"Furthermore, the climate modelling community are now predicting "the possibility" of a reduction in global heat content in the next decade"
Er. One paper, Keenlyside et al., raised the possibility of a reduction in surface temperature due to an interesting modeling methodology that they were testing that re-initialized ocean states every 5 years to try and capture ENSO type variability.
Of course, the Keenlyside paper noted that their model performed _worse_ than standard models in predicting past global mean temperature: where they beat standard models was in predicting past temperatures in ENSO-sensitive areas like the edges of the Pacific and western Atlantic basins.
The "community" certainly does not expect a reduction in heat content.
Ah, but NOx is converted to Nitrate in the atmosphere in the long run anyway, the titanium just speeds up the process. (where do you think acid rain comes from? NOx and SOx are precursors to acids, HNO3 and H2SO4)
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So you'll get a localized increase of nitrates over the counterfactual, but regionally the nitrate level will remain the same. Also, I'm guessing that the amount of nitrate formed by this process will be much less than the nitrate we use in fertilizer, though I haven't looked up the numbers for that.
Why is positive radiative forcing for natural cirrus clouds dubious? Yes, they reflect sunlight during the day (cooling). But they trap IR radiated from the planet 24 hours a day (warming). A priori, I wouldn't know which effect would be larger, and the majority of the people who study the issue seem to have decided that certain kinds of clouds are cooling and some are warming, and that natural cirrus are in the latter category. Yes, there's uncertainty, but without a fairly definitive study saying otherwise, I'd have to say that the balance of evidence points towards airplane contrails as a warming influence (including the persistent cirrus formation).
IPCC AR4 Working Group I, pg 186-187. That's fairly definitive in terms of summarizing the state of the science. Also, wikipedia on contrails (less definitive). Admittedly, the best estimate is 0.01 W/m2 with 95% bounds from -0.007 to +0.02, so there is still some doubt as to the sign...
The IPCC (AR4, Working Group I, pg. 186-187) summary of current best science seems to indicate that aviation induced cloudiness on average creates warming. Sorry. I'd be interested in seeing the paper that claims otherwise, though. (You can also look at the wikipedia page on contrails which says the same thing as the IPCC)
Contrails can be formed _both_ by turbulence _and_ by engine exhaust as shown in nice pictures in Wikipedia.
However, the PhD atmospheric scientist I know who was working on aircraft contrails and climate change interactions seemed to mostly concentrate on the heat and humidity of engine exhaust combined with whether the ambient conditions are saturated and whether a line drawn from the engine exhaust conditions to ambient conditions passes through a critical supersaturation point. This is backed up by papers such as this AMS paper.
According to the IPCC AR4, Working Group 1, pg. 186-187, on average contrails and aviation-induced-cloudiness have a positive radiative forcing: therefore, reducing contrails will lead to cooling.
Also see the wikipedia page actually devoted to contrails which says the same thing.
Of course, this is a complex issue, and it depends on altitude, time of day, and humidity as to whether any individual aircraft's contrails have positive, negative, or zero impact. There has been some research (personal communication) done into whether aircraft routes could be planned so as to avoid areas that form contrails in order to reduce warming due to contrails...
So, why is it that when scientists say "the last 50 years of warming can be attributed mainly to humans" that all the idiots come out from under their stones saying "well, where were the SUVs 10000 years ago?" As I said, " It is possible for something to have both natural and human based drivers". Milankovitch cycles have likely driven the glacial/interglacial cycle for the last several hundred thousand years. However, since we can measure the incoming solar radiation, we know that it hasn't been increasing for the last half century - therefore, unlikely to have caused recent warming. Whereas we can calculate the radiative forcing increase due to human caused CO2 increases, and measure the radiative imbalance at the top of the atmosphere which matches the calculations pretty well, and therefore assign modern (not ancient) changes to humans.
On the Club of Rome report - a) Just because experts get it wrong occasionally, doesn't mean they always get it wrong. It is just that the thousands of times they get it right aren't very newsworthy. b) have you actually read the report? Basically, they point out that they have made certain assumptions about population growth, agricultural productivity, and pollution control, and then did some sensitivity calculations to show that if you had more optimistic parameters for all of them you would push disaster out to well into the 21st century. And therefore, encouraged the world to attempt to improve those things, and lo and behold, we have had higher agricultural productivity, better pollution control, and lower population growth (I'm not claiming that these improvements are because of the Club of Rome report in any way, of course).
Finally, under business as usual scenarios it is likely that within 500 or 1000 years the 3 kilometers of ice on Greenland will melt. Because once it warms up enough to melt at the top, the altitude will drop, and the temperature will therefore go up...
ps. If you really believe that something awesome to replace fossil fuels will come up naturally, why would you object to a policy that will just bring it about somewhat sooner by putting a price on GHG emissions?
1) Er. We can pretty accurately determine the direct radiative forcing impact of anthropogenic increases in CO2, which is by itself nearly 1% of solar insolation at the surface, and it would be surprising if that did NOT have a significant impact. I'm pretty sure that your body heat is nowhere near that. And there isn't any other credible non-anthropogenic forcing on that order of magnitude in the right direction in the last 50 years to explain the current warming trend.
