Huge ice shelf calving revives global warming debate

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Is climate change a hoax as claimed by US President Donald Trump, who has even pulled his country out of the Paris Climate Agreement, or is it really something to worry about as former US vice-president Al Gore and many others would have us believe?

According to a recent study that consisted of taking temperatures from 692 different “natural thermometers” on every continent and ocean on the planet, Earth is warmer than it has been for at least 2,000 years. In what is being termed the most comprehensive assessment of how the climate has changed in that period, researchers looked at a host of sources of historic information, including tree rings, ice cores, lake and sea sediments, corals, mineral deposits and written records to come to their conclusion last week.

On the same day this study came out with “definitive” proof that man-made climate change is real, researchers reported that the massive Larsen C ice shelf had finally ruptured, releasing an iceberg twice the size of Luxembourg into the Southern Ocean.

But rather than ringing the alarm on man-made climate change, Martin O’Leary, a Swansea University glaciologist and member of Britain’s Project MIDAS team, called the massive calving “natural”, and stated that his team was “not aware of any link to human induced climate change”.

Professor Adrian Luckman of Swansea University, lead investigator of Project MIDAS, added: “We have no evidence to link this directly to climate change, and no reason to believe that it would not have happened without the extra warming that human activity has caused. But the ice shelf is now at its most retreated position ever recorded and regional warming may have played a part in that.”

He continued: “This event does not directly affect anyone, and repercussions, if there are any, will not be felt for years. However, it is a spectacular and enormous geographical event which has changed the landscape.”

Wake-up call

Not all scientists agree about the lack of impact, though, especially given the context of global climate change.

It’s clear that global warming, which most scientists believe has been caused largely by burning fossil fuels and agricultural practices, is contributing to the broader destabilization of Antarctica, said Eric Rignot, professor of Earth systems sciences at the University of California, Irvine, and a senior research scientist at the National Aeronautics and Space Administration’s Jet Propulsion Laboratory.

“This break-up signals that the ice shelf got too thin,” Rignot said in an e-mail to CNN. “It got thinner because climate has been warming, over decades; the ice shelf will eventually collapse in the coming decades. This is absolutely related to climate warming. The ice-shelf front has not calved this far back in 125 years (first seen by Carl Larsen in 1893) and Larsen C is on a course to collapse, very reminiscent of what happened to Larsen B in 2002.

“This is yet another wake-up call,” he said, “that Antarctica is on the rise and we should be concerned about what that means for future sea level.”

Warning signs

Maybe Professor Rignot is on to something here. There are enough indications of a climate shift resulting in global sea levels rising about 20 centimeters in the past century. The rate in the past two decades, in particular, is nearly double that of the last century, endangering low-lying countries like Maldives, Fiji and Seychelles.

Further evidence of man-made global warming is the fact that the planet’s average surface temperature has risen about 1.1 degrees Celsius since the late 19th century, a period of increased carbon-dioxide and other emissions into the atmosphere, according to Nasa. Most of the warming occurred in the past 35 years, with 16 of the 17 warmest years on record occurring since 2001.

Not only was 2016 the warmest year on record, but eight of the 12 months that made up the year – from January through September, with the exception of June – were the warmest on record for those respective months.

Moreover, there have been shrinking ice sheets in Greenland and Antarctic, declining Arctic sea ice and glacial retreat. There have also been extreme weather conditions all over the world in recent years.

So, while facts on the ground suggest climate change is at least partly a natural phenomenon, evidence so far also supports the view that it is largely man-made.

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