Slashdot Mirror
How Well Do Our Climate Models Match Our Observations?
bunratty writes "According to recent articles by Roy Spencer and John Christy, our climate models have done a poor job of predicting warming due to humans burning fossil fuels. They claim that we've observed only a fraction of the warming they predict. But when I look at the source they claim to use, the State of the Climate in 2012, I see that it shows a warming of 0.7 degrees Celsius worldwide since 1980, close to the 0.8 degrees Celsius warming predicted by the climate models. Take a look at the data for yourself. How well do our predictions match our observations?"
That's because you are looking at climate models calibrated against that data that you are comparing to. Circular logic.
If you look at the predictions from past IPCC reports, very few of their predicted temperature profiles match the later observed conditions. That is a failure of the models' predictive power. That doesn't mean there isn't warming, just that the Earth's climate is a more complex system than can be accurately simulated with modern computing hardware.
It's almost as if there aren't big walls in the sky that keep emissions from leaving the countries that produce them.
Spencer has contributed specific work in peer reviewed journals that is part of the scientific discussion, but his overall opinion on climate change is motivated more by his own religion than anything else. He's both sympathetic to intelligent design and signed a statement which said among other things ""Earth and its ecosystems – created by God's intelligent design and infinite power and sustained by His faithful providence – are robust, resilient, self-regulating, and self-correcting." http://en.wikipedia.org/wiki/Roy_Spencer_(scientist)#Climate_change Essentially he believes that climate change isn't happening because his religion won't let him. Note how that statement wasn't even just about climate, but about ecosystems as a whole. Christy doesn't seem to have that same sort of underlying motivation and might make more sense to pay attention to, but in this context, the vast majority of experts disagree with both of them, and when dealing with complicated scientific issues, using expert consensus is a useful heuristic, that's before we get to the serious issue that not only is the expert consensus clear, it is a consensus about some very bad results, not just a consensus about an issue which doesn't have substantial impact.
That is a perfect example on how to misalign graphs to make them match your agenda. He should be jailed for that.
As the old song goes, little things mean a lot. You couldn't see the difference between a little botulin toxin and a lethal dose without a microscope. And I'm sure you wouldn't notice a 0.7 C difference between one room in your house and another, but multiply that amount of energy to a global scale and it starts to add up. Consider what climatologist James Hansen said about the current rate of increase in global warming: “(it's) equivalent to exploding 400,000 Hiroshima atomic bombs per day, 365 days per year. That’s how much extra energy Earth is gaining each day.”
Ask me about my sig!
Or the fact that we are still coming off of an Ice Age that lasted for more than 100,000 years, and ended less than 10,000 years ago (Or the little Ice Age that ended in 1850). Several models predict that the average temperature at the END of the last Ice Age was 15-20C lower than today.
Is global warming happening? Yes. Is the human race a contributing factor? Probably to some degree. Is the human race the only cause? No.
I can't speak to the accuracy of historic weather data or modern weather models, but I can say this:
Global Warming / Climate Change (pick one, please) alarmists do themselves an incredible amount of damage when they do the following:
1. Grossly exaggerate predictions and base everything on the worst case they can find.
2. Manipulate charts to make changes look far more significant than they really are.
3. Instantly ridicule anyone who disagrees with them on anything, even if that disagreement is valid.
Let's say for the sake of argument that all of the predictions from these weather models are 100% accurate, all of the research and data is correct, and that the climate is indeed warming because of CO2 emissions, and that the climate will warm 5 Celsius degrees in the next 200 years. Let's pretend that the science is completely perfect.
Even if all of that is true, you will find a lot of people who won't even bother listening because they remember crazy predictions like "New York city will be underwater in 20 years!" and "We're all going to be cannibals! Cannibals, I say!"
Do you see why so many people don't listen to those who are trying to push human-caused climate change?
Politics needs to be taken out of the equation. Completely. Everything needs to be 100% transparent. The science needs to be broken down in ways the average person can understand. Even if that happens, it will be decades before the damage the global warming alarmists have caused can be reversed.
Love sees no species.
Small fluctuations in local weather are much, much, much, much more chaotic than large fluctuations in global climate. This is hardly unique to atmospheric sciences.
