October 13, 2006

Where are the Droughts?

Filed under: Droughts, Precipitation

One of the pillars of the greenhouse apocalypse is the global warming will lead to a higher frequency, intensity, duration, and spatial extent of droughts in the future. This prediction is fairly easy to understand in terms of basic physical principles. Higher temperatures will lead to higher rates of potential evapotranspiration (PE), so even if rainfall stays the same or even increases slightly, the increase in PE will make droughts worse, make them last longer, make them more frequent, and make them expand their spatial extent. To make the matter even scarier, many climate models predict a decrease in precipitation in continental interiors, so with less rainfall, higher temperatures, and higher PE rates, drought frequency, intensity, spatial extent, and duration may substantially increase in places like the American heartland.

Literally dozens of articles have appeared in the scientific literature showing results that lead to the prediction of increased drought conditions in the central United States. The Intergovernmental Panel of Climate Change (IPCC) states in the Summary for Policymakers that “Increased summer continental drying and associated risk of drought” is “Likely, over most mid-latitude continental interiors” during the 21st century. In terms of seeing such a pattern in the observed climate record in the 20th century, the IPCC concludes it is “Likely, in a few areas.”

An important article appeared in the literature recently with some surprising results given the predictions of the climate models. Konstantinos Andreadis and Dennis Lettenmaier of the University of Washington have published a paper in Geophysical Research Letters entitled “Trends in 20th century drought over the continental United States,” and the results are peculiar—in light of climate model projections—to say the least. In the abstract, they write “Droughts have, for the most part, become shorter, less frequent, and cover a small portion of the country over the last century.”

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October 11, 2006

Antarctic Ice Sheet (and the Plot) Thickens

Filed under: Antarctic, Glaciers/Sea Ice, Polar

Glaciers the size of Rhode Island breaking off and floating away…grass growing along the periphery of Antarctica…coastal inundation from rising sea levels…even a forecast that Europe will freeze solid the “day after tomorrow.” These are a few of the doomsday portraits painted by a politicized few that are clamoring to have a full-throated voice in the great global climate change debate.

Evidence that lends support to some of the theories behind these supposedly dire portraits can be found throughout the scientific literature, as is the case with many of the issues in the debate about the warming of the global atmosphere. In reference to the scenes described above, many studies have presented measured and modeled data that suggest that the greatest amount of atmospheric warming is occurring or will occur across Earth’s polar regions. However, one can just as easily search the literature and find conflicting evidence.

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October 10, 2006

Raining on Greenhouse Predictions

Filed under: Precipitation

Every school child in our country has heard that burning fossil fuels emits carbon dioxide (CO2) into the atmosphere and that this extra CO2 will act like an extra blanket covering the Earth thereby causing temperatures to increase. The story is a bit more complex, and could go something like this: burning fossil fuels indeed emits CO2 into the atmosphere, and the CO2 alone should cause the temperature to rise a bit if all else is held equal. As the temperature creeps upward, evaporation will increase worldwide, and the atmosphere will increase its water vapor content as well. Water vapor is a powerful greenhouse gas, and the increase water vapor is far more important to the resulting temperature rise than the extra molecules of CO2.

The climate models all include this water vapor feedback, otherwise, the projected temperature rise would seem insignificant and not worthy of policy actions or funding of scientific research into global warming. To say the least, the water vapor feedback is important!

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October 9, 2006

Kilimanjaro Glaciers Exit the Debate

Snow cover and sea ice extent have long been thought of as monitors of climate change, and so it is no surprise that the global warming crusade has promoted any signal of glacial decline as clear evidence of global warming. The simplicity of the concept that “warming means less ice” makes a decline in snow and ice an appealing piece of ammunition for their cause. However, wielding this with a narrow view of the issue makes it dangerous ammunition, or useless, as appears to be the case for one set of tropical glaciers that are widely referenced in the global warming debate.

In a recent article in Geophysical Research Letters entitled “Kilimanjaro glaciers: recent areal extent from satellite data and new interpretation of observed 20th century retreat rates,” the glaciers of Africa’s highest mountain are in effect removed from the debate of climate change in the 20th century. The work of a team led by Nicolas Cullen of the Tropical Glaciology Group at the University of Innsbruck is significant because drastic retreats in tropical glaciers during the mid- to late-20th century have attracted broad attention among global warming alarmists.

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October 5, 2006

El Niño is Back

Don’t look now but it appears an El Niño event is brewing-up in the Pacific and by Christmas of this coming year, we could be feeling the effect of this oceanic phenomenon. Imagine the potential here – pictures of floods in the Southwest, avalanches in the Rockies, mudslides in California, fires in Australia, and calamities from throughout the world. Every event will be blamed on El Niño and like clockwork, global warming will get mixed into the story.

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October 3, 2006

Overturning the Gulf Stream Myth

Filed under: Climate Changes, Gulf Stream

Do you recall seeing the classic film Day After Tomorrow? The theme of the movie was that humans warmed the earth, the global hydrological cycle was severely disrupted, fresh water began flowing into the North Atlantic, the Gulf Stream slowed rather suddenly, and Europe, and then the rest of the world, plunged into a glacial state. If you did not get the message in that film, Al Gore raised the possibility in his recent thriller.

But one is hard pressed to find evidence to support the idea that this is a real possibility. While there are some articles in the professional literature suggesting that the freshening of the waters of the North Atlantic has already begun, the conclusions in these articles are far from being universally accepted, and even farther from being the last word. There also exist articles showing no theoretical or empirical evidence to support the Gulf Stream story as it is pitched by Gore and followers.
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October 2, 2006

Hurricane Data Not Cooperating

Filed under: Hurricanes

During fall of 2005, the United States experienced an unusually high number of landfalling hurricanes and the global warming crusade was having a field day. Hardly a day could go by without some one making the claim that global warming was elevating sea surface temperatures in the Gulf of Mexico, Caribbean Sea, and Atlantic Ocean, and those warmer seas over vast areas provided the necessary fuel to heat up hurricanes. If you saw the Al Gore movie, you undoubtedly recall his explanation of the cause behind Katrina and other hurricanes of a year ago – global warming, of course.

Now that hurricane season is upon us (and things seem incredibly quiet), we can look more carefully at some recent literature on the subject.

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