The NASA Earth Observatory Image of the Day for the 24th of February showcases just how much energy is reflected back into space by the planet’s chryosphere, and how much that amount has decreased over the past 30 years.
Mark Flanner of the University of Michigan and his colleagues have used satellite data to measure how much changes in snow and ice coverage in the Northern Hemisphere have affected rising temperatures over the last 30 years. According to their data, the loss of snow and ice warmed the planet more than models had previously predicted.
The left image shows how much energy the Northern Hemisphere’s chryosphere has reflected on average between 1979 and 2008. Dark blue indicates the most reflected energy, and fades away as the amount of energy reflected does. Not surprisingly, Greenland is the location that reflects the most energy, followed by the ice cap over the Arctic Ocean.
The right image shows how that reflected energy has changed over the same period of time. The image shows that the Northern Hemisphere is absorbing more and more energy each year, particularly along the outer edges of the Arctic Ocean which has been the focal point of much speculation as the extent of the sea ice decreases each year.
“On average, the Northern Hemisphere now absorbs about 100 PetaWatts more solar energy because of changes in snow and ice cover,” says Flanner. “To put it in perspective, 100 PetaWatts is seven-fold greater than all the energy humans use in a year.”
Source: NASA Earth Observatory