Greenland’s ice sheet may have shrunk past the point of return, with the ice likely to melt away no matter how quickly the world reduces climate-warming emissions, new research suggests.
Scientists studied data on 234 glaciers across the Arctic territory spanning 34 years through 2018 and found that annual snowfall was no longer enough to replenish glaciers of the snow and ice being lost to summertime melting.
That melting is already causing global seas to rise about a millimeter on average per year. If all of Greenland’s ice goes, the water released would push sea levels up by an average of 6 meters — enough to swamp many coastal cities around the world. This process, however, would take decades.
“Greenland is going to be the canary in the coal mine, and the canary is already pretty much dead at this point,” said glaciologist Ian Howat at Ohio State University. He and his colleagues published the study Thursday in the Nature Communications Earth & Environment journal.
The Arctic has been warming at least twice as fast as the rest of the world for the last 30 years, an observation referred to as Arctic amplification. The polar sea ice hit its lowest extent for July in 40 years.
The Arctic thaw has brought more water to the region, opening up routes for shipping traffic, as well as increased interest in extracting fossil fuels and other natural resources.
Greenland is strategically important for the US military and its ballistic missile early warning system, as the shortest route from Europe to North America goes via the Arctic island.
Last year, President Donald Trump offered to buy Greenland, an autonomous Danish territory. But Denmark, a US ally, rebuffed the offer. Then last month, the US reopened a consulate in the territory’s capital of Nuuk, and Denmark reportedly said last week it was appointing an intermediary between Nuuk and Copenhagen some 3,500 kilometers away.
Scientists, however, have long worried about Greenland’s fate, given the amount of water locked into the ice.
The new study suggests the territory’s ice sheet will now gain mass only once every 100 years — a grim indicator of how difficult it is to re-grow glaciers once they hemorrhage ice.
In studying satellite images of the glaciers, the researchers noted that the glaciers had a 50% chance of regaining mass before 2000, with the odds declining since.
“We are still draining more ice now than what was gained through snow accumulation in ‘good’ years,” said lead author Michalea King, a glaciologist at Ohio State University.
The sobering findings should spur governments to prepare for sea-level rise, King said.
“Things that happen in the polar regions don’t stay in the polar region,” she said.
Still, the world can still bring down emissions to slow climate change, scientists said. Even if Greenland can’t regain the icy bulk that covered its 2 million square kilometers, containing the global temperature rise can slow the rate of ice loss.
“When we think about climate action, we’re not talking about building back the Greenland ice sheet,” said Twila Moon, a glaciologist at the National Snow and Ice Data Center who was not involved in the study. “We’re talking about how quickly rapid sea-level rise comes to our communities, our infrastructure, our homes, our military bases.”
Reporting by Cassandra Garrison; Editing by Katy Daigle and Aurora Ellis
Image: A fishing vessel sails in the ice fjord near Ilulissat, Greenland September 12, 2017. Picture taken September 12, 2017. REUTERS/Jacob Gronholt-Pedersen
Scientist Shows There Are Two Ways to Measure a Day on Earth – The Union Journal
How long does it take Earth to complete a 360-degree rotation? Not quite 24 hours, it turns out – it’s precisely 23 hours and 56 minutes.
But because Earth is constantly moving along its orbit around the Sun, a different point on the planet faces the Sun directly at the end of that 360-degree spin.
For the Sun to reach the exact same position in the sky, Earth has to rotate 1 degree further.
That’s how humans have chosen to measure days: not by the Earth’s exact rotation, but the position of the Sun in the sky.
Technically, these are two different types of day. A day measured by the completion of a 360-degree rotation is called the sidereal day.
A day based on the position of the Sun, however, is a solar day. The latter is four minutes longer than the former, making the even 24 hours we’re used to.
“It’s only because we move around the Sun in an orbit that the solar day takes 24 hours,” James O’Donoghue, a planetary scientist at the Japanese space agency (JAXA), told Business Insider.
“If we didn’t orbit the Sun, both days would be the same.”
He made the below animation to show how this works.
Because we go by solar days in our calendars, we count 365 days in a year. But Earth actually completes a full rotation (a sidereal day) 366 times per year.
O’Donoghue describes the difference between these two types of day as a matter of choosing which background object we use as a basis of comparison for Earth’s rotation. A full rotation relative to the position of the Sun is a solar day. A full rotation relative to all the other stars we see is a sidereal day.
If we used the sidereal day instead, “the Sun would rise about four minutes earlier every day,” O’Donoghue said. “After six months of doing this, the Sun would be rising 12 hours earlier.”
