Guest Post by Ira Glickstein.
The graphic from RealClimate asks “How well did Hansen et al (1988) do?” They compare actual temperature measurements through 2012 (GISTEMP and HadCRUT4) with Hansen’s 1988 Scenarios “A”, “B”, and “C”. The answer (see my annotations) is “Are you kidding?”
HANSEN’S SCENARIOS
The three scenarios and their predictions are defined by Hansen 1988 as follows
“Scenario A assumes continued exponential trace gas growth, …” Hansen’s predicted temperature increase, from 1988 to 2012, is 0.9 ⁰C, OVER FOUR TIMES HIGHER than the actual increase of 0.22 ⁰C.
“scenario B assumes a reduced linear growth of trace gases, …” Hansen’s predicted temperature increase, from 1988 to 2012, is 0.75 ⁰C, OVER THREE TIMES HIGHER than the actual increase of 0.22 ⁰C.
“scenario C assumes a rapid curtailment of trace gas emissions such that the net climate forcing ceases to increase after the year 2000.” Hansen’s predicted temperature increase, from 1988 to 2012, is 0.29 ⁰C, ONLY 31% HIGHER than the actual increase of 0.22 ⁰C.
So, only Scenario C, which “assumes a rapid curtailment of trace gas emissions” comes close to the truth.
THERE HAS BEEN NO ACTUAL “CURTAILMENT OF TRACE GAS EMISSIONS”
As everyone knows, the Mauna Loa measurements of atmospheric CO2 proves that there has NOT BEEN ANY CURTAILMENT of trace gas emissions. Indeed, the rapid increase of CO2 continues unabated.
What does RealClimate make of this situation?
“… while this simulation was not perfect, it has shown skill in that it has out-performed any reasonable naive hypothesis that people put forward in 1988 (the most obvious being a forecast of no-change). … The conclusion is the same as in each of the past few years; the models are on the low side of some changes, and on the high side of others, but despite short-term ups and downs, global warming continues much as predicted.”
Move along, folks, nothing to see here, everything is OK, “global warming continues much as predicted.”
CONCLUSIONS
Hansen 1988 is the keystone of the entire CAGW Enterprise, the theory that Anthropogenic (human-caused) Global Warming will lead to a near-term Climate Catastrophe. RealClimate, the leading Warmist website, should be congratulated for publishing a graphic that so clearly debunks CAGW and calls into question all the Climate models put forth by the official Climate Team (the “hockey team”).
Hansen’s 1988 models are based on a Climate Sensitivity (predicted temperature increase given a doubling of CO2) of 4.2 ⁰C. The actual CO2 increase since 1988 is somewhere between Hansen’s Scenario A (“continued exponential trace gas growth”) and Scenario B (“reduced linear growth of trace gases”), so, based on the failure of Scenarios A and B, namely their being high by a factor of three or four, it would be reasonable to assume that Climate Sensitivity is closer to 1 ⁰C than 4 ⁰C.
As for RealClimate’s conclusion that Hansen’s simulation “out-performed any reasonable naive hypothesis that people put forward in 1988 (the most obvious being a forecast of no-change)”, they are WRONG. Even a “naive” prediction of no change would have been closer to the truth (low by 0.22 ⁰C) than Hansen’s Scenarios A (high by +0.68 ⁰C) and B (high by 0.53 ⁰C)!
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I predicted the UK Wildcats would make a good showing in the Tourament this year… clearly my prediction “out-performed any reasonable naive hypothesis that people put forward” back in January.
I love outcome based predictions! LOL!
Climate sensitivity to CO2 is exactly 0C !….period..
Thanks Ira, for presenting this info from Real Climate’s website, I never go there. It’s an unhealthy place to visit, what with blood pressure, and all.
They convict themselves with efforts like this, but who could convince them of it?
Now wait a minute there Anthony, let’s think this through for a minute.
If RealClimate is arguing that Hansen’s predictions are accurate because we’re in Scenario C, doesn’t that mean that our (non existent) mitigation efforts have been successful? We’re not emitting CO2 into the atmosphere anymore, is basically what they’re saying; we haven’t been since 2000. Great! Let’s quit with the legislative efforts to destroy the fossil fuel industry, stop the wind and solar subsidies, dismantle the IPCC, declare victory and go home.
Maybe? Somehow I have a nagging feeling that won’t work, although I can’t quite put my finger on why… /sarc
Mark Bofill says:
Your comment is awaiting moderation.
March 20, 2013 at 7:33 am
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Gah, beg pardon, I should have addressed Ira, not Anthony.
Reblogged this on This Got My Attention and commented:
It’s time to hold the know-it-all predictors accountable for their exaggerations.
Comparing forecasts to the real world is patently unfair. If you were to compare the forecasts to other forecasts, you would find them spot on, indicating a concensus.
Besides, you didn’t correct the measured temperatures upward to compensate for all the energy used in our plethora of severe storms. We don’t need a weatherman to know which way the winds blows…..(apology & /Sarcoff)
Realclimate and others ignore the hiatus global temperture rise,its as if they stick fingers in ears and go BLAH,BLAH BLAH when ever the data is put in front of them…and these people have the nerve to call themselves scientists
ER, it must be really really warm in Lexington this morning.
Good summary. The whole sensitivity debate is a red herring however. Changes in co2 level FOLLOW changes in temperature, at ALL timescales. Cause precedes effect.
http://tallbloke.wordpress.com/2011/06/26/which-causes-which-out-of-atmospheric-temperature-and-co2-content/
CO2 emissions will continue because nature contributes MORE than we do by 33 times. Climate will continue its natural change pattern despite this because climate change is solar driven NOT CO2 driven.
