What do you think of James Hansen's 1981 predictions?

Question

Some AGW deniers have called Hansen a "political hack" and "fascist".

http://answers.yahoo.com/question/index;_ylt=Aij9luZzvHlRZ0gEclymgonsy6IX;_ylv=3?qid=20080820151504AAhC2ny&show=7#profile-info-Zs3B6Lwbaa

Others have attibuted claims to Hansen that he never made and then stated that his predictions (the ones he never made) have been inaccurate, implying that he does poor science.

In 1981, Hansen and six other NASA atmospheric physicists published an article in Science entitled “Climate Impact of Increasing Atmospheric Carbon Dioxide.”

http://pubs.giss.nasa.gov/abstracts/1981/Hansen_etal.html

From the abstract:

"It is shown that the anthropogenic carbon dioxide warming should emerge from the noise level of natural climate variability by the end of the century, and there is a high probability of warming in the 1980s. Potential effects on climate in the 21st century include the creation of drought-prone regions in North America and central Asia as part of a shifting of climatic zones, erosion of the West Antarctic ice sheet with a consequent worldwide rise in sea level, and opening of the fabled Northwest Passage."

Subsequently, there was significant warming in the 1980s (and beyond) due to human CO2 emissions

http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.lrg.gif

the US southwest is in a decade-long drought

http://www.usatoday.com/weather/climate/2006-03-05-southwest-drought_x.htm

Which is expected to continue indefinitely

http://www.livescience.com/environment/070405_southwest_drought.html

The West Antarctic Ice Sheet has indeed begun eroding

http://geology.com/research/west-antarctic-ice-sheet.shtml

And the Northwest Passage has indeed opened

http://news.nationalgeographic.com/news/2007/09/070917-northwest-passage.html

Considering this, what do you think about Hansen and his 1981 predictions?

Answer 1

I don't think he really went out on a limb here.

1) There is still a debate even amongst the scientific community as to the cause of the recent warming trend.

2) Since the earth cooled for about 30 years prior to his prediction, it would make sense that there was a high probability of warming since the climate is a dynamic system

3) Much of the Southwest is a desert, predicting a drought isn't exactly a home run

4) The western Antarctic Ice Sheet has been melting for over 10,000 years, so this isn't even a prediction.

http://abob.libs.uga.edu/bobk/ccc/cc0108...

5) The Northwest passage will open up - since the temperature had been rising for over 100 years before his prediction, and ice tends to melt when the temperature increases, this isn't much of a prediction either.

I also disagree with the ad hominem attacks - they are tiresome and don't lend any support to one's position.

Answer 2

I think it's hilarious that the deniers call Hansen a hack and claim that his predictions have just been lucky.  "If you make enough predictions, one is bound to come true", says Jim.  Yeah, except Hansen has made a lot of predictions and they've ALL come true!

Just goes to show you the strength of some people's denial.  Our good ol' friend Jello even asked a follow-up question where he suggested that scientists can't make predictions period, that they're just random guesses.  Again, random guesses will be right 50% of the time, not 100%.

Answer 3

I will stick to my original posting on this-- namely-- that NASA should fire his behind for making PUBLIC and radical political announcements such as oil company CEOs should be indited for crimes against humanity--

If you went on TV and said that you would be out of a job tomorrow.

Answer 4

jim z - If you want to make a "point" about the accuracy or inaccuracy of Hansen's work, then linking to an op-ed piece in Investors Business Daily doesn't quite cut it.  Rhetoric is rhetoric and this piece is nothing but trash talking.  I've written over a million lines of software code in my career, trying to link me to any statements made by anyone that's used my software or worked at the same organization would be ludicrous.

The credible approach would be to point out as many misses in Hansen's projections as Dana has pointed out hits.  Anything less than that merely sounds like partisan noise.

Answer 5

I don't know about the gentleman that you refer to,but if you google " Greenhouse Warming Scorecard" their predictions are not very accurate at all.

Answer 6

Re the “Climate Impact of increasing atmospheric carbon dioxide”

I’m sorry, but your first link held nothing of interest for me. I don’t much care for name calling and labelling, it doesn’t achieve anything.  So, somebody bad mouthed your buddy; big deal nobody died.

