Tipping Points

The increasing melt may be a harbinger of greater changes such as the release of methane compounds from frozen soils that could exacerbate warming, and a thaw of the Greenland ice sheet, which would contribute to rising sea levels, NASA’s top climate scientist, James Hansen, said in an e-mail interview, reports Bloomberg.

“Our greatest concern is that loss of Arctic sea ice creates a grave threat of passing two other tipping points -- the potential instability of the Greenland ice sheet and methane hydrates,” Hansen said. “These latter two tipping points would have consequences that are practically irreversible on time scales of relevance to humanity.”

Above image shows methane levels over a period of four years, from August 1, 2008, to August 1, 2012.

Above image shows methane levels over one years, from August 1, 2011, to August 1, 2012. This shows a marked increase in methane levels on the last of the four years further above.

Above image shows methane levels from August 1, 2012, to August 15, 2012. The image shows high levels of methane across the northern hemisphere. Note the high levels above Greenland.