Hansen: What Global Warming Looks like (So Far)

[Dead_Parrot]

We'd kind of noticed, but it's nice(?) to see the plot.

Abstract: We update the Goddard Institute for Space Studies (GISS) analysis of global surface temperature change, compare alternative analyses, and address questions about perception and reality of global warming. Satellite-observed nightlights are used to identify measurement stations located in extreme darkness and adjust temperature trends of urban and peri-urban stations for non-climatic factors, verifying that urban effects on analyzed global change are small. Because the GISS analysis combines available sea surface temperature records with meteorological station measurements, we test alternative choices for the ocean data, showing that global temperature change is sensitive to estimated temperature change in polar regions where observations are limited. We use simple 12-month (and n×12) running means to improve the information content in our temperature graphs. Contrary to a popular misconception, the rate of warming has not declined. Global temperature is rising as fast in the past decade as in the prior two decades, despite year-to-year fluctuations associated with the El Nino-La Nina cycle of tropical ocean temperature. Record high global 12-month running-mean temperature for the period with instrumental data was reached in 2010.



http://data.giss.nasa.gov/gistemp/paper/gistemp2010_draft0803.pdf

[another saigon]

1. k&r

thank you

[msongs]

2. we are enjoying our cooler than normal summer here in so cal :-) nt

[Dead_Parrot]

4. Technically, it's just not hotter than normal

:p

[joshcryer]

3. Thanks, will make a good read soon.

And yes, 2010 is well on its way to being the warmest year on record. 1998 will finally be unseated.

[Nederland]

5. Funny what he doesn't say

Global temperature is rising as fast in the past decade as in the prior two decades, despite year-to-year fluctuations associated with the El Nino-La Nina cycle of tropical ocean temperature.

This is absolutely true, but I wonder why Hansen fails to report what that rate is. Could it be that the actual rate of increase--which is between 0.15 °C and 0.19 °C per decade depending on what record you choose--is nearly half of what Hansen predicted it would be?

:shrug:

[caraher]

6. Or maybe because that's a sentence from the abstract

You can't say everything about a topic in a 1-paragraph summary of a 52-page document.

[joshcryer]

7. Hansen's original predictions were models. You're chosing the high end estimates.

Hansens base prediction, the one with the highest confidence interval, is shockingly good (though it's still off compared to more recent models).

[joshcryer]

8. Heh, Hansen reports exactly that at the last freaking line of the paper:

On the contrary, we conclude that there has been no reduction in the global warming trend of 0.15-0.20°C/decade that began in the late 1970s.

[Nederland]

9. Good catch

Glad to see that Hansen is admitting that the observed global warming trend is nowhere near his Scenario A or Scenario B predictions.



Scenario A: Continued growth rate in emissions at 1.5% / year.
Scenario B: Emissions frozen at 1988 rates.
Scenario C: Drastic reductions in emissions in 1990.

[joshcryer]

10. "Frozen at 1988 rates" is ambigious or misleading, it was set at the annual growth observed in 1988.

It also includes three supervolcanos erupting. For a 1988 model with 1988 computational power, I think it's pretty damn impressive. There's a lot missing from the 1988 Hansen model, which the original paper confesses.

Hansen points out how close it (B) was to reality here: http://www.columbia.edu/~jeh1/2005/Crichton_20050927.pdf

Have Lucia Liljegren redo that graph at the end of 2010, when the numbers are in. He'll find that the B scenario is a heck of a lot closer to reality than would be imagined.

He can even use Roy Spencers data (as UAH will indeed show 2010 as the warmest year on record)! On a somewhat related note, I've been feeling bad for Ol' Roy. The "climate skeptics" have been harassing him on his blog for disagreeing with the almighty Miskolczi. What they don't realize is that if they keep it up, Roy might just change his mind about the forcings being negative / at equilibrium. Even a minor move (from "no forcings" to "a little forcing") would be a major blow to the skeptics.

[The Croquist]

12. What 3 super volcanoes?

The chart in post #9 starts in 1900. The last super volcano was about 26,000 years ago. There was the impressive Tambora eruption of 1815 and that certainly had an effect on the climate but that was 85 years prior to the chart and it was not a super volcano.

More recently we've had El Chichón 1982 and Mount Pinatubo in 1991 and they probably had an effect for a few years but I don't think they were unusual. If anything, they input a positive bias into the last 30 years of data since we have not had a similar eruption in 19 years.

You realize of course that if a super volcano does erupt all concerns about CO2 and global warming are moot, right?

We've argued this before. Ol' Roy's data does not support your call of 2010 being the warmest year on record and since you apparently read Spenser's site you know that he has posted that the El Nino looks to be dead and that it looks like we've got a La Nina brewing.

