Staff Contributors
Guest Contributors

Unspun climate numbers

Move over, 1998

Posted by Sean Casten (Guest Contributor) at 4:00 PM on 15 Aug 2007

Read more about: climate | climate science

Turns out that in the U.S., 1934 was a bit hotter than 1998. Which matters not a whit for global temperatures, but it's worth reading the story below before the spin machine gears up. Mr. Limbaugh has already started.

"1934, not 1998, the hottest year on record, NASA confirms," from Greenwire ($ub req'd):

The hottest year on record in the United States was 1934 -- not 1998 as had long been believed -- NASA scientists announced this week.

The change to the record books came about when Canada-based blogger Steve McIntyre of the blog Climateaudit.org e-mailed NASA earlier this month to point out an unusual jump in temperature data between 1999 and 2000.

When agency scientists checked his question they found that two temperature history data sets that were incorrectly assumed to match were merged several years ago.

When the data was corrected it showed a decrease of 0.27 degrees Fahrenheit in yearly temperatures since 2000 and a smaller decrease in earlier years. That meant that 1998 went from being 0.02 degrees Fahrenheit warmer than 1934 to 0.04 degrees cooler.

The agency also reduced the mean U.S. temperature anomalies for the years 2000 to 2006 by 0.15 degrees Celsius.

The reranking of the hottest year in the United States does not affect world temperature records though, where 1998 is tied with 2005 as the hottest year ever, NASA climatologist Gavin Schmidt said. The data adjustment changes "the inconsequential bragging rights for certain years in the U.S.," he said. But "global warming is a global issue, and the global numbers show that there is no question that the last five to 10 years have been the hottest period of the last century," he added.

With the new U.S. rankings, four of the 10 warmest years in the United States occurred during the 1930s.

"But in big-picture terms, the adjustments didn't change anything for global warming or climate change issues," Schmidt said. "The changes were pretty negligible" (Thomas H. Maugh III, Los Angeles Times, Aug. 15).

Radio show host Rush Limbaugh last week said the record adjustments are evidence that climate change science is unsound. "What do we have here? We have proof of man-made global warming. The man-made global warming is inside NASA ... is in the scientific community with false data" (Daniel Dale, Toronto Star, Aug. 14).

Who's "the Chimp" Now??? FDR!


Clearly the outdated policies of Franklin Delano Roosevelt, were ruination to this planet.   I wonder if Greenpeace will make one of those big paper mache heads of FDR and hold an anti-New Deal rally for having the "worst record" on global warming of any President.


Not really accurate

Even Greenwire's getting this wrong.

The uncertainty in the annual temperature anomalies is at least 0.1 C, so it's never been scientists saying 1998 was the hottest or 1934 was the hottest.

In fact, the only peer-reviewed statement from Hansen's team was that 1934 was marginally warmer than 1998. From Hansen 2001 et al.:

The U.S. annual (January-December) mean temperature is slightly warmer in 1934 than in 1998 in the GISS analysis (Plate 6)... the difference between 1934 and 1998 mean temperatures is a few hundredths of a degree.

Later adjustments to normalize the US temperature record by GISS put 1998 a few hundredths of a degree above 1934, but they never trumpeted that, since it wasn't significant. And now it's been renormalized again to bring 1998 a few hundredths of a degree below 1934 again. Wow. What a news story.

What's remarkable is how every single right-winger and mainstream journalist on this story has repeated the claim that 1998 "has long been believed" to be the hottest year in the US.

And yet noone has provided any sources to back up that claim. Why? Because that claim was hardly, if ever, made.

Hill Heat

Steven McIntyre interview on BBC Radio Four

Steven McIntyre interview on BBC Radio Four 'Today' programme ~ 6.52 a.m. 17 August 2007

Link valid until expiry Monday 20th August.

http://www.bbc.co.uk/radio4/today/listenagain/ram/today1_ ...

