Greenland’s ice sheet may have hit a tipping point that puts it on an irreversible path to disappear completely.
Snowfall that normally fills the glaciers of Greenland every year can no longer keep up with the rate of ice melting, according to researchers from Ohio State University.
This means that the Greenland ice sheet – the second largest ice body in the world – will continue to lose ice, even if global temperatures stop rising.
In her study, published Thursday in the journal NatureFor 40 years, scientists have been studying satellite data from more than 200 large glaciers floating in the ocean across Greenland.
“What we have found is that the ice extracted in the ocean overcomes the snow that collects on the surface of the ice sheet,” said Michalea King, lead author and researcher of the study at Byrd Polar and Climate Research Center. e Ohio State University, said in a press release.
Full melting of the Greenland ice sheet could raise sea levels 23 feet (~ 7 meters) by the year 3000.
If that happened, the ocean would ruin coastal cities all over the world.
Greenland’s ice is already the largest single participant in sea level rise. In just the next 80 years, the current melting rate would add another 6.75 inches (6.9 cm) to global sea levels, according to a study published in December.
“Glacier Retreat has thrown the dynamics of the entire ice sheet into a constant state of loss,” Ian Howat, a glacier and co-author on paper, said in the release.
“Even if the climate remained the same or even got a little colder, the ice sheet would still lose mass.”
But this is just one of many tip points for climate change that human activity can bring. There is still time to prevent irreversible paths to other disasters.
There are more points of return
The amount of ice that Greenland loses each year has steadily increased over the last two decades. Before 2000, the researchers found, the ice sheet had an equal chance of gaining or losing mass each year.
But in the climate of the last 20 years, it will only get mass one in every 100 years, the researchers found.
Greenland dumped an unusual amount of ice and water into the ocean in the summer of 2019, when a heat wave from Europe washed over the island.
The ice sheet lost 55 billion tons of water over five days – enough to cover the state of Florida in nearly five inches of water.
Melt brings more melt, because water that pools over the ice sheet absorbs more sunlight and warms everything around it. That’s why tipping points like Greenland’s ice loss are accelerating so much.
Rising global temperatures and certain human activities could bring tip points into other parts of the world.
In the Arctic, ice melt exposes permafrost – frozen ground that releases powerful greenhouse gases as it thaws. If warming enough permafrost is detected, the released gases will capture the heat faster than human fossil fuel emissions.
In the Amazon rainforest, humans have been cutting down and burning trees for years, allowing moisture to escape the ecosystem. Sufficient deforestation could trigger a process called ‘dieback’, in which the rainforest would dry up, burn and become a savannah-like landscape, releasing up to 140 billion tons of carbon into the atmosphere.
Last year, leading rainforest scientists warned that the Amazon is “teetering on the edge” of that threshold.
Still, scientists say switching to less carbon-intensive forms of energy, such as solar energy, and reducing unsustainable logging and mining can help us prevent those disasters.
Even for the Greenland ice sheet, the future has more tipping points – degrees of collapse that will accelerate the melting of the glaciers even more. Limiting global warming could slow those tipping points and give the world more time to prepare.
“We have passed the point of no return, but there are obviously more to come,” Howat told CNN.
“Instead of being a single tipping point in which we went from a happy ice sheet to a rapidly collapsing ice sheet, it’s more a trap where we’ve fallen from the first step, but there are many more steps to the bullet. “
This article was originally published by Business Insider.
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