Probably the most famous of all the climate alarmists, and one of the creators of the climate alarm genre, is a guy named James Hansen. Naturally, he long had a comfortably-funded government perch from which to create and disseminate his predictions of catastrophe. For some 32 years (1981 - 2013) Hansen headed the branch of NASA called GISS (Goddard Institute for Space Studies) that is incongruously located in Manhattan (at Columbia University), and that somehow has come to be one of the repositories of world temperature data within the U.S. government. Although he retired from GISS in 2013, Hansen still has some kind of appointment at Columbia, and still regularly makes apocalyptic pronouncements of impending climate doom.
Hansen first leapt into the public consciousness in the late 1980s with testimony before Congress predicting rapid increase in global temperatures resulting from the atmospheric greenhouse effect, in turn supposedly stemming from increased use of fossil fuels by mankind. The most-remembered of his Congressional appearances occurred in late June 1988 at a hearing orchestrated by then Colorado Senator Tim Wirth, on what happened to be a day where the temperature in Washington rose to over 100 degrees Fahrenheit. But the Washington Post helpfully reminds us in a feature article on June 11 that Hansen's 1988 testimony was not his first venture before Congress. A prior round of Hansen testimony -- and of predictions of climate doom -- occurred during two days of hearings on June 10 and 11, 1986. The host of these prior hearings was the Senate Committee on the Environment and Public Works, chaired by Senator John Chafee of Rhode Island. We have now reached the 30th anniversary of those 1986 hearings. Should we check in on how Hansen's predictions have fared?
The tenor of that Washington Post article can be summarized as "How right Hansen was!" The headline is "30 years ago scientists warned Congress on global warming. What they said sounds eerily familiar." Then they quote Hansen's fellow climate doomsayer Michael Oppenheimer as follows:
“This hearing helped bring the concern together, and essentially painted a picture that things are kind of spinning out of control, that science is trying to tell us something, that the world seems to be changing even faster than our scientific understanding of the problem, and worst of all, our political leaders are way behind the eight ball,” said Michael Oppenheimer, a Princeton climate scientist who testified that day, and argued that action was warranted on climate change even though not everything was known about its consequences.
But here's the funny thing about the article: read it all the way through, and you will find that they studiously avoid stating what Hansen's actual quantitative predictions of temperature rise were. Did he make a prediction in the 1986 hearings of how much the temperature would rise and by when? You won't find the answer to that question in the Post article, although there is this bit of a negative pregnant:
Granted, in some cases the future temperature projections made in the 1986 hearings — based on assumptions about the rate of increase in greenhouse gas emissions and a high sensitivity of the climate to them — suggested temperatures might rise even more, or even faster, than scientists now believe they will.
It seems that they don't want us to know. Are you curious as to why? Well, lucky for us, the New York Times published an article on June 11, 1986, reporting on the Chafee hearings, and that article tells us Hansen's quantitative predictions. Ready?
Average global temperatures would rise by one-half a degree to one degree Fahrenheit from 1990 to 2000 if current trends are unchanged, according to Dr. Hansen's findings. Dr. Hansen said the global temperature would rise by another 2 to 4 degrees in the following decade.
This prediction gives a temperature increase range of 2.5 - 5 deg F (1.4 - 2.8 deg C) in the period from 1990 to 2010. And now we've gone yet six more years, to 2016. On Hansen's midpoint projection, we should have close to 3 deg C of warming by now -- right?
The actual data through May 2016 are now known. Go to the UAH satellite data here, and here's what you'll find. In November 1990 the UAH "global lower troposphere temperature anomaly" hit 0.25 deg C. Twenty years later, for which date Hansen made a specific quantitative prediction that global temperature would have increased by at least 1.4 deg C and up to 2.8 deg C, the UAH global lower troposphere temperature anomaly was -- drumroll !!!!!! -- 0.17 deg C. That's right, for the specific period covered by Hansen's testimony, the temperature not only did not follow the magnitude of his alarmist prediction, it actually went the opposite direction -- down, not up. But, you say, how about bringing that up closer to the present? The next five years beyond Hansen's prediction take us to November 2015. Although Hansen's 1986 testimony contained no specific prediction for 2015, human greenhouse gas emissions have only increased. If his prediction for 2010 had any validity, then temperature post-2010 should be going up by around 1 deg C every five years. The UAH global lower troposphere anomaly for November 2015 was 0.33 deg C. Whoopee! It was up from November 1990 by 0.08 deg C! On a straight-line extrapolation, Hansen's mid-point prediction for 2015 would be close to a full 3 deg C. That means that he was off by a factor of, say, around 40.
