Allergy season is extending, scientists find

Bad news for those who suffer their way through ragweed season: A team of researchers has found that increased warming, particularly in the northern half of North America, has added weeks to the fall pollen season. A changing climate means allergy-causing ragweed pollen has not only a longer season but one that extends further north than it did just 16 years ago.

In research that gibes with projections by the U.N. Intergovernmental Panel on Climate Change, plant and allergy experts found that ragweed pollen season lasted as much as 27 days longer in 2009 than it did in 1995. The further north in the Western Hemisphere, the more dramatic the change in the length of pollen season.

Minneapolis has tacked 16 days to the ragweed pollen season since 1995; LaCrosse, Wisc. has added 13 days, Winnipeg and Saskatoon in Canada have added 25 and 27 days, respectively.

The new research, published Monday in the journal Proceedings of the National Academy of Sciences, finds the longer pollen seasons correlate with the disproportionate warming happening around the planet and attributed to greenhouse gas emissions.

Upper latitudes are warming faster than mid-latitudes, and the pollen season is lengthening in proportion. Scientists and health officials found no appreciable warming in Texas, Arkansas or Oklahoma.

The impact goes far beyond mere sniffles and inconvenience. Some 50 million Americans have allergies, according to the Asthma and Allergy Foundation of America. Of those, 35 million suffer nasal allergies, known broadly as hay fever, said Mike Tringale, the association's vice president.

For 75 percent of those 35 million, ragweed (right) is the primary allergen, he added. And in many cases, allergies can trigger a bout of asthma, or make it worse.

Ragweed pollen can cause asthma flare-ups and hay fever, and costs about $21 billion a year in the United States, according to the study published in the Proceedings of the National Academy of Sciences.

"This is not something that's hypothesized, this is not something that's modeled, this is not something that may or may not occur depending on the math that you do," said study author Lewis Ziska of the U.S. Department of Agriculture crop system and global change laboratory. "This is something that we're actually seeing on the ground in recent years."

Even in places where ragweed season didn't lengthen or even shortened slightly -- such as Texas, Oklahoma and Arkansas -- there was lots more pollen, which caused more intense symptoms, said co-author Dr. Jay Portnoy of the Allergy, Asthma and Immunology Section at Children's Mercy Hospital, the University of Missouri-Kansas City School of Medicine.

Ragweed is probably not the only pollen likely to have a longer season as the planet warms, Portnoy said in a telephone interview.

"We used ragweed as a marker but it's probably true for other pollens too," he said, including tree pollen that causes allergy symptoms in the U.S. spring. (Right: pollen seasons. click to see enlarged image)

Ragweed pollen was a reasonable marker because its season is naturally easy to track.

It's what's known as a short-day plant, which begins blooming when the days start getting shorter, that is, after the Northern Hemisphere summer solstice around June 21. It stops flowering with the first frost.

As global average temperatures have warmed, the first frost has been delayed, especially at higher latitudes, which has meant a longer season for ragweed. Because warming is greater at these high latitudes, the length of the season has been more pronounced.

The findings correlate with analysis last year by the National Wildlife Federation that found ragweed growth rates and pollen counts increased with global warming. In one study, accelerating spring's arrival by 30 days prompted a 54 percent increase in ragweed pollen production.

The danger with a lengthening season - and perhaps a more intense one - is pollen's potential to overwhelm immune systems that, up till now, have withstood the onslaught, Tringale said.

Much as water in a bathtub is not a problem until it starts to overflow, pollen for many is not an irritant until it crosses a particular threshold, he said.

"With the longer season, with the creeping breadth of the geographic footprint of the season, and with more powerful plants producing more pollen, it's a triple threat," he added. "Now you've got yourself a much wider population that could potentially be affected that might not have been affected before.'

Source:
Daily Climate,"Allergy season is extending, scientists find",accessed February 21,2011
Reuters,"Climate change creates longer ragweed season", accessed February 21, 2011
Scientific American, "Climate Change Extends Allergy Season in North America", accessed February 21, 2011

Australia's floods a glimpse of warmer future

Though you can't make a direct link between Australia's killer floods and climate change, they do hold a warning for the future: Scientists predict such extreme weather events will increase both in intensity and frequency as the planet warms.

Raging floodwaters have swamped thousands of homes and businesses in Queensland, leaving at least 25 people dead and dozens more missing since late November. Rail lines and highways (right) have been washed away in what is shaping up to become Australia's costliest natural disaster.

The flooding follows a spate of severe natural disasters in the past year. While the most deadly was Haiti's earthquake, extreme weather also killed thousands of people across the globe, including a scorching heat wave that choked Russia in the summer and devastating floods that engulfed more than 60,000 square miles (150,000 square kilometers) in Pakistan.

"The Earth is delivering a message to us. And the message is that more extreme weather is becoming the norm rather than the exception," said John Magrath, a climate change researcher at British charity Oxfam.

