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Entries in Climate Change (4)

Wednesday
Sep192012

Arctic Sea Ice at Lowest Extent Ever Recorded

iStockphoto/Thinkstock(BOULDER, Colo.) -- Sea ice around the North Pole melted away to record-breaking levels over the summer of 2012, surpassing the previous 2007 record by 293,000 square miles -- an area about the size of Texas.

The northern polar ice cap measured 1.32 million square miles on Sunday, according to the National Snow and Ice Data Center (NSIDC) in Boulder, Colo. The 2007 record was 1.61 million square miles.

The trend continues a downward spiral that a majority of climate scientists say is being accelerated by humans burning fossil fuels, contributing to a greenhouse effect that is warming the planet.

Since 1980, the amount of Arctic ice lost roughly equals the combined area of all states east of the Mississippi, plus Minnesota, Iowa, Missouri, Arkansas, Louisiana, Nebraska, Kansas and the Dakotas, NSIDC director Mark Serreze told ABC News.

“We are now in uncharted territory,” Serreze said.

Scientists have been tracking Arctic ice using satellites since 1979. The ice melts over the summer and then refreezes during winter. Scientists worry, however, that the ice isn’t as “healthy” as it used to be. Thick “multiyear” ice capable of surviving warm summers is increasingly replaced by thinner ice that is more vulnerable to rising temperatures.

As a consequence, disappearing sea ice (which reflects much of the sun’s energy) reveals darker sea water underneath, absorbing more of the sun’s energy and speeding up warming.

The effect of losing what scientists sometimes refer to as “the refrigerator at the top of the planet” goes far beyond the Arctic.

New research suggests a changing Arctic may cause weather patterns like the jet stream to shift, leading to more extreme weather in the United States and around the globe.

While melting sea ice is already floating and does not increase sea level, warming ocean waters can affect what happens in places like Greenland. As ice calves off the land into the water, sea level rises. If Greenland melted away completely (and that won’t happen anytime soon), scientists say global sea level could rise by about 20 feet.

Copyright 2012 ABC News Radio

Sunday
Apr012012

Global Warming Denialism 'Just Foolishness,' Scientist Says

Comstock/Thinkstock(NEW YORK) -- One of the world’s most widely known and respected senior scientists told ABC News that current denial about the basic daunting realities of manmade global warming is “just foolishness.”

He also reports that the rest of the world has now “pretty well given up” on its hope for U.S. leadership in dealing with global climate change.

His assessment reinforces ABC News’ findings at the recent global climate summit in Durban, South Africa, that the vigorous anti-climate science movement in the United States has significantly damaged American prestige among European leaders who are struggling to deal with the daunting impacts of global warming.

Peter Raven, co-inventor in 1964, along with biologist Paul R. Ehrlich, of the bedrock concept of co-evolution, has long been a trusted adviser of American presidents, many other heads of state and government, religious leaders including popes, and countless congressional, academic and scientific leaders in the United States and around the world.

A frequent world traveler for his work, Raven reconfirmed in an email from the international Planet Under Pressure conference in London what he first told ABC News in 2010 in St. Louis.

When asked what he thought about the increasing claims of some parties in the United States that the science and alarm about manmade global warming was “a hoax” or greatly overblown, he responded patiently, “Oh, it’s just foolishness.”

“It’s not a matter of conjecture anymore,” he said. “Climate change is the most serious challenge probably that the human race has ever confronted.”

Raven quickly summarized the virtually unanimous understanding of the world’s climate scientists and other responsible experts about the great upheavals manmade global warming is now producing.

 “There is virtually unanimous consensus among the world’s scientists who work in the area that human beings are the major reason that this is so (the world’s average temperature rising),” Raven wrote from London.

“Because, just as first noted by the Swedish chemist Arrhenius in 1895, when you add more carbon dioxide or other co-called greenhouse gases to the atmosphere, you make it warmer.”

Copyright 2012 ABC News Radio

Friday
Nov182011

Climate Change Report: Weather Extremes Increasing

Comstock/Thinkstock(GENEVA) -- A new report on the effects of a warming climate on the world’s weather by the United Nations-sponsored Intergovernmental Panel on Climate Change (IPCC) says that much of the world is already seeing more weather “extremes” -- stronger hurricanes and more intense heat waves -- at least partly because of the buildup of greenhouse gases in the atmosphere.

A draft summary of the report, called “Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation,” or “SREX” for short, was obtained by ABC News.

Here is a sampling of some of its findings:

On temperatures: “It is very likely that there has been an overall decrease in the number of cold days and nights, and an overall increase in the number of warm days and nights, on the global scale, i.e., for most land areas with sufficient data.”