Lets us an IT analogy, lets say you manage a large data center and your head of IT comes up and says something like this:
"Over the next 5 years, 15% of the hard drives in this data center will fail. We need to take these basic precautions."
Your response would be like:
"Why on earth should I trust your estimate for 5 years from today when you can't tell me exactly which servers will fail within the next 6 months!?"
And then you'd get angry at him 5 years down the road when only 14% of the drives failed and be all like:
"See! I told you there was nothing to worry about!"
China are experts on big walls, though.
The State of the Climate 2012 paper is... get this... from two years ago. After they had to start "adjusting" their models to reflect reality.
When you look at the actual historical AGW models, we're below their "optimistic" model (the one where we cut CO2 drastically over the last couple of decades - which didn't happen). And a good 0.2 C below their "probable" models.
If you're looking at predictions, go back and look at the climate models from the late 1980s and early 1990s. They're off, by a ridiculous amount.
Out of 90 models (yes, ninety), a grand total of TWO managed to predict the current temperature.
Well, no, it doesn't just need a 2C drop to get an ice age. It needs a continuous temperature shift of 2C or more in higher-latitude temperate regions without any significant actions to remove the snow. After a couple years of that remaining true, the increased snow cover will become self-sustaining until acted on by a sufficient contrary change of some kind. Then you get an ice age.
Dramatic climate changes don't work off the global average temperature, they work off regional interactions across large enough scales to become resistant to the minor fluctuations.
No scientist says humans are the only cause. There are other forcings, positive and negative. The very likely (95%-100%) in the IPCC is to the contention that "most" of the rise in temperature is caused by human forcings. Not "all".
I don't think it should be surprising if changes in climate affect the behavior of people in areas. If food becomes more plentiful I bet crime goes down. If food and water become more scarce I bet it goes up. If the weather patterns are changing surely some areas are going to get drier and some are going to get wetter. Also, as events become more extreme all the extreme weather events you sited are likely to happen more often too, don't you think? So you're right, global warming almost certainly is doing all those things.
I don't see why it's controversial to think that. Even if you don't think people have anything to do with changing climate all those effects are obvious outcomes of it changing, and I don't think many people actually doubt that it is changing.
For several years Gavin Schmidt, one of the principals of the NASA/GISS Model/E climate model, has been doing a comparison of model output to observations. There isn't an update for 2013 yet but the comparison through 2012 is available here.
Look back before that, the period from 1950-1974 (approximately). How well do the models match there?
Cherry picking is bad science. You have to look at the whole record from the start of the Industrial Age... and the models haven't been particularly good.
That's not an anti anthropogenic global warming statement, by the way. It's a "science is hard and you can't understand a subject after ten minutes of reading" statement.
#DeleteChrome
When it comes to modeling, "predicting" old data is actually an invaluable technique for developing useful models. For instance, if you're working with machine learning algorithms, it's typical to segregate your data into a training set and a test set (sometimes an additional validation set as well). The training set is used to teach the machine learning algorithms, thus establishing a model. You then take that model and run it over the test set to see how well it matches.
Put differently, rather than creating a model from all of the old data (which, as you said, is trivial and not really that impressive), you put yourself in the shoes of a 1970s scientist and try to use the data from only up to that point to create a model that will work for the next 40 years. You then get to fast forward 40 years and see how you did. If you didn't get it right, you go back and try again.
There was no decision to change it, they are two different terms. Global Warming is a subset of Climate Change. The confusion of terms exists only in the reporting of the general, non-scientific press and the minds of Internet dogs who think checking a household thermometer means they themselves are qualified to hold a valid opinion.
The IPCC was created back in 1988 at the request of WMO (World Meteorological Organization) and the UNEP (United Nations Environment Program).
The UNEP was formed in 1972 to study man's interaction with and impact on the environment.
The WMO was researching "potential global warming caused by the build-up of greenhouse gases in the atmosphere" back in the mid-1970s.
Back in 1956 scientist Gilbert Plass published a study titled "The Carbon Dioxide Theory of Climatic Change".
In a 1975 Science article by geochemist Wallace Broecker of Columbia University's Lamont-Doherty Geological Observatory: "Climatic Change: Are We on the Brink of a Pronounced Global Warming?"
Learning HOW to think is more important than learning WHAT to think.
