industrial age, it coincides with the data source for the graph changing too. The proxy data reconstruction ends at 1900, and from 1900 on the data source changes to the instrumental record.
There's plenty of reason to argue it's a reasonable step to take, but you can't exactly say it's unfair to point out that the change in data source might also play a role in the sharp delta starting at that exact point in the graph.
Climate science is entirely falsifiable - it just hasn't been falsified despite all the fortunes spent on trying to do so. Nobody has yet managed to do a real experiment that showed CO2 NOT acting as a greenhouse gas (that would falsify it). Nobody has yet found a single shred of evidence that disproves the theory - while there are thousands of independent sources of evidence that all support it, and nobody has yet come up with a better explanation for the observations than that offered by climate change theory. Any of these things would: 1) Falsify the theory 2) Win you a nobel prize 3) Guarantee you tenure and an endless supply of grant money for the rest of your life at any academic institution of your choosing.
Basically EVERY incentive is to disprove climate change.
The failure of those trying to actually falsify something does not imply it is not falsifiable. It implies the theory is almost certainly correct.
At this stage, the most single most tested scientific theory in the history of science is so unlikely to be false - that we will almost certainly never see it replaced, modified and gradually improved - yes, replaced probably not. At least not for the next several centuries. Because at this point the only thing that could do so is an observation that actually does not fit the theory. It took 500 years for technology to give us a measuring device that could pick up the things that didn't quite follow Newton, and I'd say it will take about twice that long before something fundamentally alters climate science.
If you set the bar at CO2 causing warming, humans raising CO2 levels and things getting warmer, you are right about those being well established. We aren't gonna upset or falsify that anytime soon.
News flash, policy and behaviour changes aren't really driven by any of those points. What's the severity of the future we face is the question. On that we have two examples below: 1.The IPCC worst case scenario, with 95% confidence levels cited sea level rise relative to today of no more than 3ft by 2100 2.Adam Fenech, a Nobel Prize-winning climate scientist and the director of the Climate Research Lab at the University of Prince Edward Island:"A lot of the most recent science is telling us it could rise as much as three metres during that time," says Fenech. "Probably in about 50 years, with a three-metre increase, we'd probably lose about half the island under water completely."
So we have a Nobel winning committee declaring no more than 3 feet in 100 years, and a Nodel winning research director predicting 3 metres in 50 years. One of these are gonna be falsified, and the scope of difference in their predictions makes an outrageous difference to what our responses should be.
Climate, while much simpler than weather, is still rather more complicated than school grades. So 100% accurate ? No. But not 50% either - more in the 95%+ range. That's also not an entirely true assessment because you're measuring it the wrong way. Climate models are written by experts who are aware they can't factor in everything, and that some things are still being worked on, so they don't give you an exact temperature - they give you a range within which the outcome is likely to lie and, if you take the average over the period predicted for, they overwhelmingly do lie in those averages.
The one major discrepency is IPCC reports, there are several decades where the average warming was significantly higher than IPCC models predicted. The reason for this is that the IPCC is particularly conservative in their estimates, fear of being called alarmists have led to the IPCC only publishing the bottom end of the likely range and also excluding anything they don't have extremely high confidence in (far higher than any other science would need for a minor variable in a big set with limited influence) - as a result they tend to to somewhat under-predict warming.
The lesson from that is that IPCC reports should be read as an absolute best-case scenario, reading the papers they are based on - the upper limit worst-case scenarios should be considered as well and we can generally expect reality to lie somewhere in the middle between those.,
It's posts like yours that turn people into skeptics.
1. You want to claim that climate models as a whole are 95% accurate. 2. You want to claim there are several decades where warming exceeds the IPCC prediction because they are so conservative and are clearly biased to a best-case scenario.
1. On what basis can you claim 95% accuracy for models, because it surely isn't in a predictive sense. Climate models have NOT managed to predict future climate with 95% accuracy. More accurately, if I said temperature averages for the next 30 years will be similar to this year +/- 0.5c, I'd have great accuracy, but I really haven't predicted a bloody thing either, now have I? The real benchmark used for climate modelling is still exclusively hindcasts, which means nobody is successfully publishing models that fail to hindcast accurately, which proves exactly nothing about the accuracy of the modelling. What is more, the basic physics are pretty well understood, the global energy imbalance at the edge of the atmosphere is the problem that the greenhouse effect is driving. Climate models regrettably still require manual fine tuning to poorly understood variables like clouds to prevent unrealistic runaway energy imbalances. So I don't think your characterisation of climate models in anyway reflects reality.
