Antarctic ice melting 10 times faster than 600 years ago

Updated

A report has found that the Antarctic summer ice melt is now occurring 10 times faster than it did 600 years ago.

Scientists from the British Antarctic Survey and the Australian National University drilled a 360-metre ice core near the northern tip of the peninsula to to identify past temperatures.

The ice core gave an extraordinary insight into the temperatures, revealing the coolest conditions, and the lowest melt, occurred six centuries ago.

By comparison, it found temperatures now are 1.6 degrees Celsius higher, and the ice melt is 10 times as fast.

The lead author of the report, Dr Nerilie Abram from the Australian National University, says the most rapid melt has occurred in the last 50 years.

"The lowest levels of melt were about 600 years ago and then the melt has increased almost tenfold over that time," she said.

"But it's really in the last 50 years or so that melt has increased dramatically.

"When we build the ice core we're able to see these visual layers in the ice that we were pulling up.

"Those layers showed times when the snow had melted and then refrozen. We were able to use those to actually build up a record and look at how melting had changed over the last 1,000 years."

The lowest levels of melt were about 600 years ago and then the melt has increased almost tenfold over that time. But it's really in the last 50 years or so that melt has increased dramatically. Dr Nerilie Abram

Dr Abram says even the slightest increase in temperature is now having an impact.

"A lot of changes have happened in the last 50 years ... there has been ice shelves [that have] collapsed, there's been glaciers flowing faster and losing more mass, [and] more ice into the oceans," she said.

"Summer melting is what scientists believe is causing those changes.

"To have this record that shows that even just a small amount of temperature increase now can cause a large increase in melt in this area is reason for concern."

Dr Abram says the ice core showed that changes in the environment when the climate warms do not necessarily happen gradually.

"As the climate has warmed ... the summer temperatures are getting closer and closer to that zero degrees melting threshold," she said.

"Now, for every little bit of warming that happens, you get more days that go above that temperature ... [and that] small increase in temperature can causes a very large increase in melting."

The research paper is being published in the journal Nature Geoscience.

Topics: environment, climate-change, antarctica, australia, act

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