2) Well, we've pretty well adapted to our current climate conditions. Therefore, it is likely that any significant deviation from those climate conditions will be net negative. And we are looking (in the absence of climate policy) at a temperature change on the order of 2 degrees to 6 degrees celsius over the next century (and still rising): 6 degrees is interglacial to glacial numbers.
3) Kyoto isn't really my plan. I have other, preferred methods. But Kyoto would be better than nothing. And yes, we can quantify the reductions that various plans would make (with uncertainty bounds, of course)
4) Consensus is actually perfectly good science. If I go into a chemistry lab and want to take an NMR spectra of a compound, do I need to rederive fourier transforms? No? Why not? Because there is consensus out there that people have figured out how this stuff works. Now, consensus doesn't mean that you stop poking at stuff, because consensus is sometimes wrong (though rarely in a big way) and there are almost always additional details which are worth delving into. And in the case of climate change, it is a very complex system and we probably won't ever understand it completely (at least within my lifetime), so there are plenty of ways to improve our understanding by doing good science.
5) Um. You think the ozone hole didn't exist? What planet do you live on??? Or do you use your own private definition of the term? And the scientific community never had anything like a consensus about a coming ice age - if you read the original literature there are caveats up the wazoo about it - including a lot of comments about the possibility that increasing CO2 might turn a hypothetical approaching ice age around.
So, sorry, no, you are much more laughable than is climate science.
Er. The NAS study can be found here: the Wegman report is an entirely different beast and not worth so much. realclimate is actually a fairly good website - I don't agree with everything they write, but in areas of my expertise they do fairly well, so I trust them in general.
Thanks for the quote and citation: but if I look at the IPCC AR4, they have a similar quote which if you include the full context makes a lot of sense: "Urban heat island effects are real but local, and have not biased the large-scale trends. A number of recent studies indicate that effects of urbanisation and land use change on the land-based temperature record are negligible (0.006 degrees C per decade) as far as hemispheric- and continental-scale averages are concerned because the very real but local effects are avoided or accounted for in the data sets used. In any case, they are not present in the SST component of the record. Increasing evidence suggests that urban heat island effects extend to changes in precipitation, clouds and DTR, with these detectable as a 'weekend effect' owing to lower pollution and other effects during weekends."
Paleoclimatologists that I know are very dubious about Steve's methods, and have convincingly demolished his own statistical techniques (sadly, I can't reconstruct their elegant arguments myself, it was around the time of the NAS study that a couple of them did a presentation for my group on the subject, and my memory isn't so great that far outside my own speciality).
Who dismissed UHI as being non-existent? It is taken into account when developing global temperature trends!
See realclimate for a complete discussion of the subject.
The global trend is a robust dataset, and the pattern is scientifically explainable and is not correlated with urban areas, which is what you would expect if it was a UHI effect.
Junk Science is an aptly named site, since it is full of junk science.
Just to pull apart one thing: they quote Hansen and Dyson on the difficulty of measuring global temperature: but it turns out that measuring global temperature _anomalies_ is much much easier and are accurate to within 0.1 degrees. And that's what climate scientists do, and therefore this is just another climate skeptic smokescreen.
(though I do agree that the models are not good at short term or regional level forecasts yet)
"so chances are their calculations are wrong as well" - how did you determine this? 1) A change of 0.02 degrees will only reorder years that were statistically indistinguishable anyway, leaving 11 of the last 12 years in the global datasets still the warmest since measurements started, with 2005 and 1998 still the warmest two years on record globally. 2) The particular correction was specific to a change in how US datasets were handled.
And we don't need to know all of Earth's climatological history in order to know that adding several watts per meter squared of radiative forcing to the planet will lead to warming all other things being held constant. A more interesting question is how much warming, and there is uncertainty there, but it looks likely that in the next two centuries we will see warming on the order of magnitude of a glacial to interglacial transition (so not outside of the Earth's historical norms, because history includes some fairly huge temperature swings, but certainly outside anything humans have had to deal since writing was invented and possibly since the evolution of homo sapiens. And more importantly, sufficient temperature rise to cause us a decent amount of misery, which is worth spending a decent amount in order to avoid)
Here is a response I wrote the last time someone brought up the Card article:
Point 1: He starts with Mann and Santer and their 1998 "hockey stick" paper. Now, having not done paleoclimate research myself, I'm not going to spend a long time defending the paper. But I don't have to. There have been half a dozen independent analyses or more using different sets of paleo data that come up with very similar results. And that National Academy of Sciences stepped in to do an analysis of all these reconstructions, and published their results last year (http://books.nap.edu/openbook.php?isbn=0309102251 ). Their conclusion? "No reconstruction shows temperatures in the Medieval Warm Period as large as the last few decades of the 20th century". Because of the difficulty of estimating global mean temperatures 1000 years ago, the NAS study declined to assert more than a 70% chance that the last few decades were the very warmest of the millennium, and that is was only "plausible" that they are the warmest of the past 2000 years.
My conclusion: Yeah. Figuring out how warm it was 1000 years ago is hard. But the experts all seem to think it is pretty likely that we are seeing warmth unprecedented in 1000 years, possibly 2000, and it is just getting warmer. Plus, this 1000 year old data isn't fundamental to our theory or our estimates of how bad things will be in 100 years.