2. The first IPCC report is 26 years old, would you care to point out which decades it grossly underestimated? There are really only 2 full decades there to pick from so I'm interested to hear how you managed to get that plural usage of decades in. Also, if you want to look at the older IPCC reports for comparisons, the real world temperatures since the Third assessment in 2001 have trended right near the bottom end of the error bars of the most optimistic IPCC projections right up until a year ago.
Seriously, we have overwhelming evidence that the planet is warming and that our CO2 emissions are contributing meaningfully to that. You don't need to make up stupid exaggerations of the known science to try and make it sound scarier than it is. That's not science. That's not defending science. It's actively undermining and misrepresenting science. False statements like yours lead people to question and doubt everything else they hear when they find out your claims were bunk.
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Why did the USA have to go and protect all those enemies of saddam hussein?
If the millions of victims that Saddam murdered aren't a reason without some manner of paperwork or legal justification there's always the Convention on the Prevention and Punishment of the Crime of Genocide. All 147 signatories are obliged to act to prevent genocide, and failing that to act to punish those who have committed it. So, by 1990 already, 147 countries around the world were obliged to go and protect those 'enemies' of Saddam Hussein. The world failed to do what they signed on for though, as they later did in Rwanda, and the next time Saddam committed another genocide, and finally when somebody did act folks like you come out defending the genocidal dictator. All the worse, defending him in the name of his people(aka victims).
So your argument is that the US is better than Saddam, which considering what has happened is actually debatable. By very convincing.
My argument is more that nearly 3 decades of brutal repression, sectarian warfare and genocide at the hands of Saddam might have played a larger formative role in the Iraqis troubles than the much shorter lived, incompetent, American occupation.
Ahem, shit brain. We could have just left it all alone.
Ignoring problems doesn't always make them better.
Like when Saddam was left in power after the Iran-Iraq war, he went on to commit a genocide because he was left alone.
He then went on to invade Kuwait, because he was left alone.
He then was pushed out of Kuwait, but otherwise left in power, he then committed another genocide because he was left free to.
You noticing a trend?
It's folks like you willing to ignore everyone else's suffering that Bill Clinton catered to during the Rwandan genocide. He played it exactly your way, even going as far as to actively fight to prevent any action being taken to intervene. There comes a point where actively failing to save people when you have the capacity to do so is itself immoral.
Was it worth 5000 dead soldiers to prevent that for-sure? I dunno, whadda you think?
You seem to be forgetting the ~1 million civilian dead.
Okay, it's hard to estimate, I'll give you 500k. And helping ISIS grow in the subsequent power vacuum. And some torture.
What is the exchange rate of American lives to everyone else's lives?
How many dead from Saddam's war against Iran? How about his genocide of the Kurds? How about his war against Kuwait? How about his genocide of the Shia Iraqis? How many people did Saddam kill beyond that just for suspicions of disloyalty in his decades of rule?
If you can't already answer those questions you can't pretend to appreciate the cost of inaction on Saddam's regime. You think ISIS didn't equally find it's roots from the brutal dictatorships of guys like Saddam and Assad? Do you honestly believe that prior to Saddam's removal by American forces the region was free of sectarian hatred, violence and massacres? Step 1 through 20 of dictator class is divide and conquer, and Assad and Saddam made an extreme practice of deliberately fomenting and encouraging sectarian hatreds to make it all the easier to divide and conquer those under them.
But yeah, the troubles in Iraq and Syria today are all the result of American intervention and nothing else...
How about the numerous reports indicating that the CIAs reports were completely wrong.
They had a single expatriate source that had serious credibility problems bit the directive was go at all costs. So it was ignored.
Cheney would go on talk shows claiming that leaks in the media confirmed the Govs position. When the Gov had been the original leaker.
I believe one of the most prominent voices you are talking about is former Iraqi weapons inspector Scott Ritter. He very vehemently opposed the Iraq invasion and has been on of the leading voices in discussing how awful the intelligence was and obvious it was before hand that there were no WMD's in Iraq.
Regrettably for him and other revisionists his comments and those like him sang a different tune before the war. Ritter was quoted shortly before the war cautioning against it because Saddam would use his WMD's to defend Baghdad. This was a commonly made argument against the war, where if Saddam has nothing to lose, we can be sure he will deploy his chemical weapon arsenal:
As I testified to the U.S. Senate in 1998, Iraq has the indigenous capability right now to reconstitute a chemical weapons program within a matter of weeks. And my concern is if we continue to push for military action against Iraq, and once the writing becomes clear on the wall -- and believe me, if Saddam Hussein doesn't understand that President Bush is dead serious about going to war against him now, I don't know when he'll be -- when he'll recognize that. But at some point, I believe that Iraq will seek to reconstitute militarized nerve agent that will be used in defense of Baghdad. And I think the Iraqi government's efforts to acquire significant stockpiles of atropine are an indication that this is the direction that Saddam Hussein is heading.
