Too Hot, Too Dry

Have you been scratching your head at the seemingly endless barrage of “weather anomalies” we’ve been subjected to, wondering what role human-induced climate change is playing?

A new scientific study out this week may help fill in some of the blanks for you.  NASA’s senior climate scientist, Dr. James Hansen and two co-authors published a study in the Proceedings of the National Academy of Sciences about extreme heat waves and droughts.  Their main finding: The percentage of Earth’s land surface hit by extreme heat during summer has expanded from less than 1% in the years 1951-1980, to as much as 13% from 1980 to now.

The authors use the metaphor of “climate dice” to explain what we are doing to our planet by burning fossil fuels and destroying forests.  A normal set of dice gives a standard set of outcomes based on statistical likelihood of hitting a certain number.  For example, the odds of rolling a “7″ with two dice are about one in six.  However, if you “load” the dice in such a way that makes them almost always land with a “4″ on one dice and a “3″ on the other dice, you are substantially increasing the odds of rolling a 7; likewise with climate.  By significantly increasing the amount of greenhouse gases in the atmosphere, we are in essence loading the climate dice to land more frequently on “extreme weather”.

Dr. Hansen and his colleagues conclude that the extreme heat anomalies (and subsequent drought) we’ve seen across the United States, Russia, and India in recent time are the result of us loading the climate dice through increased greenhouse gas emissions.  And “hot off the press” (literally) – according to the National Oceanic and Atmospheric Administration (NOAA), the U.S. has just experienced the hottest July in the 112 years we’ve been keeping records.  The drought footprint, they report, covers 63% of the lower 48 states, with near record dry conditions in the middle of the nation (ie. where we grow most of our food).

This is not a small development.  These extreme droughts have immediate human and economic consequences. The Russian heat wave caused thousands of deaths and destruction to large swaths of forested land.  The current heat wave hitting the central part of the U.S. is expected to destroy thousands of acres of crops, driving up the price of food and hitting your wallet.  With more and more of our land surface hit by these heat waves and droughts, the impacts will only be felt by more people.

The cost of inaction is getting higher by the day. With more scientific certainty on the impacts of human induced climate change, our excuses for doing nothing are drying up faster than the American bread basket.