A week or two ago, Andrew Dessler and Steven Sherwood published a “Perspectives” (largely opinion) piece in Science magazine that argued that the water vapor feedback was unassailably strong and positive. This means that the warming from the increase in greenhouse gas concentrations leads to more water vapor in the atmosphere which leads to even more warming (water vapor is a strong greenhouse gas itself). This positive feedback results in roughly twice as much warming as would occur from anthropogenic greenhouse gas increases alone.

Dessler and Sherwood concluded:

There remain many uncertainties in our simulations of the climate, but evidence for the water vapor feedback—and the large future climate warming it implies—is now strong.

This conclusion has drawn a lot of attention within the community of researchers investigating the behavior of water vapor and the role of water feedback in climate change—and most of it has been highly critical.

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Thousands of websites present the usual view of global warming claiming that greenhouse gases are increasing in atmospheric concentration, this is causing the planet to warm, and if we don’t act immediately, an endless number of calamities are certain to become reality. These sites then make every effort to make you believe that much of the problem can be placed at the feet of President Bush, Vice President Cheney, and just about anyone associated with the gas, oil, and coal companies in the United States. There are mentions here and there of contributions from other countries, but you will constantly be reminded that the United States is the largest emitter of greenhouse gases, that the relatively small population of the USA has an immoral per capita emission level, and that no one on the planet should feel more guilty about global warming than folks who voted for the current administration.

To be fair, there have been news reports recently that China’s total emission of carbon dioxide (CO2) has surpassed the emission from the United States. Along these lines, an important article has appeared in Geophysical Research Letters that shows China is now our global leader in CO2 emission, which is certainly newsworthy, but other results presented in their article may be received as bad news by the global warming alarmists. The research was conducted by three scientists at the University of Maryland, the Oak Ridge National Laboratory, and Austria’s International Institute for Applied Systems Analysis; a portion of the research was funded by the U.S. Department of Energy, Office of Science, Biological and Environmental Research Programs.

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The American Geophysical Union (AGU) recently released its new and improved “position statement” on global warming. Andy Revkin of the New York Times featured the AGU’s release on this DotEarth blog site and asked AGU members to chime in on their opinions of the statement that was developed by the AGU’s ruling Council. While there were definitely members who expressed dismay at the position statement, a majority of commentors gave it their hearty endorsement. Apparently, most of the endorsers have not given a very in depth consideration of all that is contained in the AGU’s statement, for otherwise, (we would hope anyway) that they would have been a bit more reserved.

For instance, the AGU’s position statement includes the following sentence: “If this 2 degrees Celsius warming [above 19th century levels] is to be avoided, then our net annual emissions of carbon dioxide must be reduced by more than 50 percent within this century.” This is akin to stating “If pigs had wings, they could fly.” Sure, you could endorse the statement, but to do so would seem a bit foolish. First off, pigs don’t have wings, and it would take nothing short of a miracle for them to acquire them, and secondly, even if they had wings, it is not guaranteed that they could fly. The most pig-shaped bird we can think of—the penguin which is large and rotund and flopping around on its belly a lot of the time—has wings, but can’t fly. Thus even if the impossibility of pigs sporting wings was overcome, it wouldn’t insure a successful flight.

The same is true of the AGU’s statement about a 50% CO2 reduction this century and its impacts on global temperature. First off, it will take nothing short of a miracle for the 50% reduction to take place, and secondly, it probably wouldn’t stop the temperature from rising 2ºC above “natural” levels. Endorse it if you want, but it doesn’t reflect well on your scientific reasoning skills.

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The recent wildfires in California have certainly provided an opportunity for the greenhouse crusade to further claim that global warming is already increasing fire frequency, duration, and intensity all over the planet. In the midst of the disaster in California, Nevada Democrat and Senate Majority Leader Harry Reid told reporters that “One reason why we have the fires in California is global warming.” However, when pressed by astonished reporters on whether he really believed global warming caused the fires, he appeared to back away from his comments, saying there are many factors that contributed to the disaster. Since then, literally hundreds of newspaper articles appeared throughout the country reinforcing the idea that emissions of greenhouse gases have warmed the earth, dried the forests, and made fires a lot worse.

