Greenland is the world's largest island, located in the northeast of North America and the northwest of the North Atlantic Ocean. Greenland, which literally means "greenland" or "green land" in English, is also the largest region of continental glaciers outside of Antarctica, covering the world's second continent ice sheet with an area of about 1.83 million square kilometers and an average thickness of 2300 meters, the Greenland Ice Sheet.
It's just that this ice-cover island may really become its name "Green Island".
A study published Aug. 29 in Nature Climate Change shows for the first time that Greenland's ice sheet is already so out of balance with the current Arctic climate that it can no longer maintain its current size. According to paper co-author Alun Hubbard, a professor of glaciology at the University of Tromsø in Norway, the Greenland ice sheet will inevitably retreat by at least 59,000 square kilometers, a much larger area than Denmark. The paper's international team of authors found that even if all of today's greenhouse gas emissions that drive global warming stop, ice loss from the Greenland ice sheet at current temperatures would raise global sea levels by at least 27.4 centimeters.
8 months loss of 166 billion tons
A recent study of the Greenland ice sheet found that glaciers are retreating in almost every part of the island, and according to data provided by the Polar Portal website of the Danish Arctic Monitoring Service, the Greenland ice sheet lost about 166 billion tons in the last eight months alone, with the most exaggerated day losing 8 billion tons.
Associate Professor An Lu of Tongji University said: "From 1995 to 2000, the Greenland ice sheet lost about 39 billion tons of mass per year; Between 2001 and 2009, this figure reached an average of 175 billion tons per year; Between 2010 and 2019, the average annual reached 243 billion tons. The rate of loss of ice mass is accelerating, and most of the ice-free mossy area of Greenland has now been exposed. ”
Greenland Ice Sheet Changes, from NASA Satellite Image
In 2020, scientists announced that the Greenland ice sheet has melted beyond the "tipping point" and is now irreversible, and even if the world stops warming now, snowfall will no longer be able to make up for the lost ice.
Greenland's massive melting began in the 1990s, when global industrialization and shipping trade were in full swing. According to 1993 data analysis, Greenland's glaciers at that time were rapidly transitioning to an unstable state.
By around 2000, as the greenhouse effect increased, weather monitoring at the Swiss camp in Greenland showed that the average winter temperature had risen by nearly 6°C, causing Greenland's glacier melting to cause global sea levels to rise faster than before. In 2000 alone, the losses were four times greater than before.
By last year, temperatures in northern Greenland had also exceeded 20°C, and the Greenland ice sheet lost more ice in the summer for the 25th consecutive year than the amount of ice accumulated in winter.
Record-breaking bipolar sea ice melted
Rising sea levels are one of the important impacts of melting polar ice, with the Greenland and Antarctic ice sheets being the largest contributors to global sea level rise. Melting glaciers exacerbate sea-level rise, which in turn exacerbates coastal erosion and leads to rising storm surges. This is because the ever-warming air and ocean temperatures have created more frequent and intense coastal storms, such as hurricanes and typhoons. The extent and rate at which the greenland and Antarctic ice sheets melt in the future will largely determine the extent of sea level rise.
At the same time, the area of sea ice is also decreasing on a large scale. According to NASA observations, the arctic summer sea ice area has been reduced by nearly half in the last 40 years (after 1979); It is expected that by 2040, the Arctic Ocean may be ice-free in the summer. Antarctic sea ice also experienced an extraordinary melt between 2014 and 2017, losing the equivalent of the Arctic in just 4 years, and the rate is accelerating (NASA data).
Unlike melting ice sheets on land, melting sea ice does not cause sea level rise. However, the reduction in the area of sea ice will cause the sun's heat to shift from being reflected by the white sea ice to being absorbed by the dark sea water, which will lead to a further rise in temperature, which in turn will aggravate the melting of sea ice, creating a vicious circle.
While the disappearance of sea ice at the poles is clearly linked to global warming caused by human activities, the two are very different. The Arctic is heavily affected by atmospheric circulation and is more closely linked to extreme weather, such as the European heatwave. Because the Arctic is an ocean surrounded by continents, exposed to warming air, and Antarctica is a frozen continent surrounded by oceans, which has been protected from the warming air by a strong wind.
Researchers believe that the Arctic has become a classic example of global warming, and this effect will eventually occur in the Antarctic region.
