Select the search type
  • Site
  • Web

The natural world. Looking pretty for 3.5b years.

Sliding Down…Tipping Up

Author: Guest Writer/Sunday, January 13, 2013/Categories: Uncategorized

Environmental measurements are one thing but visualizing the data over a timeline is a better way to see trends. Research just published in Geophysical Research Letters and the Arctic Report Card: Update for 2012 found that, between 1979 and 2012,  Arctic snow cover in June decreased nearly 18 percent per decade. Maps of the measurements over the 30 year time span show above-average snow cover in blue and below-average cover in orange.

Declining cover means decreasing albedo, or reflectivity. Snow has a high albedo, reflecting nearly 90 percent of the sunlight it receives, while dark soils and vegetation absorb the Sun’s energy. The new analysis show that with declining snow cover ground temperatures rise and the thickness of the active permafrost layer---the zone that thaws each summer---grows. As organic permafrost decomposes, it releases methane into the atmosphere. Methane is a strong greenhouse gas and could become a far larger contributor to global warming than carbon dioxide. At some level, a ‘tipping point’ might occur with radical shifts in global temperature, climate, and weather and you don’t want to experience those events.

The 30 year data maps summarize the emerging story well.


Arctic Snow Cover, 1979-2012

(credit: GPL)



Number of views (3328)/Comments (0)

Please login or register to post comments.