Interview transcript

Interviewer
A blogger in Toronto has caused an international stir over climate change. Steven McIntyre discovered that some of the measurements used by NASA to track average annual temperatures in the US were, to put it bluntly - wrong. The leaps over the last few years have not been as dramatic as previously thought. Global Warming sceptics in America are delighted.
Steven McIntyre explained to me how he spotted NASA's mistakes.
McIntyre
I compared the input data that NASA was using for US temperature to the original data in that was archived at other sources. When I made those comparisons, I noticed that there was a sharp jump in 2004 mini-series and the jump was up to one degree centigrade for some stations in the US, it was a negative jump in other stations.
Interviewer
And this was because NASA had not adjusted their figures correctly, is that right?
McIntyre
What they had done is they used one version of  US data before 2000 and a different version after 2000. The version before 2000 had certain adjustments in it, the version after 2000 didn't have those adjustments in it.
Interviewer
And what sort of adjustments are we talking about?
McIntyre
At the level of an individual station, the jump could be as much as one degree centigrade. For the United States temperature history as a whole, the jump was about point one five degrees centigrade, which compares to a increase of about half a degree for the entire century, so relative to the reported US increase, it wasn't a small adjustment.
Interviewer
So the conclusion that you drew was essentially that the world, or America at least is not getting hotter at the rate that others had previously assumed.
McIntyre
When I examined the changes that NASA made to their yearly rankings after they corrected this error: four of the top ten warmest years were in the thirties, whereas only three of the of the top ten were in the last ten years.
Interviewer
So your conclusions is that the trend is till up, but not just quite as sharp as most people originally thought it was.
McIntyre
As to what trend exists in the US data, one would have to enquire very closely as to why the nineteen thirties were so warm, relative to the modern period. And one thing that people should keep in mind is that NASA adjusts the temperature and the adjustments can be almost as large as the effect that's being measured, so that the adjustments can be half a degree per century, where the observed warming is half a degree. What I think is necessary is that there should be very careful scrutiny of how temperatures are measured over time, how we know whether the nineteen thirties compared to the two thousands and here we run into the problem that many of the weather stations are not meeting World Meteorological Organisation Standards. For example, the station in the US with the highest increase: the sensor is located in a parking lot in Tucson and if you can picture a worse environment for having a unbiased temperature reading than having a sensor above asphalt in Tucson in the Summer day, it's hard for me to imagine.
Interviewer
Steven McIntyre, Thank-you very much.

Punctuation has been added for readability.

----------------------------
Science - our understanding of nature and the universe, trumps everything - religion, politics!

Steven McIntyre has a dig at weather station data

I rather rushed the transcript, it's correct [I checked it carefully], but the punctuation is not as good as it could be.

I have recorded the McIntyre BBC Radio 4 interview 3.5 MB, so it might be made available. I'll see! If I could post it here, I might.

The BBC only keeps this type of material on its website for 7 days, so grab it now before the link evaporates.

Steven McIntyre has a predictable dig at the meteorological station locations i.e. the Urban Heat Island effect. Why are scientists so dumb? Especially those at NASA!
If they're so dumb, what does it say about the rest of us?

McIntyre knows how to impugn the reputations of climate scientists at NASA and virtually everywhere else by his nasty innuendos. What a shame that the rather accusatory triumvirate of S. McIntyre, R. McKitrick and P. Michaels have made quite so many bloopers!

One thing you have to admire about Steven McIntyre, he's quite a politician when it comes to evading answering questions he doesn't like!


----------------------------
Science - our understanding of nature and the universe, trumps everything - religion, politics!

You are not logged in. Thus, you cannot post a comment. If you have an account, log in. If you don't have an account, well, by all means go make one! Meet you back here in five.
sign in
Search Gristmill
Subscribe
  • subscribe via RSSStay updated with the Gristmill RSS feed.
  • Add to My Yahoo!
  • Subscribe with Bloglines
  • Subscribe in NewsGator Online
  • Subscribe in Netvibes
  • Subscribe in Google
Using Gristmill
  • What is Gristmill?
  • Posting rules
The comments of Gristmill users reflect the opinions of those individuals only, and do not necessarily reflect the viewpoints of Grist, its staff, its board members, their psychotherapists, or their aestheticians. Got it?

Gristmill is powered by Scoop.

ADVERTISING POLICY


About Grist | Support Grist | Job Board | Archives | Grist by Email | RSS | Podcast
Gristmill Blog | In the News | Ask Umbra | Muckraker | Victual Reality | 'Tis the Season | The Grist List | The Bottom Line



Grist: Environmental News and Commentary
a beacon in the smog (tm) ©2008. Grist Magazine, Inc. All rights reserved. Gloom and doom with a sense of humor®.
Webmaster | Sitemap | Privacy Policy | Terms of Service | Trademarks