Ablated Arctic sea ice. Unlike the Antarctic continent, the Arctic is a sea in general. | NASA
The Crisis of Ice
The existing continental ice sheets on Earth are the Antarctic Ice Sheet and the Greenland Ice Sheet. These two ice sheets account for about 97% of the world's total glacier area and 99% of the total ice volume. The Antarctic ice sheet accounts for about 85.7% of the world's glaciers, and the Greenland ice sheet accounts for about 10.9%.
Arctic ice is mainly concentrated on Greenland, the second largest deposit of continental base ice on Earth after Antarctica. Formed in the Quaternary Period, the Greenland Ice Sheet was seven times larger than the present-day ice sheet at about 18,000 years ago and was connected to the North American Ice Sheet at that time. The Greenland ice sheet is second only to Antarctica in size, but it is more fragile. It is much farther from the cold polar region than the Antarctic Ice Sheet, which is at its southernmost tip south of 60 degrees north latitude, almost at the same latitude as the Shetland Islands in northeastern Scotland.
Greenland's ice has melted faster and faster since the 1990s, with studies showing that Greenland's ice sheet is not only melting, but also melting faster than ever before, with ice disappearing four times faster than in 2003. Since 1972, Greenland's contribution to sea level rise has been about 1.4 centimeters. This process is accelerating as human emissions of greenhouse gases into the atmosphere increase. The gradually growing melting season appears to have a much greater impact on sea-level rise than in past decades.
Melting glaciers exacerbate sea-level rise, which in turn exacerbates coastal erosion and leads to rising storm surges. This is because the ever-warming air and ocean temperatures have created more frequent and intense coastal storms, such as hurricanes and typhoons. The extent and rate at which the greenland and Antarctic ice sheets melt in the future will largely determine the extent of sea level rise.
According to NASA observations, arctic summer sea ice area decreased by nearly half after 1979; It is expected that by 2040, the Arctic Ocean may be ice-free in the summer. Antarctic sea ice also experienced an extraordinary melting between 2014 and 2017, losing the equivalent of the amount of sea ice lost in the Arctic in 34 years in just four years, and the rate is accelerating.
If in the future, Greenland's glaciers all melt, and the Inuit people on the island, or even the entire human race, where will they go?
It is not difficult to see that the melting of the Greenland ice sheet is inextricably linked to the rising temperature, and the more vicious circle is that as the permafrost melts, a large amount of methane will be released, and the gas entering the atmospheric environment will further exacerbate the greenhouse effect.
Greenland, at such a high latitude, is unlikely to rain, but in August last year it took just three days to rain more than 7 billion tons, and a large amount of fresh water would quickly neutralize the nearby seawater and cause the ice cap to recede, and large and small glacier faults formed tsunamis of different sizes, destroying the Homes of innuts near shore.
Icebergs formed by glaciers entering the sea have seriously disturbed inuit fishing boats, and their homemade boats were previously able to navigate the sea freely, but as the icebergs became more numerous and denser, traditional fishing boats could no longer cope with the huge icebergs, and navigating in the drifting ice became more difficult.
In addition to the impact on human life, the fading of the ice sheet has also had an impact on animals.
As permanent residents of Antarctica, the survival of the Emperor Penguin and the Adélie Penguin is directly affected by climate change.
The emperor penguin is the only penguin that breeds in winter, and the impact of sea ice on it is particularly important. There are two main areas of activity for emperor penguins: predation areas and breeding areas, and they travel between the two areas all year round. Every year from January to March (Antarctic summer), emperor penguins disperse to the ocean to hunt. But as sea ice deteriorates, the 54 existing habitats will face a devastating decline by the end of the century. The Halley Bay of the Weddell Sea in Antarctica is the second largest habitat of the Emperor Penguin, and many Emperor Penguins choose to breed here, but since 2016, the Emperor Penguins seem to have abandoned this once reliable breeding site because they have experienced catastrophic breeding failures here, and the once stable breeding ground was destroyed before the fledgling wings were fledgling. According to a 2019 study in the journal Global Change Biology, if global warming continues as it does now, the number of emperor penguins will be reduced by 80%, and the number of emperor penguins will even be reduced by 81% to 86%.
