Weather Extremes

For a very long time (decades) scientists have predicted that the distribution of weather we get would shift toward higher temperatures.

Well, that has been happening:

More information about that graph, and the science behind it, can be found here.

What the graph says is that heat events that used to be very rare now are quite common.  The extreme events that used to happen less than 1% of the time now are 10% and more.

There are important implications to dealing with this.

First, these events come in heat waves like the one that hit the US this spring, causing fruit trees to bloom early and then have buds killed by frost when the heat wave ended.  In other words, heat waves can come at the wrong time and screw up the way nature works.

Second, the severity of the heat waves causes problems.  Heat causes drying, and thus drought.  Dry soils don't supply water for evaporative cooling, which drives temperatures up even further.  Heat begets heat, as they say.  So you end up with very intense heat waves that kill by sheer temperature.  There was a "global warming type" drought, i.e., not just dry but also very hot, in the Southwest in the early 2000s which killed pinyon pines by heat, which was pretty much unheard of.  It was about an 800-year drought.

Well, an 800-year drought according to the climate we used to have.  There have been an awful lot of 100-year and 500-year and 1000-year events in the past several years.  That's what the graph above is all about - extremely rare events now are becoming common.