Scientists and policymakers are considering a range of geoengineering options to address the consequences of climate change, dismayed by the prospects of reaching a political agreement to reduce emissions and unnerved by new findings that indicate that the climate could shift in sudden and unpredictable ways.

Six months is all it took to flip Europe’s climate from warm and sunny into the last ice age, researchers have found. They have discovered that the northern hemisphere was plunged into a big freeze 12,800 years ago by a sudden slowdown of the Gulf Stream that allowed ice to spread hundreds of miles southwards from the Arctic.

The changing global climate will pose profound strategic challenges to the United States in coming decades, raising the prospect of military intervention to deal with the effects of violent storms, drought, mass migration and pandemics, military and intelligence analysts say.

Researchers have warned for years of a nightmare global warming scenario caused by melting Arctic freshwater overwhelming the North Atlantic current, and triggering rapid climate change. However, new research indicates that the current rate of glacial melt is occurring at a more gradual pace which will "give ecosystems more time to adjust to new conditions."

Researchers have warned for years of a nightmare global warming scenario caused by melting Arctic freshwater overwhelming the North Atlantic current, and triggering rapid climate change. However, new research indicates that the current rate of glacial melt is occurring at a more gradual pace which will "give ecosystems more time to adjust to new conditions."

A new report from the US Climate Change Science Program concludes that "rapid and sustained September arctic ice loss is likely" in this century, and that the southwestern United States already may be entering a sudden shift into increased drought.

In the debate over global warming, there has been a widespread assumption that if humans are changing the earth's climate, the effects will be felt gradually and smoothly, making it easier to adapt to the change. But a growing accumulation of geological evidence is making it ever clearer that in the past, the climate has undergone drastic changes in temperature and rainfall patterns in the space of a human lifetime, in a decade or in even less time.

Six U.S. National Laboratories have launched a program to research abrupt climate change which could be caused by methane release from thawing permafrost, the collapse of ice sheets, or other positive feedback mechanisms.