But, you ask, hasn't there been a big spike in global temperatures in the first half of 2016? Actually, there has been a substantial spike, although the term "big" is relative. The spike has indeed been big relative to past spikes in the 37-year satellite temperature record; but it has been quite small relative to Hansen's alarmist predictions. In February 2016 the UAH global lower troposphere temperature anomaly hit an all-time record of 0.83 deg C. (The prior record was 0.74 deg C in April 1998.) The 0.83 was only 0.57 deg C above November 1990 -- a far cry from Hansen's (extrapolated) prediction of 3 deg C or so. And then after February the anomaly immediately started a sharp decline. By May it was back to 0.55 deg C; and indications are that there will be a further substantial decline during June. Will it shortly go back below the 0.25 deg C of 1990? That's anybody's guess, but my bet is yes.
And, as one looks at the data, it only gets worse for Hansen's prediction of warming driven by greenhouse gases in the atmosphere. The 1998 temperature spike was associated with a strong El Nino (i.e., unusually warm ocean surface temperatures in the tropical Pacific). The early-2016 temperature spike was also associated with a strong El Nino. Nobody has come up with any plausible explanation of a mechanism by which atmospheric greenhouse gas effects can cause El Ninos. The decline in temperatures over the most recent several months has further been associated with the dissipation of the 2015-16 El Nino. In other words, there is every reason to think that such warming as there has been might have been caused by something entirely different from greenhouse gases: If "global warming" is driven principally by atmospheric greenhouse gases, then why do the big spikes only occur when there is a big El Nino, and even more importantly, why do they promptly go away as soon as an El Nino dissipates?
The invaluable Tony Heller weighs in with a comparison of Hansen's 1986 predictions to actual results in a "30th anniversary" post here:
Thirty years ago, James Hansen made some spectacularly poor global warming predictions before Congress. . . . Hansen predicted two degrees global warming by 2006. . . . He was off by a factor of ten. . . . Earth warmed about 0.2 degrees from June 1986 to June 2006.
I would only remark that Heller is extremely generous to Hansen in concluding that he was only off by a factor or ten. Exactly how far off Hansen was depends on your exact start and end months for the 20-year measuring period. As shown above, based on the New York Times paraphrase of Hansen's testimony and a November 1990 to November 2010 20-year measuring period, Hansen's error was effectively infinite (wrong sign). Whatever. Different start and end months can slightly change the precise result, but cannot change Hansen's fundamental problem of an error of, plus or minus, at least an order of magnitude.
If you are still somehow wondering if Hansen and the Washington Post are playing straight with you, consider this. After acknowledging (as quoted above) that the 1986 predictions might have suggested that temperatures would "rise even more" than they in fact have, the Post gives Hansen a chance to explain. Here is what he comes up with:
By email, Hansen clarified that we now know the world is closer to one scenario he presented in 1986 — called Scenario B — than to Scenario A, which assumed a much more rapid rate of greenhouse gas growth, and accordingly, much faster warming.
So what's he talking about with "Scenario A" and "Scenario B"? While those terms do not appear in press descriptions of his 1986 testimony, they do appear in descriptions of his 1988 testimony, and in a 1988 article authored by him and others that backed up that testimony. Here is an excerpt from the abstract of the 1988 article:
Scenario A assumes continued exponential trace gas growth, scenario B assumes a reduced linear linear growth of trace gases. . . .
So, since about 1988, have we had a "continued exponential trace gas growth" or a "reduced linear growth of trace gases"? Well, perhaps we can look to this abstract of an article by James Hansen from 2013 in a journal called Environmental Research Letters:
Annual fossil fuel CO2 emissions have shot up in the past decade at about 3% yr-1, double the rate of the prior three decades (figure 1). The growth rate falls above the range of the IPCC (2001) 'Marker' scenarios, although emissions are still within the entire range considered by the IPCC SRES (2000). The surge in emissions is due to increased coal use (blue curve in figure 1), which now accounts for more than 40% of fossil fuel CO2 emissions.
Three percent per year increase through 2013: Is that "continued exponential trace gas growth" or "reduced linear growth of trace gases"? How dumb does this guy think we are? And how dumb does the Washington Post think we are?