Point 2: "Global warming vs. Climate change": First: the reason that the wording has changed is because we're worried about more than just increased in global average surface temperature, but also in changes in precipitation patterns, hurricanes, droughts, variability, etc. So climate change was more inclusive.
2nd: If temperatures fall for three years, that doesn't really mean much. There is noise in the system. El Nino years are warm. Years after massive volcanoes like Pinatubo in 1992 are cool. This displays fundamental ignorance of statistics. If you are looking for trends in noisy data, you use running averages. Otherwise... shoot, it is colder this week than it was last week in Boston. I guess summer is over already, and it is just going to keep getting colder. Sheesh! The number of times this sort of reasoning has been repeated is ridiculous. So called "warming stopped in 1998" arguments are all over the net, even though any climate scientist in 1998 would have told you it was an anomalously warm year because of a very strong El Nino event that moves heat out of the Pacific and into the atmosphere temporarily.
3rd: And it isn't even true that temperatures have been falling for 3 years! The last 12 months have been the warmest 12 months on record! See the GISS temperature record. http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt
4th: The Alarmists (at least the scientists) usually talk about 2100, not 2010 or 2020, and have been doing so for the past 20 years. And indeed, in the past twenty years average temperatures have gone up by 0.4 degrees C. That may not sound large but... 6 degrees C is the difference between an Ice Age and today.
5th: The models do quite a good job at replicating the large patterns of the past century. See the Fourth Assessment Summary for Policymakers released in February. It has a nice graph of "temperatures for each continent in data and from models using: natural forcings, human forcings, or all forcings". www.ipcc.ch
6th: Who is everyone? Why, ocean experts, atmospheric dynamicists, atmospheric chemists, modelers, paleoclimate people, ecologists: they each have their own area, and in each area, the fingerprints of climate change are clearly visible, and those who does interdisciplinary work (like me) can draw all the results together and see a ridiculously clear picture (given how complex the climate is, there is a surprising amount of evidence).
7th: Card says: "Even the IPCC, which was so heavily biased in favor of
I'm willing to bet money that I've read more of the original literature related to climate change than you have. Admittedly, paleoclimate is not my speciality: however, the impression I've gotten from what I've read, from the portion of the congressional testimony from the NAS report authors that I've listened to, from the talks I've gone to by people who _are_ paleoclimate experts, as well as from reading realclimate, all seem to agree that Mann's work was a good first step, and that the major conclusion of his paper holds up pretty well in subsequent research by other groups (eg, likely unprecedented 20th century warming), though many of them do take issue with his claims about "warmest decade" and "warmest year" because they think that the resolution of the data isn't good enough to pick up short term events.
On the other hand, I notice that you do seem to like parrotting climate audit...
There are things I dislike about the IPCC AR4 report (most of my complaints have to do with the design and use of their SRES scenarios) but it really isn't "just another political report". It is a nearly comprehensive gathering of the quality climate science for the past half-decade with fairly good analysis of what conclusions are robust and which are tentative.
On the uncertainty analysis: attributing a cause with a percentage probability is fairly standard across many scientific fields. Look up Bayesian statistics. There is some subjectivity involved when attempting to synthesize information from a variety of sources: it may be easier to defend a number if it comes from a single model where you can definitively state that a trend is statistically significant to 2 sigma or whatever, but you don't want to depend on a single model, so you do the best you can to make estimates based on all the information available.
On realclimate: I put faith in realclimate because they have demonstrated a firm grasp of the science, and, in my opinion, a fairly unbiased attitude (recognizing of course that there is no such thing as purely neutral opinion).
On disagreement among scientists: I also read the peer reviewed climate literature, and even have a few peer reviewed publications to my name. Yes, there is disagreement. No, there aren't absolutes. The IPCC doesn't give absolutes either - why do you think they have ranges and probabilities? The media _really_ doesn't give absolutes, since they have a bad tendency of giving equal weight to two "sides" to the issue when you actually have 95% of the science on one side and 5% on the other.
I also agree that we have measured warming. Obviously the increase in CO2 is due to anthropogenic emissions. But I think we do have enough evidence to have some confidence in our ranges for numbers like climate sensitivity. I also agree that there are many things we should be doing: reducing deforestation is important for climate reasons and ecosystem reasons. Reducing CO2 emissions is important for reduced ocean acidification as well as global warming. Reducing oil use is important for foreign policy reasons as well as CO2 reasons. Energy efficiency makes sense from an economic standpoint as well as an environmental standpoint. Etc. etc.
My understanding was that the lead authors have final say on whether a change is acceptable or not. Mind you, the all night sessions just before the release of the summary due to Chinese and US delegates trying to water down some of the conclusions might have lead to lead authors finally giving in from sheer exhaustion, but they do have to give the final ok. See realclimate for a more complete discussion, but this also jibes with what those of my colleagues who were contributors to the IPCC draft chapters have told me...
The IPCC writes its draft report first. Then it writes a summary based on the draft report. In the process of writing the summary, the lead authors (along with government representatives) scrutinize the key statements in the drafts which are going into the summary, and occasionally determine that a given statement is not supported or precisely accurate. So after they publish the summary they go back and make the report consistent. But the key point is that scientists vet all the changes. (Though, if anything, the changes at this point usually make the Summary statement more conservative that the original drafts, so it is kind of ironic that all the people who object to this process are the climate change deniers).
