Scientist: “With the global warming we have had during the 20th century, we have already crossed the threshold where more than half of all ‘Katrinas’ are due to global warming.”

New Orleans post-Katrina. Credit: NOAA.

By Aslak Grinsted via the Nils Bohr Institute.

By examining the frequency of extreme storm surges in the past, previous research has shown that there was an increasing tendency for storm hurricane surges when the climate was warmer. But how much worse will it get as temperatures rise in the future? How many extreme storm surges like that from Hurricane Katrina, which hit the U.S. coast in 2005, will there be as a result of global warming? New research from the Niels Bohr Institute show that there will be a tenfold increase in frequency if the climate becomes two degrees Celcius warmer. The results are published in the scientific journal, Proceedings of the National Academy of Science, PNAS.

The extreme storm surge from Superstorm Sandy in the autumn 2012 flooded large sections of New York and other coastal cities in the region – here you see Marblehead, Massachusetts. New research shows that such hurricane surges will become more frequent in a warmer climate.

Tropical cyclones arise over warm ocean surfaces with strong evaporation and warming of the air. The typically form in the Atlantic Ocean and move towards the U.S. East Coast and the Gulf of Mexico. If you want to try to calculate the frequency of tropical cyclones in a future with a warmer global climate, researchers have developed various models. One is based on the regional sea temperatures, while another is based on differences between the regional sea temperatures and the average temperatures in the tropical oceans. There is considerable disagreement among researchers about which is best.

New model for predicting cyclones

“Instead of choosing between the two methods, I have chosen to use temperatures from all around the world and combine them into a single model,” explains climate scientist Aslak Grinsted, Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.

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Hurricane Sandy approaches the Atlantic coast October 29, 2012. (NASA image.)

By Adam Voiland, via NASA’s Earth Observatory

Few images are as beautiful and as terrifying as a satellite view of a hurricane about to make landfall. On October 29, 2012, the Suomi NPP satellite captured an ominous nighttime view of Sandy — an enormous hybrid storm that was part hurricane, part Nor‘easter — churning off the coast of New Jersey.

The string of city lights that stretches from Washington to Boston was mostly gone, blanketed by thick, ghostly storm clouds. One of the most brightly lit cities in the world, New York, was little more than a faint smudge through Sandy’s clouds.

In a matter of hours, that smudge of light would go dark. Large swaths of Manhattan were under water. The Rockaways were on fire. Rooftops along the New Jersey shore became temporary islands for people escaping a wall of seawater that surged inland.

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Killer tornadoes are marking the transition from a freakishly warm winter into yet another freakishly dangerous spring. The multi-billion-dollar drought in Texas and Oklahoma is expected to continue into the indefinite future. Planting seasons, maple syrup seasons, and cherry blossom festivals are starting at weirder and weirder times. Torrential rains and record heat waves are becoming commonplace. Migrating birds are straying from their normal path, insect pests are multiplying, and trees are dying.

Americans are starting to trust the evidence of their own senses about the growing impacts of climate change, instead of the barrage of misinformation and confusion that comes from media sources. A new poll from the Brookings Institution shows that a strong majority of the American public agree that there is “solid evidence that average temperatures on earth have been getting warmer over the past four decades,” and “about half of Americans now point to observations of temperature changes and weather as the main reasons they believe global warming is taking place”:

A sampling of the open-ended comments provided by survey respondents helps demonstrate the role that weather plays in shaping individual views on global warming. A male senior citizen from Illinois, who feels that there is solid evidence of global warming, said that the primary reason that led him to this conclusion was “winters just aren’t as cold as they were in the past.” Similarly, a middle-aged woman in Florida attributed her position on global warming primarily to her observations that “this time of year is warmer than it is expected to be.” A young man in Texas identified the primary reason for his view that the Earth is warming to “temperatures last summer that were awful,” while another young Texan stated that the “droughts this past summer” were the primary reason that she believed temperatures on earth were increasing. In these cases and many others Americans turn first to the weather they experience as the key reason for their acceptance of global warming.

This intuitive, natural approach tying the long-term warming of the entire planet by fossil-fuel pollution to local observations is backed by the science. Scientific research has determined that the continental United States is growing hotter in every state, with greater extremes in precipitation. The warming of the oceans and atmosphere has fueled the freak droughts and heat waves that the poll respondents cited. In almost every measure, the weather of the United States has diverged perceptibly from the 20th-century norm — in line with scientific projections of the consequences of global warming pollution.

In 1988, NASA climate scientist James Hansen predicted that the local changes in temperature caused by global warming pollution would become apparent in everyday life by the 21st century. That prediction has now come to pass — despite billions of dollars spent by polluters to argue against the evidence of people’s own senses.

In short, our weather has been poisoned by the fossil fuel industry, and every day more and more Americans know it, just by going outside.

