January 30, 2008

What the Future Holds in Store

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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January 28, 2008

Warming Reduces Landfalling Hurricanes (Again)

Filed under: Climate Extremes, Hurricanes

World Climate Report could easily become World Hurricane Report given all of the articles we have featured in the last few years on the subject. Despite growing empirical and theoretical evidence to the contrary, the global warming advocates continue to insist that hurricanes will become worse in the coming decades. They argue that warmer seas will support more evaporation and more energy to spin-up and sustain more and/or stronger hurricanes. They rely heavily on a very few number of articles on this subject, and they disregard the bulk of material published in leading journals showing that global warming will likely not lead to any substantial changes in hurricane activity.

Yet another article has appeared in a leading journal of this subject. The piece is by Chunzai Wang and Sang-Ki Lee of NOAA’s Atlantic Oceanographic and Meteorological Laboratory in Miami and the Cooperative Institute for Marine and Atmospheric Studies at the University of Miami; the research was funded by NOAA. The begin their article noting “the 2005 hurricane season is the most active year on record, with 28 named tropical storms in the Atlantic basin and 15 of them reaching hurricane intensity. The recent increase in Atlantic hurricane activity has fueled a debate on the role of global warming in the increase.” (There’s the “d-word” again that we thought wasn’t used anymore!). The last sentence of Wang and Lee’s first paragraph tips the world off that this piece is not headed to the top of the hurricane alarmists’ lists. “This paper uses observational data to demonstrate that the attribution of the recent increase in Atlantic hurricane activity to global warming is premature and that global warming may decrease the likelihood of hurricanes making landfall in the United States.”

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January 24, 2008

Tibet’s Temperature Story

Hardly a week goes by without some story hitting the news about global warming and retreating glaciers, and for whatever reason, retreating glaciers in the Himalayan region get more than their fair share of coverage. The recent death of Sir Edmund Hillary served to further focus attention on this part of the world.

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January 21, 2008

Antarctica Snowfall Increase

Filed under: Antarctic, Polar

The ice caps hold a special place in the cold hearts of the global warming advocates who are all too quick to insist that our ice caps are currently melting at an unprecedented rate. We suspect that they will not be particularly thrilled to learn that a paper has just appeared in Geophysical Research Letters entitled “A doubling in snow accumulation in the western Antarctic Peninsula since 1850.” The article is by scientists with the British Antarctic Survey and the Desert Research Institute in Reno, Nevada; the work was funded by the UK Natural Environment Research Council and the U.S. National Science Foundation. In case you think that the Desert Research Institute in Nevada would have little interest in Antarctica, recall from geography classes you’ve had that Antarctica receives little precipitation and is regarded by climatologists as a frozen desert.

We have covered Antarctica many times in past essays, and despite literally thousands of websites claiming that some calamity is occurring in Antarctica related to global warming, we side with the United Nations Intergovernmental Panel on Climate Change (IPCC) in this matter. Magazine covers have wonderful pictures of melting of the Antarctic, but IPCC in their 2007 report clearly states “Antarctic sea ice extent continues to show inter-annual variability and localized changes but no statistically significant average trends, consistent with the lack of warming reflected in atmospheric temperatures averaged across the region” (in fact, Antarctic sea ice extent has recently set record highs for both total areal extent as well as total extent anomaly (see here and here)). Furthermore, IPCC tells the world (and we wonder if anyone is listening) “Current global model studies project that the Antarctic ice sheet will remain too cold for widespread surface melting and is expected to gain in mass due to increased snowfall.”

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January 17, 2008

Cycles in Landfalling U.S. Hurricanes?

Filed under: Climate Extremes, Hurricanes

To many global warming alarmists, every disastrous weather event becomes yet another piece of evidence of the coming man-made apocalypse. One only needs to look at their exploitation of Hurricane Katrina victims in the furtherance of the global warming crusade. Most average citizens are shocked to find out that at landfall, Katrina was not a record-setting Category 5 monster hurricane, but really a Category 3 storm—hardly unprecedented in intensity but devastating with respect to the landfall location and timing.

Most reasonable people believe that there exist natural cycles in climatic events, perhaps even hurricanes. But to the aforementioned alarmists, cycles are anathema—with increasing greenhouse gases, temperatures (and the related disastrous repercussions) must only trend inexorably upward. The declining (cooling) limb of any cycle is simply unacceptable.

This background is at the heart of the ongoing debate on trends in Atlantic hurricanes. While the alarmists see only trends in hurricane numbers and strength arising from warmer ocean waters, others point to evidence of cycles in Atlantic sea-surface temperature tied to something called the Atlantic Multidecadal Oscillation, a multi-decadal scale shifting in Atlantic temperatures between cold and warm phases.

