April temperature difference from average (NOAA)

In records dating back to 1880, this past April’s warmth was unsurpassed around the globe, according to NOAA’s latest monthly climate report.

The average land and ocean temperature was 58.09 degrees F, 1.39 degrees above the 20th century average, tying for the warmest April on record with 2010.  It was the 350th consecutive month and 38th consecutive April with above average temperatures.  The last cooler than average April occurred 38 years ago, in 1976 –  coincidentally (or not?) the month I was born.

NASA’s independent analysis of April temperatures ranked it as the second warmest on record, slightly differing from NOAA.

Interestingly, the U.S. was not particularly warm in April, ranking as just the 46th warmest on record.  Many parts of Canada were cooler than normal, NOAA said.  But more locations around the world were warm than not, with some achieving record warmth, as NOAA describes:

Many areas of the world were much warmer than average, with much of central Siberia observing temperatures more than 9°F (5°C) above the 1981-2010 average. This region, along with parts of eastern Australia and scattered regions in every major ocean basin, were record warm. Parts of southern and eastern Canada, the northern U.S., and southern Kazakhstan were cooler than average. No land areas were record cold…

Northern Hemisphere snow cover difference from average (NOAA) Northern Hemisphere snow cover difference from average (NOAA)

Snow and ice around the world – on balance – was depleted compared to long-term norms due to the toasty temps.  Eurasian snow cover was the lowest on record for April, while Northern Hemisphere snow cover – overall – was 6th lowest on record.

Arctic sea ice extent was the 5th lowest on record for April while Antarctic sea ice continued its outlier behavior – reaching its highest April extent on record.

The record-setting April global temperature comes on the heels of a flurry of studies and reports painting an unmistakable picture of a warming world:

*  The U.S. government released its national assessment of climate change boldly stating “climate change has moved firmly into the present”
* Two new studies concluded large sections of the West Antarctic ice sheet  are likely in irreversible retreat.  Valuable insights and context on this can be found in blog posts by Tom Yulsman (Discover) and Andy Revkin (NY Times)
* Hurricanes are reaching peak intensity farther north as the tropics expand – plausibly due to climate warming

The global warmth experienced in April may just be the tip of the iceberg.  More monthly temperature records may fall in future months if El Niño develops.  El Niño events – characterized by warming ocean temperatures in the tropical Pacific – tend to inject significant amounts of heat into the atmosphere.  NOAA predicts a 65 percent chance of El Niño by the summer and an 80 percent chance by early winter.