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

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

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

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