Hudson Bay melting ice and snow: (left) 06 April 2012; (right) 05 June 2012: NASA Earth Observatory image by Jesse Allen using data obtained from the Land Atmosphere Near real-time Capability for EOS (LANCE). The latest Arctic report from the National Snow and Ice Data Center (NSIDC) is out and it's a sobering read. Records were broken in the month of June on two fronts:
- The largest ice loss in the satellite record for the month of June: of 1.10 million square miles (2.86 million square kilometers)
- The lowest June snow cover on the ground in the Northern Hemisphere: falling 386,000 square miles (1 million square kilometers) below the previous record low set in 2010
Monthly June ice extent for 1979 to 2012 shows a decline of 3.7 percent per decade: National Snow and Ice Data Center
On the sea ice front, the June loss was especially rapid (I wrote more about that here).
It was facilitated in part by remarkably high atmospheric temperatures—up to 7.2 degrees Fahrenheit (4 degrees Celsius) above the 1981-2000 average over northern Eurasia and southern Baffin Bay. These temperatures were measured ~3,000 (914 meters) feet above the ocean's surface.
That made the June 2012 ice extent the second lowest in the satellite record; 2010 is still the record holder.
This year's rapid ice loss contributed to a linear rate of decline for June Arctic ice at 3.7 percent per decade since the satellite record began (graph above).
Record low snow-cover extent in the Northern Hemisphere June 2012 compared to 1971-2000 average. National Snow and Ice Data Center courtesy Rutgers University Snow Lab.
Snow cover over the landmasses of the Northern Hemisphere also retreated rapidly to the lowest levels ever recorded for the date by the end of June.
By then the shores of the entire Arctic Ocean coastline were basically snow free (map above). From the NSIDC report:
This rapid and early retreat of snow cover exposes large, darker underlying surfaces to the sun early in the season, fostering higher air temperatures and warmer soils.
Annual global temperature anomalies combined for land and ocean from 1901 to 2000: NOAA | National Climatic Data CenterThat positive feedback loop between warming/melting landmasses and warming/melting sea ice will contribute to the trend in the graph above (shown in degrees C).
You can see how the global mean combined temperature over land and ocean has risen a whopping ~1 degree Fahrenheit in a century. And that only includes up to the year 2000. The biggest records continue to be serially broken after 2000.