Why don't you take a look at the US National Academy Assessment of the hockey-stick cluster of studies rather than relying on climateaudit.org? Though the 4th Assessment Report isn't a bad place to look either. Also, I believe that the hockey stick always came with error bars, and was fairly good for a first pass, and subsequent studies have mostly confirmed Mann's argument that the current global scale warming is likely unprecedented in the past 1000 years.
Historically (eg, glacial/interglacials): current best theory is that the first mover was orbital variations (Milankovitch cycles) leading to ice sheet retreat. Ice sheet retreat leads to warming. Warming leads to CO2 outgassing from oceans, CH4 being produced from melting permafrost. CH4 and CO2 increases lead to more warming.
Present-day: CO2 increase is solely due to human activity. This CO2 increase is a priori expected to lead to temperature increases, and the actual temperature increase seems to be largely explained only by human induced atmospheric changes in forcing, if you include feedbacks (increased water vapor, glacial retreat, etc.)
Long long ago historically there is evidence that we never would have left snowball earth without the CO2 increases caused by volcanic eruptions over hundreds of thousands of years, and no CO2 sink through rock weathering/ocean uptake because everything was covered by ice.
Er. If you want good science, perhaps you should be reading the literature rather than watching movies? The IPCC puts out nice documents covering the state of climate science every 5 or 6 years which are all available online (ipcc.ch) if you don't have access to Science, Nature, JGR, Climatic Change, or any of the other major journals which publish in this area.
If you want a nice chart examining all the GHGs and solar activity, look at SPM-2 from the 4th Assessment Policy for Summarymakers.
We have a heck of a lot more than correlation. Why don't you go back and read Arrhenius (1896) on the fundamental relationship between CO2 concentrations and infrared trapping, and his estimates of the warming that a doubling of CO2 would give? Of course, back then he thought it was impossible that we'd ever _reach_ a doubled CO2 level, because it would require unthinkable amounts of burning CO2... but 110 years later, we are well on our way...
Also: Hint: Look at the US Climate Change Science Program Product 1 on the corrections to satellite readings of tropospheric temperatures: your argument is outdated. Another hint: increased solar radiation would heat the stratosphere as well as the troposphere and the ground: the stratosphere is cooling. What would cause warming of the ground + troposphere and cooling of the stratosphere? Well, greenhouse gases are one good possibility. Another fingerprint: night time versus day time temperature changes.
So perhaps you should actually read and understand the science before you call BS. Also: "history shows that consensus has almost always started out wrong to begin with"? I'd like to see some data on this... preferably from the past century when science has become more formalized. I would argue that 99% of the time consensus is pretty good, so we never hear about it.
Hmm. So my theory is that for the last century we have temperature changes which we can mostly explain by using natural, known forcings (volcanoes, measured solar irradiance changes, ENSO variability) and anthropogenic known forcings (GHGs, aerosols). Of course, we have multiple knobs (aerosol forcing, cloud feedback, ocean heat uptake) with which we are tuning our data to fit, so this isn't a slam dunk of attribution. But the Pinatubo eruption did give us a nice measure of what forcing change will lead to what short term temperature response, and we have a good measure of total forcing change due to anthropogenic greenhouse gases, and given _just_ these two pieces of data, it would be quite suprising for the anthropogenic forcing increase in the last half century to not lead be leading to a temperature increase on a similar scale to what we have seen. And there's plenty of other data out there that leads to the same conclusion.
Therefore, I don't see why we should think that an unknown mechanism (namely effect of sunspot variation on temperature) would be a better explanation. The Maunder minimum is certainly interesting, but I was under the impression that it could be explained by known natural variations (one of which was the presumption due to other proxies that there was less solar irradiance which may be related to the lack of sunspots - sadly, we don't have direct measures of solar irradiance back then). In the past 2 decades of climate research, there have been various papers published on sunspot to climate correlations, and most of them have proved statistically invalid (the 1991 study by Friis-Christiansen and Lassen, was widely cited by skeptics for a while until its flawed foundations were shown).
So 1) I am not convinced that sunspots have that big an effect on temperature outside of their correlation with actual irradiance, which we can directly measure and already do take into account (though not my area, so I could be wrong), and 2) if you want to attribute the last few decades of warming to a poorly understood sunspot-climate link, you really have to first explain why the forcing mechanisms we do understand involving GHG concentrations aren't having any effect.
Re: Jupiter: I was under the impression that there were significant changes in circulation patterns (eg, little red eye) leading to local large temperature variations, but I hadn't hear about any evidence of general solar-induced warming?
Funny. All of the solar physicists and planetary scientists I've interacted with in the EAPS departments at MIT and Caltech believe anthropogenic global warming is a real phenomena. Where is your solar physics community based?
Mostly, those of us who work in the global warming field know that there are lots of uncertainties still remaining to be resolved about feedbacks, emissions projections, and oceanic processes, but most of the skeptics running around talking about "Mars is warming!" and "it has cooled since 1998!" and "you guys were global cooling fanatics 30 years ago!" and all the rest of that are just repeated long-ago debunked junk, and it is very frustrating to deal with all the noise, and so yes, we try and shout such arguments down.