Now, does anyone have a link to those charts which show the models continue to run much hotter than the real climate?
The IPCC's Fifth Assessment has it for you in Figure 11.9. They graph the instrumental record against an ensemble of 42 models and the instrumental consistently falls on the lowest end of the error margins for the predicted warming. IE, the very, very coldest models are the closest to matching the instrumental record.
Now, that is working from a short term prediction, which isn't where we expect the models to really start showing their promise, but the IPCC saw fit to print it regardless. You can compare the IPCC's first assessment from back in the 1990's, if you want a longer term prediction to compare against. The trouble is the IPCC back then hard referenced their predictions to the year 1975. Practice since then is to show anomaly against something like a 10 year average, so you don't cherry pick a particularly hot/cold year as your initial reference. IF you do use 1975 as the reference for the IPCC FAR predictions from 1990 though their predictions that come closest to the last 25 years are the ones using a CO2 sensitivity of 1.5C.
So you have to look at the overlap with the instrumental record for 1850 onwards to get an idea of how much the proxies under- or over-estimate warming. Looking at the EIV line at 1850, it's about 0.2C under the instrumental temperature at that time, so one could assume it might under-estimate temperatures by 0.2C.
I think see our misunderstanding now. I'm not talking about any corrections for over/under estimation. I have no desire to treat the proxy reconstructions as absolutely accurate plus a blind +/- correction for if they are too cold/hot. That'd be stupid and if you ever thought I in any way advised that we can agree to reject it as stupid.
The uncertainty I'm talking about is the strength and precision of the signal temperature leaves in proxy records for us to extract. The actual problem the researchers themselves are working at. That signal can fluctuate in as many ways as the proxy's themselves can have varied responses to temperatures and other factors. If precipitation AND temperature combine to impact tree rings, which we know is the case, the signal we extract has imprecision in it that we are working around that has no static +/- adjustment we can make to accommodate that. That's why the large variety of complex statistical analysis methods are being thrown at the problem to try and sort the signal from the noise.
Fig.2 shows proxy reconstructions for 20th century temperatures, which allows us more overlap with the instrumental record and thus a better idea of proxy bias, but if anything Fig.2 C/D shows the EIV proxies over-estimating temperatures, so that doesn't help your case.
Again, Fig 2 is NOT meant to illustrate some over/under absolute adjustment factor that should be applied to the proxies. As I've repeated numerous times, he is being upfront about the well-known bias the proxy methods(particularly CPS) has in reflecting recent warming. It isn't an absolute the proxies underestimate the entire instrumental record, but rather if calibrated with data prior to 1950, they systematically underestimate the warming after 1950. Mann includes Fig 2 to be upfront about this, and to show that although not entirely gone, the EIV method greatly reduces this bias. Given this particular paper is Mann introducing the EIV method as being superior he felt it important to point out it's greater ability to overcome this known systematic bias.
If that's true (it's unclear to me) - if the Fig.3 results have been re-calibrated to the instrumental record - then none of the proxy temperatures gets even slightly close to recent temperatures.
I can't find the exact quote now myself either, I might be remembering it from Mann's earlier papers and just assuming the same here. You can suggestively tell though because the Fig 2 reconstructions don't match well with Fig 3, presumably because they are a calibration test using only data prior to 1950 for calibrating.
So if I am to understand you correctly, your sole point is that the Northern Hemisphere proxy reconstructions by themselves do not show any higher temperatures than those during medieval times (because they cut off early and don't even try to include current temperatures). You don't consider the instrumental record to be pertinent to this point.
You say that like it's crazy. The anomalous nature of temperature since 1900 only exists when we take data from different sources and compare them to one another. That's a relevant point to observe. Particularly so when the degree of skill in the proxies are an active area of research. Doubly so when the older methods of reconstruction are WELL KNOWN to systematically underestimate recent warming whenever we do calibration testing.
I'm curious why you feel you can interpret his data better than he can, since he clearly disagrees with you. Are you assuming that he is ignoring this bias himself, despite him describing it clearly in his graphs and his results? Did you factor in any of his mentioned caveats, such as the "divergence problem" of recently-declining tree-ring sensitivity (accounted for in Fig.2 B)?
I'm sorry, but I'm not interpreting anything when I observe that Fig 3 shows the Had and CRU instrumental records hitting 0.8C by 2000 and NONE of the reconstructed lines sitting higher than 0.2C. Nor am I interpreting anything in observing that the EIV reconstruction exceeds 0.2C multiple times historically. That is a statement of fact about the graph.
