Thursday, March 29, 2012

Climate Crisis Update: Arctic Heating and Weather Disasters

In my most recent Climate Crisis update, I focused on some consequences of the fast melting Arctic ice.  In the update before that one, I reviewed some of the latest on this year's weird weather, which has been freakishly warm in much of North America, especially east of the Mississippi, but there have been unusual extremes of hot and cold in other parts of the world--as in Europe, where a killer cold spell was followed by a hot spell.  In this update, those two subjects come together: as scientists suspect this weird weather is causally related to Arctic melting.

In a New York Times story on this subject:The question really is not whether the loss of the sea ice can be affecting the atmospheric circulation on a large scale,” said Jennifer A. Francis, a Rutgers University climate researcher. “The question is, how can it not be, and what are the mechanisms?”

The story continues: "A report released on Wednesday by the Intergovernmental Panel on Climate Change, the United Nations body that issues periodic updates on climate science, confirmed that a strong body of evidence links global warming to an increase in heat waves, a rise in episodes of heavy rainfall and other precipitation, and more frequent coastal flooding."

A summary of evidence based on recent weather:    "United States government scientists recently reported, for instance, that February was the 324th consecutive month in which global temperatures exceeded their long-term average for a given month; the last month with below-average temperatures was February 1985. In the United States, many more record highs are being set at weather stations than record lows, a bellwether indicator of a warming climate."

And March may turn out to be more extreme than February.

The mechanism that may be at work involving the Arctic has to do with the effect of longer iceless periods on the water changes the pattern of heating and cooling from the ocean, and may then change the Jet Stream.  That's the contention of one scientist quoted in the Times story, and although it is not yet a consensus view (according to the Times,) the story does make this general statement:

 "Yet mainstream scientists are determined to figure out which climate extremes are being influenced by human activity, and their attention is increasingly drawn to the Arctic sea ice."

Other stories concerning the IPCC Report emphasize the basic finding that the frequency and extent of at least some kinds of extreme weather are linked to the Climate Crisis, and the future threat, especially to vulnerable places in the world.   For example, from the Independent:

    "Global warming is leading to such severe storms, droughts and heat waves that nations should prepare for an unprecedented onslaught of deadly and costly weather disasters, an international panel of climate scientists says in a report issued on Wednesday.

The greatest danger from extreme weather is in highly populated, poor regions of the world, the report warns, but no corner of the globe - from Mumbai to Miami - is immune. The document by a Nobel Prize-winning panel of climate scientists forecasts stronger tropical cyclones and more frequent heat waves, deluges and droughts."    

The Montreal Gazette led with this conclusion:

A future on Earth of more extreme weather and rising seas will require better planning for natural disasters to save lives and limit deepening economic losses, the United Nations said on Wednesday in a major report on the effects of climate change.

Another study making news Wednesday:

"By 2050, global average temperature could be between 1.4°C and 3°C warmer than it was just a couple of decades ago, according to a new study that seeks to address the largest sources of uncertainty in current climate models. That's substantially higher than estimates produced by other climate analyses, suggesting that Earth's climate could warm much more quickly than previously thought."

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