Monday, March 14, 2016

February Smashes Earth's All-Time Global Heat Record by a Jaw-Dropping Margin

Figure 1. Monthly global surface temperatures (land and ocean) from NASA for the period 1880 to February 2016, expressed in departures from the 1951-1980 average. The red line shows the 12-month running average. (Image credit: Stephan Okhuijsen,, used with permission) Click to Enlarge.
On Saturday, NASA dropped a bombshell of a climate report.  February 2016 has soared past all rivals as the warmest seasonally adjusted month in more than a century of global record keeping.  NASA’s analysis showed that February ran 1.35°C (2.43°F) above the 1951-1980 global average for the month, as can be seen in the list of monthly anomalies going back to 1880.  The previous record was set just last month, as January 2016 came in 1.14°C above the 1951-1980 average for the month.  In other words, February has dispensed with this one-month-old record by a full 0.21°C (0.38°F)--an extraordinary margin to beat a monthly world temperature record by.  Perhaps even more remarkable is that February 2015 crushed the previous February record--set in 1998 during the peak atmospheric influence of the 1997-98 “super” El NiƱo that’s comparable in strength to the current one--by a massive 0.47°C (0.85°F).

An ominous milestone in our march toward an ever-warmer planet
Because there is so much land in the Northern Hemisphere, and since land temperatures rise and fall more sharply with the seasons than ocean temperatures, global readings tend to average about 4°C cooler in January and February than they do in July or August.  Thus, February is not atop the pack in terms of absolute warmest global temperature: that record was set in July 2015. 

The real significance of the February record is in its departure from the seasonal norms that people, plants, animals, and the Earth system are accustomed to dealing with at a given time of year.  Drawing from NASA’s graph of long-term temperature trends, if we add 0.2°C as a conservative estimate of the amount of human-produced warming that occurred between the late 1800s and 1951-1980, then the February result winds up at 1.55°C above average.  If we use 0.4°C as a higher-end estimate, then February sits at 1.75°C above average.  Either way, this result is a true shocker, and yet another reminder of the incessant long-term rise in global temperature resulting from human-produced greenhouse gases.  Averaged on a yearly basis, global temperatures are now around 1.0°C beyond where they stood in the late 19th century, when industrialization was ramping up.

Michael Mann (Pennsylvania State University) notes that the human-induced warming is even greater if you reach back to the very start of the Industrial Revolution.  Making matters worse, even if we could somehow manage to slash emissions enough to stabilize concentrations of carbon dioxide at their current level, we are still committed to at least 0.5°C of additional atmospheric warming as heat stored in the ocean makes its way into the air, as recently emphasized by Jerry Meehl (National Center for Atmospheric Research).  In short, we are now hurtling at a frightening pace toward the globally agreed maximum of 2.0°C warming over pre-industrial levels.

Read more at February Smashes Earth's All-Time Global Heat Record by a Jaw-Dropping Margin

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