There are NO peer reviewed papers that show that CO2 drives climate. There are model runs that do but these are based on CO2 driving climate so constitute zero proof and show a circular argument when introduced. There are plenty of peer reviewed papers showing that CO2 does NOT drive either temperature or climate.
Get real.
Interesting that the nearest match is the “no forcing increase past 2000” which actually seems to match reality since 2000 fairly well, but had already run “high” by the millenium to create the over-estimate today.
Since CO2 hasn’t stopped increasing, surely that suggests that CO2 is not the relevant forcing and (assuming the simple radiative forcing model is basically sound in the first place) we should be looking for some other variable that was increasing up to 2000 and has flattened / fallen since?
CO2? This is not the forcing you’re looking for.
I wonder , if the temperature is driving Co2 and not Co2 driving the temperature , than at what temperature drop does the amount of Co2 go down ?
Did anyone ever publish any data about that ?
[Great question! According to the Ice Core data over several hundred thousand years:
1) Temperature drops and stays low for hundreds of years until CO2 begins to drop. Then there is a period of hundreds of years while Temperatures stay low and CO2 drops to a minimum level. Then a long period where both Temperature and CO2 are low.
2) Then, Temperature rises and stays high for hundreds of years until CO2 begins to rise. Then there is a period of hundreds of years while Temperatures stay high and CO2 rises to a maximum level. Then a long period where both Temperature and CO2 are high.
3) Repeat above process for multiple cycles.
Of course, that was well before humans evolved on Earth and everything changed :^)
Ira]
RealClimate as ever is asking, “Who are you going to believe? Us or your own lying eyes?”
It has been 26 years since Hansen et al did the work noted above. The IPCC is in the process of producing the fifth report since then, involving “thousands” of “top-notch” “climate” “scientists” (each category is, of course, a piece of misinformation). In the world of science and business and general human lives, during that period we would expect the range of Scenarios to have been narrowed. But we are still faced with A through C.
This is why references of how Hansen’s predictions are still relevant. The most recent forecast is still as wild and wooly as it was in ’88 – despite the new ones being curve-matched to data from 1988 to about 1997. There has been no progress. And that is because the fundamental assumptions that drive the model Scenarios have not changed.
And they can’t. The whole CAGW narrative rides on a high sensitivity of CO2 and a significant, positive feedback from water vapour. The disaster, however, is not present but projected. Any reduction in the impact of additional atmospheric CO2 is not just a short-term problem for the story – you can’t have “extreme” weather from CO2 if there has been little or no global warming from CO2 – but a long-term problem. A world warmer by 2C in 200 years (by model) is a world that adapts, not collapses.
Each day the newspapers have articles touting the terrible things to happening in a warming and changing world of weather. All of them – and I mean “all” – are written with the present and future conditionals: the “may”, “could”, “might” and “should”. Whatever event we are to be alarmed about is “possibly” related to CO2 warming. Hansen and others behind the Scenarios continue to use the wide range because they know that the earlier they try to turn to the words “does”, “will” and “shall”, narrow the Scenarios to get us a clearer picture of what lies ahead (under the current use of fossil fuels) the earlier we will be looking for the proof of their puddings. And discovering them to be tasteless.
Beautiful graphic. That really says it all without being overly complicated. Good job!
Incorrectly predicting the imperitive to entirely remake our economic system still “shows skill?”
No wonder these guys don’t work in the real world where results matter!
Ahhh, a retro-cast! Will Hansen wear it, his hair-shirt?
“It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it doesn’t agree with experiment, it’s wrong.” — Feynman
Hansen 1988 was wrong.
Excellent
My predictions for this week wining lottery numbers are 6 numbers in the range 01-50 , given that is the total range possible, and this is the good part , I must be right no matter what numbers come up.
Does this make me overqualified to be a ‘climate scientists.
squid2112 (March 20, 2013 at 7:31 am):
I would not go so far as to say Climate Sensitivity is exactly 0.00 ⁰C. All else being equal, I am pretty sure Climate Sensitivity is somewhere between 0.25 ⁰C and 1 ⁰C. If Atmospheric CO2 had zero effect, the Earth Surface temperatures would be over 30 ⁰C cooler, because the Atmospheric “Greenhouse Effect” is real. Thus, if you could hold Cosmic Rays and Multi-Decadal Oscillations and everything else constant, and then increased Atmospheric CO2, Earth Surface temperatures would increase.
Calculations say doubling of CO2 would result in about 1 ⁰C average temperature rise, but feedback, assuming clouds have, on net, a negative effect on temperatures, would reduce that temperature rise, possibly as low as 0.25 ⁰C. (As we know, nighttime clouds have a positive feedback effect and daytime clouds have a negative feedback effect.) There are also other negative (and positive) feedback effects.
Thanks for your comment.
Ira
I also enjoyed Gavin’s comment:
“Short term (15 years or less) trends in global temperature are not usefully predictable as a function of current forcings.”
I look forward to 2018, when 20 years will not be long enough.
Meanwhile, as shown above,. there are no successful predictions of that length, either, but climate models don’t need to be proven, we’re just supposed to assume they’re correct until proven otherwise. Because that’s Science.
[Good points. Actually, it has been 24 years since Hansen 1988 was published, and according to the RealClimate posting, Hansen’s data was from 1984, so it has been around 28 years. By any measure, Even Gavin’s, 28 years should be LONG ENOUGH! Ira]
“Atmospheric CO2 at Mauna Loa Observatory – measured at height???
At ground level? Then it is a vulcano activity indicator …
“What does RealClimate make of this situation?
… while this simulation was not perfect, it has shown skill in that it has out-performed any reasonable naive hypothesis that people put forward in 1988 ”
Or as any 13 year old would say: “Yeah, well I maybe wrong but not as wrong as some other people.”