The statistics have been compiled and now the analysis and discussion will really start. It was so warm across the US in March 2012 that the average US March temperature was 8.6 degrees F warmer than any other March on record (dating back to 1895). The beat out March 1910, the previous warmest March on record (by a decent margin). If I were to cherry-pick climate records like many skeptics do, I could easily claim that there is global warming from 1910 to 2012. Actually, I don’t have to cherry-pick the data. The fact that the 2000s were warmer than the 1990s which were warmer than the 1980s and so on does that for me. Also, Jan-Mar 2012 saw an average of 42 degrees F across the US – which is 6 degrees F warmer than normal.
Figure 1. Depiction of divisional ranking of March 2012 temperature anomaly [Courtesy NOAA].
Figure 2. Statewide rankings of average March 2012 temperature. Note the number of states setting all-time warm temperature records (labeled `118` on map with red state backgrounds) and the additional near-records set in another 16 states. Note also only 1 state had below normal temperatures for the month. [Courtesy NOAA]
Figure 3. Statistical deviation from normal conditions for March 20th, 2012 as calculated by the GFS model. This day occurred at the peak of the heat wave and was illustrative of the kind of conditions that were found for days in a row.
Figure 4. Anomalous temperature readings across the US for the week of March 8-16, 2012.
And while it is accurate to say, “This is exactly the kind of scenario which ‘loaded climate dice’ says should occur as the planet continues to respond to man-made greenhouse gases,” that isn’t exactly true in the sense that we can’t show that these conditions won’t occur in climate projections. Scientists do acknowledge that this warmth is in response to the GHG levels that existed ~25-30 years ago: the accumulation of gases and absorbed energy since then won’t be felt for another generation.
The Summer in March 2012 raises another interesting question: what would have happened if this heat wave occurred instead in July or August – the hottest months of the year for the US? Moreover, what would have happened if that hypothetical heat wave occurred instead during an El Nino and most of the US happened to be a little warmer than usual anyway, instead of during a moderate La Nina? If these different phenomena occur at the same time, what will happen in the US; or Europe; or Asia? We’re simply not prepared for that kind of event. Of course, the warmth last month is projected to become “normal” for March in the US by the end of the century. That sounds good until you think about the simultaneous lack of precipitation across much of the country.
I’ll have more on this information later this week.