Here's the extent of my own 'interpretation' of Mann's graph. Imagine that the HAD and CRU(red and grey) lines are removed from the graph. The reconstructions you are left with show the temp since 1900AD rising, but still lower than 1400, 1000, 800 and close to 600 and 400.
Yes, I too looked at the data, and unless you're just slapping an arbitrarily-large boost onto the proxy data, I don't see anywhere that it supports your own conclusion. E.g. the CPS Land proxy slightly overestimates the instrumental record (in the period of overlap of Fig.3),
The under estimation problem SHOULDN'T exist in Fig 3. As Mann stated, the systematic underestimation was when calibrated to early years and then projected onto later years. In Fig 3 the calibration will have been to the entire instrumental record. My observation above though stands, the reconstructions since 1900 ARE NOT higher than the reconstructions themselves back in 1400, 1000, 800.
. The EIV proxies barely overlap the instrumental record at all, but you could perhaps assume about a 0.2C underestimation where they do (though this is not well supported by Fig.2 C/D)
No, assuming an understimation in Fig 3 would be wrong, As noted above that only occurred for early calibration and Fig 3 was not calibrated that way. The early calibration was for separate validation testing as Mann performed for Fig 2. As for Fig 2 c/d supporting a bias with the EIV method, Mann had this to say: Interestingly, the problem is greatly diminished (although not absent—particularly in the older networks where a decline is observed after 1980) with the EIV method, whether or not tree-ring data are used
It seems to me that you're taking an out-of-context quote about finding a bias, making an unsupported assumption as to how big that bias must be, then reinterpreting his conclusion to suit yourself
At the risk of repeating myself beyond all reason, I'm assuming NOTHING about the size of any bias. I am observing the fact that the reconstructions themselves as the represent the warming since 1900 do NOT show unrivalled temperatures, but instead reflect a current warming that was matched by the reconstructions multiple times earlier. It is only when including the instrumental record that the comparison becomes anomalous. That is a statement of fact with no interpretation, bias or nuance involved. My sole reason for noting the early calibration late verification bias observed by Mann was that it is a suggestive explanation for this difference between reconstructed and instrumental. The observation stands regardless.
Higher resolution reconstructions by groups like Mann... show temperatures matching the current day within the last 2k years
Mann says otherwise, right in the first paragraph of the study you linked to (emphasis mine):
Our results extend previous conclusions that recent Northern Hemisphere surface temperature increases are likely anomalous in a long-term context. Recent warmth appears anomalous for at least the past 1,300 years whether or not tree-ring data are used. If tree-ring data are used, the conclusion can be extended to at least the past 1,700 years, but with additional strong caveats. The reconstructed amplitude of change over past centuries is greater than hitherto reported, with somewhat greater Medieval warmth in the Northern Hemisphere, albeit still not reaching recent levels.
Your reading his summary and not his data, and that matters. The recent warmth as recorded by thermometers is anomalous compared with the proxy reconstruction over the last 2000 years. As I noted in the post you replied to, Mann equally noted that the proxy reconstruction of 1950 onward has a systematic bias in the underestimation of recent warming. AKA, the warming since 1950 is anomalous against the proxy reconstruction since 1950 as well.
So, if you look at Mann's data in the linked article you can see that the proxy reconstruction for 2000AD is no warmer than 1400AD, 1000AD, 800AD, and very close around 400AD. It is only the instrumental record that is much higher.
Proxy data might give a rough idea of the temperature of a century, but is it precise enough to show climate change within a century? And why would we use that when we have much more reliable measurements for the last century?
You do realise that by asking 'why would we use that' is the same as asking why the researchers that built the reconstruction in question should have ever bothered doing so. You are burying your head in the sand as badly as those denying man can affect the climate at all.
The importance of reconstruction covering the instrumental record is to give context to our current warming. We know the planet has been warming for the last century because of our CO2 emissions. Putting that into a context of how normal or abnormal that trend is historically helps us understand the scope of the problem we are creating. Halting the proxy record when the instrumental record begins limits that understanding. The best test of the sensitivity of the proxy sources to current change is to run compare the proxies over the current century as well and compare the result to the instrumental record. The only efforts to that affect I've seen have been in the calibration phase of proxy reconstructions and they have shown a systematic underestimation of recent warming. Identifying the degree of that bias MATTERS to more accurately understanding things.
Are you saying you would prefer a study based on measurements from 1000 years ago? Digital thermometers were so precise back then.
Nope, never said anything stupid like that. Let me repeat myself: ...before leaping up and declaring human industrial era began at 1900, also note that the SOURCE OF DATA changed at 1900 too.