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January 11, 2008

Raining on the Drought Parade

Filed under: Climate History

One of the many pillars of fear regarding global warming is the claim that droughts will become more severe in the future, particularly in continental interiors. The story is very simple and is told over and over – temperatures rise, evaporation rates increase, and even with no change in rainfall, soil moisture levels decrease and droughts last longer and are more severe. Then, crops will fail, ecosystems will collapse, major cities will run out of water, diseases will spread – you know the story. There is always some drought occurring some place on the planet, so supporting evidence is easy to find.

We have written on this subject many times, and like everything else, there is a lot more complexity to the story. Changes in wind and/or clouds could impact future evaporation rates, global dimming could cause a decease in evaporation, plants could become more water use efficient thanks to higher levels of atmospheric carbon dioxide and therefore extract less water from the soil, and on and on. One of the problems is that long term soil moisture data are rare to non-existent, but an article in a recent issue of the International Journal of Climatology brings us a story about soil moisture extending back 1,426 years!

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January 8, 2008

Musings on Satellite Temperatures

(January 9, 2008: An important update has been added to the bottom of this post)

A couple of interesting items have come to light recently regarding the temperature of the earth’s lower atmosphere as measured by satellites. Here we run briefly run through some of them, in no particular order.

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January 4, 2008

The Hadley Center Tries Again

The U.K.’s Hadley Center has issued a forecast that 2008 will come in as one of the top 10 warmest years in its 150+ year record of global average temperature. While this forecast is about as risky as predicting that the next box of a dozen doughnuts you buy will contain twelve of the one-holed wonders, the press seems enthralled by it, as virtually all major news wires ran the story under with some variant of the headline “2008 to be among hottest years on record.”

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Lowering Sea Level Rise

Filed under: Sea Level Rise

Have you seen the latest on sea level rise? If not, you will find over one million websites on the topic and according to almost all of them, global sea level is rising ever faster, the acceleration will increase into the future (by some estimates resulting in a rise of several meters by century’s end) and the entire mess is caused by burning fossils fuels and increasing the atmospheric concentration of greenhouse gases. But is what you find on these sites really the latest on sea level rise? Are sea levels really rising at the pace that they are so often made out to be?

We have written about sea level rise many times in the past, and there is no doubt that the sea is currently rising worldwide. However, the sea level rise has been taking place almost monotonically over the past 8,000 years, with substantial decadal variability embedded in the trend. In 2001, the Intergovernmental Panel on Climate Change (IPCC) concluded that “No significant acceleration in the rate of sea level rise during the 20th century has been detected.” In 2007, IPCC notes “Global average sea level rose at an average rate of 1.8 [1.3 to 2.3] mm per year over 1961 to 2003. The rate was faster over 1993 to 2003: about 3.1 [2.4 to 3.8] mm per year. Whether the faster rate for 1993 to 2003 reflects decadal variability or an increase in the longer-term trend is unclear.” A key question is not whether sea level is rising, but rather, has there been any acceleration in the rise – the jury is still very much out on that issue.

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January 3, 2008

Arctic Fingerprint Doesn’t Match?

Filed under: Arctic, Polar

Remember the good old days when “fingerprinting” was in vogue as the way to demonstrate a human impact on global climate? The idea was to show that observed temperature changes throughout the atmosphere match well the temperature changes predicted by climate models to occur there. One of the most prominent, and ultimately disproven, attempts was made by Ben Santer and colleagues, back in 1996. Santer et al. published an article in Nature magazine titled “A search for the human influences on the thermal structure of the atmosphere” in which they concluded that “Our results suggest that the similarities between observed and model-predicted changes in the zonal-mean vertical patterns of temperature change over 1963-1987 are unlikely to have resulted from natural internally generated variability of the climate system.” In other words, there must be a human influence on the observed changes. However, we (Michaels and Knappenberger, 1996) published a subsequent Comment in Nature, titled “Human effect on global climate?” describing how the correspondence between the observed patterns of vertical temperature change in the atmosphere and those projected by climate models broke down if a longer time period were considered. In other words, if the comparison was extended from 1958 to 1995 (instead of Santer et al.’s 1963 to 1987) the correspondence between model and observations became much less obvious. We concluded “Such a result… cannot be considered to be a ‘fingerprint’ of greenhouse-gas-induced climate change.” (See here for more details)

Now, 12 years later, another study appears in Nature magazine that suggests that there is a poor correspondence between the observed patterns of vertical temperature change and those predicted to occur by climate models over the high latitudes of the Northern Hemisphere. This time, Rune Graversen and colleagues from the Department of Meteorology at Sweden’s Stockholm University, conclude in their article “Vertical structure of recent Arctic warming” that variations in atmospheric heat transport from the lower latitudes into the northern high latitudes (via atmospheric circulation patterns) are largely responsible for the enhanced warming of the Arctic atmosphere. This leaves less temperature change there ascribable to our current understanding of anthropogenic global warming.

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