On whether human beings are contributing to the change: “It is likely that anthropogenic influences have led to warming of extreme daily minimum and maximum temperatures on the global scale.  There is medium confidence that anthropogenic influences have contributed to intensification of extreme precipitation on the global scale.  It is likely that there has been an anthropogenic influence on increasing extreme sea levels via mean sea level contributions.”

On hurricanes and tropical storms: “Mean tropical cyclone maximum wind speed is likely to increase, although increases may not occur in all ocean basins.  It is likely that the global frequency of tropical cyclones will either decrease or remain essentially unchanged.”

A summary of the report is now up on the IPCC's website [click here to read it].  The full report will be available in February 2012, according to the site.

The report is dense, and addresses a subject that provokes strong and opposing opinions.  In part because of this, definitions of basic terms have been negotiated.  For instance, “likely” means at least a 66 percent probability that a conclusion is true, and “very likely” means at least a 90 percent probability.

Copyright 2011 ABC News Radio

Tuesday
Sep132011

Arctic Sea Ice: Why Pay Attention, Record or No Record?

Michael Blann/Thinkstock(BREMEN, Germany) -- Did Arctic sea ice melt to a record-low level this summer? Researchers at the University of Bremen in Germany believe that it did, dipping 27,000 square kilometers below the previous record low set in 2007.

However, U.S. scientists at the National Snow and Ice Data Center in Boulder, Colo., are not ready to declare that the extent of Arctic sea ice has dropped below the record level.  At this point, the expectation is that 2011 will rank second -- right behind 2007 -- for record Arctic sea ice melt. Scientists at the International Arctic Research Center in cooperation with the Japan Aerospace Exploration Agency concur. Final numbers will come in a few days.

Regardless of whether or not 2011 breaks a record, here’s the important point: Scientists say human-driven climate change continues to help push Arctic sea ice on a disturbing three-decade downward slide.

“Is Arctic ice in a death spiral? Maybe not yet, but it’s in big trouble,” NSIDC director Mark Serreze tells ABC News.

Serreze points out that the five lowest amounts of Arctic sea ice on record (since 1979) have all been recorded in the last five years. And it’s not just the amount of ice, but the quality. It’s also getting thinner, making it more sensitive to increases in temperature.

So why should we care about Arctic sea ice?

-- SEA LEVEL: Scientists tell ABC that Arctic sea ice acts as a giant air conditioner at the top of the planet, helping regulate the planet’s overall temperature. But as the white sea ice (which reflects a portion of the sun’s energy) melts, the darker water underneath absorbs energy, warming the water and creating a “feedback” that in turn, helps melt additional ice in a vicious cycle. Because it is already floating, this does not raise sea level much as it melts.

But in Greenland, it’s a different story. When ice calves off of Greenland’s glaciers, sea level rises. One recent study reported that Greenland glaciers lost 592 square miles of ice between 2000 and 2010. If Greenland melted entirely, global sea levels would rise about 20 feet.

-- WEATHER: Scientists say ice loss may help alter weather patterns across the planet. The jet stream, for example, could shift further north. That could bring more frequent and intense droughts to the U.S. A jet stream change might also affect the path of storms and hurricanes. And more open water and heat could help supercharge those storms.

Many scientists believe human-emitted greenhouse gases warming the planet are already loading the dice toward a future with more weather extremes.

-- WILDLIFE: Melting sea ice also bad news for a number of animals and organisms, including polar bears, who use the ice to hunt for food.

-- OIL AND GAS EXPLORATION: Melting ice literally removes a major barrier to oil and gas exploration in a remote and harsh environment. For years, oil companies and nations have been fighting turf wars over who gets which part of the (potentially very lucrative) sea floor. Exxon, for example, just entered into a new Arctic exploration deal with the Russian government that could be worth tens of billions of dollars.

So what’s causing the ice to melt?

It has been well-established through several peer-reviewed scientific papers that Arctic sea ice loss cannot be explained by natural causes alone. One recent study from the National Center for Atmospheric Research found that roughly half of the Arctic sea ice decline from 1975 to 2005 can be blamed on increasing amounts of greenhouse gases.

Those same researchers were surprised by computer models that predict a 10-year period where the ice melt could pause, and the amount even increase, thanks to natural weather variability that is hard to predict.

The latest thinking among scientists has summer sea ice vanishing from the Arctic well before the end of the century, perhaps within the next 50 years. Given that greenhouse gases are only expected to increase between now and then, scientists do not see a reversal of sea ice declines in the near future.

Copyright 2011 ABC News Radio







ABC News Radio