Category Archives: Climate science

Key excerpts from Mojib Latif’s WCC presentation

The following is an edited transcript of key excerpts from Dr. Mojib Latif’s presentation at the World Climate Conference 3, held in Geneva in September 2009. Also see my subsequent post on misinterpretations and distortions of these remarks.

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Is ENSO “responsible for recent global warming?” No.

A raging controversy, one almost as hot as the record-breaking heat wave on the North American west coast, has broken out over a recent paper in the Journal of Geophysical Research (Atmospheres), a peer-reviewed periodical published by the American Geophysical Union (AGU).

Authors John McLean, Chris de Freitas and Bob Carter all have a long history of links to climate disinformation groups and associated PR campaigns (many of which lead back to Canadian spinmeister Tom Harris, director of the International Climate Science Coalition).

Now the trio have claimed that their analysis demonstrates that global warming is primarily a result of natural processes with little role for anthropogenic influences such as greenhouse gases.

A barrage of criticism has forced the authors and their champions to backpedal furiously. Along the way, a PDF of the paper has been removed from the New Zealand Climate Science Coalition (NZCSC) website, presumably to rectify an egregious copyright breach. Even worse, the NZCSC parent affiliate, the above-mentioned International Climate Science Coalition (ICSC), was caught substituting its preferred title for the actual one in its link to the paper.

And, of course, a look at the actual data clearly shows that the trio’s touted source of global warming, namely a 1976 “shift” in the El Nino Southern Oscillation (or ENSO), can not possibly account for the recent upward trend in temperatures. All this raises serious questions about JGR’s editorial processes, and leads to the inevitable conclusion that the paper should be withdrawn.

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More heavy lifting with “suppressed” Alan Carlin

The kerfuffle over the EPA’s so-called “suppression” of Alan Carlin continues apace, with two new commentaries from right-wing columnists. Both syndicated columnist Mark Steyn and the Wall Street Journal’s Kim Strassel cite Carlin in support of the tired contrarian assertion that “global temperatures are on a downward trend”. (Of course, at the risk of repeating myself, this has been debunked thoroughly here, there and everywhere, as John Lennon might have put it)

But, once again, it turns out that Carlin did not write certain relevant key passages himself, and also failed to attribute them to the original author.

[Update, July 8: In another astonishing twist, I have just discovered that Marlo Lewis, the National Review columnist whose piece Carlin lifted as discussed below, is – wait for it – a Senior Fellow at the Competitive Enterprise Institute, which just happens to be the right-wing think tank that has been touting the so-called “suppression” of Alan Carlin’s report. I’ll have more on this soon.]

[Update, July 7: I’ve added a comparison of the “updated” chart of global temperature projections and observations given by Carlin, and the original found in the IPCC Fourth Assessment Report (AR4). As well, an ironic twist to Steyn’s quote from Carlin is noted.]

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EPA’s Alan Carlin channels Patrick Michaels and the Friends of Science

A new uproar in the blogosphere has broken out over the supposed “suppression” by the EPA (Environmental Protection Agency) of an internal review of the EPA’s proposed endangerment finding on greenhouse gases. The review purported to show that the latest “research” calls into question the scientific consensus on climate change. It turns out that the report, written by Alan Carlin, with assistance from John Davidson, of the EPA’s National Center for Environmental Economics, is drawn heavily from the contrarian blogosphere, especially Ken Gregory of the Calgary-based “astroturf” group Friends of Science.

And in one case, a lengthy “analysis” of a recent peer-reviewed paper has been lifted, without attribution, straight out of World Climate Report, the climate “news” blog run by uber-contrarian Patrick Michaels.

[Update, June 29: In the immediately subsequent post, I’ve now established that the Carlin report’s central premise, along with four key sections, came directly from a November, 2008 World Climate Report blog  attack on the EPA proposed endangerment finding on greenhouse gas emissions.]

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UAH annual cycle continues in 2009

Roy Spencer has just released the UAH satellite analysis team’s estimate of the lower troposphere global temperature anomaly for the month of May. It stands at 0.04 deg C; the anomaly has dropped each month since February when it stood at 0.36 deg C.