And there is a _lot_ of industry sponsored junk being promulgated on this issue. And the current administration is very tightly connected with some of the biggest junk-pushers.
Your statement betrays three kinds of ignorance:
1) The difference between a "stock" pollutant and a short-term pollutant. CO2 and N2O both stay in the atmosphere for 100+ years. Therefore, what we've emitted in the past few decades will be with us for a while, and we haven't seen their full impact yet. We could stop emitting all greenhouse gases today and we would probably still see another degree celsius warming.
2) The difference between trace pollutants which we can clean up with "end-of-pipe" technology, and pollutants which are integral to the process. Don't like carbon monoxide? Add more oxygen and higher temperatures to your burn mix. Don't like SO2? Add a scrubber, or use cleaner coal. Don't like CO2? You have a problem. Because CO2 is an end product of combustion. (I will note that some people suggest we use carbon sequestration technologies to condense CO2 in the exhaust of coal plants and stick it underground. This may help, but it isn't going to deal with the whole problem). Therefore, we have not "created more pollution... than we could ever do again", because we are likely to continue emitting CO2 and other GHGs at very high rates for the foreseeable future.
3) The ice age cycle (from ice age to interglacial) is actually a relatively recent phenomena, geologically speaking. It is controlled by small changes in solar forcing due to orbital cycles. If we do burn most of the fossil fuels currently buried underground, the forcing increase from that CO2 will be _far_ more than the forcing decrease at the nadir of the Milankovitch cycles, and we will _not_ have the next ice age. But I personally don't so much care about what happens 10,000 years from now, I care about the next couple hundred years, and from everything I've read in the literature, and the modeling work I've done myself, I think we are going to see order 5 degrees celsius average warming over the next 2 hundred years. It won't be the end of the world, humans are adaptable, but it will lead to a lot of suckage.
Slashdot Mirror
Er. One paper, Keenlyside et al., raised the possibility of a reduction in surface temperature due to an interesting modeling methodology that they were testing that re-initialized ocean states every 5 years to try and capture ENSO type variability.
Of course, the Keenlyside paper noted that their model performed _worse_ than standard models in predicting past global mean temperature: where they beat standard models was in predicting past temperatures in ENSO-sensitive areas like the edges of the Pacific and western Atlantic basins.
The "community" certainly does not expect a reduction in heat content.
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So you'll get a localized increase of nitrates over the counterfactual, but regionally the nitrate level will remain the same. Also, I'm guessing that the amount of nitrate formed by this process will be much less than the nitrate we use in fertilizer, though I haven't looked up the numbers for that.
Why is positive radiative forcing for natural cirrus clouds dubious? Yes, they reflect sunlight during the day (cooling). But they trap IR radiated from the planet 24 hours a day (warming). A priori, I wouldn't know which effect would be larger, and the majority of the people who study the issue seem to have decided that certain kinds of clouds are cooling and some are warming, and that natural cirrus are in the latter category. Yes, there's uncertainty, but without a fairly definitive study saying otherwise, I'd have to say that the balance of evidence points towards airplane contrails as a warming influence (including the persistent cirrus formation).
IPCC AR4 Working Group I, pg 186-187. That's fairly definitive in terms of summarizing the state of the science. Also, wikipedia on contrails (less definitive). Admittedly, the best estimate is 0.01 W/m2 with 95% bounds from -0.007 to +0.02, so there is still some doubt as to the sign...
The IPCC (AR4, Working Group I, pg. 186-187) summary of current best science seems to indicate that aviation induced cloudiness on average creates warming. Sorry. I'd be interested in seeing the paper that claims otherwise, though. (You can also look at the wikipedia page on contrails which says the same thing as the IPCC)
However, the PhD atmospheric scientist I know who was working on aircraft contrails and climate change interactions seemed to mostly concentrate on the heat and humidity of engine exhaust combined with whether the ambient conditions are saturated and whether a line drawn from the engine exhaust conditions to ambient conditions passes through a critical supersaturation point. This is backed up by papers such as this AMS paper.
Also see the wikipedia page actually devoted to contrails which says the same thing.
Of course, this is a complex issue, and it depends on altitude, time of day, and humidity as to whether any individual aircraft's contrails have positive, negative, or zero impact. There has been some research (personal communication) done into whether aircraft routes could be planned so as to avoid areas that form contrails in order to reduce warming due to contrails...
On the Club of Rome report - a) Just because experts get it wrong occasionally, doesn't mean they always get it wrong. It is just that the thousands of times they get it right aren't very newsworthy. b) have you actually read the report? Basically, they point out that they have made certain assumptions about population growth, agricultural productivity, and pollution control, and then did some sensitivity calculations to show that if you had more optimistic parameters for all of them you would push disaster out to well into the 21st century. And therefore, encouraged the world to attempt to improve those things, and lo and behold, we have had higher agricultural productivity, better pollution control, and lower population growth (I'm not claiming that these improvements are because of the Club of Rome report in any way, of course).
Finally, under business as usual scenarios it is likely that within 500 or 1000 years the 3 kilometers of ice on Greenland will melt. Because once it warms up enough to melt at the top, the altitude will drop, and the temperature will therefore go up...
ps. If you really believe that something awesome to replace fossil fuels will come up naturally, why would you object to a policy that will just bring it about somewhat sooner by putting a price on GHG emissions?
2) Well, we've pretty well adapted to our current climate conditions. Therefore, it is likely that any significant deviation from those climate conditions will be net negative. And we are looking (in the absence of climate policy) at a temperature change on the order of 2 degrees to 6 degrees celsius over the next century (and still rising): 6 degrees is interglacial to glacial numbers.
3) Kyoto isn't really my plan. I have other, preferred methods. But Kyoto would be better than nothing. And yes, we can quantify the reductions that various plans would make (with uncertainty bounds, of course)
4) Consensus is actually perfectly good science. If I go into a chemistry lab and want to take an NMR spectra of a compound, do I need to rederive fourier transforms? No? Why not? Because there is consensus out there that people have figured out how this stuff works. Now, consensus doesn't mean that you stop poking at stuff, because consensus is sometimes wrong (though rarely in a big way) and there are almost always additional details which are worth delving into. And in the case of climate change, it is a very complex system and we probably won't ever understand it completely (at least within my lifetime), so there are plenty of ways to improve our understanding by doing good science.
5) Um. You think the ozone hole didn't exist? What planet do you live on??? Or do you use your own private definition of the term? And the scientific community never had anything like a consensus about a coming ice age - if you read the original literature there are caveats up the wazoo about it - including a lot of comments about the possibility that increasing CO2 might turn a hypothetical approaching ice age around.
So, sorry, no, you are much more laughable than is climate science.
Thanks for the quote and citation: but if I look at the IPCC AR4, they have a similar quote which if you include the full context makes a lot of sense: "Urban heat island effects are real but local, and have not biased the large-scale trends. A number of recent studies indicate that effects of urbanisation and land use change on the land-based temperature record are negligible (0.006 degrees C per decade) as far as hemispheric- and continental-scale averages are concerned because the very real but local effects are avoided or accounted for in the data sets used. In any case, they are not present in the SST component of the record. Increasing evidence suggests that urban heat island effects extend to changes in precipitation, clouds and DTR, with these detectable as a 'weekend effect' owing to lower pollution and other effects during weekends."
Paleoclimatologists that I know are very dubious about Steve's methods, and have convincingly demolished his own statistical techniques (sadly, I can't reconstruct their elegant arguments myself, it was around the time of the NAS study that a couple of them did a presentation for my group on the subject, and my memory isn't so great that far outside my own speciality).
See realclimate for a complete discussion of the subject.
The global trend is a robust dataset, and the pattern is scientifically explainable and is not correlated with urban areas, which is what you would expect if it was a UHI effect.
Junk Science is an aptly named site, since it is full of junk science.
Just to pull apart one thing: they quote Hansen and Dyson on the difficulty of measuring global temperature: but it turns out that measuring global temperature _anomalies_ is much much easier and are accurate to within 0.1 degrees. And that's what climate scientists do, and therefore this is just another climate skeptic smokescreen.
(though I do agree that the models are not good at short term or regional level forecasts yet)
"so chances are their calculations are wrong as well" - how did you determine this? 1) A change of 0.02 degrees will only reorder years that were statistically indistinguishable anyway, leaving 11 of the last 12 years in the global datasets still the warmest since measurements started, with 2005 and 1998 still the warmest two years on record globally. 2) The particular correction was specific to a change in how US datasets were handled.
And we don't need to know all of Earth's climatological history in order to know that adding several watts per meter squared of radiative forcing to the planet will lead to warming all other things being held constant. A more interesting question is how much warming, and there is uncertainty there, but it looks likely that in the next two centuries we will see warming on the order of magnitude of a glacial to interglacial transition (so not outside of the Earth's historical norms, because history includes some fairly huge temperature swings, but certainly outside anything humans have had to deal since writing was invented and possibly since the evolution of homo sapiens. And more importantly, sufficient temperature rise to cause us a decent amount of misery, which is worth spending a decent amount in order to avoid)
Here is a response I wrote the last time someone brought up the Card article:
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Point 1: He starts with Mann and Santer and their 1998 "hockey stick" paper. Now, having not done paleoclimate research myself, I'm not going to spend a long time defending the paper. But I don't have to. There have been half a dozen independent analyses or more using different sets of paleo data that come up with very similar results. And that National Academy of Sciences stepped in to do an analysis of all these reconstructions, and published their results last year (http://books.nap.edu/openbook.php?isbn=0309102251 ). Their conclusion? "No reconstruction shows temperatures in the Medieval Warm Period as large as the last few decades of the 20th century". Because of the difficulty of estimating global mean temperatures 1000 years ago, the NAS study declined to assert more than a 70% chance that the last few decades were the very warmest of the millennium, and that is was only "plausible" that they are the warmest of the past 2000 years.
My conclusion: Yeah. Figuring out how warm it was 1000 years ago is hard. But the experts all seem to think it is pretty likely that we are seeing warmth unprecedented in 1000 years, possibly 2000, and it is just getting warmer. Plus, this 1000 year old data isn't fundamental to our theory or our estimates of how bad things will be in 100 years.
