Weatherdem's Weblog

Bridging climate science, citizens, and policy

November 2010 = Warmest Average November Globally

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A rather stunning piece of news was released by NASA earlier this week that received absolutely no attention by corporate stenographers.  According to NASA, global average temperatures for November 2010 were higher than any other November in recorded history.  Furthermore, the likelihood that 2010 will end up as the warmest calendar year on record to date increased.  Recent months have seen consecutive 12-month periods rank as the hottest on record already.  But people tend to think along calendar date lines, so perhaps 2010 ranking at or near the top of the recorded history list will help spur folks to action.

Let’s start with November 2010 by itself.  November’s global average temperatures were 0.74C above normal (1951-1980), according to NASA.  The warmest regions on Earth are exactly where climate models have been projecting the most warmth to occur for years: high latitudes (think Arctic & Antarctic Circles).  The past three months have a +0.63C temperature anomaly.  And the latest 12-month period (Dec.2009-Nov.2010) had a +0.65C temperature anomaly, the warmest on record.

Now let’s look at year-to-date values.  The two warmest years in the NASA dataset were 2005 and 1998.  January-November average surface temperatures for 2010 were +0.66C above normal (1951-1980).  January-November 2005 saw +0.63C and January-November 1998 saw +0.57C above normal.  Regions experiencing abnormally warm or cool conditions in any of these years changes somewhat, of course.  But for the most part, the same regions are staying warmer during these record years and they’re getting warmer than they were one or two decades ago.

As if record global warmth wasn’t enough, coincident climate signals that provide monthly-to-seasonal and multi-year forcing on the climate system aren’t at cause.  What am I talking about?  Well, there was a moderate-to-strong El Nino earlier this year, but it ended by July 2010.  El Nino forcing typically takes 3-6 months to be seen in global surface temperatures.  Moreover, a moderate-to-strong La Nina has developed this fall.  We should be seeing a general cooling trend already as a result and we’re not.  Global temperature anomalies have instead been increasing since July, which means these temperature anomalies are responding to a forcing that is stronger than the weakening El Nino and strengthening La Nina.

Furthermore, the sun is still just coming out of what was an extended solar minimum.  The intensity of the current solar cycle (#24), as measured by sunspots and solar flux, is less than what was predicted by space agencies a few months ago.  The solar cycle operates on an approximate 11-year cycle.  Since we remain near the minimum of that cycle, the relative weakness of solar output is also clearly being dominated by a stronger forcing mechanism here on Earth.

For additional context, think of what global temperatures are likely to be in 2013 or 2014 as the solar cycle continues to ramp up.  Then add on another El Nino event, even one of moderate strength.  With the failure of the U.S. political system to come up with common-sense strategies of dealing with global warming, it’s not as if the U.S.’s greenhouse gas pollution will be decreasing between now and then.  It’s also not likely that the global pollution emissions will be lower in 2013 than they were in 2010, absent another economic disaster.  Warmer and warmer we go…

Cross-posted at SquareState.

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