Tag: global warming

Study eyes link between giant Tibet avalanche and global warming

Lubrication by meltwater may have enabled massive slide

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Credit: NASA Earth Observatory images by Joshua Stevens and Jesse Allen, using Landsat data from the U.S. Geological Survey, Sentinel data from the European Space Agency, and ASTER data from NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

Staff Report

Although the world’s ice and snow is melting rapidly on a geologic time scale, it still seems to be a gradual process, at least for casual observers. But last summer, July 16, to be exact, 70 million tons of ice broke off the Aru Glacier in western Tibet and crashed far down into the valley, killing nine nomadic yak herders. NASA scientists reported on the avalanche here.

A team of scientists who analyzed the giant avalanche now say there’s a good chance that global warming was a key factor in the unusual slide. The researchers, who published their findings this week in the Journal of Glaciology, said that that the avalanche lasted about four or five minutes, burying 3.7 square miles of the valley floor in that time. Something — likely meltwater at the base of the glacier — must have lubricated the ice to speed its flow down the mountain, they said. Continue reading “Study eyes link between giant Tibet avalanche and global warming”

Global sea ice at record low in November

Arctic sea ice declined in mid-November

Researchers are starting to understand how shifting wind patterns are driving changes in Antarctic sea ice extent. Bob Berwyn photo.
Researchers are starting to understand how shifting wind patterns are driving changes in Antarctic sea ice extent. @bberwyn photo.

Staff Report

Arctic sea ice extent set a new record low this near, heightening concerns that the pace of the Arctic meltdown is speeding up. Antarctic sea ice extent also declined to a record low for the month, with sea ice cover worldwide dropping to an exceptionally low level, according the scientists at the National Snow and Ice Data Center.

Specifically, the blanket of ice around the North Pole averaged 3.51 million square miles for the month, the lowest November in the satellite record, and 309,000 square miles below the record set in November 2006. Through 2016, the linear rate of decline for November is 21,400 square miles per year, or 5.0 percent per decade. Continue reading “Global sea ice at record low in November”

At the nexus of climate change and invasive species

What happens when the trout streams warm?

A palm-size brook trout, caught in the Tenmile Creek drainage near Copper Mountain.
A palm-size brook trout, caught in the Tenmile Creek drainage near Copper Mountain. @bberwyn photo.

Staff Report

U.S. Geological Survey scientists have completed one of the first experimental studies to explore links between climate change and invasive species, specifically how  brook trout and brown trout interact with rising stream temperatures. They found that non-native browns limit the ability of brook trout to use warmer water temperatures, By contrast, removin of browns brook trouts’ reach into warmer waters.

Brookies are freshwater fish native to eastern North America and threatened by climate change because of their requirement for cold stream temperatures. Brown trout are native to Europe and have been introduced all around North America. Continue reading “At the nexus of climate change and invasive species”

Life under the ice

Scientists eye winter ecosystems in ice-covered lakes

Pond glow.
Evening glow on a the slowly melting surface of Dillon Resevoir, in Summit County, Colorado. @bberwyn photo.

Staff Report

A team of international scientists who studied more than 100 lakes during the winter said there’s more going on beneath the ice than we realized. Their findings stand to complicate the understanding of freshwater systems just as climate change is warming lakes around the planet, and shortening the ice season on many lakes. Other parts of the planet’s cryosphere are also melting under the thickening layer of heat-trapping greenhouse gas pollution.

“As ice seasons are getting shorter around the world, we are losing ice without a deep understanding of what we are losing,” said Stephanie Hampton, a Washington State University professor and lead author of a new study published in the journal Ecology Letters. “Food for fish, the chemical processes that affect their oxygen and greenhouse gas emissions will shift as ice recedes.” Continue reading “Life under the ice”

Australian scientists say parts of Great Barrier Reef survived bleaching

Northern section hammered by warm ocean temperatures

This NASA photo shows southern portion of the reef adjacent to the central Queensland coast
This NASA photo shows a southern portion of the Great Barrier Reef adjacent to the central Queensland coast.

Staff Report

Australian researchers this week released results of their latest Great Barrier Reef surveys, concluding that huge swaths of coral died in the past year under the onslaught of an ocean heatwave that led to widespread coral bleaching.

In the hardest-hit area along a 700-kilometer section of the northern reef, an of 67 percent of shallow-water corals died in the last six to nine months. Farther south, over the vast central and southern regions of the Great Barrier Reef, the scientists were relieved to find a much lower death toll. Continue reading “Australian scientists say parts of Great Barrier Reef survived bleaching”

Study confirms global warming threat to alpine insects

A glacier stonefly (Zapada glacier) on a snowy backdrop in Glacier National Park. The species is threatened by climate warming induced glacier and snow loss and has been petitioned for protection under the U.S. Endangered Species Act due to climate-change-induced habitat loss. (Credit: Joe Giersch, USGS. Public domain.)
A glacier stonefly on a snowy backdrop in Glacier National Park. The species is threatened by climate warming induced glacier and snow loss. Credit: Joe Giersch, USGS.

‘There is nowhere to go because they’re literally at the top of the continent … ‘

Staff Report

The findings of a new 20-year study suggest what already appeared obvious — that certain insects reliant on cold water from glaciers and snowmelt are endangered from global warming. The U.S. Geological Survey research focused on two stonefly species in Montana, and will be used to inform the status review for consideration of protection under the U.S. Endangered Species Act .

The scientists found that the meltwater stonefly and western glacier stonefly have a narrow distribution and are restricted to short sections of cold, alpine streams often below glaciers predicted to disappear over the next two decades. Continue reading “Study confirms global warming threat to alpine insects”

Sea snails showing signs of global warming wear and tear

Study helps quantify ocean acidification impacts

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Scientists estimate that pteropod shell dissolution has increased 20 to 25 percent on average in waters along the U.S. West Coast due to CO2 emitted by humans.

Staff Report

By mapping CO2 emissions and comparing that information with data on CO levels in the ocean, scientists say they can now show to what degree the build-up of heat-trapping pollution contributes to the dissolving of shells of microscopic marine sea snails called pteropods.

Other studies from the Southern Hemisphere have reached similar conclusions. Pteropods are an important food for commercially valuable fish species like salmon, sablefish and rock sole.

“This is the first time we’ve been able to tease out the percentage of human-caused carbon dioxide from natural carbon dioxide along a large portion of the West Coast and link it directly to pteropod shell dissolution,” said Richard Feely, a NOAA senior scientist who led the research. Continue reading “Sea snails showing signs of global warming wear and tear”