Or the fact that we are still coming off of an Ice Age that lasted for more than 100,000 years, and ended less than 10,000 years ago (Or the little Ice Age that ended in 1850). Several models predict that the average temperature at the END of the last Ice Age was 15-20C lower than today.
So over 10k years temperature raised 20C, that is (20 / 10000) * 10 = 0.02C per decade, very far from 0.7 / 3 = 0.23 per decade that we see now.
I don't have sources from your numbers, and it's probably safe to assume that the rate of temperature change isn't constant either... So maybe we shouldn't try to model this at all, my calculations above are certainly as ignorant and non-sense as your postulation of numbers...
Is global warming happening? Yes. Is the human race a contributing factor? Probably to some degree. Is the human race the only cause? No.
True, there are many factors that affect the environment, but non other does it with the same speed as humans.
Global warning is primarily man-made, it's a real problem, that's the scientific consensus. And I'm fairly sure that most people on slashdot as just as qualified to discuss the scientific consensus around global warming, as soccer moms are qualified to discuss the merits and "dangers" of vaccinations.
Or the fact that we are still coming off of an Ice Age that lasted for more than 100,000 years, and ended less than 10,000 years ago (Or the little Ice Age that ended in 1850). Several models predict that the average temperature at the END of the last Ice Age was 15-20C lower than today.
Is global warming happening? Yes. Is the human race a contributing factor? Probably to some degree. Is the human race the only cause? No.
I like this game.
.002C/year. .7C over 30 years is .023C/year
Do humans have the capability to mitigate their contribution to warming? Yes. Does any other warming phenomenon? No
Do humans care if these warming effects drastically disrupt the climate that our current society has adapted to so well? Yes. Does anything else? No.
Also a quick note, 20C over 10000 years is
Just so you know: That "97 percent of all scientists in the world" silliness came from a rigged "poll."
Basically, an AGW-supporting scientist polled a number of his AGW-supporting scientist friends and co-workers - 30 or so - and asked them if they thought AGW was real.
That's where your number came from. Which should tell you something about the actual support for AGW among the scientific population at large...
They recently came up with another poll, where they cherry-picked a bunch of papers, and said "97% of scientific papers agree!" While not mentioning that only about a third of them actually addressed AGW, and they got their "new" 97% by only looking at 65 papers. Out of 12,000. Oops.
ok, so.. read through all of this page, and repeat that this is just a guy polling his friends:
http://climate.nasa.gov/scient...
I, too, used to think climategate showed all those things. I read article after article about them and how it's all over for AGW, etc. However, when taken in context, those emails actually refer to something totally other than what they were made out to refer to. I highly recommend you check out this video and this one wherein potholer54 takes an in-depth and impartial look into climategate and reveals what it actually shows... as a spoiler, it doesn't reveal that there's a giant AGW conspiracy amongst all the climate scientists in the world.
This all came out in the Climategate emails. But you never heard about those, did you?
We are well aware of release of emails from the University of East Anglia. The attempt at connecting it with watergate fails, as unlike watergate there is no smoking gun. Nothing in the emails shows any conspiracy. There is no blocking of "anti-AGW" papers. There are no "anti-AGW" papers to block. And nothing in the emails says otherwise
"Hide the decline" ring a bell?
It sure does.
"Many commentators quoted one email in which Phil Jones said he had used "Mike's Nature trick" in a 1999 graph for the World Meteorological Organization "to hide the decline" in proxy temperatures derived from tree ring analyses when measured temperatures were actually rising. This 'decline' referred to the well-discussed tree ring divergence problem, but these two phrases were taken out of context by climate change sceptics, including US Senator Jim Inhofe and former Governor of Alaska Sarah Palin, as though they referred to some decline in measured global temperatures, even though they were written when temperatures were at a record high.[32] John Tierney, writing in the New York Times in November 2009, said that the claims by sceptics of "hoax" or "fraud" were incorrect, but that the graph on the cover of a report for policy makers and journalists did not show these non-experts where proxy measurements changed to measured temperatures.[33] The final analyses from various subsequent inquiries concluded that in this context 'trick' was normal scientific or mathematical jargon for a neat way of handling data, in this case a statistical method used to bring two or more different kinds of data sets together in a legitimate fashion.[34][35] The EPA notes that in fact, the evidence shows that the research community was fully aware of these issues and that no one was hiding or concealing them.[36]"
http://en.wikipedia.org/wiki/H...
