Antarctic clams may take a hit from global warming

Posted on April 19, 2013 by Bob Berwyn

Study shows climate change may affect overall population numbers

dfgh

Changes in Antarctic clam populations could have a ripple effect on other species in the region like these blue-eyed cormorants in the South Shetlands. Bob Berwyn photo.

By Summit Voice

FRISCO — Warming ocean temperatures and increased glacial outflow around Antarctica may have a big impact on clams living on the ocean floor. Younger clams try to move away when they sense warmer temperature or reduced oxygen levels, but older clams stay put.

The findings by a team of British and German scientists indicate how climate change may affect biodiversity in the region, suggesting that the overall population of Antarctic clams may dwindle, since it’s the older animals that reproduce.

“Our study shows that the physiological flexibility of young clams diminishes as they get older. However, the species has evolved in such a way that the fittest animals, that can tolerate life in an extreme environment, survive to reproduce into old age,” said Doris Abele, of the Alfred Wegener Institute in Germany. “Climatic change, affecting primarily the older clams, may interfere with this evolutionary strategy, with unpredictable consequences for ecosystems all around Antarctica.” (more…)

Filed under: Antarctica, biodiversity, climate and weather, Environment, global warming | Tagged: , , , , , , , | Leave a Comment »

Climate: Does El Niño drive West Antarctic warming?

Posted on April 17, 2013 by Bob Berwyn

Ice cores suggest current climate is in the natural range of variability

fghj

Climate scientists track Antarctic changes, Bob Berwyn photo.

By Summit Voice

FRISCO — Ice cores from West Antarctica spanning the last 2,000 years suggest that recent warming and glacier loss in the region is comparable to other warm periods during that span.

Most of the recent warming may be related to powerful El Niño phases in the tropical Pacific in the 1990s, said University of Washington researcher Eric Steig. The ice core record shows similar temperature spikes in the 1830s and 1940s, he said, adding that the recent warming  cannot be attributed with confidence to human-caused global warming.

Steig built on previous research showing that rapid thinning of Antarctic glaciers was accompanied by rapid warming and changes in atmospheric circulation near the coast. The new study suggests that the 1990s were not all that different from some of those earlier warm spells. (more…)

Filed under: Antarctica, climate and weather, El Niño, Environment, global warming | Tagged: , , , | Leave a Comment »

Global warming: Will wet regions get even wetter?

Posted on April 16, 2013 by Bob Berwyn

New research focuses on tropical rainfall changes

IDL TIFF file

A NASA GOES satellite image shows the intertropical convergence zone.

By Summit Voice

SUMMIT COUNTY — Researchers say they’re getting closer to mapping how global warming will change rainfall patterns across the tropics. Their models project increases in precipitation in areas that already wet, and also in regions where temperatures increases surpass the average warming of the tropics.

“Because our present observations of seasonal rainfall are much more reliable than the future sea surface temperatures, we can trust the models’ projections of seasonal mean rainfall for regional patterns more than their annual mean projections,” said University of Hawaii meteorologist Shang-Ping Xie. “This is good news for monsoon regions where rainfall by definition is seasonal and limited to a short rainy season. Many highly populated countries under monsoon influences already face water shortages.” (more…)

Filed under: climate and weather, global warming, seasons | Tagged: , , , | Leave a Comment »

Climate: Antarctica surface melting speeds up

Posted on April 14, 2013 by Bob Berwyn

Ice core study shows rapid pace of change along Antarctic Peninsula

dfgj

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. (more…)

Filed under: Antarctica, climate and weather, Environment, global warming | Tagged: , , , , , , , | 3 Comments »

Study projects earlier sea-level rise threat to islands

Posted on April 14, 2013 by Bob Berwyn
dfgh

Midway Atoll is likely to face serious flooding problems as sea level rises. Photo courtesy NASA.

Dynamic modeling suggests serious flooding threats much sooner than thought

By Summit Voice

FRISCO — Low-lying islands may be facing more global warming trouble than previously thought.

New modeling that includes storm wind and wave action shows some islands could face regular inundation within the next few decades as sea level rises.

Even if the islands are not permanently submerged, ocean flooding is likely contaminate freshwater supplies, damage agriculture and infrastructure and threaten important bird, sea turtle and marine mammal habitat. (more…)

Filed under: Environment, global warming, biodiversity, climate and weather, wildlife | Tagged: , , , , , , | 1 Comment »

Winter sports athletes urge action on global warming

Posted on April 10, 2013 by Bob Berwyn
dfh

Winter sports athletes are urging action on climate change and energy in a letter to President Obama.

Olympic medalists, ski stars ask President Obama to speed the shift to clean energy

By Summit Voice

SUMMIT COUNTY — As Colorado ski areas struggle with a second consecutive season of below-average snowfall and the Sierra Nevada snowpack only about half of average, a group of 75 Olympic medalists and other winter sports athletes are warning that winter is in trouble.

Stepping up to represent the global snow sports community on the political stage, the athletes this week sent a letter to President Barack Obama, urging him to take action on climate and clean energy.

