Friday, July 10, 2009

Extreme Heat

In the midst of our steamy, Midwestern summer, it is reassuring to know that our high temperatures are not even close to the conditions endured in other parts of the globe. As one might expect, the hottest weather occurs in desert regions, where the humidity is low and the air is sinking; both factors augment the density of air, increasing its ability to absorb heat. While, for any given temperature, humid air will feel more uncomfortable, the presence of water vapor limits the air's heating capacity.

The highest air temperature ever recorded on the planet was 136 F, in Libya, followed closely by 134 F in Death Valley, California. High temperature records across the desert regions of the Middle East and Australia are generally in the mid to upper 120s. In contrast, Norway's record high is 96F, Iceland has not topped 87F and the highest recording in Antarctica has been 59F. Perhaps the most unnerving record (for those of us who prefer cool weather) is that held by the Danakil Basin in Ethiopia: a mean annual temperature of 94 degrees F!

Faced with the threat of global warming, it is interesting to note that most of the regional, high temperature records were recorded in the early to mid 20th Century. Then again, local weather patterns and global climate trends have no direct relationship.