You have nothing.
Our chief weapon is surprise. Fear and surprise. Two chief weapons, fear, surprise, and ruthless efficiency! Er, among our chief weapons are: fear, surprise, ruthless efficiency, and near fanatical devotion to the Pope! Um, I'll come in again...
Also a quick note, 20C over 10000 years is .002C/year. .7C over 30 years is .023C/year
Also worth noting is that the global temperatures didn't change 20C. The last glacial maximum was only 3C to 5C cooler than the present (http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch6s6-es.html). The height of the current interglacial period occurred about 8000 years ago. Since then temperatures have been dropping (up until recently).
"Basically, an AGW-supporting scientist polled a number of his AGW-supporting scientist friends and co-workers - 30 or so - and asked them if they thought AGW was real."
Not quite true. The original "huge consensus" rumor was started by an article (NOT a peer-reviewed paper) that appeared in Nature by one Naomi Oreskes, years ago. Oreskes claimed to have surveyed a database of science papers and concluded that none of them (not one) disagreed with the greenhouse gas global warming idea.
It was soon shown that Oreskes' "study" was in fact a textbook example of cherry-picking. She had searched the database for papers that included the phrase "global climate change". Only those were included in her analysis. The problem with that being that at the time, only papers that were ABOUT the effects of greenhouse gas warming mentioned the phrase "global climate change" at all. So, in effect, she selected out of the scientific literate just the papers about greenhouse global warming, and then conclude that they all agreed about greenhouse global warming! How surprising!
The fact was, of course, that the majority of climate papers were not about greenhouse warming and never mentioned the subject at all. But those weren't counted.
This "consensus" idea was bolstered by people claiming that almost all of the "thousands" of scientists behind the latest IPCC report had agreed about it. This, too, was a distortion of the truth. The scientists involved in the AR report at the time numbered in the hundreds. There were about 2,500 or so reviewers, and not all of those were scientists. Further, not all of them actually agreed.
Shortly after that, the Petition Project was undertaken to show that scientists in fact did not agree. Some 30,000 people with actual science or engineering credentials signed the petition DISagreeing with greenhouse global warming, and their names and professions are still publicly available at petitionproject.org. More than 9,000 of those were PhDs... far more than the 2500 who supposedly agreed, again many of whom had no advanced degrees.
Another "study" was done in this last year, which came up with that "97%" figure. Unfortunately, THAT "study" suffered from exactly the same flaw as the discredited Oreskes study: it searched the literature for papers that contained the phrase "global climate change". Self-selection at its finest.
And of course then there's the real kicker here: even if these "studies" had not been statistical nonsense, the fact remains that "consensus" is not science. If consensus were a scientifically valid measure of anything, we'd still be in the stone ages.
The thing is, it really doesn't matter how many scientists support it. Science isn't a democracy. See the pamphlet called 100 authors against Einstein. Einstein replied that it didn't need 100 people do disprove his theory of relativity, rather all it needed was one fact. I really hate how modern science has turned into this "if the majority believes it, it must be true." I'm sure the majority of the world still believes in creationism, but they're also still wrong.
(By the way, who decides what makes you a scientist anyways?)
Careful with names containing L slashdot.org/~AiphaWolf_HK slashdot.org/~AlphaWoif_HK slashdot.org/~AiphaWoif_HK
If you want to assert the anthropogenic greenhouse effect is both real, and dangerous, the burden of proof is on the affirmative to come up with a necessary and sufficient falsifiable hypothesis statement which rules out natural climate change as the reason for observed temperatures.
OK. My prediction is that if you aim an infrared spectrometer at the sky, you will see downwelling infrared radiation from the CO2 spectrum.
This prediction is falsified if you don't see downwelling infrared radiation.
Hey, we see it! I win. Carbon dioxide actually does re-radiate absorbed thermal infrared. The greenhouse effect is real.
This was done over a century ago, by the way. The greenhouse effect has been known for a long time. Good thing, too; the Earth would be frozen if it didn't exist.
http://www.geoffreylandis.com