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In 1998, Balling et al. published an article in Climate Research dealing with summer and winter warming rates in several widely-used gridded temperature time series. As seen in Figure 1 below, the Balling crew (which includes several World Climate Report team members) found that winters were warming far more than summers, based on near-surface thermometer records, for a large part of northern and central Asia over the period 1946-1995. We repeated the analyses for the satellite-based lower-tropospheric temperature measurements over the period 1979-1995 and found the same red blob (wamer temperatures) over northern and central Asia. We suggested in the article that the build-up of greenhouse gases would most impact the coldest and driest air masses of the world, which just happen to be the air masses that cover northern and central Asia in the winter. Elevated greenhouse gas concentrations in warm and moist air masses would have less of an effect given the overwhelming greenhouse effect of naturally occurring water vapor. We had produced what appeared to be a smoking gun – the greenhouse “fingerprint” looked rather obvious in our analyses. Of course, finding that the coldest and driest air masses of the planet were warming slightly is seen by some as a blessing and not a great cause for concern – are residents of northern Siberia really worried about their winters being a bit warmer?

Figure 1. Seasonal difference (winter minus summer) in temperature trends (°C per decade) for the thermometer-based near-surface data over the period 1946-1995 (from Balling et al., 1998).

Well, the smoking gun has become a bit cloudier given a recent article in Nature entitled “Warming trends in Asia amplified by brown cloud solar absorption.”

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The global warming story is told over and over, and today every school child in America is aware that burning fossil fuels increases the atmospheric concentration of carbon dioxide, and they have learned that carbon dioxide is a greenhouse gas that will warm the Earth as its concentration increases. Of course, the United States is largely responsible for this mess, and children are given terrific suggestions on how they can get their parents to stop global warming.

Should someone begin to look more into the global warming issue, they will uncover literally hundreds of additional gems in the greenhouse apocalypse – they will rather quickly discover that Arctic region permafrost is melting at an unprecedented rate, and somehow this will lead us to a runaway greenhouse effect that might warm the Earth far more than any of us ever feared. The melting of permafrost is a solid, never-weakening pillar, of the greenhouse – global warming story.

But all is not as it seems (or as Al Gore would have you believe).

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We all know the story – humans are burning fossil fuels, greenhouse gases are increasing in atmospheric concentration at an alarming rate, the temperature of the earth is soaring upward, the ecosystems are struggling to cope with all the related changes, and if we don’t act now, we will soon push the entire system past the dreaded tipping point. We at World Climate Report have presented evidence from a growing number of scientific papers that challenge this simple but highly popularized and publicized global warming story. Now another recent paper calls into question one of the most basic assumption – the article questions whether the second most important greenhouse gas, namely methane, is continuing to increase in atmospheric concentration.

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This week an interesting paper was published in Geophysical Research Letters by climate modelers at the National Center for Atmospheric Research. They estimated future temperature changes if the atmospheric concentration of carbon dioxide (CO2) were held constant at current levels (well, actually 2000 levels). The results are shown in Figure 1.

Figure 1. Global average temperature change projected from 16 different climate models for the 21st century if atmospheric CO2 levels are held constant at the year 2000 levels.

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About a year ago, the newswires were ablaze about a report from the National Oceanic and Atmospheric Administration (NOAA) that the year-over-year change in atmospheric carbon dioxide levels had reached an all-time high. This was reported to be an indication that the atmospheric CO2 concentration was accelerating and that the worst climate change scenarios were being borne out.

At the time, however, we urged everyone not to get too exercised about a year or two’s worth of data because there is a large degree of variation in the annual CO2 levels as measured at the observatory atop Hawaii’s Mauna Loa volcano. Now, comes this year’s NOAA report on CO2 concentration levels , which begins:

A spike in the amount of carbon dioxide released into the atmosphere between 2001 and 2003 appears to be a temporary phenomenon and apparently does not indicate a quickening build-up of the gas in the atmosphere, according to an analysis by NOAA climate experts.

We hate to say ‘we told you so,” but we did. To see what had to say a year ago, click here.

With each passing year, the trend in atmospheric carbon dioxide levels better establishes itself at about 1.5 ppm/yr. If this trend continues, by the year 2050, the atmospheric CO2 level will be about 446ppm—below nearly all of the projections made by the Intergovernmental Panel on Climate Change (IPCC) in the 2001 Third Assessment Report. Consequently, the temperature rise, over the same period, will also likely be at or below the lowest IPCC forecast.

The specter of catastrophic climate change is rapidly fading.

Despite a slew of British press reports to the contrary, the data reveal no unnatural “jump” in atmospheric carbon dioxide levels.

The British press lit up this week with a story about an unprecedented, and surprising “jump” in the levels of atmospheric carbon dioxide. But a check of the data reveals nothing of the kind. Instead, recent fluctuations appear to be just part of natural variability.
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