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Friday, January 11, 2013

Jeff Masters: Top Ten Global Weather Events of 2012

by Jeff Masters, Ph.D., WunderBlog, Wunderground, January 11, 2013

It was another year of incredible weather extremes globally during 2012. The year featured two of the most expensive weather disasters in world history -- Hurricane Sandy and the Great U.S. Drought of 2012, which will both cost more than $50 billion. Thankfully, no disasters had a death toll in excess of 2,000, though the 1,901 people dead or missing due to Super Typhoon Bopha in the Philippines may rank as that nation's 2nd deadliest typhoon ever. Twenty-six weather disasters costing at least $1 billion occurred globally, according to insurance broker AON Benfield. Eleven billion-dollar weather disasters hit the U.S., a figure exceeded only by the fourteen such disasters in 2011. Nine billion-dollar weather disasters hit China, their highest total in a decade of record-keeping. I present for you, now, the top ten global weather stories of 2012, chosen for their meteorological significance and human and economic impact:

1. New Record Minimum for Arctic Sea Ice (September 16)
Sea ice extent in the Arctic fell to 3.41 million square kilometers on September 16, breaking the previous all-time low set in 2007 by 18% --despite the fact that 2012's Arctic weather was much cloudier and cooler than in 2007. Nearly half (49%) of the icecap was gone during 2012's minimum, compared to the average minimum for the years 1979-2000. This is an area approximately 43% of the size of the contiguous United States. And, for the fifth consecutive year -- and fifth time in recorded history -- ice-free navigation was possible in the Arctic along the coast of Canada (the Northwest Passage), and along the coast of Russia (the Northeast Passage or Northern Sea Route). 

"We are now in uncharted territory," said NSIDC Director Mark Serreze. "While we've long known that as the planet warms up, changes would be seen first and be most pronounced in the Arctic, few of us were prepared for how rapidly the changes would actually occur. While lots of people talk about opening of the Northwest Passage through the Canadian Arctic islands and the Northern Sea Route along the Russian coast, twenty years from now from now in August you might be able to take a ship right across the Arctic Ocean." 

Arctic sea ice is an important component of the global climate system. The polar ice caps help to regulate global temperature by reflecting sunlight back into space. White snow and ice at the poles reflects sunlight, but dark ocean absorbs it. Replacing bright sea ice with dark ocean is a recipe for more and faster global warming. The fall air temperature over the Arctic has increased by 4-6 °F in the past decade, and we could already be seeing the impacts of this warming in the mid-latitudes, by an increase in extreme weather events. Another non-trivial impact of the absence of sea ice is that is causes increased melting in Greenland, contributing to sea level rise.

Figure 1. A sunny, slushy day near the North Pole on September 1, 2012. Webcam image courtesy of the North Pole Environmental Observatory. It won't be many years before Santa's workshop needs pontoons in the summer to stay afloat.

2. Agricultural Drought in the U.S., Europe, and Asia (Summer)
Drought is civilization's great enemy, and the most dangerous threat from global warming. Drought impacts the two things we need to live -- food and water. When the rains stop and the soil dries up, cities die and civilizations collapse, as people abandon lands no longer able to supply them with the food and water they need to live. In a harbinger of things to come, severe droughts affected important agricultural regions across the globe during summer 2012, including eastern Russia, Ukraine, Kazakhstan, and central North America. Wheat, corn, and soybean crops were among those heavily impacted; global food prices rose by 10% during July. While it will be several months before the costs of America's worst drought since the 1930s Dust Bowl are known, the 2012 drought is expected to cut America's GDP by 0.5-1.0 percentage points, said Deutsche Bank Securities. Since the U.S. GDP is approximately $15 trillion, the drought of 2012 represents a $75-$150 billion hit to the U.S. economy. This is in the same range as the estimate of $77 billion in costs for the drought, made by Purdue University economist Chris Hurt in August, and the Great U.S. Drought of 2012 is going to be one of the top-five most expensive weather disasters in world history.

Figure 2. Corn in Colby, Kansas, withers in the Great Drought of 2012 on May 27. Image credit: Wunderphotographer treeman.

3. Superstorm Sandy (October 29)
Hurricane Sandy was the most powerful and second most destructive Atlantic hurricane in recorded history. Ten hours before landfall, at 9:30 a.m. EDT October 29, the total energy of Sandy's winds of tropical storm-force and higher peaked at 329 terajoules -- the highest value for any Atlantic hurricane since at least 1969, and equivalent to more than five Hiroshima-sized atomic bombs. At landfall, Sandy's tropical storm-force winds spanned 943 miles of the the U.S. coast. No hurricane on record has been larger. Sandy's huge size prompted high wind warnings to be posted from Chicago to Eastern Maine, and from Michigan's Upper Peninsula to Florida's Lake Okeechobee -- an area home to 120 million people. Sandy's winds simultaneously caused damage to buildings on the shores of Lake Michigan at Indiana Dunes National Lake Shore, and toppled power lines in Nova Scotia, Canada -- locations 1,200 miles apart! Sandy made landfall near Atlantic City, NJ, on October 29, with sustained winds of 80 mph and a central minimum pressure of 946 mb -- the lowest pressure on record along the Northeast coast. The Battery, in New York City Harbor, had an observed water level of 13.88 feet, besting the previous record set by Hurricane Donna in 1960 by 3 feet. Sandy's catastrophic storm surge was responsible for the majority of the 131 deaths and $62 billion in damage in the U.S. Sandy also brought torrential rainfall in excess of 12 inches to the mid-Atlantic, and blizzard conditions to the central and southern Appalachians. Sandy's late-season show of unprecedented strength, unusual track, and exceptionally damaging storm surge were made more likely due to climate change, and the storm helped bring more awareness and debate about the threat of climate change to the U.S. than any event since Hurricane Katrina in 2005.

