Global Temperature Trend Update: April 2011

Every month University of Alabama in Huntsville climatologists John Christy and Roy Spencer report the latest global temperature trends from satellite data. Below are the newest data updated through April, 2011.

April temperatures rebound after March's La Nina lows


Global Temperature Report: April 2011


Global climate trend since Nov. 16, 1978: +0.14 C per decade


April temperatures (preliminary)

Global composite temp.: +0.12 C (about 0.22 degrees Fahrenheit) above 30-year average for April.

Northern Hemisphere: +0.20 C (about 0.36 degrees Fahrenheit) above 30-year average for April.

Southern Hemisphere: +0.04 C (about 0.07 degrees Fahrenheit) above 30-year average for April.

Tropics: -0.23 C (about 0.41 degrees Fahrenheit) below 30-year average for April.


March temperatures (revised):

Global Composite: -0.10 C below 30-year average

Northern Hemisphere: -0.07 C below 30-year average

Southern Hemisphere: -0.13 C below 30-year average

Tropics: -0.34 C below 30-year average

(All temperature anomalies are based on a 30-year average (1981-2010) for the month reported.)

Go here to view the satellite data.

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  • Tony||

    So you guys dismiss anything Michael Mann ever says because of one graph. How do you feel about Bailey's continued inexplicable reliance on two of the least credible climate scientists in the world?

  • Libertard||

    I FEEL HORRIBLE ABOUT IT!!! *MADFACE*

    Seriously, he's using satellite data, you know, the stuff that climate scientists use as undeniable proof of imminent Armageddon. WTF do you want him to use?

  • ||

    He wants Ron to do what Mann did.

    Erase the actual data and replace it with unicorns.

  • ||

    Tony: Mann, at the very least, has been shown to be a bad statistician.

    With regard to the global temperature trends, you might want to take a look over Jim Hanson's shop at GISS at their version of the monthly mean temps based on sea and weather station data. The trend is pretty much the same as the satellite data. I prefer the satellite data because of its comprehensive global coverage.

    As for their credibility, no one as far as I know, among climate scientists now question their temperature data.

  • Neu Mejican||

    As for their credibility, no one as far as I know, among climate scientists now question their temperature data.

    True enough.

    Regarding Mann: "has been shown to be" is a bit strong. I would go with "some have claimed that."

  • Brett L||

    from the first link:
    "Here we have shown, in the case ofMBH98, that a ‘‘standardization’’ step (that the authors didnot even consider sufficiently important to disclose at thetime of their study) significantly affected the resulting PCseries. Indeed, the effect of the transformation is so strong that a hockey-stick shaped PC1 is nearly always generated from (trendless) red noise with the persistence properties ofthe North American tree ring network. This result isdisquieting, given that the NOAMER PC1 has beenreported to be essential to the shape of the MBH98 Northern Hemisphere temperature reconstruction"

    His statistics created an artefact that had nothing to do with his data. That's problematic.

  • Neu Mejican||

    That is the claim.

  • Brett L||

    The one they proved by running random number sets. Multiple randomly generated statistically trendless sets.

  • Neu Mejican||

    Articles following on M&M(2005) have shown the artifact to be small, having little impact on the overall outcome. Whether a failure to control for that small bias makes him a "bad statistician" or not is more a matter of opinion than fact. If he failed to control for it in analysis after 2005, you would have a stronger claim against him.

  • Tony||

    Spencer and Christie have much bigger problems than Mann in the credibility department. Isn't one of them a creationist?

    I get that they're the pet climatologists of anti-regulatory people. I'm really just indicting people who dismiss everything Mann ever says but who don't utter a peep over Spencer and Christie's many problems with being plain wrong and peddling outright distortions over the years.

  • Libertard||

    Many libertarians are really stupid about climate change. News at 11.

    In other news, liberals skipped econ101.

  • Tony||

    Only because they passed the AP test in high school.

    Libertarians never seem to get beyond Econ 101.

  • Neu Mejican||

    In case the irony is missed on everyone:

    Ron says that Mann is "a bad statistician" based on an article which identifies a methodological error in an important analysis.

    He then points out that people no longer dispute Christy and Spencer's numbers. He fails to point out that their data contained systematic errors for years. Errors that had to be rooted out by others. Those errors have been found and corrected, and Mann and others have replicated his original findings using better methods. So, certainly, given the two examples presented, Michael Mann is no worse a statistician than Christy and Spencer.

  • Ben Wolf||

    Not only were the data from Spencer and Christy error ridden because they failed to compensate for drift, they spent a decade encouraging skeptics to use their numbers as the temperature record which disproved anthropogenic global warming. And as Neu stated, other scientists had to come in to clean up their mess.

    As for the hockey stick, Mann's paleo-climate reconstruction has been reproduced in a dozen independent papers.

    Sorry, but it ain't 1999 any more.

  • ||

    As for the hockey stick, Mann's paleo-climate reconstruction has been reproduced in a dozen independent papers.

    The only problem being that 6 of those dozen depend on one tree in Siberia and the other 6 of those dozen depend on a handful of trees in North America....kind of hard to call a multi-proxy temperature record multiproxy when they lose any meaning if you remove not only one proxy but lose their hockystick simply by taking a few trees from that proxy...not to mention that everyone of those authors have coauthored papers with Mann.

    But why write this myself when Muller does it better then me:

    http://www.youtube.com/watch?v=8BQpciw8suk

  • Ben Wolf||

    Joshua,

    Those proxy reconstructions use corals, stalagmites, boreholes and icecores in addition to tree rings.

    SkepticalScience has links to many of those reconstructions here.

  • ||

    you are correct

    It would appear you did not read what i wrote.

    He used a whole bunch of proxies and got a hockey stick.

    If you remove one tree ring proxy or even simply remove a few trees from that proxy then the hockey stick disappears.

  • ||

    He fails to point out that their data contained systematic errors for years.

    You really are dishonest.

    Ron is a warmist, switching from skeptic, because of that error.

    To say he fails to point that out is the height of strawman masturbation.

  • Neu Mejican||

    Joshua,
    I was referring to his comment above.
    Please show me where he points it out in that comment before accusing me of being dishonest.

  • ||

    Ron should explain why he switched from a skeptic to a warmist in every comment he makes?

    If your claim to irony is going to be that strained then how about you go get Mann to correct (let alone admit) his statistical errors in his work like Spencer and Christy did.

  • Neu Mejican||

    Ron should explain why he switched from a skeptic to a warmist in every comment he makes?

    No, but when he is explaining why they are credible, he might refrain from pointing to someone else's past errors...if he wants to avoid the irony.

    If your claim to irony is going to be that strained then how about you go get Mann to correct (let alone admit) his statistical errors in his work like Spencer and Christy did.

    I think you've sprained your irony muscle. Just for fun, I would like to point you to the title of the article you are discussing.

    "Northern Hemisphere temperatures during the past millennium: inferences, uncertainties, and limitations"

    Note this: 1998 article: "Northern Hemisphere temperatures during the past millennium: inferences, uncertainties, and limitations"

    From Mann: "more widespread high-resolution data are needed before more confident conclusions can be reached... the uncertainties were the point of the article."

    The authors seem appropriately skeptical and cautious. Don't ya think?

  • ||

    Global climate trend since Nov. 16, 1978: +0.14 C per decade

    Ron where are you getting this number?

    I cannot find it on Spencer's web site.

    If you are generating it yourself can you get a trend for 2000 to present?

  • Ben Wolf||

    You can't generate a statstically significant trend with only ten years of data, which is why the standard in climatology is thirty years.

    You can play with a lot of the numbers and generate your own graphs at http://www.woodfortrees.org/

  • ||

    You can't generate a statistically significant trend with only ten years of data.

    The IPCC made a specific claim that for the next degree or two (starting in 2000) the trend would be .2 degree per decade increase.

    Obviously that claim has been falsified over the last decade....I just want to see how wrong the IPCC was.

    If you want to cry about statistical significance then go cry to the IPCC.

  • ||

    next degree or two

    next decade or two

  • Neu Mejican||

  • Neu Mejican||

    Note that the point estimate of the 20 year trend is +0.16 C per decade, within a rounding error of 0.2. But, of course, the short time frame means the confidence intervals range from -0.34 to +0.34 (non-significant trend). The numbers since 2000 fit well within the 20 year trend with only two years below the trend line.

    So the question I have for, Joshua, is what you think all of that means for the IPCC prediction you cite? Do you feel this proves or disproves the prediction?

  • ||

    Can someone just tell me when we are all supposed to die, so that when that time comes and we are all still alive I have adequate time to come up with new BS to pretend I'm an expert on for the purpose of getting large chested loose hippie chicks in the sack?

  • ||

    Not very surprising. The data hasn't show a spike in a decade.

    http://www.intellectualtakeout.....change-101

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