Earth headed for climate extremes
The forecast comes from the Intergovernmental Panel on Climate Change, a global body of scientists who make periodic pronouncements on global warming and its likely effects.
The panel released a special report Friday on climate extremes and how to deal with them, and while some conclusions are more certain than others, the big picture is sobering: we'll be living on a far warmer world, with dangerous heat waves that were once rare becoming more frequent.
It will perhaps become a stormier planet as well.
But not all the potential extreme events can be tied to human influence. While scientists remain confident that the release of greenhouse gases is the main driver of a sharp upward curve in global warming, they are less sure about the connection to extreme weather events.
Human influence can be tied to the rise in daily maximum and minimum temperatures, for example. The scientists have "medium confidence" that our activities are helping increase precipitation, and it's "likely" we are helping increase sea levels as well.
But there is "low confidence" in attributing the frequency of tropical cyclones, including hurricanes, to humans.
"The problem with extreme events is that they are rare," said Michael Prather, a UC Irvine professor who is an IPCC assessment author and who reviewed the newest report. "Heat waves and precipitation becoming more intense -- that one is fairly strong. Then you go down to the ones you can't say anything about because the are rare. We don't have enough of a climate record to say how frequent they are."
The report says changes in extreme events, mainly daily temperature extremes and heat waves, have been showing up in observations since the 1950s.
The panel's next global climate assessment is due out in 2013.