Figure 3. Hurricane Sandy at 10:10 a.m. EDT, October 28, 2012. Image credit: NASA/GSFC.

4. Greenland Ice Sheet melt and Glacier Calving (July)
Measurements from three satellites showed that on July 8, about 40% of the Greenland ice sheet had undergone thawing at or near the surface. But during four consecutive days July 11-14, temperatures rose above freezing at the top of the Greenland Ice Sheet, which is 10,551 feet (3,216 meters) above sea level and 415 miles (670 km) north of the Arctic Circle. Melting of the ice sheet dramatically accelerated, and an estimated 97% of the ice sheet surface had thawed by July 12. This was the greatest melt since 1889, according to ice core records. 

On July 16, an iceberg twice the size of Manhattan calved from the Petermann Glacier in Northeast Greenland. This was the second huge ice island to calve from the glacier since 2010. The glacier's margins have now retreated to the farthest point in the last 150 years. The record melt in Greenland caused the highest loss of ice mass observed in the satellite era, and melting from Greenland is now thought to cause about 0.7 mm/year of global sea level rise, which is about 20-25% of the global total.

Figure 4. The massive 46-square-mile iceberg two times the size of Manhattan that calved from Greenland's Petermann Glacier on July 16, 2012, as seen on July 21, 2012, using MODIS satellite imagery. Image credit: NASA.

5. Super Typhoon Bopha (December 3-4)
The deadliest weather disaster of 2012 was Super Typhoon Bopha. Bopha was the strongest typhoon ever hit the southern Philippine island of Mindanao, making landfall as a Category 5 super typhoon with winds of 160 mph (260 km/h) on December 3. Bopha made two additional landfalls in the Philippines, on central Visayas and on Palawan, on December 4. The typhoon left 1,901 people dead or missing, mostly on the island of Mindanao. If the missing people are presumed dead, this total would make Bopha the 2nd deadliest typhoon in Philippine history. Bopha affected over 5.4 million people and left over 700,000 people homeless. With damages estimated at $1.04 billion, Bopha is the most costly typhoon ever to hit the Philippines. The previous record was the $600 million price tag of 2009's Typhoon Parma. 

Figure 5. December 7, 2012: rescuers and residents look for missing victims amongst toppled tree trunks and coconut shells after flash floods caused by Super Typhoon Bopha hit Compostela Valley on Mindanao Island in the Philippines on December 3-4, 2012. (AP Photo/Jay Morales, Malacanang Photo Bureau, HO)

6. Northern Hemisphere Warmth (throughout 2012)
Land areas in the Northern Hemisphere reached record warm monthly values for four consecutive months (April-July). Much of the unusual warmth occurred in North America; Canada was 3rd warmest on record for the period January-September, and the United States had its warmest year on record. Many European countries and Russia had record to near-record warm summer temperatures in 2012.

Figure 6. This young lady chose to cool her heels in the Fox River on June 28, 2012, as the temperature was topping 102 degrees in Carpentersville, IL, imag credit: wunderphotographer pjpix.

7. Eurasian Continent Cold Wave (January 24- February 17)
Europe's worst cold snap in at least 26 years hit central and eastern Europe hard during a 3-week period in late January and the first half of February. The 824 deaths being blamed on the cold wave made it 2012's second deadliest weather disaster. Parts of the Danube River froze over for the first time in 25 years, and Northeast China through eastern Inner Mongolia recorded extremely cold minimum temperatures ranging between -30 and -40 °C.

Figure 7. Snow falls in Trogir, Croatia, on February 3, 2012. Image credit: wunderphotographer antoniomise.

8. China Floods (July 21-22)
Torrential downpours on July 21-22 affected Beijing, Tianjin, and Hebei, with several stations recording their highest daily precipitation on record. Mentougou recorded an impressive 305.2 mm (12 inches) of precipitation in one day. The floods killed 129 people and did $4.8 billion in damage, one of a record 9 billion-dollar weather disasters to affect China in 2012.

Figure 8. A Chinese man uses a signboard to signal motorists driving through flooded street following a heavy rain in Beijing Saturday, July 21, 2012. China's government says these were the heaviest rains to hit Beijing in six decades. The torrential downpour left low-lying streets flooded and knocked down trees. (AP Photo)

9. Pakistan Floods (August 21-September 30)
Torrential monsoon rains caused deadly floods in Pakistan, with Balochistan, Punjab, and Sindh provinces the hardest hit. Over 5 million people and over 400,000 hectares of crops were affected by the floods, with more than 460,000 houses and infrastructures damaged or destroyed. The death toll of 455 made it Earth's 3rd deadliest weather-related disaster of 2012.

Figure 9. A driver makes his way on a street flooded from heavy rain in Peshawar, Pakistan, Tuesday, August 28, 2012. (AP Photo/Mohammad Sajjad)

10. African Floods (July-October)
Heavy rains in Nigeria killed at least 431, making it Earth's 4th deadliest weather disaster of 2012. Over 3 million people were affected by flooding across 15 countries in Africa, most notably Nigeria, Niger, Senegal, and Chad. The floods destroyed farmlands, homes, and schools, and caused outbreaks of cholera and other diseases.

Other Top Ten Weather Lists of 2012
My Top Ten U.S. Weather Events of 2012.

Wunderground's Angela Fritz's has a list of Top Climate Events of 2012.

A group of seventeen climate scientists and climate bloggers created a Climate Disruption: Critical 2012 Events and Stories list of 19 key climate change events that occurred in 2012.

TWC's Stu Ostro has his annual post showing his pick for top weather images of 2012.

Climate Central has a top-ten most striking images of 2012 post.

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