Feeds

Last time CO2 was this high, the world was underwater? NO, actually

Ice sheets DIDN'T melt 3 million years B.C., say boffins

SANS - Survey on application security programs

OK, so levels of atmospheric CO2 are rising through 0.0004 (or 400 parts per million) at the moment. Disaster, right? The last time the world saw carbon levels like this, some three million years ago, the mighty ice sheets of Greenland and the Antarctic had melted from the heat and the seas were 35 metres higher than they are today. Anybody who doesn't live up a mountain will soon find themselves underwater. Aaargh!

Not so much, according to new research.

The idea that the seas were 35 metres higher 3 million years back comes mainly from scientists examining ancient high-tide marks found along coastal cliffs and scarps - particularly some often-used ones on the US eastern seaboard. By determining the ages of the rocks and marks, scientists have come to the conclusion that the seas were much, much higher then - and thus, that the Greenland ice and large parts of the Antarctic ice as well must have been melted at the time.

According to a crew of top boffins led by Professor David Rowley of Chicago uni, the problem with this is that over these sorts of timescales, areas of the Earth's crust rise and fall as much as the sea does. And nobody thus far has taken account of that - it has just been assumed that the rocky coasts have remained fixed with respect to the centre of the Earth, which means that the studies thus far have been - basically - wrong.

"No prediction of ancient ice volumes can ever again ignore the Earth's interior dynamics,” says Rowley.

The prof and his colleagues' new investigation has sought to reconstruct the behaviour of the crust along the oft-studied scarp running up the US coast from Florida to Vermont. And it turns out that over the past three million years, interactions in the Earth's mantle have lifted the entire coastline and the ancient tidemarks with it - giving a false impression of much higher sea levels.

Using the corrected, much lower sea levels, Rowley's team say that in fact the world's ice sheets didn't melt nearly as much back in the old days of 400+ ppm CO2 as people think. According to a statement highlighting the new research:

Until now, many research groups have studied this shoreline and concluded that during a warm period three million years ago, the Greenland, West Antarctic and a fraction of East Antarctic ice sheets collapsed, raising the sea level at least 35 metres. But the new findings by Rowley and his team suggest that these ice sheets, particularly the East Antarctic Ice Sheet (the world’s largest), were probably more stable.

The new paper has just been published in hefty boffinry mag Science.

"It is the kind of study that changes how people think about our past climate and what our future holds," comments Rowley, bluntly. ®

Top three mobile application threats

More from The Register

next story
Red-faced LOHAN team 'fesses up in blown SPEARS fuse fiasco
Standing in the corner, big pointy 'D' hats
KILLER SPONGES menacing California coastline
Surfers are safe, crustaceans less so
Fancy joining Reg hack on quid-a-day challenge?
Recruiting now for charity starvation diet
LOHAN's Punch and Judy show relaunches Thursday
Weather looking good for second pop at test flights
Discovery time for 200m WONDER MATERIALS shaved from 4 MILLENNIA... to 4 years
Alloy, Alloy: Boffins in speed-classification breakthrough
Curiosity finds not-very-Australian-shaped rock on Mars
File under 'messianic pastries' and move on, people
Elon Musk's LEAKY THRUSTER gas stalls Space Station supply run
Helium seeps from Falcon 9 first stage, delays new legs for NASA robonaut
Top Secret US payload launched into space successfully
Clandestine NRO spacecraft sets off on its unknown mission
prev story

Whitepapers

Designing a defence for mobile apps
In this whitepaper learn the various considerations for defending mobile applications; from the mobile application architecture itself to the myriad testing technologies needed to properly assess mobile applications risk.
3 Big data security analytics techniques
Applying these Big Data security analytics techniques can help you make your business safer by detecting attacks early, before significant damage is done.
Five 3D headsets to be won!
We were so impressed by the Durovis Dive headset we’ve asked the company to give some away to Reg readers.
The benefits of software based PBX
Why you should break free from your proprietary PBX and how to leverage your existing server hardware.
Securing web applications made simple and scalable
In this whitepaper learn how automated security testing can provide a simple and scalable way to protect your web applications.