Rather than suggesting a stupid impossibility to the problem of disparate data sets from 1900 onward. Maybe a REAL answer like extending the proxy data forward AFTER 1900 and looking at what THAT shows. Other researchers like Michael Mann, famous for the original hockey stick kick off, have done similar test as part of testing their calibration of their reconstructions against the instrumental record. Here's a quote:
in the case of the early calibration/late validation CPS reconstruction with the full screened network (Fig. 2A), we observed evidence for a systematic bias in the underestimation of recent warming..
He went on later to note a new and improved statistical method(EIV) tested out in the same paper was much LESS prone to this problem. It also, incidentally, showed much greater range in historic temperatures as well, matching the current temperatures 2 or 3 times over the last 2k years.
Specifically the part where it notes that the trend from 1900 onwards is graphing the instrumental record, while the period before 1900 is from their proxy reconstruction.
They can graph the trend based on a proxy measurement of observations discovered on stone tablets for all I care. What's important is not the source of the measurement (despite what the anti AGW crowd like to claim) but rather the accuracy and repeatability.
Amen on the accuracy. The original article has the graph data available here.
The overall reconstructions show about a 0.4 to 0.5C change in temperature with an error margin +/- 0.2C, so an error margin that's nearly as large as the signal. And that's just for the statistical uncertainty, not any other unaccounted for factors. When the comparison between that and an instrumental record differ, it's a bit less shocking and perhaps that difference in precision is a factor and not solely human activity starting in 1900.
The math of climate change is fairly straightforward. CO2 and methane in the atmosphere cause more heat to be trapped in the atmosphere and oceans. There's a certain amount of carbon that was stored underground over millions of years in the form of oil and coal. That carbon was slowly extracted from the atmosphere by plants over the course of 500 million years and stored underground. During that time, the planet's temperature went up and down for various reasons 1) Earth's orbit and distance from the sun 2) volcanic activity releasing CO2 3) aerosols reflecting light back into space 4) the reflectivity of the surface of the earth from accumulation of snow or melting of snow during those other changes 5) sudden die off or surge of plant life 6) other reasons.
The rate of change for temperature and CO2 levels during all of those changes was gradual, with the changes taking place over thousands or millions of years. When CO2 was released in previous times, it was gradual. What's different about the current climate is that humans have raised the CO2 levels in the atmosphere by 140% in 200 years (280ppm to 400pm). That rate is way faster than any natural change in the history of the planet. That rate is what is so significant about human caused release of CO2 into the atmosphere. There are simply no natural factors to compare the methodical migration of carbon from the ground into the atmosphere.
So, yes this is significant.
Quick, tell the climate modelling teams how easy the problem is, they've been mistakenly making it much more complicated than required...
Let's try an analogy. We're stuck in a bathtub over top a fire. The water's kind of warm, we aren't freezing and we aren't so hot we need to get out. Simple math does tell us that putting more fuel into the fire beneath us will make things warmer. Same goes for more CO2 in our atmosphere, we equally know that will make things warmer. The more important question is how much warmer will it make things, and that is NOT a simple question. Now we need to know how much fuel are we adding, how far is that fuel from the tub, is the fire space beneath enclosed, how much fuel is left, what kind of fuel, how fast does it burn, how much water in the tub, what material is the tub made of, how dense is it, what's it shape and how is it attached to anything around it.
The bathtub analogy is trivial compared to the interactions of all the molecules that compose our planet's surface, oceans and atmosphere. Assessing the degree and speed of warming MATTERS and it's not anywhere as trivially easy as you imply.
That's not undermining, questioning or denying anything, it's a restating of the words of the author's themselves.
Then why did you say anything at all?
it's pretty blasted important not to leave that out when analyzing an abrupt change in trend exactly coinciding with a change in data source.
Which you just said isn't a problem because you are not undermining, questioning, or denying anything. So again, why did you say anything at all?
Sorry, I was already worried about sounding condescending by adding the detail I was, but it seems required.
The proxy reconstruction data is the best reconstruction that the researchers were able to produce. It's sensitivity to short term trends is uncertain, we only know so much and have limited data to work with. Within that context, the 100 years of instrumental data is a short term trend. Higher resolution reconstructions by groups like Mann(the original hockey stick author) show temperatures matching the current day within the last 2k years(look for his most recent EIV research if you wish).
In fact, Mann even notes that: in the case of the early calibration/late validation CPS reconstruction with the full screened network (Fig. 2A), we observed evidence for a systematic bias in the underestimation of recent warming.. Meaning that if they calibrate their reconstruction to the instrumental record prior to 1950, the proxies systematically underestimate recent warming since 1950. This is not listed as proof positive proxies miss current warming, but it is suggestive.
