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Global warming: Many U.S. coastal areas to see frequent flooding sooner rather than later

High water at the mouth of the Mississippi River, near Venice, Louisiana.

High water at the mouth of the Mississippi River, near Venice, Louisiana. bberwyn photo.

Study eyes flood ‘tipping’ points

Staff Report

FRISCO — Rising sea levels will subject many coastal areas in the U.S. to frequent flooding by the middle of the century, according to a new NOAA study aimed at identifying flood “tipping points.” By 2050, a majority of U.S. coastal areas are likely to be threatened by 30 or more days of flooding each year the study concluded.

The research was led by NOAA scientists William Sweet and Joseph Park and published this week in the American Geophysical Union’s online peer-reviewed journal Earth’s Future. Continue reading

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Global Warming: Is the Greenland Ice Sheet melting faster than we think?

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How fast will the Greenland ice sheet melt?

243 gigatons of ice per year …

Staff Report

FRISCO — The most detailed look yet at the dynamics of the Greenland ice sheet suggests that current climate models may not be capturing the full extent of melting.

A team of scientists tracking the behavior of the ice sheet said they found unexpected shrinking in southeastern Greenland, and other signs suggesting that current models may underestimate ice loss in the near future. Continue reading

Climate: Robotic gliders probe secrets of Southern Ocean

Detailed measurements to help pinpoint rate of ice shelf melt

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Melting Antarctica ice shelves are raising global sea level. bberwyn photo.

Staff Report

FRISCO — The Southern Ocean, surrounding Antarctica, is mostly separated from the rest of the world’s oceans by a sharp temperature boundary and swift currents. But the border between the different masses of water is regularly blurred by giant swirls of water that may be transporting warmer water to the edge of the frozen continent.

Knowing how that process works could help scientists understand how fast Antarctic ice shelves will melt and raise global sea level, according to Caltech scientists who used robotic gliders to track the movement of water in the region. Continue reading

Is the Greenland Ice Sheet slip-sliding away?

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.

New study probes role of subglacial runoff channels

Staff Report

FRISCO — Scientists continue to probe and poke at the Greenland Ice Sheet to try and figure out exactly how fast it will melt as global temperatures rise. In one of the newest studies, an international team drilled boreholes to measure melt rates and ice movements, finding that the story is even more complicated than we thought.

“Although the Greenland Ice Sheet initially speeds up each summer in its slow-motion race to the sea, the network of meltwater channels beneath the sheet is not necessarily forming the slushy racetrack that had been previously considered,” said Matthew Hoffman, a Los Alamos National Laboratory scientist on the project, which clarifies the evolution of the meltwater flow rates over the seasons. Continue reading

Climate: Coastal threats should be tackled now

Sea level is rising, and will continue to rise for centuries even if we cut greenhouse gas emissions.

Sea level is rising, and will continue to rise for centuries even if we cut greenhouse gas emissions.

Addressing non-climatic impacts will improve long-term resilience

Staff Report

FRISCO — From mountains, forests and rivers down to the seashore, a common theme among researchers is that, in many places, human impacts stemming from land use and development still outweigh the global warming signal.

That includes coastal regions, were there is an immediate need to tackle the threats from non-climatic changes, an international research team said this week after a detailed review of Intergovernmental Panel on Climate Change assessments. Continue reading

Study tracks historic Antarctica meltdowns

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Reading the history of Antarctica’s ice sheets is helping climate scientists project the future.

Transition from glacial periods punctuated by sudden surges of ice melt and sea level rise

Staff Report

FRISCO — Even without the addition of heat-trapping greenhouse gases from fossil fuel combustion, the Antarctica ice sheets may be vulnerable to sudden collapse and melting. One such episode, about 14,600 years ago, is thought to have caused sea level to rise by more than 12 feet in just 100 years.

Scientists are racing to understand the dynamics of the Antarctic ice sheets because of the potentially significant consequences of rapid changes, and in one of the newest studies, they’ve traced some of the big iceberg calving events between about 19,000 and 9,000 years ago by analyzing deep sea sediment cores extracted from the region between the Falkland Islands and the Antarctic Peninsula. Continue reading

Climate: Study redefines Greenland Ice Sheet topography, finds greater risk of fast melting

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 — New data on Greenland’s rugged shoreline topography doesn’t bode well for coastal cities around the world. A series of deep canyons stretching for miles under the Greenland Ice Sheet will enable warming ocean water to flow beneath the ice, accelerating melting and sea level rise, according to a new study published in the journal Nature Geoscience.

The bedrock canyons sit well below sea level, meaning that as subtropical Atlantic waters hit the fronts of hundreds of glaciers, those edges will erode much further than had been assumed and release far greater amounts of water, the study found. Continue reading

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