Point 2: "Global warming vs. Climate change": First: the reason that the wording has changed is because we're worried about more than just increased in global average surface temperature, but also in changes in precipitation patterns, hurricanes, droughts, variability, etc. So climate change was more inclusive.
2nd: If temperatures fall for three years, that doesn't really mean much. There is noise in the system. El Nino years are warm. Years after massive volcanoes like Pinatubo in 1992 are cool. This displays fundamental ignorance of statistics. If you are looking for trends in noisy data, you use running averages. Otherwise... shoot, it is colder this week than it was last week in Boston. I guess summer is over already, and it is just going to keep getting colder. Sheesh! The number of times this sort of reasoning has been repeated is ridiculous. So called "warming stopped in 1998" arguments are all over the net, even though any climate scientist in 1998 would have told you it was an anomalously warm year because of a very strong El Nino event that moves heat out of the Pacific and into the atmosphere temporarily.
3rd: And it isn't even true that temperatures have been falling for 3 years! The last 12 months have been the warmest 12 months on record! See the GISS temperature record. http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts
4th: The Alarmists (at least the scientists) usually talk about 2100, not 2010 or 2020, and have been doing so for the past 20 years. And indeed, in the past twenty years average temperatures have gone up by 0.4 degrees C. That may not sound large but... 6 degrees C is the difference between an Ice Age and today.
5th: The models do quite a good job at replicating the large patterns of the past century. See the Fourth Assessment Summary for Policymakers released in February. It has a nice graph of "temperatures for each continent in data and from models using: natural forcings, human forcings, or all forcings". www.ipcc.ch
6th: Who is everyone? Why, ocean experts, atmospheric dynamicists, atmospheric chemists, modelers, paleoclimate people, ecologists: they each have their own area, and in each area, the fingerprints of climate change are clearly visible, and those who does interdisciplinary work (like me) can draw all the results together and see a ridiculously clear picture (given how complex the climate is, there is a surprising amount of evidence).
7th: Card says: "Even the IPCC, which was so heavily biased in favor of
On the other hand, I notice that you do seem to like parrotting climate audit...
On the uncertainty analysis: attributing a cause with a percentage probability is fairly standard across many scientific fields. Look up Bayesian statistics. There is some subjectivity involved when attempting to synthesize information from a variety of sources: it may be easier to defend a number if it comes from a single model where you can definitively state that a trend is statistically significant to 2 sigma or whatever, but you don't want to depend on a single model, so you do the best you can to make estimates based on all the information available.
On realclimate: I put faith in realclimate because they have demonstrated a firm grasp of the science, and, in my opinion, a fairly unbiased attitude (recognizing of course that there is no such thing as purely neutral opinion).
On disagreement among scientists: I also read the peer reviewed climate literature, and even have a few peer reviewed publications to my name. Yes, there is disagreement. No, there aren't absolutes. The IPCC doesn't give absolutes either - why do you think they have ranges and probabilities? The media _really_ doesn't give absolutes, since they have a bad tendency of giving equal weight to two "sides" to the issue when you actually have 95% of the science on one side and 5% on the other.
I also agree that we have measured warming. Obviously the increase in CO2 is due to anthropogenic emissions. But I think we do have enough evidence to have some confidence in our ranges for numbers like climate sensitivity. I also agree that there are many things we should be doing: reducing deforestation is important for climate reasons and ecosystem reasons. Reducing CO2 emissions is important for reduced ocean acidification as well as global warming. Reducing oil use is important for foreign policy reasons as well as CO2 reasons. Energy efficiency makes sense from an economic standpoint as well as an environmental standpoint. Etc. etc.
My understanding was that the lead authors have final say on whether a change is acceptable or not. Mind you, the all night sessions just before the release of the summary due to Chinese and US delegates trying to water down some of the conclusions might have lead to lead authors finally giving in from sheer exhaustion, but they do have to give the final ok. See realclimate for a more complete discussion, but this also jibes with what those of my colleagues who were contributors to the IPCC draft chapters have told me...
The IPCC writes its draft report first. Then it writes a summary based on the draft report. In the process of writing the summary, the lead authors (along with government representatives) scrutinize the key statements in the drafts which are going into the summary, and occasionally determine that a given statement is not supported or precisely accurate. So after they publish the summary they go back and make the report consistent. But the key point is that scientists vet all the changes. (Though, if anything, the changes at this point usually make the Summary statement more conservative that the original drafts, so it is kind of ironic that all the people who object to this process are the climate change deniers).
Why don't you take a look at the US National Academy Assessment of the hockey-stick cluster of studies rather than relying on climateaudit.org? Though the 4th Assessment Report isn't a bad place to look either. Also, I believe that the hockey stick always came with error bars, and was fairly good for a first pass, and subsequent studies have mostly confirmed Mann's argument that the current global scale warming is likely unprecedented in the past 1000 years.
Historically (eg, glacial/interglacials): current best theory is that the first mover was orbital variations (Milankovitch cycles) leading to ice sheet retreat. Ice sheet retreat leads to warming. Warming leads to CO2 outgassing from oceans, CH4 being produced from melting permafrost. CH4 and CO2 increases lead to more warming.
Present-day: CO2 increase is solely due to human activity. This CO2 increase is a priori expected to lead to temperature increases, and the actual temperature increase seems to be largely explained only by human induced atmospheric changes in forcing, if you include feedbacks (increased water vapor, glacial retreat, etc.)