I put the notice of a distinction because so do the author's of these papers! It's not mentioned just for interest, but because it is important to the integrity of the graphed data. When comparing disparate data sets you need to take into account their different error margins, precision and uncertainty. The precision and uncertainty on the proxy construction is grossly larger than that from thermometer measurements. Accurately assessing the uncertainty and errors in the proxy estimates is an active area of research. I'm not decrying or reject it. I'm stating that because it's still on going it is wrong to jump ahead and simply assume it isn't contributing to the change in trend between the two data sets. Doubly so when work within the field, as noted by Mann, gives indications that could very well be the case.
Yup, we can't trust any reckoning of temperatures before the "instrumental" temperature record.
Oh wait, they've moved the instrument due to construction on campus and now the temperatures need to be adjusted! OMG IT'S NOT RAW DATA!!!!eleven!!!11!!1!
Now here comes satellite measurements! We can't trust any numbers before 1980-ish! Oh noes! We can't know anything about anything!
Upside to not knowing anything about anything: when Florida sinks, can we just pretend it never existed?
The flames from all the straw men makes it hard to hear you.
Nowhere did I call into question any of the data sets. I provided a link to the actual journal article no less so anyone could fact check. What I DID point out is that we have two data sets on the graph, one that is the proxy record and one for the instrumental. That's not undermining, questioning or denying anything, it's a restating of the words of the author's themselves.
The reconstructed data is going to have different accuracy, precision and sensitivity than the instrumental record. The authors of course did their best to account for that. None the less, it's pretty blasted important not to leave that out when analyzing an abrupt change in trend exactly coinciding with a change in data source.
From the IPCC's first assessment report from 25 years ago we were supposed to hit this point by 2010. Look for the graph in chapter 1 where CO2 concentrations are graphed for various scenarios. The scenario with human emissions increasing every year by 2% hits 400ppm in 2010.
On the whole, that's not a terrible estimation though given the limits folks were working under back then. Doesn't sound as scary though in the papers to declare that we are about 6 years behind early estimates of when we'd hit this point...
Just going to note that here's what this means in terms of how the global average temperatures have been changing, and how rapidly so compared to the past:
http://xkcd.com/1732/
Here's a link to the actual paper the xkcd graph is derived from.
Before drawing conclusions from the graph trend starting at the year 1900, read the journal article more closely. Specifically the part where it notes that the trend from 1900 onwards is graphing the instrumental record, while the period before 1900 is from their proxy reconstruction. As in, before leaping up and declaring human industrial era began at 1900, also note that the SOURCE OF DATA changed at 1900 too.
The fact that the argument keeps changing should tell anyone everything they need to know.
Not to mention we're still in a cold period.
And the notion that there's some global temperature that climate is "supposed to be' is patently unscientific and ignorant of history.
The data shows we SHOULD be in a cold phase but the Earth has been warming rapidly compared to the last 10,000 years. The last time the average temperature rose 1c rapidly it took 900 years. Since the Industrial Revolution( roughly 1850s) the average temperature has risen a bit over 1C.
You can insist that given the great complexity of the Earth's ecosystem, scientists could not possibly know what will happen. They can theorize about weather change and some are right and some are wrong. But there is no doubt that the average temperature is rising and some areas close to the equator will start to be come uninhabitable in 20-30 years.
http://xkcd.com/1732/
Here's the main journal article xkcd referenced for that comic.
You've noted, in different words, that the trend since around 1900 is unprecedented in the entire time frame of the temperature reconstruction, last 20k years or more. You are absolutely correct, the journal article re-confirms that the graph trend from 1900 onward is unlike anything in the 20,000 years prior in the entire dataset.
If you read closer though, there is another potential explanation beyond human CO2 emissions that must also be accounted for. If you check the article, you will find that the data set from 1900 backwards is a DIFFERENT data set than the one graphed from 1900 forwards. The data graphed prior to 1900 is reconstructed from proxy sources, the data graphed after 1900 is the instrumental record.
When temperatures averaged over 100+ years, it's tough to average the tail end last 100 years well so using the instrumental record isn't wrong. Drawing conclusions SOLELY on the divergence that happens at 1900 though is to say the least, nuanced. Plainly, the most important and probable factor that must first be thoroughly ruled out is that the change in data sets is having an impact. There's a possibility that thermometers measure temperature more accurately than proxy records that are statistically analyzed and averaged over hundreds or thousands of years.
Your concern about measurement tech would be more significant if there was a step change in the data when there was a step change in the measurement tech.
The step change doesn't exist because the instrumental record is what the entire reconstruction is calibrated against. The alignment to 1900 isn't happening spontaneously, but by design. You can check out the details in Marcott's paper here, and more detailed methodology in the supplementary notes.