As per the two charts, post #9 and the link you provided (Hansen's), The Hansen chart seems to start about 1958 and end in 2005 where post #9 starts about 1900 and is almost current. Hansen also uses an "updated version" of his own paper "Hansen and Lebedeff 1987" for the "actual" temperatures. Why he didn't use an actual published source is beyond me. Perhaps there is published source but if so why not reference it specifically?

Nowhere do we see UAH, GISS NOAA or HADCrut. In fact, "Hansen and Lebedeff 1987" shows 2005 to be the hottest year on the chart. UAH disagrees.

Steve McIntyre has a chart of Hansen et al projections compared to GISS & RSS and it doesn't show the same thing. It shows a significant divergence between Hansen B and both GISS (that Hansen runs) & RSS. Here is the link:

[joshcryer]

13. In the models they just threw some in there.

Maybe they weren't supervolcanos though, possibly misspoke. In any event, I don't see any conclusive data in Spencer's data that 2010 will not be the warmest year on the UAH record, Roy hasn't said anything to that effect.

FYI Hansen produces his own temperature record using raw data, I don't know what the problem is.

[The Croquist]

14. I think we both could have done better

There were large volcanoes that threw allot of crap in the Stratosphere but not "Super Volcanoes". I misread you post to read that there WERE three super volcanoes not that the MODEL included them.

From your link:
Scenario B had continued growth of greenhouse gas emissions at a moderate rate and it sprinkled three large volcanoes in the 50-year period after 1988, one of them in the 1990s.

The real world even had one large volcano in the 1990s, the eruption of Mount Pinatubo, which occurred in 1991, while Scenario B placed a volcano in 1995.

If nothing else I'll give him credit for calling the volcano. I don't know when the others were projected to be but if you spread them out we're probably about due for another one. The one in Iceland, "Mount Nobodyknowshowtopronounceit", didn't really pan out. It made a mess but it didn't put it's crap into the stratosphere where it won't get washed down for years.

Hansen produces his own temperature record using raw data, I don't know what the problem is.

The problem is that he is defending his model by using a temperature record that is created by him. There is no independence there. That is like a bank auditor taking the word of the person he is auditing that he used "Generally Accepted Accounting Principles". in determining that there are no issues. Maybe that's why Steve McIntyre calls his site "Climate Audit".

Hansen may start with raw data but he certainly doesn't use it as raw data. He describes the methodology here:

http://pubs.giss.nasa.gov/docs/1987/1987_Hansen_Lebedeff.pdf

[joshcryer]

15. The methodology for his temperature record is open for anyone to review, just like UAH.

I don't understand what your issue with it is. The source code for GISS is even available. It's ridiculous that anyone would be critical of Hansen's temperature record, when it is the most comprehensive of them all, going back the furthest.

I'm less inclined to agree with Mann's temperature record than GISS. As it stands now I believe GISS and UAH (after orbital drift anomalies were sorted) are the two best records we have so far, with GISS being the best long term record out of all of them.

At least GISS is available, and the data is raw, yes there is tweaking, but that tweaking has scientific basis and introduces absolutely no statistically significant warming, as various people have shown. You take the raw data (which anyone with an .edu account can get for free) and you compare it to the outputted data, and the results are that there are just as many stations being 'cooled' by the adjustments as are 'warmed,' the point of the adjustments are to remove the overall noise.

[The Croquist]

16. Anyone with an .edu account can get for free

I don't have an ".edu" account". That didn't come with my retirement package as a banker. Free checking did as did free checks but I haven't ordered new checks since before the last bank name change 10 or so years ago.

Seriously I would love to see the annual data of his temperature record to present and his predictions instead of a chart. http://pubs.giss.nasa.gov/docs/1987/1987_Hansen_Lebedeff.pdf has it up to 1985 but his defense uses an "updated" version of it. I would like to compare his predictions with GISS, HadCrut, UAH & RSS. As you know I think GISS is crap and I won't rehash about why that is unless asked, but the bottom line is that Hansen is defending his prediction using his own version of the temperature record instead of other more widely accepted records. Now maybe McIntyre's chart is completely made up but I would bet my bottom dollar against it. I'd be only to happy to recreate it but I don't have an ".edu" account". Hint, hint, can you get me the data?

I don't know if I agree that GISS is the best long term record out there. I just don't think that they have any quality control and I'm convinced that the records just aren't accurate. They weren't meant to be.

Case in point:

If it is so accurate how come in Feb 2010 they changed their January 1880 temperature anomaly from +0.47 degrees C. to -0.02? That's a swing of almost half a degree and 0.52 degrees from August 2009.

We keep being told that they are accurate but were they accurate in 2009, 2010 or neither? Frankly I don't think there is an accurate measurement going back before 1979 and the satellites.

[joshcryer]

11. Kick.