He said there is a misconception that global warming only means higher temperatures. "It actually means more energy in the climatic system, which stimulates extremes and more chaotic behavior," Magrath said.

Droughts and floods are expected to become more severe as global temperatures climb. Less clear is the impact on wind patterns and ocean currents, factors that could alter climate in potentially dramatic ways not fully understood yet.

Last year tied with 2005 as the warmest on record, with combined global land and ocean surface temperatures rising 1.12 degrees Fahrenheit (0.62 degrees Celsius) above normal, the National Oceanic and Atmospheric Administration said Wednesday.

In the U.S., it was the 23rd warmest year on record and the 14th year in a row with an annual temperature above the long-term average, according to NOAA's preliminary analysis.

Meanwhile, the extent of Arctic sea ice in the summer - a key indicator of global warming - was at its third lowest level, behind 2007 and 2008.

Most atmospheric scientists attribute most of the warming seen in recent decades to gases released into the air by industrial processes and gasoline-burning engines.

Australia's floods, which started in late November, have been linked to the La Nina weather phenomenon, which refers to cooler than normal surface sea temperatures in parts of the Pacific, causing disruptions in weather patterns. La Nina occurs naturally, and the link to climate change remains unclear, said Omar Baddour of the World Meteorological Organization.

"But as we know, extreme events whether their cause is due to La Nina or El Nino or other factors, will be more intense in the era of climate change," he added.

Reinsurer Munich Re counted nearly 1,000 natural disasters in 2010 - nine-tenths of them weather-related - the second highest number since 1980. The resulting economic losses totaled $130 billion, the German company said earlier this month.

"The high number of weather-related natural catastrophes and record temperatures both globally and in different regions of the world provide further indications of advancing climate change," Munich Re said.

Scientists caution against drawing conclusions about climate change from a single storm, flood, cold snap or heat wave. Natural variability is and will always be a factor when it comes to extreme weather.

Still, single events can be useful in highlighting shortcomings in our preparedness for a warmer world more prone to extremes, said Markku Rummukainen, a climate scientist at Lund University in Sweden.

"For example, that Hurricane Katrina hit New Orleans does not have to have anything to do with climate change, but it revealed vulnerabilities that hadn't been considered," said Rummukainen, who is also involved in drafting the next report by the U.N.'s expert panel on climate change. "It remains to be seen what conclusions can be drawn in Australia."

Source:
Lake Wylie Pilot,"Australia's floods a glimpse of warmer future",By Karl Ritter, accessed January 15, 2011

Climate change leaves Assam tea growers in hot water

Climate change is affecting the cultivation of Assam tea, with rising temperatures reducing yields and altering the distinctive flavor of India's most popular drink, researchers say.

High hills and abundant rainfall make the north-eastern state of Assam an ideal place to grow tea, with 850 gardens over 320,000 hectares (593,000 acres) producing the majority of the country's harvest. But in the last 60 years, rainfall has fallen by more than a fifth and minimum temperature has risen by a degree to 19.5C.

"This is clearly climate change, and it is bound to have major impact on the tea industry," said Debakanta Handique, a climate scientist in Assam.

The Tea Board of India said it had recorded a steady decline in tea production in recent years. In 2007, Assam produced 512,000 tons of tea. By 2008 this had declined to 487,000 tons, with estimated production in 2009 down again to 445,000. A further decrease is expected this year.

Mridul Hazarika, director of Tocklai Tea Research, the oldest tea research station in the world, said rainfall and minimum temperature were two of the most important factors affecting both quality and quantity of harvests.

"The decline has been taking place although there has been an increase in the area of tea cultivation as new gardens have come up, and many gardens have added new areas for tea plantation. This is an indication of the seriousness of the threat," said Hazarika. Efficient rainwater harvesting and new breeds of tea plants were needed to reverse the trend.

"Changes have already been observed in the flavor, but it is not possible to blame only climate change for this," he said. "Other factors like the fertilizers used and cultivation methods might also be partly responsible."

The changing taste of Assam tea is a serious concern for growers. Sudipta Nayan Goswami, an Assam-based planter, said subtle changes had already been observed: "The flavor has changed from what it was before. The creamy and strong flavor is no more."

"There is a huge demand for Assam tea abroad, and this is due to its strong, bright flavor. The changes will sharply hamper the demand for this variety of tea abroad."

Source:
The Guardian,"Climate change leaves Assam tea growers in hot water", accessed December 28, 2010

Wolverine latest wildlife endangered by climate change

Climate change may spell disaster for wolverines (left), a reclusive resident of the mountains of the Northwest, but other species are in more imminent danger and will delay protection for the small, ferocious mammals, wildlife officials said Monday.

The population of wolverines in the contiguous United States has rebounded to an estimated 250 to 300 since the early 20th century, when predator control in the West nearly wiped them out, the U.S. Fish and Wildlife Service said in its report.

