Greenland’s ice sheets are melting too quickly, and we’re already halfway to the point of no return

Having the oceans reliably remain where they are is an excruciatingly overlooked blessing. Being permanently located at relatively safe distances from us also means that we have to deal with the potentially treacherous waters only when we want or need to.

However, as we know, this isn't always the case. We've heard of the tragedies that tsunamis and localised flooding can wreak havoc on coastal communities. And with melting ice sheets dangerously inflating global sea levels, oceans have begun encroaching land at feverish rates all over the planet.

One of the leading proponents of this sea level spike includes the ice sheet that covers the island country of Greenland. This sheet covers about 17 lakh square kilometres of land in the Arctic. If this gargantuan area were to melt entirely, we could see sea levels rise by about seven metres globally, meaning your socks getting a little wet is going to be the least of your problems.

Imagine you stand by the ocean line at the beach, where the rolling waves periodically drench your sand-covered feet. Now, imagine a two-storey building at your feet. The terrace of the building is where the new ocean level could stand if we let the Greenland sheets melt.

As much effort as we have put into trying to reverse the melting, there still exists a point beyond which we can no longer halt the melting process. Many studies have been undertaken to find this defining point of no return to help us understand exactly where we stand vis-à-vis our climate war.

A new study published in the American Geophysical Union journal attempted to do the same and yielded terrifying results. Releasing 1,000 gigatons of carbon into the atmosphere will cause the southern portion of the Greenland Ice Sheet to melt irreversibly, making it the first tipping point.

The scary part? We've already oozed about 500 gigatons of carbon into the air, meaning we're already halfway there.

"The first tipping point is not far from today's climate conditions, so we're in danger of crossing it," notes Dennis Höning, lead author of the study. "Once we start sliding, we will fall off this cliff and cannot climb back up."

Most of the Greenland melting is currently concentrated in its southern parts. Between 2003 and 2016, the sheet lost about 255 billion tons of ice annually. All of the island's ice will be permanently lost if 2,500 gigatons of carbon are released into the atmosphere, making it the second tipping point.

Air and water temperatures, ocean currents, and precipitation are crucial factors determining the melting rate and subsequent tipping points. In addition, the more the ice melts, the surface of Greenland also lowers. This means that the new ice surface is exposed to lowered air temperatures, further accelerating the melting process.

Höning warns that if we cross the second tipping point, even reducing atmospheric carbon dioxide content to pre-industrial levels wouldn't help Greenland grow its ice sheets back.

"We cannot continue carbon emissions at the same rate for much longer without risking crossing the tipping points," Höning warns. "Most of the ice sheet melting won't occur in the next decade, but it won't be too long before we will not be able to work against it anymore."

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