Michael Rubinkam / AP
Debris from flooding caused by Tropical Storm Lee sits on a sidewalk in West Pittston, Pa., on Dec. 21 -- more than three months after the storm hit. Some locals were still not back in their homes for Christmas.
Last year's status as "extreme" in terms of weather was elevated further on Thursday, when government scientists announced that two more disasters topped the $1 billion mark and noted that, had it not been for La Nina's cooling effect, 2011 would have been much warmer.
Tropical Storm Lee in September and severe weather in the Rockies and Midwest in mid-July were added to a list that now has 14 disasters with economic losses of $1 billion or more for a total of $55 billion, the National Oceanic and Atmospheric Administration announced.
The previous record was set in 2008 with 9 disasters over $1 billion.
The year tied with 1997 as the 11th warmest since records were started in 1880, and it would have been much warmer had it not been for two La Nina cycles, one that ended in early 2011 and another that started up later in the year and is still impacting weather. La Nina cools Pacific Ocean waters and affects weather worldwide.
La Nina years have been trending upward as far as temperatures go and 2011 was "the warmest 'La Nina year' on record for the land, the ocean and the combined temperatures," NOAA stated.
"It's an impressive upward trend," Thomas Karl, director of NOAA's National Climatic Data Center, told reporters, adding that while it is premature to tie 2011's weather events to global warming, "it fits the pattern."
NOAA released this map showing the 14 disasters that topped $1 billion in 2011.
Record drought in the South and wetness records set in the Northeast last year also fit the La Nina pattern, Karl said.
NASA's Goddard Institute for Space Studies, which tracks surface temperatures using slightly different tools, issued its own findings Thursday, saying that 2011 was the ninth warmest on record.
"We know the planet is absorbing more energy than it is emitting," GISS Director James Hansen, who has become an activist in clamoring for tougher curbs on warming gases, said in a statement. "So we are continuing to see a trend toward higher temperatures. Even with the cooling effects of a strong La Nina influence and low solar activity for the past several years, 2011 was one of the 10 warmest years on record."
NOAA mapped areas that saw records for drought or precipitation in 2011.
The years 2005 and 2010 remain tied for the warmest on record.
With solar activity rising and an El Nino, the counterpart to La Nina, expected to raise sea temperatures, global average temperatures should rise in the next two to three years, Hansen added.
"It's always dangerous to make predictions about El Nino, but it's safe to say we'll see one in the next three years," Hansen said. "It won't take a very strong El Nino to push temperatures above 2010."
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