But as seen in the graph below, this is a continuation of the clear annual pattern seen over the last few years.

UAH Monthly Anomaly Continue reading

IPCC AR4 projections and observations, part 1

AR4 SmoothIn the past year or so, the blogosphere has been full of claims concerning short-term global temperature trends and their supposed falsification of the scientific consensus on anthropogenic global warming as set forth in the IPCC Fourth Assesment Report (AR4). In this post, I’ll present a comparison of the AR4 near-term projection to smoothed observed trends. This comparison shows the recent observed trend to be somewhat below the projection, but still well within a reasonable confidence interval.

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Recent surface temperature trends relative to baseline

[Updated May8] This post seems to have caused some controversy and even derision in some quarters (especially Lucia’s blackboard). Some of that was even justified. That’s what I get for posting overly quickly (a mistake I won’t make again).

The essential point, though, is that short-term trend analysis is of dubious value when comparing global temperature observations to IPCC projections, because such trends fluctuate so much. Comparisons of  the analysis period to the baseline, whether using average anomaly, linear trend or smoothed trend, is likely to be more indicative of the true situation.

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20-year surface trends close to models

Recently, I’ve been commenting to anyone who’ll listen (or not) that short-term comparisons of global temperature trends are not very meaningful and that at least the last 20 years should be analyzed. This was based on the seemingly paradoxical observation that, while trends from 2001 to present are down or flat, long term trends increased during the same period.

Finally someone (Lucia of Blackboard fame) has listened. Unfortunately, she has compared 20-year observed trends to a model subset that has an unrealistically high projected trend.

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Seasonal divergence in tropospheric temperature trends, part 2

In a recent post, I examined seasonal divergence in troposphere temperature (LT) trends produced by teams at  RSS (Remote Sensing Systems) and UAH (University of Alabama at Huntsville). The strong annual cycle in the recent UAH data set has led to a wide divergence of temperature trends depending on time of year.

Since then, the blogosphere has been atwitter over the marked divergence between UAH and RSS for the month of February, which showed the UAH estimated anomaly (0.35) more than a full tenth of a degree higher than RSS (0.23).

Update (April 9, 2008): The March LT global temperature anomalies are out and they show both RSS (0.17) and UAH (0.21) down from February. The divergence has narrowed from 0.12 deg C in February to 0.04 deg C in March, which is exactly the divergence seen for that month in 2004-2008 (see below). So far in 2009, the UAH annual cycle is alive and well.

However, a detailed look at the divergence month-by-month shows that this latest discrepancy is not so surprising. I’ll also take a look at the effect on UAH of the recent switch to the newer AQUA satellite, which has actually resulted in an enhancement of  the UAH annual cycle. AQUA has a self-correcting propulsion system, so the UAH annual cycle, and the cyclic component of UAH-RSS divergence, can not be the result of differing methods of correction for diurnal drift resulting from orbital decay.

I start by showing the global temperature trends for each month for the 1979-2008 period for both LT and surface temperature sets.


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Seasonal divergence in tropospheric temperature trends


The two most commonly cited estimates of temperature in the troposphere based on satellite data are provided on an ongoing basis by Remote Sensing Systems (RSS) and University of Alabama at Huntsville (UAH). Last year, a strong annual cycle was identified in the UAH data by Atmoz and was examined in detail by Tamino at Open Mind here and here. In UAH, the annual cycle results in significantly higher anomalies at the beginning of the year (northern hemisphere winter) than in the middle of the year. And this pattern appears to be present in all latitude zones.

It seems reasonable that such a cycle would affect the observed trends over the 30-year period of the satellite temperature record. And indeed, it turns out there is a strong seasonal divergence; UAH trends for June-July-August (NH summer or JJA) are markedly lower than for December-January-February (NH winter or DJF). This strong seasonal divergence can be seen not only globally, but even in the tropics, as shown in detail below. This suggests that UAH trends lack physical realism, and should not be relied upon until the source of annual cycle problem is identified and fixed.

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