This site is not maintained. Click here for the new website of Richard Dawkins.

Rising Seas Look Inevitable

It may be too late to stop the seas from eventually rising and flooding Earth's coastlines. Even if humans manage to eliminate carbon dioxide emissions completely by the year 2100, ocean warming set in motion by the end of this millennium could trigger the collapse of the West Antarctic Ice Sheet and flood New York City, Hong Kong, and other coastal cities, a new study suggests.

Sea level rises when meltwater from land-based masses of ice, such as glaciers, flows into the ocean. But sea level also increases when heat from the atmosphere gets mixed into the upper layers of the ocean, causing that water to expand. In recent decades, this thermal expansion has provided, on average, only about one-quarter of the 1.8 millimeters of sea level rise seen each year, but its contribution is increasing, studies suggest.

Now researchers point to an even bigger threat from warm ocean waters. The floating ice shelves that ring Antarctica could melt. So could the seaward end of land-based ice streams. That would lead to a long-term, catastrophic rise in sea level.

The new analysis, conducted by Nathan Gillett, a climate scientist at the University of Victoria in Canada and his colleagues, considers a rosy scenario. The team assumes that carbon dioxide emissions will rise at moderate rates from now until 2100, when people will switch to renewable energy sources and stop producing carbon dioxide. In this scenario, atmospheric concentrations of the greenhouse gas peak at about 770 parts per million (approximately twice today's level of approximately 390 ppm), Gillett says. Even though no new humanmade carbon dioxide emissions are produced after 2100 and terrestrial and marine ecosystems continue soaking it up, carbon dioxide levels remain above 550 ppm for the next 9 centuries.
Read more

TAGGED: EARTH SCIENCES


RELATED CONTENT

Draining of world's aquifers feeds...

Damian Carrington - The Observer 3 Comments

"In the long run, I would still be more concerned about the impact of climate change, but this work shows that even if we stabilise the climate, we might still get sea level rise due to how we use water."

'Ring of fire' eclipse to begin

- - BBC News - Science & Environment 6 Comments

An "annular eclipse" will be visible from a 240 to 300km-wide swathe of Earth stretching from Asia across the Pacific to the western US on Monday.

Arctic melt releasing ancient methane

Richard Black - BBC News - Science &... 6 Comments

Scientists have identified thousands of sites in the Arctic where methane that has been stored for many millennia is bubbling into the atmosphere.

How much water is there on, in, and...

- - USGS Water Science for Schools 27 Comments

'Save the planet', science leaders urge...

Pallab Ghosh - BBC News - Science &... 35 Comments

No Love for Comet Wipeout

Sid Perkins - Science - AAAS.org 8 Comments

Did a comet wipe out woolly mammoths and an ancient Indian culture almost 13,000 years ago? Geologists have fiercely debated the topic since 2007. Now a new study says an extraterrestrial impact wasn't to blame, though the scientists who originally proposed the impact idea still aren't convinced.

MORE

MORE BY SID PERKINS

No Love for Comet Wipeout

Sid Perkins - Science - AAAS.org 8 Comments

Did a comet wipe out woolly mammoths and an ancient Indian culture almost 13,000 years ago? Geologists have fiercely debated the topic since 2007. Now a new study says an extraterrestrial impact wasn't to blame, though the scientists who originally proposed the impact idea still aren't convinced.

MORE

Comments

Comment RSS Feed

Please sign in or register to comment