Tornadoes can be terribly destructive and deadly. Before we jump to hasty (and often erroneous) conclusions about their cause, let us consider some facts, gained from careful study and observation. Here is a relatively simple explanation. It is extremely foolish to assume that tornadoes are caused by carbon dioxide emissions which supposedly cause global warming. The weather systems that generate tornadoes are not affected by atmospheric CO2 in any way. There are many other factors at work. The following article explains it well.
“Environmentalists bound to use recent storm events to ‘prove’ their dogma."
Tornadoes not a sign of global warming
By Dr. Tim Ball Monday, February 18, 2008
In his book State of Fear, Michael Crichton wrote about exploitation of fear by environmental extremists. He should write another book about exploitation of lack of knowledge.
Climate and environment were previously outside of politics, but once they became potential election issues politicians exploited them better than environmentalists. It fulfills H.L Mencken’s observation that, “The whole aim of practical politics is to keep the populace alarmed (and hence clamorous to be led to safety) by menacing it with an endless series of hobgoblins, all of them imaginary.”
So before anyone attempts to make political gain from the tragic events of the tornados that killed people across the southern US recently, let’s put the science on the record. And while we’re at it let’s explode another false claim that storms and severe weather will increase with global warming.
Most major storms and severe weather, including tornadoes, occur in the middle latitudes between approximately 30 and 65 degrees of latitude. Much weather terminology such as Advancing Fronts, Retreating Fronts, outbreaks of warm or cold air reflect its World War I genesis. Fronts are the battle zone between different air masses and as they move they are labeled warm or cold. If you are warm and the temperature drops, a Cold Front has passed; if you are cold and the temperature rises, a Warm Front has passed. It’s the cold air that dictates what happens because it is more dense and heavier than the warm air. It pushes the warm air out of the way or allows the warm air to move in behind. Overall, Earth’s atmosphere is in two air masses with a dome of cold polar air over each pole and over-running warm subtropical air separated by the Polar Front. Temperature difference across the Front is variable but quite dramatic most of the time. It is this difference that creates pressure differences and very strong winds. Above the surface this manifests as the powerful Jet Stream.
At the surface waves develop and spiral into low pressure systems known as mid-latitude cyclones. They migrate along the Front like a wave moving through the ocean. In winter they bring snow and are called blizzards; in summer they bring heavy rain, occasionally with severe thunderstorms and tornadoes. The Front moves seasonally as the cold dome expands and contracts with the changing sun angle (the Greeks understood this - the word climate comes from their word klimat meaning angle). As it moves through latitude the seasons change, marked by these low pressure storm systems.
In the US, the most extreme temperature contrast across the Front occurs when cold air pushes well south and meets with warm moist air coming off the Gulf of Mexico. This pattern creates a general zone running from the Texas panhandle northeast through the Ohio valley and in to southwest Ontario. This zone is known as Tornado Alley. It’s a wide zone that varies with the season and conditions. The loss of life is tragic, but is a sad part of living in the tornado zone. Natural risks exist in every part of the world. People weigh the risks against the potential for obtaining a living or a lifestyle. In Bangladesh, millions risk cyclones and flooding to farm the rich soils. In Indonesia they live on the side of active volcanoes because of the fertile soils. People ignore the risk of earthquakes for the lifestyle in California.
Despite what the environmentalists want you to think, it is not, and cannot be, a no-risk world and risks, in general, are not being enhanced by human activity. But environmental alarmists’ ideas about risk underpin their foolish ideas that we can stop the risk of climate change. We can certainly reduce other risks and that is apparent from an analysis of the statistics gathered in Tornado Alley - National Oceanographic and Atmospheric Administration information shows how the loss of life from tornadoes has decreased significantly. This is even more dramatic when you consider the increase in population density in this region. (Source: http://www.nssl.noaa.gov/users/brooks/public_html/tornado/)
When asked about a tornado in New York on August 8, 2007 NASA’s James Hansen, a climate change alarmist of the first order, said. “No, you cannot blame individual events like that on climate change, as it was possible for them to occur even without the human-made changes to the atmosphere. However, it is fair to ask whether the human changes have altered the likelihood of such events. There the answer seems to be yes. Storms driven largely by latent heat, and that includes thunderstorms, are expected to become stronger as the air becomes warmer and contains more moisture. Global warming does cause just such a tendency. (Source: http://blog.wired.com/wiredscience/2007/08/climate-expert-.html)
But, this is only half the story. It is, however typical of statements from climate catastrophizers. Hansen also claims that global warming will result in greater warming in polar air than in tropical air. This means the temperature difference across the Polar Front will decrease and, as a result, the strength of the major mechanism for storm creation will decrease. Fewer storms means fewer tornadoes. Storm and accompanying tornadoes that caused the recent deaths were partly created by increased warm moist air off the Gulf of Mexico as a result of La Nina. Specifically, NOAA reports, “For the contiguous United States, potential impacts include above-average precipitation in the Northern Rockies, the Pacific Northwest, and Ohio and TennesseeValleys.” (Source: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.pdf)
This influx of warm moist air is needed to meet with the cold air that pushes far south, as it has all this winter. It will continue to do as the Earth continues to cool, as it has generally since 1998. The dilemma then is that storms will most likely increase in frequency and severity, but it will be because of global cooling, not warming. Proponents of the anthropogenic global warming hypothesis have positioned themselves to continue to claim they are right no matter what ultimately happens. They switched from calling it ‘global warming’ to ‘climate change’ as the concern as global temperatures began to decline while carbon dioxide levels increased. This position produces incredible statements that merely demonstrate ignorance such as Greenpeace climate spokesperson Steven Guilbeault’s comment, “Global warming can mean colder, it can mean drier, it can mean wetter, that’s what we’re dealing with.” Unfortunately most of the public are not yet knowledgeable about the issue to know how silly Guilbeault’s comment is, but they’re learning.
Dr. Timothy Ball is a Victoria, British Columbia-based environmental consultant, former climatology professor at the University of Winnipeg, and Chairman of the Natural Resources Stewardship Project (http://www.nrsp.com/).