If a 54-degree climate swing were not reason enough to lament the end of vacation, Mr. Obama certainly had others.
Whatever the cause of the climatic gyrations, the records suggest that the worst climate swing that would naturally occur in the present interglacial is a modest 1°C chilling.
Another natural climate swing, called the Atlantic Multidecadal Oscillation, also contributes to the intensification of monsoon rainfall.
It turns the Seattle Art Museum Olympic Sculpture Park into an AR landscape, or ecosystem, where "native aquatic and terrestrial plants have mutated to cope with the increasing unpredictable and erratic climate swing.s".s
Such a relationship between climate swings and political instability seems, at least anecdotally, to have a long history, says Thomas Homer-Dixon, a nature and society researcher at the University of Waterloo in Canada: "What we're seeing is a modern-day manifestation of a phenomenon that goes back millennia".
The working hypothesis behind the mission is that not long ago--tens of thousands to a few millions of years--periodic climate swings might have melted the subsurface ice confirmed by Phoenix to make the soil a few centimeters down a habitable, if temporary, environment for microbial life.
The material, 4,200 years old, includes fish scales, seeds, pollen and evidence of everything from climate swings to devastating forest fires.
Because the climate record is still short, more work needs to be done to determine how much of the warming results from natural climate swings and how much from the warming effects of carbon dioxide released by the burning of fossil fuels, Dr. Steig said.
Indeed, Dr. Briffa and Dr. Osborn wrote that if past climate swings were bigger than they appeared, this could mean the earth's climate system might be more sensitive to external influences like shifts in the sun's output or the concentration of greenhouse gases than scientists had estimated.
Much of the last ice age was characterized by violent climate swings.