He added: “We’ve decided to tie our daily rhythm to the Sun, not the stars. In fact, the stars rise about four minutes earlier every day because of our choice.”
This article was originally published by Business Insider.
More from Business Insider:
Scientist Shows There Are Two Ways to Measure a Day on Earth – Armenian Reporter
How long does it take Earth to total a 360-degree rotation? Not rather 24 hr, it ends up – it’s specifically 23 hours and 56 minutes.
But due to the fact that Earth is continuously moving along its orbit around the Sun, a various point on the world deals with the Sun straight at the end of that 360-degree spin.
For the Sun to reach the specific very same position in the sky, Earth has to turn 1 degree even more.
That’s how human beings have actually selected to measure days: not by the Earth’s specific rotation, however the position of the Sun in the sky.
Technically, these are two various kinds of day. A day determined by the conclusion of a 360-degree rotation is called the sidereal day.
A day based on the position of the Sun, nevertheless, is a solar day. The latter is 4 minutes longer than the previous, making the even 24 hr we’re utilized to.
“It’s only because we move around the Sun in an orbit that the solar day takes 24 hours,” James O’Donoghue, a planetary scientist at the Japanese area company (JAXA), informed Business Insider.
“If we didn’t orbit the Sun, both days would be the same.”
He made the below animation to demonstrate how this works.
Because we pass solar days in our calendars, we count 365 days in a year. But Earth in fact finishes a complete rotation (a sidereal day) 366 times each year.
O’Donoghue explains the distinction in between these two kinds of day as a matter of picking which background item we utilize as a basis of contrast for Earth’s rotation. A complete rotation relative to the position of the Sun is a solar day. A complete rotation relative to all the other stars we see is a sidereal day.
If we utilized the sidereal day rather, “the Sun would rise about four minutes earlier every day,” O’Donoghue stated. “After six months of doing this, the Sun would be rising 12 hours earlier.”
He included: “We’ve decided to tie our daily rhythm to the Sun, not the stars. In fact, the stars rise about four minutes earlier every day because of our choice.”
This short article was initially released by Business Insider.
More from Business Insider:
Science Saturday 0919 – CGTN
In this week’s Science Saturday, we look at science news ranging from possible signs of life on Venus to wildlife protection.
Scientists detect gas in Venus clouds linked to life on Earth
First, evidence of potential for life on the planet next door! A smelly, flammable gas called “phosphine” has been found on Venus. Here on Earth, phosphine is produced predominantly by anaerobic biological sources. So with this discovery, there’s a chance that there are some living organisms in the clouds of Venus. But scientists say further observations and modeling are needed to explore the origin of the gas in the planet’s atmosphere. The findings are published in the peer-reviewed journal – Nature Astronomy.
Washington bans TikTok downloads from U.S. app stores
Washington has announced a decision to ban TikTok downloads from app stores in the United States. Donald Trump, the U.S. president, is questioning plans by Chinese tech firm, ByteDance, to keep a majority stake in TikTok’s U.S. operations as part of a partnership deal with Oracle. Trump says any agreement to continue operating in U.S. must be “100% as far as national security is concerned.” He has called the popular video-sharing app a security threat, and says he will ban it unless it’s sold by ByteDance.
WWF report: Wildlife populations down by an average of 68 percent over past four decades
The world’s wildlife population is under threat! A new report by the World Wildlife Fund says human activity has wiped out two-thirds of the world’s wildlife since 1970. Latin America and the Caribbean are the world’s worst-affected areas, which have seen an average drop of 94 percent. The report says humans’ over-exploitation of wildlife, grassland conversion and climate change are among the major drivers of this devastating decline. Researchers are calling for changes in production and consumption patterns of food and energy, increased conservation efforts and a global collective effort.
Winners of Breakthrough Prizes announced for 2021
The winners of the 2021 Oscars of Science, also known as Breakthrough Prizes, have been revealed. Eight scientists have been recognized for their achievements in Mathematics, Fundamental Physics and Life Sciences. One of the recipients is David Baker, whose team designed a molecule that potentially inhabits the coronavirus that causes COVID-19. The team also successfully synthesized the proteins, which demonstrated a neutralizing antibody, shedding light on a potential new treatment to the disease. The prizes total 21 million U.S. dollars. Due to the global coronavirus pandemic, this year’s ceremony has been postponed until March 2021.
“Science Saturday” is part of CGTN’s science and technology series “Tech It Out.” The segment brings you the latest news about innovations and technological breakthroughs in the past two weeks from across the world.
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