31 de dezembro de 2009

O porquê do frio


Polar Pressure, Snowstorms and Sea Ice - Dot Earth Blog - NYTimes.com:
"The unusual pattern of atmospheric high and low pressure over and around the Arctic that has contributed to the recent snow and cold from Alabama to Washington, to East Anglia, England (and rain and warmth along the west coast of Greenland) is also an important influence on the shifting sheath of sea ice on the Arctic Ocean. Several specialists studying Arctic sea ice told me that there’s a good chance that, if current conditions persist, the ice this spring could be in better shape than it has been over the last few years. In all of this, though, it’s important to step back from the lure of the moment, which quickly attracts bursts of attention from climate commentators when conditions favor one view or another, and examine long-term trends." 

"[...]Over all, Dr. Rigor says, the enduring trend is toward diminishing sea ice in summers. He and many other Arctic specialists say that human-caused climate change is undoubtedly playing a role, but one still largely hidden amid layers of complex natural influences and variability."

Sem comentários: