Climate: More melting ahead for East Antarctica glaciers

Seafloor channels sluicing warm ocean water toward base of East Antarctica’s Totten Glacier

Increasing concentrations of CO2 could turn this Antarctic beach into a tropical zone. Photo by Bob Berwyn.

Are Antarctica’s ice sheets near a global warming tipping point? bberwyn photo.

Staff Report

FRISCO — Scientists say they’re a step closer to understanding the extreme thinning of East Antarctica’s largest glacier, which contains enough ice to raise global sea level by about 11 feet.

Ocean gateways are sluicing warm water toward the base of the Totten Glacier near the shoreline, undercutting the icy anchors that slow the advance of the ice toward the sea, according to researchers with the University of Texas at Austin’s Institute for Geophysics, who outline their findings in the March 16 edition of the journal Nature Geoscience.

Similar findings from the region were reported by Australian scientists just a few weeks ago, and another study showed widespread thinning of ice in East Antarctica. Continue reading

How do Antarctica snowfall rates affect sea level rise?

New ice core analysis shows less of an ‘offset’ than most models currently project

Antarctica permafrost

Increasing snowfall in Antarctica will moderate the rate of global sea level rise — but not as much as previously thought. bberwyn photo.

Staff Report

FRISCO — Detailed ice core records from Antarctica show that snowfall over the frozen continent increased about 5 percent for each degree (Celsius) of warming as Earth emerged from the last ice age.

The findings confirm that the increased snowfall will slightly offset sea level rise, as suggested by other research — but not as much as previously thought. That means that some computer models may be underestimating the amount and rate of future sea level rise if they’re based on inaccurate assumptions. Continue reading

Climate: Study shows that just a little bit of warming could destabilize West Antarctic ice sheets

Meeting in Uruguay, an Antarctic science committe advocated for the 2012 establishment of marine reserves in the Southern Ocean and the Ross Sea. PHOTO BY BOB BERWYN.

Will the West Antarctic Ice Sheet slip-slide away as the Southern Ocean warms up? bberwyn photo

A delicate balance

Staff Report

FRISCO — West Antarctica ice sheets are delicately anchored in place along a narrow sliver called the grounding zone, and new research shows that even slight increases in regional ocean and air temperatures are likely to destabilize the ice. The grounding zone is a sloping rock bed that lies below sea level.

In the new study, published this month in the Journal of Glaciology, Caltech scientists said future estimates of sea level rise need to take into account that the ice sheets are more sensitive to temperature perturbations driven by climate change than previously thought.

“Our results show that the stability of the whole ice sheet and our ability to predict its future melting is extremely sensitive to what happens in a very small region right at the grounding line. It is crucial to accurately represent the physics here in numerical models,” said study coauthor Andrew Thompson, an assistant professor of environmental science and engineering at Caltech. Continue reading

Study explores Greenland Ice Sheet plumbing

A meltwater lake on the surface of the Greenland Ice Sheet. Now researchers are tracking where that water goes, and how it may affect ice sheet movement. Photo courtesy Thomas Nylen, NSF.

A meltwater lake on the surface of the Greenland Ice Sheet. Now researchers are tracking where that water goes, and how it may affect ice sheet movement. Photo courtesy Thomas Nylen, National Science Foundation.

Surface meltwater feeds subglacial lakes

Staff Report

FRISCO — Scientists who recently took a close look at the “plumbing” of the Greenland Ice Sheet say that meltwater from the surface is building up lakes beneath the ice and transporting heat to the bottom of the ice sheet.

The research, led by Cornell University Earth and Atmospheric Sciences researcher Michael Willis, includes groundbreaking findings that give new information about atmospheric warming and its affect on the critical zone at the base of the ice. The warmth provided by the water could make the ice sheet move faster and alter how it responds to the changing climate. The research is detailed in a new paper published online by the journal Nature on Jan. 21. Continue reading

Study: Florida’s beach-hardening strategy threatens green sea turtle nesting areas

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A green sea turtle. Photo courtesy NOAA.

‘Smart’ adaptation plans needed to protect critical beach nesting habitat

Staff Report

FRISCO — Florida’s strategy of trying to “harden” beaches to prevent erosion poses a serious threat to sea turtles, university scientists said this week, outlining results of a study that tracked reproduction for 30 years.

Hardening beaches puts up barriers to wildlife and impacts sea turtles’ ability to nest,” the researchers said. Continue reading

Climate: Is sea level rise speeding up?

New study shows acceleration in past 20 years

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Coastal flooding along the Gulf Coast. bberwyn photo.

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Sea level is going up, up … up.

Staff Report

FRISCO — Estimating the pace of global sea level rise isn’t easy, but a team of Harvard researchers say their new study helps fill in some of the data gaps, showing that the acceleration in the rise global sea level from the 20th century to the last two decades has been significantly larger than scientists previously thought.

Part of the reason for that is because scientists may have been over-estimating sea level rise between 1900 and 1990, according to co-authors Carling Hay, a post-doctoral fellow in the Department of Earth and Planetary Sciences, and Eric Morrow, a recent PhD graduate of EPS. Continue reading

Climate: Scientists map Greenland’s snow-melt rivers

Massive flows contribute to sea level rise

How fast will the Greenland Ice Sheet melt? Map courtesy Change in Elevation over Greenland ICESat's precise elevation change measurements, combined with information from other technologies, are producing a comprehensive look at the behavior of Earth’s ice sheets -- critical for quantifying forecasts of sea level rise. Scientists used ICESat data to show changes in elevation over the Greenland ice sheet between 2003 and 2006. White regions indicate a slight thickening, while the blue shades indicate a thinning of the ice sheet. Gray indicates areas where no change in elevation was measured.  Credit: NASA Goddard's Scientific Visualization Studio

How fast will the Greenland Ice Sheet melt?
Credit: NASA Goddard’s Scientific Visualization Studio.

Staff Report

FRISCO — After criss-crossing the Greenland Ice Sheet with a helicopter and deploying a remote-operated boat, a team of UCLA-led scientists say they’ve mapped an intricate network of rivers and streams flowing on top of the ice sheet.

The water from those rivulets and rivers could be responsible for as much, if not more, sea-level rise that the ice sheet’s ephemeral lakes and the monster chunks of ice that slide into the ocean to become icebergs. Continue reading

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