“The Summer in March 2012″: Is the extreme weather related to climate change?
What the climate scientists have to say: The following map from Dr. Jeff Masters’ WunderBlog gives a nice overview of the record-setting “Summer in March.” While climate scientists cannot state with exact certainty that this “off the charts” event is related to climate change, the shear magnitude of departures from normal temperature ranges suggests that something has changed the basic “ground rules” governing the behavior of the atmosphere.
According to an article in Climate Central by Andrew Freedman, scientists have not yet studied in detail the main factors that triggered this specific heat wave including climate change. However, scientific studies of previous heat events clearly show that global warming increases the odds of heat extremes. You can see a wonderful video that compares global warming to a batter that takes steroids to boost his odds of hitting homers here. (A product of the National Center for Atmospheric Research and University Corporation for Atmospheric Research).
However, climate scientists also believe that the atmospheric warming caused by CO2 and other greenhouse gases (e.g. methane) causes other extremes, like flooding, severe tornadoes, and extraordinary droughts. There are several reasons for this. As the oceans heat up more water vapor is added to the atmosphere which leads to instability — in effect energizing the atmosphere with a greater tendency for extremes.*
* The greenhouse effects makes the oceans warmer; this increases the rate of evaporation of water into the atmosphere. However, evaporation requires energy, and the surface of the ocean loses some heat. The energy is not really lost but is transferred into the gas molecules that comprise water vapor. As the warm moist air rises it cools and the air becomes saturated and droplets begin to form; this process known as condensation releases ‘the latent heat of evaporation” into the air. The net process is a transfer of energy from sea to air. The addition of this energy to the atmosphere drives the formation of thunderstorms, hurricanes, and other weather systems and also increases the potential for extreme events.