The U.S. Fish and Wildlife Service said in their report that the wolverine warrants protection under the Endangered Species Act.

"After review of all available scientific and commercial information, we find that the North American wolverine occurring in the contiguous United States is a distinct population segment and that addition of this population to the lists of endangered and threatened wildlife and plants is warranted," said the agency.

The agency said the impact of climate change constitutes a threat to the contiguous U.S. population of the wolverine and will likely be irreversible within the foreseeable future. The population of the wolverine of North America is likely to become in danger of extinction in the foreseeable future due to destruction, modification and curtailment of its habitat and range. (Left: historical wolverine distribution in western US)

The wolverine is the largest member of the weasel family, weighing up to thirty pounds. With its dark, shaggy hair and short bushy tail, the wolverine looks something like a small bear. It lives in northern forests. Wolverines are cousins to everything from sea otters to skunks. They are known for their voracious appetites, cantankerous dispositions, skunk-like scent for defense and preference for extreme alpine environments.

Wolverines need deep snow for successful wolverine reproduction because female wolverines dig elaborate dens in the snow for their offspring. The den structures are thought to protect wolverine kits from predators as well as harsh alpine winters. However, warmer winter temperatures are reducing the snow pack in the West, making climate change the "primary threat to the wolverine population," the report said.

Environmental models project the wolverines' habitat will shrink by roughly a quarter by 2045 and nearly two-thirds by 2099, agency wildlife biologist Shawn Sartorius said. (at left:Historical wolverine distribution overlaid on map of probable snow cover during denning period.)

That means the animals will not be added to the federal Lists of Endangered and Threatened Wildlife and Plants. Instead, it will join the sage grouse, plains bison and hundreds of other species on a candidate species list awaiting federal protection.

While the polar bear in 2008 was the highest profile species to receive U.S. government protection because of the warming global climate, the wolverine is also affected.

Scientists say wolverine numbers in the high country of Idaho, Montana, Washington and Wyoming have dwindled to fewer than 300 and they are virtually gone from the rest of their historic range in the lower 48 states -- including Michigan where the University of Michigan mascot is the wolverine. (At right: recent distributions of wolverines)

Wolverines, which eat meat and range from 17 to 40 pounds, need deep snow in seclusion to reproduce and raise their young. Mother wolverines dig elaborate snow caves for dens.

A study by the University of Washington and U.S. Forest Service Rocky Mountain Research Station predicts that a warming West will cut suitable wolverine habitat by 23 percent in 2045 and by 63 percent in 2099.

"The threats to the wolverines are long-term due to the impacts of climate change on their denning habitat, especially important to assist the species in successfully reproducing," said Steve Guertin, the U.S. Fish & Wildlife director for the agency's mountain-prairie region. "If we work with state and other partners to help the wolverine now, we may be able to counter the long-term impacts of climate change on their habitat and keep them from becoming endangered."

Extreme winter sports are making it even more difficult for wolverines, with snow-mobliers and skiers seeking the rugged and remote terrain preferred by the people-shy animals.

But Fish and Wildlife officials say the animals must get in line behind other species deemed by the service to have a higher priority as candidates for listing.

Conservation groups praised the government's decision to acknowledge the wolverine's dwindling population, but this does not does not result in a plan to protect them.

"It's a tough species to restore because we still know very little about them but it is frustrating and disappointing that we will have to wait for years until they're actually listed," said David Gaillard, Rocky Mountain representative with Defenders of Wildlife.

Wolverine whereabouts and numbers have been tracked only recently, with an estimated 100 in the Sawtooth Range of central Idaho and a high-density population of up to 50 animals in Glacier National Park (left).

Development, including cities, roads and ski resorts, has confined wolverine range to isolated islands. Scientists say that places the animals at undue risk by forcing them to wander hundreds of miles in search of mates. The distance between the semi-isolated populations is growing, making it more difficult for the wolverine groups to exchange genes and maintain a viable population.

Environmentalists last petitioned in 2000 to have wolverines added to the endangered species list. Eight years later, the government said protections were not warranted.

Conservation groups sued, forcing the Fish and Wildlife Service to revisit -- and now reverse -- the decision by the administration of former President George W. Bush.

Wolverines join more than 250 animal and plant species considered candidates for federal protections.

The wolverine has a broader range in Canada and Alaska, territory separate from the newly designated distinct population segment in Montana, Idaho, Washington, Wyoming, Colorado, Oregon, Utah and California.

In Canada, wolverines are considered endangered in the eastern part of the country and a species of special concern in the western part of the nation.

Source:
Reuters, "Wolverine latest wildlife endangered by climate change", accessed December 15, 2010
Denver Post, "Feds: Wolverine warrants protection", by Harold Pankratz, accessed December 15, 2010
Google News, "Feds: Wolverines need protection but have to wait", accessed December 15, 2010