The second link was to an abstract of a paper which you quoted almost entirely. The abstract is not the whole paper. Here is the paper. http://pubs.giss.nasa.gov/docs/1981/1981...

You then offer four links demonstrating that Dr Hansen’s predictions in 1981 have come true.

The 3rd link is a graph of temperature over time. It does not attribute any warming to the “human CO2 emissions” that you mention.

The 4th link, concerning droughts in the south-west, I note is from a news media source... which you normally berate people for.  Also, I see that it is discussing “weather” not “climate”. That aside, the reference you give does not attribute the drought in to AGW...  it says “The dryness and warmth have been heightened by La Niña, a weather pattern that sends more storms to the Northwest but fewer across the southern USA”

The 5th link does not say that the drought will “continue indefinitely”, as you did, indeed it points out that other droughts have “ended abruptly”. You omitted to link the actual study on which this reporting was based. It is this one http://www.sciencemag.org/cgi/content/ab...

The 6th link, concerning ice melt in the West Antarctic, says “The recent series of reports from the Intergovernmental Panel on Climate Change (IPCC) did not include such bold predictions for the possible loss of Antarctic ice. The IPCC's estimate was that Antarctic ice flow would continue at the same rate it did from 1993 to 2003”

The 7th link says that the Northwest Passage “is ice free for the first time since satellite records began in 1978”. What it does not say is that the Northwest Passage was successfully navigated in 1940, 1941, 1942, 1944, 1957, 1969, 1977, 1984, 1988, and 2000. This makes interesting reading. http://freestudents.blogspot.com/2007/09...

I read recently that...  ÃƒÂ¢Ã‚€ÂœThe major difficulty in accepting this theory has been the absence of observed warming coincident with the historic CO2 increase.”

This is one of the fundamental problems sceptics have with AGW.  

Where did I read it? Oh yes... it was in the document you invited us to comment on.  ÃƒÂ¢Ã‚€ÂœClimate Impact of increasing atmospheric carbon dioxide”, Hansen et al. (page 957)

Also in the same document... “The time history of the warming obviously does not follow the course of the CO2 increase (Fig 1) indicating that other factors must affect global mean temperature.” (Page 961)

Then we get “The hot dry summer of 1980 may be typical of the United States in the next century if the model results are correct” (Page 965)

Below is the change in precipitation in the United States in July from 1980 to 2006. The summers in the United Sates have become wetter. The model was not correct.

http://www.ncdc.noaa.gov/nacem/NACEMMap?...

What’s particularly interesting about his model is that it attempts to predict the climatic consequences of CO2 doubling from 300 ppm to 600 ppm. Given that atmospheric CO2 is currently about 4% anthropogenic, this would require a 25 fold increase in the amount of Co2 we put into the atmosphere. Where is all this CO2 going to come from? And given that the last 100 ppm increase in CO2 concentration ‘caused’ (depends who you listen to) a 0.6 deg rise, where is his “3 to 4.5C” coming from?

Overall you can’t really give Dr Hansen a very high score for his 1981 model predictions... especially when he says ... “ and it is not certain whether CO2 warming will cause the ice sheets to shrink or grow” (Page 965). That’s quite remarkable when he also says that we should expect “a sea level rise of 5 to 6m” (page 965).

The IPCC report in 2007 only suggested less than .6m (at the top end of its projections)  for sea level rise in the same time period.

Answer 7

Wow, I googled Hansen and "political hack" and presto, I found the link where I refered to the former as the latter.  I feel somewhat misty eyed with the honor.  Here was the link I was looking for

http://www.investors.com/editorial/edito...

The point is, if you make enough predictions, one is bound to come true.  Most scientists discount prophecy.

I have noticed that once again Ken has showed his leftist leanings and what does a million lines of code have to do with anything?   That went over my head.   I think many leftists don't like it that their beloved AGW may be nothing more than a poliitical illusion generated by their belief system (which is true) but when that particular truth gets too close to the surface they strike out in anger.