<h2><a href="http://www.noaanews.noaa.gov/stories2012/20120710_stateoftheclimatereport.html">http://www.noaanews.noaa.gov/stories2012/20120710_stateoftheclimatereport.html</a></h2><h2>Back-to-back La Niñas cooled globe and influenced extreme weather in 2011</h2>
<h3>New NOAA-led report examines climate conditions experienced around the world</h3>
<div id="releaseDate">July 10, 2012</div><p>Worldwide, 2011 was the coolest year on record since 2008, yet
temperatures remained above the 30 year average, according to the <em>2011 State of the Climate</em> report released <a href="http://www.ncdc.noaa.gov/bams-state-of-the-climate/2011.php">online</a>
today by NOAA. The peer-reviewed report, issued in coordination with
the American Meteorological Society (AMS), was compiled by 378
scientists from 48 countries around the world. It provides a detailed
update on global climate indicators, notable weather events and other
data collected by environmental monitoring stations and instruments on
land, sea, ice and sky.</p><p>“2011 will be remembered as a year of extreme events, both in
the United States and around the world,” said Deputy NOAA Administrator
Kathryn D. Sullivan, Ph.D. “Every weather event that happens now takes
place in the context of a changing global environment. This annual
report provides scientists and citizens alike with an analysis of what
has happened so we can all prepare for what is to come.”</p><p>Two back-to-back La Niñas, each characterized by
cooler-than-average water temperatures in the eastern equatorial
Pacific, affected regional climates and influenced many of the world’s <a href="http://www.climatewatch.noaa.gov/article/2012/state-of-the-climate-in-2011-highlights/2">significant weather events</a>
throughout the year. These included historic droughts in East Africa,
the southern United States and northern Mexico. La Niña conditions
contributed to an above-average tropical cyclone season in the North
Atlantic hurricane basin and a below-average season in the Eastern
North Pacific. It was also associated with the wettest two-year period
(2010–2011) on record in Australia, which was particularly remarkable as
the wet conditions followed a decade-long dry spell.</p><p>The Arctic continued to show more rapid changes than the rest of the
planet. Sea ice shrank to its second smallest “summer minimum” extent
on record during 2011, as older ice (four to five years old) reached a
new record minimum at more than 80 percent below average. Overall,
glaciers around the world continued to lose mass. Loss from Canadian
Arctic glaciers and ice caps were the greatest since measurements began
in 2002.</p><p>The report used 43 climate indicators to track and identify
changes and overall trends to the global climate system. These
indicators include greenhouse gas concentrations, temperature of the
lower and upper atmosphere, cloud cover, sea surface temperature, sea
level rise, ocean salinity, sea ice extent and snow cover. Each
indicator includes thousands of measurements from multiple independent
datasets.</p><p><strong><em>Highlights:</em></strong></p><ul>
<li><strong>Warm temperature trends continue:</strong> Four
independent datasets show 2011 among the 15 warmest since records began
in the late 19th century, with annually-averaged temperatures above
the 1981–2010 average, but coolest on record since 2008. The Arctic
continued to warm at about twice the rate compared with lower latitudes.