Long long ago historically there is evidence that we never would have left snowball earth without the CO2 increases caused by volcanic eruptions over hundreds of thousands of years, and no CO2 sink through rock weathering/ocean uptake because everything was covered by ice.
Er. If you want good science, perhaps you should be reading the literature rather than watching movies? The IPCC puts out nice documents covering the state of climate science every 5 or 6 years which are all available online (ipcc.ch) if you don't have access to Science, Nature, JGR, Climatic Change, or any of the other major journals which publish in this area.
If you want a nice chart examining all the GHGs and solar activity, look at SPM-2 from the 4th Assessment Policy for Summarymakers.
We have a heck of a lot more than correlation. Why don't you go back and read Arrhenius (1896) on the fundamental relationship between CO2 concentrations and infrared trapping, and his estimates of the warming that a doubling of CO2 would give? Of course, back then he thought it was impossible that we'd ever _reach_ a doubled CO2 level, because it would require unthinkable amounts of burning CO2... but 110 years later, we are well on our way...
Also: Hint: Look at the US Climate Change Science Program Product 1 on the corrections to satellite readings of tropospheric temperatures: your argument is outdated. Another hint: increased solar radiation would heat the stratosphere as well as the troposphere and the ground: the stratosphere is cooling. What would cause warming of the ground + troposphere and cooling of the stratosphere? Well, greenhouse gases are one good possibility. Another fingerprint: night time versus day time temperature changes.
So perhaps you should actually read and understand the science before you call BS. Also: "history shows that consensus has almost always started out wrong to begin with"? I'd like to see some data on this... preferably from the past century when science has become more formalized. I would argue that 99% of the time consensus is pretty good, so we never hear about it.
Therefore, I don't see why we should think that an unknown mechanism (namely effect of sunspot variation on temperature) would be a better explanation. The Maunder minimum is certainly interesting, but I was under the impression that it could be explained by known natural variations (one of which was the presumption due to other proxies that there was less solar irradiance which may be related to the lack of sunspots - sadly, we don't have direct measures of solar irradiance back then). In the past 2 decades of climate research, there have been various papers published on sunspot to climate correlations, and most of them have proved statistically invalid (the 1991 study by Friis-Christiansen and Lassen, was widely cited by skeptics for a while until its flawed foundations were shown).
So 1) I am not convinced that sunspots have that big an effect on temperature outside of their correlation with actual irradiance, which we can directly measure and already do take into account (though not my area, so I could be wrong), and 2) if you want to attribute the last few decades of warming to a poorly understood sunspot-climate link, you really have to first explain why the forcing mechanisms we do understand involving GHG concentrations aren't having any effect.
Re: Jupiter: I was under the impression that there were significant changes in circulation patterns (eg, little red eye) leading to local large temperature variations, but I hadn't hear about any evidence of general solar-induced warming?
For a rebuttal with actual science, go to realclimate.org.
Mostly, those of us who work in the global warming field know that there are lots of uncertainties still remaining to be resolved about feedbacks, emissions projections, and oceanic processes, but most of the skeptics running around talking about "Mars is warming!" and "it has cooled since 1998!" and "you guys were global cooling fanatics 30 years ago!" and all the rest of that are just repeated long-ago debunked junk, and it is very frustrating to deal with all the noise, and so yes, we try and shout such arguments down.
And there is a _lot_ of industry sponsored junk being promulgated on this issue. And the current administration is very tightly connected with some of the biggest junk-pushers.
Your statement betrays three kinds of ignorance: 1) The difference between a "stock" pollutant and a short-term pollutant. CO2 and N2O both stay in the atmosphere for 100+ years. Therefore, what we've emitted in the past few decades will be with us for a while, and we haven't seen their full impact yet. We could stop emitting all greenhouse gases today and we would probably still see another degree celsius warming. 2) The difference between trace pollutants which we can clean up with "end-of-pipe" technology, and pollutants which are integral to the process. Don't like carbon monoxide? Add more oxygen and higher temperatures to your burn mix. Don't like SO2? Add a scrubber, or use cleaner coal. Don't like CO2? You have a problem. Because CO2 is an end product of combustion. (I will note that some people suggest we use carbon sequestration technologies to condense CO2 in the exhaust of coal plants and stick it underground. This may help, but it isn't going to deal with the whole problem). Therefore, we have not "created more pollution ... than we could ever do again", because we are likely to continue emitting CO2 and other GHGs at very high rates for the foreseeable future.
3) The ice age cycle (from ice age to interglacial) is actually a relatively recent phenomena, geologically speaking. It is controlled by small changes in solar forcing due to orbital cycles. If we do burn most of the fossil fuels currently buried underground, the forcing increase from that CO2 will be _far_ more than the forcing decrease at the nadir of the Milankovitch cycles, and we will _not_ have the next ice age. But I personally don't so much care about what happens 10,000 years from now, I care about the next couple hundred years, and from everything I've read in the literature, and the modeling work I've done myself, I think we are going to see order 5 degrees celsius average warming over the next 2 hundred years. It won't be the end of the world, humans are adaptable, but it will lead to a lot of suckage.