The Cost of Climate Change

An article in Nature argues that released methane from melting permafrost in the Arctic could cost the world economy US$60 trillion over several decades.  That compares to a current global economy of about US$70 trillion.  Poorer countries would bear most of the cost in the form of floods, drought, and health expenses.

Also, a study in Nature Geoscience says that the East Antarctic ice sheet has experienced previous melting at a time when the atmospheric carbon dioxide concentration was similar to now. That occurred 2.6 to 5.3 million years ago when global temperatures were 2 to 3 degrees Celsius warmer and sea levels were 66 feet higher.

Update (September 4, 2015):  A Citibank report projects savings of $1.8 trillion by 2040 by investing in low carbon energy. But global GDP will be many trillions lower by doing nothing.