On the opposite pole, the South Pole station recorded its all-time
highest temperature of 9.9°F on December 25, breaking the previous
record by more than 2 degrees.<br>
<br>
</li>
<li><strong>Greenhouse gases climb:</strong> Major greenhouse gas
concentrations, including carbon dioxide, methane, and nitrous oxide,
continued to rise. Carbon dioxide steadily increased in 2011 and the
yearly global average exceeded 390 parts per million (ppm) for the
first time since instrumental records began. This represents an
increase of 2.10 ppm compared with the previous year. There is no
evidence that natural emissions of methane in the Arctic have increased
significantly during the last decade.<br>
<br>
</li>
<li><strong>Arctic sea ice extent decreases: </strong>Arctic sea
ice extent was below average for all of 2011 and has been since June
2001, a span of 127 consecutive months through December 2011. Both the
maximum ice extent (5.65 million square miles, March 7) and minimum
extent (1.67 million square miles, September 9) were the second
smallest of the satellite era.<br>
<br>
</li>
<li><strong>Ozone levels in Arctic drop:</strong> In the upper
atmosphere, temperatures in the tropical stratosphere were higher than
average while temperatures in the polar stratosphere were lower than
average during the early 2011 winter months. This led to the lowest
ozone concentrations in the lower Arctic stratosphere since records
began in 1979 with more than 80 percent of the ozone between 11 and 12
miles altitude destroyed by late March, increasing UV radiation levels
at the surface.</li><li></li><ul><li><strong>Sea surface temperature & ocean heat content rise:</strong>
Even with La Niña conditions occurring during most of the year, the
2011 global sea surface temperature was among the 12 highest years on
record. Ocean heat content, measured from the surface to 2,300 feet
deep, continued to rise since records began in 1993 and was record
high.<br>
<br>
</li>
<li><strong>Ocean salinity trends continue:</strong> Continuing a
trend that began in 2004 and similar to 2010, oceans were saltier than
average in areas of high evaporation, including the western and
central tropical Pacific, and fresher than average in areas of high
precipitation, including the eastern tropical South Pacific, suggesting
that precipitation is increasing in already rainy areas and
evaporation is intensifying in drier locations.</li>
</ul><li>
<p>The report also provides details on a number of extreme events
experienced all over the globe, including the worst flooding in
Thailand in almost 70 years, drought and deadly tornado outbreaks in
the United States, devastating flooding in Brazil and the worst summer
heat wave in central and southern Europe since 2003.</p>
<p>The <em>2011 State of the Climate</em> report is peer-reviewed and published annually as a special supplement to the <em>Bulletin of the American Meteorological Society</em>.
The report is part of a suite of climate services NOAA provides
government, business and community leaders so they can make informed
decisions. It was edited by Jessica Blunden, Ph.D., and Deke Arndt of
NOAA’s National Climatic Data Center. The <a href="http://www.ncdc.noaa.gov/bams-state-of-the-climate/2011.php">full report</a> can be viewed online. The <a href="http://www.climatewatch.noaa.gov/article/2012/state-of-the-climate-in-2011-highlights">report highlights</a> are available online.<br>
</p>
<p>Additionally, for the first time a complementary article has
been published by AMS today examining the linkages between climate
change and extreme events of 2011. The paper looks at six global
extreme weather and climate events from last year. <br>
<br>
<strong><em>Findings:</em></strong></p>
<ul>
<li>Determining the causes of extreme events remains difficult.
While scientists cannot trace specific events to climate change with
absolute certainty, new and continued research help scientists
understand how the probability of extreme events change in response to
global warming.<br>
<br>
</li>
<li>La Niña-related heat waves, like that experienced in Texas
in 2011, are now 20 times more likely to occur during La Niña years
today than La Niña years fifty years ago.<br>
<br>
</li>
<li>The UK experienced a very warm November 2011 and a very cold
December 2010. In analyzing these two very different events, UK
scientists uncovered interesting changes in the odds. Cold Decembers
are now half as likely to occur now versus fifty years ago, whereas
warm Novembers are now 62 times more likely.<br>
<br>
</li>
<li>Climate change cannot be shown to have played any role in
the 2011 floods on the Chao Phraya River that flooded Bangkok,
Thailand. Although the flooding was unprecedented, the amount of rain
that fell in the river “catchment” area was not very unusual. Other
factors, such as changes in reservoir policies and increased
construction on the flood plain, were found most relevant in setting the
scale of the disaster.</li>
</ul>
<p>The paper, <em>Explaining Extreme Events of 2011 from a Climate Perspective</em>,
was produced by NOAA and UK Met Offices scientists as well as numerous
colleagues around the world. It was edited by Thomas Peterson, NOAA’s
National Climatic Data Center; Peter Stott, UK Met Office-Hadley
Center; and Stephanie Herring, NOAA’s<strong> </strong>Office of Program Planning and Integration. The <a href="http://www.ncdc.noaa.gov/bams-state-of-the-climate/2011.php">study</a> can be viewed online.</p>
<p>NOAA’s mission is to understand and predict changes in the
Earth's environment, from the depths of the ocean to the surface of the
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</li></ul><div>---------------------------------------</div><div>Vision2020 Post: Ted Moffett</div>