Climate science is entirely falsifiable - it just hasn't been falsified despite all the fortunes spent on trying to do so. Nobody has yet managed to do a real experiment that showed CO2 NOT acting as a greenhouse gas (that would falsify it). Nobody has yet found a single shred of evidence that disproves the theory - while there are thousands of independent sources of evidence that all support it, and nobody has yet come up with a better explanation for the observations than that offered by climate change theory.
Any of these things would:
1) Falsify the theory
2) Win you a nobel prize
3) Guarantee you tenure and an endless supply of grant money for the rest of your life at any academic institution of your choosing.
Basically EVERY incentive is to disprove climate change.
The failure of those trying to actually falsify something does not imply it is not falsifiable. It implies the theory is almost certainly correct.
At this stage, the most single most tested scientific theory in the history of science is so unlikely to be false - that we will almost certainly never see it replaced, modified and gradually improved - yes, replaced probably not. At least not for the next several centuries. Because at this point the only thing that could do so is an observation that actually does not fit the theory. It took 500 years for technology to give us a measuring device that could pick up the things that didn't quite follow Newton, and I'd say it will take about twice that long before something fundamentally alters climate science.
If you set the bar at CO2 causing warming, humans raising CO2 levels and things getting warmer, you are right about those being well established. We aren't gonna upset or falsify that anytime soon.
News flash, policy and behaviour changes aren't really driven by any of those points. What's the severity of the future we face is the question. On that we have two examples below:
1.The IPCC worst case scenario, with 95% confidence levels cited sea level rise relative to today of no more than 3ft by 2100
2.Adam Fenech, a Nobel Prize-winning climate scientist and the director of the Climate Research Lab at the University of Prince Edward Island:"A lot of the most recent science is telling us it could rise as much as three metres during that time," says Fenech. "Probably in about 50 years, with a three-metre increase, we'd probably lose about half the island under water completely."
So we have a Nobel winning committee declaring no more than 3 feet in 100 years, and a Nodel winning research director predicting 3 metres in 50 years. One of these are gonna be falsified, and the scope of difference in their predictions makes an outrageous difference to what our responses should be.
downvoted as over rated, with zero votes with a post that consists virtually nothing more than 2 statements of fact backed with a link to an external quote of a highly credentialed scientist. Thanks for the reminder why I so rarely bother posting anything here anymore.
Here's Adam Fenech, a Nobel Prize-winning climate scientist and the director of the Climate Research Lab at the University of Prince Edward Island:"A lot of the most recent science is telling us it could rise as much as three metres during that time," says Fenech. "Probably in about 50 years, with a three-metre increase, we'd probably lose about half the island under water completely."
That's a claim being made TODAY, by a well credentialed leader of a climate research lab. I'm thinking that's not gonna pan out, the IPCC vehemently agrees.
The point is that a lot of the gloom and doom forecasts being used to push policy changes are CONTRARY to the IPCC projections, and are still coming from 'scientists'. Guys like Hansen aren't much better and get a lot of press.
XKCD produced this graph http://xkcd.com/1732/ to shows how temperature has changed over the last 22,000 years
xkcd is great, but the data he referenced follows the infamous "hide the decline" trick. The 'trick' is nothing more than using the instrumental temperature record to fill in gaps or quality in data. For the proxy records cited going back 20k years, the accuracy and precision over the last 100 is poor and the authors themselves state as much. Thus, to complete the data set through to today the instrumental record is included from 1900 onwards.
Nothing really wrong with that. The only caveat is in how you interpret the graph. If you look at the graph and observe that there is an unprecedented trend set off at 1900, the beginning of the industrial era you have to be careful. The unprecedented trend ALSO coincides with a change in methodology and data source in the graph. Ruling out how sensitive the proxy data is to short term spikes like today is vitally important to interpreting that part of the graph well, and we're still working that.
Is there a data set for global temperatures for the last 100 years that doesn't show a sharp rise at the end? Is there one that would have continued the rather prosaic rate of change displayed in the rest of the XKCD comic?
You are missing the point. The data trend of the last 100 years on the graph coincides not just with the industrial age, it coincides with the data source for the graph changing too. The proxy data reconstruction ends at 1900, and from 1900 on the data source changes to the instrumental record.
There's plenty of reason to argue it's a reasonable step to take, but you can't exactly say it's unfair to point out that the change in data source might also play a role in the sharp delta starting at that exact point in the graph.
Climate science is entirely falsifiable - it just hasn't been falsified despite all the fortunes spent on trying to do so. Nobody has yet managed to do a real experiment that showed CO2 NOT acting as a greenhouse gas (that would falsify it). Nobody has yet found a single shred of evidence that disproves the theory - while there are thousands of independent sources of evidence that all support it, and nobody has yet come up with a better explanation for the observations than that offered by climate change theory.
Any of these things would:
1) Falsify the theory
2) Win you a nobel prize
3) Guarantee you tenure and an endless supply of grant money for the rest of your life at any academic institution of your choosing.
Basically EVERY incentive is to disprove climate change.
The failure of those trying to actually falsify something does not imply it is not falsifiable. It implies the theory is almost certainly correct.
At this stage, the most single most tested scientific theory in the history of science is so unlikely to be false - that we will almost certainly never see it replaced, modified and gradually improved - yes, replaced probably not. At least not for the next several centuries. Because at this point the only thing that could do so is an observation that actually does not fit the theory. It took 500 years for technology to give us a measuring device that could pick up the things that didn't quite follow Newton, and I'd say it will take about twice that long before something fundamentally alters climate science.
If you set the bar at CO2 causing warming, humans raising CO2 levels and things getting warmer, you are right about those being well established. We aren't gonna upset or falsify that anytime soon.
News flash, policy and behaviour changes aren't really driven by any of those points. What's the severity of the future we face is the question. On that we have two examples below:
1.The IPCC worst case scenario, with 95% confidence levels cited sea level rise relative to today of no more than 3ft by 2100
2.Adam Fenech, a Nobel Prize-winning climate scientist and the director of the Climate Research Lab at the University of Prince Edward Island:"A lot of the most recent science is telling us it could rise as much as three metres during that time," says Fenech. "Probably in about 50 years, with a three-metre increase, we'd probably lose about half the island under water completely."
So we have a Nobel winning committee declaring no more than 3 feet in 100 years, and a Nodel winning research director predicting 3 metres in 50 years. One of these are gonna be falsified, and the scope of difference in their predictions makes an outrageous difference to what our responses should be.
Climate, while much simpler than weather, is still rather more complicated than school grades.
So 100% accurate ? No. But not 50% either - more in the 95%+ range. That's also not an entirely true assessment because you're measuring it the wrong way. Climate models are written by experts who are aware they can't factor in everything, and that some things are still being worked on, so they don't give you an exact temperature - they give you a range within which the outcome is likely to lie and, if you take the average over the period predicted for, they overwhelmingly do lie in those averages.
The one major discrepency is IPCC reports, there are several decades where the average warming was significantly higher than IPCC models predicted. The reason for this is that the IPCC is particularly conservative in their estimates, fear of being called alarmists have led to the IPCC only publishing the bottom end of the likely range and also excluding anything they don't have extremely high confidence in (far higher than any other science would need for a minor variable in a big set with limited influence) - as a result they tend to to somewhat under-predict warming.
The lesson from that is that IPCC reports should be read as an absolute best-case scenario, reading the papers they are based on - the upper limit worst-case scenarios should be considered as well and we can generally expect reality to lie somewhere in the middle between those.,
It's posts like yours that turn people into skeptics.
1. You want to claim that climate models as a whole are 95% accurate.
2. You want to claim there are several decades where warming exceeds the IPCC prediction because they are so conservative and are clearly biased to a best-case scenario.
1. On what basis can you claim 95% accuracy for models, because it surely isn't in a predictive sense. Climate models have NOT managed to predict future climate with 95% accuracy. More accurately, if I said temperature averages for the next 30 years will be similar to this year +/- 0.5c, I'd have great accuracy, but I really haven't predicted a bloody thing either, now have I? The real benchmark used for climate modelling is still exclusively hindcasts, which means nobody is successfully publishing models that fail to hindcast accurately, which proves exactly nothing about the accuracy of the modelling. What is more, the basic physics are pretty well understood, the global energy imbalance at the edge of the atmosphere is the problem that the greenhouse effect is driving. Climate models regrettably still require manual fine tuning to poorly understood variables like clouds to prevent unrealistic runaway energy imbalances. So I don't think your characterisation of climate models in anyway reflects reality.
2. The first IPCC report is 26 years old, would you care to point out which decades it grossly underestimated? There are really only 2 full decades there to pick from so I'm interested to hear how you managed to get that plural usage of decades in. Also, if you want to look at the older IPCC reports for comparisons, the real world temperatures since the Third assessment in 2001 have trended right near the bottom end of the error bars of the most optimistic IPCC projections right up until a year ago.
Seriously, we have overwhelming evidence that the planet is warming and that our CO2 emissions are contributing meaningfully to that. You don't need to make up stupid exaggerations of the known science to try and make it sound scarier than it is. That's not science. That's not defending science. It's actively undermining and misrepresenting science. False statements like yours lead people to question and doubt everything else they hear when they find out your claims were bunk.