Half of Greenland and vast areas of Antarctica are destined to melt if global warming continues at the same pace until the end of the century, scientists warned on Thursday.
Their research shows that the loss of so much ice will trigger dramatic rises in sea levels, ultimately swamping low-lying islands and coastal regions and threatening the flood defenses of cities such as London.
The last time so much ice was lost from the poles -- in a period between ice ages 129,000 years ago -- global sea levels rose between 4m and 6m.
Experts believe many coastal regions would suffer long before sea levels rose significantly, because even a minor rise will make storm surges more devastating and increase the risk of flooding.
The warning comes from climate scientists who combined historical records of Arctic and Antarctic ice melting with advanced computer models capable of predicting future environmental conditions.
They found that if nothing is done to put the brakes on climate change, Greenland, the west Antarctic ice sheet and other expanses of polar ice will be warmed beyond a "tipping point" after which their melting is inevitable.
Jonathan Overpeck, director of the Institute for the Study of Planet Earth at the University of Arizona, and Bette Otto-Bliesner, at the US National Center for Atmospheric Research in Colorado, looked back in history to find a time when sea levels were higher than they are today.
They identified a period when glacial melting increased sea levels by several meters.
They used a computer model of the environment to work out how warm the world must have been to trigger the mass melting and concluded that the Earth was between 3oC and 5oC warmer than it is today.
Using the same model, the scientists spun the clock forward to see when climate change is likely to make the world as warm again.
"We showed that that level of warming will come later in this century unless we act on carbon emissions," Overpeck said.
"An Arctic warming of 3oC to 5oC is enough to cause 4m to 6m of sea level rise," he said.
If temperatures do rise as the scientists predict, the ice at the poles will not be lost immediately. Enough ice is likely to melt within the next 100 years to raise sea levels by a meter, but ultimately the fresh water pouring into the North Atlantic would slow down the Gulf stream by a quarter.
"These ice sheets have melted before and sea levels rose. The warmth needed isn't that much above present conditions," said Otto-Bliesner.
The major concern is that unless climate change slows down significantly, the eventual loss of polar ice and subsequent 6m rise in sea levels will become unavoidable.
"There has been an increasing number of observations from the ice sheets suggesting they are responding faster to climate change than anticipated," Overpeck said.
"Now along come our results showing these kinds of changes occurred in the past and lead to large ice sheet retreat and sea level rise," he said.
A 1m rise in the sea level would see the Maldives disappear, make most of Bangladesh uninhabitable and put cities such as New Orleans "out of business," according to Overpeck.
The research was published in two papers in the US journal Science on Thursday.
ENDEAVOR MANTA: The ship is programmed to automatically return to its designated home port and would self-destruct if seized by another party The Endeavor Manta, Taiwan’s first military-specification uncrewed surface vehicle (USV) tailor-made to operate in the Taiwan Strait in a bid to bolster the nation’s asymmetric combat capabilities made its first appearance at Kaohsiung’s Singda Harbor yesterday. Taking inspiration from Ukraine’s navy, which is using USVs to force Russia’s Black Sea fleet to take shelter within its own ports, CSBC Taiwan (台灣國際造船) established a research and development unit on USVs last year, CSBC chairman Huang Cheng-hung (黃正弘) said. With the exception of the satellite guidance system and the outboard motors — which were purchased from foreign companies that were not affiliated with Chinese-funded
PERMIT REVOKED: The influencer at a news conference said the National Immigration Agency was infringing on human rights and persecuting Chinese spouses Chinese influencer “Yaya in Taiwan” (亞亞在台灣) yesterday evening voluntarily left Taiwan, despite saying yesterday morning that she had “no intention” of leaving after her residence permit was revoked over her comments on Taiwan being “unified” with China by military force. The Ministry of the Interior yesterday had said that it could forcibly deport the influencer at midnight, but was considering taking a more flexible approach and beginning procedures this morning. The influencer, whose given name is Liu Zhenya (劉振亞), departed on a 8:45pm flight from Taipei International Airport (Songshan airport) to Fuzhou, China. Liu held a news conference at the airport at 7pm,
Authorities yesterday elaborated on the rules governing Employment Gold Cards after a US cardholder was barred from entering Taiwan for six years after working without a permit during a 2023 visit. American YouTuber LeLe Farley was barred after already being approved for an Employment Gold Card, he said in a video published on his channel on Saturday. Farley, who has more than 420,000 subscribers on his YouTube channel, was approved for his Gold Card last month, but was told at a check-in counter at the Los Angeles International Airport that he could not enter Taiwan. That was because he previously participated in two
SECURITY RISK: If there is a conflict between China and Taiwan, ‘there would likely be significant consequences to global economic and security interests,’ it said China remains the top military and cyber threat to the US and continues to make progress on capabilities to seize Taiwan, a report by US intelligence agencies said on Tuesday. The report provides an overview of the “collective insights” of top US intelligence agencies about the security threats to the US posed by foreign nations and criminal organizations. In its Annual Threat Assessment, the agencies divided threats facing the US into two broad categories, “nonstate transnational criminals and terrorists” and “major state actors,” with China, Russia, Iran and North Korea named. Of those countries, “China presents the most comprehensive and robust military threat
RSS