Category: Antarctica

What’s driving the collapse of Antarctic ice shelves?

New CSU study eyes regional climate cycle as one factor

Disintegration of ice shelves in East Antarctica could result in a spiraling increase in sea levels. PHOTO BY BOB BERWYN.
Disintegration of ice shelves in East Antarctica has been linked with a regional climate pattern and could result in a spiraling increase in sea levels. @bberwyn photo.

Staff Report

This year’s rapid loss of sea ice around Antarctica may make the floating ice shelves along the coast of the continent even more vulnerable to collapse, and a  Hemisphere climate cycle known as the Southern Annular Mode is probably a factor in the equation.

Just during the past 50 years, more than 28,000 square kilometers of ice shelves have crumbled along the Antarctic Peninsula, and one of the last remaining large ice shelves looks set to shed another piece about as large as Delaware. A new study led by Colorado State University scientists offers some new information on climate processes in the region. Continue reading “What’s driving the collapse of Antarctic ice shelves?”

Advertisements

Ocean layering around Antarctica could signal major meltdown

Study warns of 10-foot sea level rise

Sunlit icebergs gleam on the horizon in the Antarctic Sound.
Antarctica could be closer to a meltdown than previously thought. @bberwyn photo.

Staff Report

As scientists learn more about the dynamics of the ocean around Antarctica, they’ve discovered a climate warming signal. Distinct layers of water, marked by temperature boundaries, are forming right now, leading to conditions similar to about 14,000 years ago, when Antarctic ice sheets melted rapidly, raising global sea level by more than 10 feet. Continue reading “Ocean layering around Antarctica could signal major meltdown”

Warm ocean melting East Antarctic ice from beneath

Time to re-adjust sea level rise estimates

sdfgadfsgadfgdfgdsf
Time to make some new estimates for sea level rise. @bberwyn photo.

Staff Report

New measurements taken in the ocean near a massive East Antarctica ice sheet confirm that warm water is melting the ice from below. The new data will help scientists determine how fast the Totten Ice Shelf will melt. In all, it contains enough water to raise global sea level by 3.5 meters, according to a new study published last week in Science Advances.

Previous studies have suggested that  Antarctic ice shelvesare thinning because of warming ocean temperatures. The fastest melting, as well as an acceleration of glaciers, has been reported from the  Bellingshausen Sea and the Amundsen Sea, where much of the ice sheet rests on bedrock below sea level that deepens upstream. Continue reading “Warm ocean melting East Antarctic ice from beneath”

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”

How will Antarctica respond to global warming?

Long-term studies show potential impacts of climate change

Antarctic biodiversity is at risk from climate change. Photo by Bob Berwyn.
Antarctic ecosystems are at risk from climate change. @bberwyn photo.

Staff Report

A new set of scientific reports highlights the value of long-term observations in relatively undisturbed ecosystems and also offers a preview of how global warming may change Antarctica in coming decades.

The research shows that a period of unusual warmth in 2001 and 2002, caused by a confluence two natural climate cycles,  accelerated the microbial food chain and shook up the distribution of penguin populations and thinned glaciers according to October issue of the journal BioScience .

The research came out of two long-term ecological research stations, including Palmer Station, on the West Antarctic Peninsula, where scientists study how “changing sea ice extent influences marine ecology and the multilayered food webs of the coastal, nearshore, and continental slope ecosystems.” Other studies were done at the  McMurdo Dry Valleys LTER, in an ice-free polar desert where glacial meltwater plays a huge role in ecosystems. Continue reading “How will Antarctica respond to global warming?”

Antarctic krill could take a big global warming hit

A feeding penguin near the Antarctic Peninsula. @bberwyn photo.

Study projects major loss in habitat

Staff Report

Changes in ocean temperatures and sea ice formation around Antarctica could imperil the region’s krill — tiny crustaceans that are at the base of the food chain. Scientists say they’ve already documented a big drop in krill populations since the 1970s. Losing more krill would reduce the amount of food available for whales, penguins, seals, squid, fish and other marine life.

A new study published online in Geophysical Research Letters says up to 80 percent of suitable krill habitat could disappear by 2100. The research examines the effects of a warmer ocean and a decline in sea ice on these small crustaceans, said Andrea Piñones, a marine scientist at Center for Advance Studies in Arid Zones (Centro de Estudios Avanzados en Zonas Aridas) in Coquimbo, Chile, and lead author of the study. Continue reading “Antarctic krill could take a big global warming hit”

Antarctic sea ice meltdown likely in a warming world

New study offers climate clues from most recent interglacial warm period

Antarctic sea ice
Antarctic sea ice is likely to decline dramatically in coming decades, which could lead to amplification of global warming in the southern hemisphere. @bberwyn photo.

By Bob Berwyn

The last time the Earth was as warm as today was about 128,000 years ago — and Antarctic sea ice extent was 65 percent smaller than it is now, according to British scientists who tracked past climate change in the region by studying ice core samples from that era.

That means Antarctic sea ice is on course to shrink dramatically in the decades and centuries ahead, said British Antarctic Survey scientist Max Holloway, who with a team of researchers analyzed oxygen isotopes in ice and air bubbles trapped for 128,000 years in the East Antarctic Ice Sheet. Continue reading “Antarctic sea ice meltdown likely in a warming world”