The Adélie penguin is another Antarctic penguin facing an existential crisis, inhabiting the entire Antarctic continent and having survived for nearly 45,000 years. The Adélie penguins have adapted to the expansion of glaciers and fluctuations in sea ice brought about by thousands of years of climate change, maintaining "resilience" in these changes. But scientists have found different trends in population changes at different sites: In some habitats, such as near palmer station at the American Research Center in northern Antarctica, penguin populations have declined by more than 80 percent. Other sites are stable, and some have even increased in numbers, possibly because the reduction in sea ice has shortened their journey to forage in the sea, giving some populations an unexpected survival advantage. But overall, the unique climate of the 21st century poses a threat to many habitats of the Adélie penguins.
Compared to the Antarctic, the Arctic is much more sensitive to climate change (strongly influenced by atmospheric circulation). Polar bears became the biggest victims. For polar bears, starvation has become the norm due to a warming climate. A 2020 study showed that climate change is bringing polar bears to the brink of extinction. The study predicts that in the current human lifetime, this predator at the top of the food chain may all go extinct. In some areas, polar bears have fallen into a vicious circle. Polar bears rely on ice floes to hunt, and the melting of sea ice shortens the time it takes for polar bears to hunt seals, while their dwindling weight reduces their chances of a safe winter in the Arctic without food. If the current rate of accelerated arctic climate change continues, polar bears in 12 of the 13 subpopulations analyzed will die in large numbers over 80 years.
In 2019, a photo of an abandoned polar bear trapped on ice floes made countless people worry about the survival of polar bears, but most people did not realize that the melting of polar ice and snow also had a negative impact on humans. As sea ice and glaciers melt and oceans warm, ocean currents will continue to disrupt global climate patterns, triggering extreme weather such as extreme cold, extreme heat, drought, snowfall, flooding, and hurricanes, causing significant loss of life and property. Warming seawater will also lead to changes in where and when fish spawn, affecting industries that are pillared by fisheries. In areas close to the polar regions, coastal communities will continue to face billions of dollars in post-disaster reconstruction costs as floods become more frequent and storms become more intense.
Global warming, which is closely intertwined, poses a major threat to human health itself. In 2014, the World Health Organization said climate change would bring malaria, dysentery, heat stress and malnutrition, with 250,000 deaths worldwide each year from 2030 to 2050. A 2019 report published in the New England Journal of Medicine warned that 250,000 deaths were a "conservative estimate." Our health is vulnerable to climate change, which could "stall and reverse" the progress made in human health over the past century, which could lead to "far more deaths" from rising temperatures around the world than WHO predicted five years ago at 250,000 a year.
The report also predicts that the number of annual adult deaths worldwide could net to 529,000 by 2050 due to food shortages linked to climate change. By 2030, climate change could force 100 million people into extreme poverty, which will make people more vulnerable to health problems.
In a very optimistic scenario, there will be about 1,000 years or so before Greenland's glaciers all melt. At that time, many lands on the earth will be submerged, and it can be said that the map of the earth will change dramatically.
But countries we are familiar with, such as Japan, Singapore, the United Kingdom, Iceland, etc., may not need to wait 1,000 years, and the lost ice sheets in 2100 alone will raise sea level by 42 centimeters and already submerge them by more than half.
At that point, the global ocean current system could collapse completely, followed by meteorological disasters such as typhoons, torrential rains, and tsunamis. The Arctic biosphere has also seen disruptions in biological chains, triggering regional extinctions.
Taking greenland's melting ice sheet, we humans are in a state of apparent irreversible "acceleration." High temperatures in the Arctic and South Poles, large-scale locust plagues, unusual rainstorms everywhere, sudden freezing snow and other events have begun to normalize, but human beings have been unable to find a solution, and the exploitation of traditional resources has not decreased.
Researchers at the Massachusetts Institute of Technology in the United States, according to the 1972 American scientists jointly published "The Limits of Growth", through big data analysis, after hundreds of simulation calculations, the results show that human development is not sustainable, about 2040, human beings will reach the peak of development.
This is like a parabola, when humans reach the highest point, they will begin to land, and human society will naturally gradually go downhill, although this will not hit human beings back to "primitive society", but it will still make human beings have more existential crises after 2040.
Whether human society will collapse or not, it is obvious that our future is not optimistic. Do you think that day will really come? What do we humans need to do to avoid that day?
All the reports remind us that the misfortunes of wildlife have inevitably spilled over to us. Reducing carbon emissions and curbing climate warming is really imminent.
Source: Ecological China Network comprehensive collation, invasion and deletion.