Climate: Antarctica surface melting speeds up

Ice core study shows rapid pace of change along Antarctic Peninsula

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Warmer summer temperatures along the Antarctic Peninsula are starting to take a toll on ice and snow in the region. Bob Berwyn photo. (Dundee Island).

By Bob Berwyn

FRISCO — Careful study of a 1,200-foot long ice core sample spanning 1,000 years suggests that summer ice melt in parts of the Antarctic Peninsula region has intensified almost tenfold. About 5 percent of the annual snowfall has been melting in recent years, compared with only about 0.5 percent during the coolest phase (about 600 years ago) of that 1,000-year span.

“This is the first time it has been demonstrated that levels of ice melt on the Antarctic Peninsula have been particularly sensitive to increasing temperature during the 20th Century,” said Dr. Nerilie Abram, a climate researcher at Australian National University who studied the ice core from James Ross Island.

Most of the increased melting occurred during the past half-century, corresponding with the era of increasing greenhouse gas emissions and a remarkable warmup around the peninsula and some other parts of Antarctica. Borehole temperature estimates from the West Antarctic Ice Sheet also indicate rapid acceleration of West Antarctic warming during the past two decades. Continue reading

Climate: World’s biggest, oldest trees dying fast

Global trend concerns leading ecologists

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Ancient Colorado lodgepole pines have been killed by pine beetles, Bob Berwyn photo.

By Summit Voice

SUMMIT COUNTY — Colorado ‘s old lodgepoles aren’t the only forest giants that are dying. Around the world, the biggest, oldest trees that harbor and sustain countless birds and other wildlife, are meeting the same fate.

Three of the world’s leading ecologists say they’ve documented an alarming increase in the death rate of trees between 100 and 300 years old in many of the world’s forests, woodlands, savannahs, farming areas and even in cities.

“It’s a worldwide problem and appears to be happening in most types of forest,” said lead author Professor David Lindenmayer, of the ARC Centre of Excellence for Environmental Decisions and Australian National University. Continue reading

Climate: Antarctic ice shelves poised for collapse

Gradual warming over centuries set stage for disintegration

New ice core studies may help predict the fate of Antarctic Peninsula ice shelves. Bob Berwyn photo.

By Summit Voice

SUMMIT COUNTY — A new set of ice cores from James Ross Island in the Antarctic are helping to shed some light on long-term climate change in the reason.

After examining the 15,000-year climate record in the ice cores, the research team concluded that the rapid warming of this region over the last 100 -years has been unprecedented and came on top of a slower natural climate warming that began around 600 years ago.

Several centuries of gradual warming set the stage for the breakup of Antarctic Peninsula ice shelves that started in the 1990s, after regional temperatures soared in the past few decades. the Antarctic Peninsula is one of the fastest-warming areas of the globe — average temperatures from meteorological stations near James Ross Island have risen by nearly 2 degrees Celsius in the past 50 years. Continue reading

State of the planet: Not so good …

Humanity has global-scale impacts on key ecosystem cycles

SUMMIT COUNTY — A four-day Planet Under Pressure conference in London started with a gloomy look at the state of the Earth, as scientists said that time is running out to minimize the risk of setting in motion irreversible and long-term climate change and other dramatic changes to Earth’s life support system.

In taking stock of the Earth’s vital signs, the scientists pointed to higher levels of carbon dioxide in the atmosphere, phosphorus extraction and fertilizer production causing many large dead zones in coastal areas; rising air and ocean temperatures; melting sea ice, polar ice sheets and Arctic permafrost; rising sea levels and ocean acidification; biodiversity loss; land use changes; and growing consumption of freshwater supplies and energy by a growing global population, of which billions of people still lack even the most basic elements of well-being.

“The last 50 years have without doubt seen one of the most rapid transformations of the human relationship with the natural world,” said speaker Will Steffen, a global change expert from the Australian National University. “Many human activities reached take-off points sometime in the 20th Century and sharply accelerated towards the end of the century. We saw a ‘Great Acceleration,’ Steffen said. “It is the scale and speed of the Great Acceleration that is truly remarkable. This has largely happened within one human lifetime.” Continue reading

Study of devastating Australian bushfire reinforces the importance of clearing defensible spaces around homes

A NASA satellite image shows plumes of smoke from Australia's 2009 'Black Saturday' bushfires.

Conclusions bolster similar studies from wildfires in western U.S.

By Summit Voice

SUMMIT COUNTY — New research conducted in the aftermath of one of Australia’s most destructive wildfires reinforces conclusions from other studies suggesting that clearing vegetation close to homes is the best way to reduce impacts of severe wildfires.

The research involved 12,000 measurements at 500 houses affected by the Black Saturday fires of February 7, 2009. The fires killed 173 people and injured 414.

“More than any other major wildfire in Australia, Black Saturday provided an unprecedented opportunity to learn about the effects of land management on house loss,” said senior author Dr. Philip Gibbons from the Australian National University.

“Clearing trees and shrubs within 40 meters of houses was the most effective form of fuel reduction on Black Saturday,” Gibbons said. “However, there was less risk to houses from vegetation in planted gardens compared with vegetation in remnant native bushland.” Continue reading

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