While Colorado’s weather this summer shifted from warm to wet to hot, it was plain and simply nothing but hot, hot, and hot in the states to our south. How hot was it?
It was so hot that Texas and Oklahoma set the U.S. record for the 1st and 2nd hottest summers: 86.8F and 86.5F, respectively, beating out Oklahoma’s 1934 record (set during the Dust Bowl years) of 85.2F. To be clear, from June through August, the average of all the temperatures taken at the top of every hour came out to above 86 degrees. Oh, Louisiana’s 2011 summer now ranks 4th warmest all-time at 84.5F.
When records from the previous hottest period in the nation’s history are falling, it’s time to pay attention. Instead of natural variability playing the primary role, the heat wave this year was by the altered background state.
Statistically speaking, it is more significant that Texas set the record instead of Oklahoma. The number of weather stations in Texas is obviously much higher than those in Oklahoma. Most, if not all of those stations were subjected to similar conditions for 3 months in order to set this kind of record – a truly amazing occurrence.
I’m going to riff off of Joe Romm’s recent post on a similar topic and re-post some graphics I’ve written about before. They are particularly salient now that the summer of 2011 is fresh in our memories.
This is a plot from a NOAA-led report that shows what the future holds under a business-as-usual emissions scheme. Focusing in on Denver, which just experienced its hottest August and 3rd hottest month ever with 22 days above 90F maximum temperatures, puts this plot into some context. Denver didn’t record a single 100F degree day this year. But if we continue along the path we’re on much longer, we’re likely to experience 7 to 9 weeks of 100F or hotter days. Moving on down to Texas and Oklahoma, things really get cooking. Between 13 and 23 weeks of 100F or hotter days are in their future. How much agriculture do you think can be successfully supported in those conditions? How much ranching can be done? How many water pipes will break in the ground as that ground swells in the heat?
And it’s not just heat, as this plot from a recent NCAR study demonstrates. Palmer Drought Severity Index values in the 1930s spiked very briefly to -6 (see scale above), but rarely exceeded -3 during the rest of the decade. By the 2030 decade, projections of -4 to -6 PDSI values cover most of the American Southwest. Texas gets off “easy” with PDSI values holding near -2 for the decade. Significantly higher temperatures in twenty years’ time accompanied by drought conditions worse than those of the Dust Bowl could easily be the future that comes to pass.
Given the scope of the tasks facing us: reduction of emission levels that are currently growing and deployment of infrastructure and technologies to do so, I’m not optimistic that we can turn things around in time in order to avoid these kinds of scenarios. Given the severity of the scenarios, we had better start doing something substantial soon.