“Without a doubt, winter is in trouble … at risk are the economies of tourist-dependent states where winter tourism generates $12.2 billion in revenue annually, supports 212,000 jobs and $7 billion in salaries. Those are the jobs and businesses owned by our friends and families, generators of billions in federal and state income.” (more…)

Filed under: climate and weather, Environment, global warming, seasons, Snow and weather | Tagged: , , , , , , | 2 Comments »

Climate: Some penguins expanding range as ice melts

Posted on April 8, 2013 by Bob Berwyn

Adélie penguins breed in ice-free areas

sdf

An Adélie penguin on Paulet Island. Bob Berwyn photo.

By Summit Voice

FRISCO — While populations of ice-loving chinstrap and emperor penguins in Antarctica may be squeezed by global warming, Adélie penguins may actually benefit from warmer  temperatures, according to University of Minnesota Polar Geospatial Center researchers.

Scientists from the United States and New Zealand studied a combination of aerial photography beginning in 1958 and modern satellite imagery from the 2000s, finding that the population size of an Adélie penguin colony on Antarctica’s Beaufort Island near the southern Ross Sea increased 84 percent (from 35,000 breeding pairs to 64,000 breeding pairs) as the ice fields retreated between 1958-2010. The biggest changes came in the last three decades, as average summer temperature in that area increased about .5 degrees Celsius.

The study showed that available habitat for Adélie penguins on the main portion of the Beaufort colony, on the south coast, increased 71 percent since 1958, with a 20 percent increase from 1983-2010. The extent of the snow and ice field to the north of the main colony did not change from 1958-1983, but then retreated 543 meters from 1983-2010. (more…)

Filed under: Antarctica, biodiversity, climate and weather, Environment, global warming | Tagged: , , , , , , , | Leave a Comment »

Environment: Climate puzzle-pieces falling into place

Posted on April 7, 2013 by Bob Berwyn
sdfg

sdfg

Dwindling Arctic ice, more intense rainstorms a sure bet, scientists say

By Bob Berwyn

FRISCO — While a handful of hardcore climate-science deniers are still trying to cast doubt on the legitimacy of what now amounts to decades of research, it’s pretty clear that some of long-term data trends are all pointing in the same direction.

Probably the best example is the research on Arctic sea ice. At this point, nobody can say exactly when the Arctic might be completely ice-free in the summer, but it’s pretty clear that the sea ice extent is on a steep downhill slide.

This past week, the National Climatic Data Center announced that this winter’s ice maximum was the fifth-lowest on record. Each month of the year shows a downward trend in sea ice extent, but the most remarkable fact in this week’s update was the finding that thin, first-year ice now dominates most of the Arctic Ocean, including the North Pole, and that older ice is dwindling even along the north coast of Greenland, previously a stronghold for thick ice. (more…)

Filed under: climate and weather, Environment, global warming | Tagged: , , , , | 7 Comments »

Global warming: More extreme rainfall events nearly certain

Posted on April 5, 2013 by Bob Berwyn

Warmer atmosphere, more moisture, more rain

Breckenridge, Colorado recently recorded an all-time 24-hour record rainfall event during a summer thunderstorm. Bob Berwyn photo.

Breckenridge, Colorado recently recorded an all-time 24-hour record rainfall event during a summer thunderstorm. Bob Berwyn photo.

By Summit Voice

SUMMIT COUNTY — Large parts of the northern hemisphere could see a 20 to 30 percent increase in extreme precipitation events by the end of the century. Extra moisture due to a warmer atmosphere dominates all other factors, leading to notable increases in the most intense precipitation rates, according to a new NOAA-led study.

The study shows a 20-30 percent expected increase in the maximum precipitation possible over large portions of the Northern Hemisphere by the end of the 21st century if greenhouse gases continue to rise at a high emissions rate.

“We have high confidence that the most extreme rainfalls will become even more intense, as it is virtually certain that the atmosphere will provide more water to fuel these events,” said Kenneth Kunkel, Ph.D., senior research professor at the Cooperative Institute for Climate and Satellites-North Carolina and lead author of the paper. (more…)

Filed under: climate and weather, flooding, global warming, Snow and weather | Tagged: , , , , , , | 1 Comment »

Pliocene data suggest climate models may be be underestimating some impacts to the oceans and tropics

Posted on April 4, 2013 by Bob Berwyn

‘The climate system is capable of remarkable transformations’

dgh

Global temperatures were well above average during this past winter.

By Summit Voice

SUMMIT COUNTY — Climate scientists have long eyed the Pliocene era (between 3 and 5 million years ago) as a standard against which to measure the potential impacts of increasing greenhouse gases. It was the last time the world was in a steady climate warmer than today, with a higher atmospheric carbon dioxide level than that of the pre-industrial age.

Research led by University College London scientists shows that a huge pool of warm water stretching from Indonesia over to Africa and South America dominated the world’s oceans during that era — but none of today’s climate models project similar conditions in the future, suggesting that they may be too conservative in forecasting tropical changes.

“An important question is how much the evidence of climate evolution over the last five million years shapes our assessment of future change,” said UCL geographer Dr. Chris Brierley. “From these observations, it is clear that the climate system is capable of remarkable transformations even with small changes in external parameters such as carbon dioxide,” Brierley said. (more…)

Filed under: climate and weather, Environment, global warming | Tagged: , , , , | Leave a Comment »

« Previous Page — Next Page »
Follow

Get every new post delivered to your Inbox.

Join 5,554 other followers