Scientists have tied the rapid decline of Arctic sea ice, caused by global warming pollution, to the recent extreme winters that hit the United States last year and Europe this year. In “Impact of declining Arctic sea ice on winter snowfall,” a new report published by the Proceedings of the National Academy of Sciences, researchers find that the loss of polar ice has changed atmospheric circulation and increased atmospheric water vapor, driving the popularly-dubbed “snowpocalypse” conditions:

We conclude that the recent decline of Arctic sea ice has played a critical role in recent cold and snowy winters.

Sea ice decline is contributing to catastrophic, deadly winters in two ways, the researchers find. The loss of ice changes wind patterns over the northern oceans, which in turn disrupts the jet stream, allowing cold polar air to plunge across the northern hemisphere. “If there is a dramatic loss of Arctic sea ice, the westerly winds that blow across the North Pacific and North Atlantic oceans are weakened,” lead author Jiping Liu, a senior research scientist at the Georgia Institute of Technology, told Climatewire. “This means we will have a wavier jet stream.”

The loss of ice and warmer temperatures mean that there is much more evaporation from the Arctic Ocean, leading to a higher moisture content in the polar air that is pulled south. That means that intense snowfall is more likely, especially as the polar air collides with warm, moist air from the south.

In 1999, Kevin Trenberth explained how global warming would lead to more intense precipitation events, including snow storms.

The decline in Arctic sea ice is one of the primary indicators of man-made global warming. Arctic sea ice cover began shrinking decades ago, with a rapid acceleration in the last decade. Sea ice decline has been much more rapid than projected by climate models. Some scientists now expect the Arctic to be effectively ice-free during the summer in less than 30 years. The United States and other nations have responded to this troubling collapse of the planetary thermostat by making plans to drill for fossil fuels in the Arctic oceans. That decision hastens our march into a “no-analogue world,” in the words of NOAA administrator Jane Lubchenco.

As carbon pollution accumulates in the atmosphere, our weather is growing more intense and unpredictable, threatening the health of the union. Following the freakishly warm and dry start of this January, extreme storms then pummeled the nation:

WASHINGTON ICE STORM: “A monster Pacific Northwest storm coated the Seattle area in a thick layer of ice Thursday and brought much of the state to a standstill, sending hundreds of cars spinning out of control, temporarily shutting down the airport and knocking down so many trees that members of the Washington State Patrol brought chain saws to work. East of Seattle, a man was killed by a falling tree as he was backing an all-terrain vehicle out of a backyard shed, authorities said.” 90,000 customers of Puget Sound Energy lost power.

OREGON FLOODS: With a persistent flow of Pacific moisture targeting the Pacific Northwest, several inches of rain have fallen across the western third of Oregon. Widespread flooding has developed with Salem, Corvallis and Philomath just some of the cities that have dealt with the worst of the rising waters. Torrential rain swept away a car from a grocery store parking lot, killing a mother and her one-year-old son.

NEVADA WILDFIRE: A destructive wildfire erupted shortly after noon on Thursday and raced quickly through the dry countryside surrounding Reno, NV, propelled by wind gusts of 82 mph. At its height, the fire forced evacuation calls for some 10,000 people. The fire destroyed 29 homes over six square miles before a storm on Saturday brought precipitation after the region’s driest winter in recorded history. Reno had no precipitation at all in December.

JANUARY TORNADOES: Last Tuesday, a powerful storm front spawned one EF-1 tornado in metropolitan Louisville, Kentucky, and a second hit near Madison, Indiana. At least 10 tornadoes struck the South overnight Sunday as a powerful storm system moved across the Great Lakes and into southern Canada, killing two in Alabama. The tornadoes were spawned along the southern end of a front that arced through the eastern US like a comma’s tail, bringing severe thunderstorms, hail, and twisters to Arkansas, Mississippi, Alabama, and Tennessee before moving into Georgia later Monday morning.

Extreme weather is wreaking increasing damage on the people of the United States. With cutbacks in local, state, and federal government services, continued inaction on fighting greenhouse pollution, and ideological opposition to preparing for the ravages of unchecked climate change, the state of our union is under threat.

The headlines of 2011 were driven by global warming disasters and the popular uprising against the powers-that-be who have accumulated profit at the expense of the future of humanity. The United States faced the most billion-dollar climate disasters ever, with 14 distinct disasters costing at least $53 billion to the U.S. economy. Stymied by the election of the science-denying Tea Party Congress, the Obama administration failed to pass climate pollution or oil and coal safety legislation in response to the disasters of 2010. The administration fought back attacks on investment in renewable energy and stopped the rush to build the Keystone XL tar sands pipeline, spurred by mass protests.

A torn American flag stands in the wreckage of a church in Joplin May 24. (Robert Ray/Associated Press)

A monstrous dust storm (Haboob) roared through Phoenix, Arizona in July. (danbryant.com)

Cars are abandoned on Chicago’s Lake Shore Drive during the “Snowpocalypse” in February. (chicagotribune.com)

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