It seems counter-intuitive, but it seems that warmer summers actually slow the flow of Greenland’s ice sheets.

A new study, published yesterday in Nature, explains how increased melting in warmer years causes the internal drainage system of the ice sheet to change, slowing the glacier’s flow towards the ocean.

Normally, the melt-water finds its way to the bottom of the ice sheet, acting as a lubricant that helps the glacier to flow towards the ocean.  With less melt-water below the glacier, its flow is impeded, so it doesn’t recede as quickly.

So, are hot summers the cure to glacial melting?  Obviously not.

Warmer temperatures do cause more melting.  Although the glaciers aren’t moving towards the ocean faster, they are melting from the surface downwards.  The big difference is in the plumbing–whether the melt-water is trapped under the glacier, lubricating its path to the sea, or whether the melt-water is drained away through a different plumbing system.  The ice will still melt.

This surprising data just shows that more research is needed to fully understand how glaciers are affected by changing temperatures.  Dr. Edward Hanna, one of the co-authors, underscored the importance of using models in studying the relationship between glacial melt and climate change:

“This work also underlines the usefulness of modern gridded climate datasets and melt-model simulations for exploring seasonal and year-to-year variations in Greenland ice sheet dynamics and their relationship with the global climate system.”

Explore the relationship between temperature and ice-melting in our activity, “What will Earth’s climate be in the future?“

http://www.sciencedaily.com/releases/2011/01/110126131538.htm