Greenland ice sheet melting at 'exceptional' rate

The disintegrating Greenland ice sheet is the leading cause of global sea level rise. And, according to a new study, it's melting faster than it ever has in recorded history.

Greenland may be a remote and scarcely populated island, but, as a new study highlights, deep environmental changes happening there are having consequences for the entire globe.

The world's largest island is a vital cog in the planet's climate system — 80 percent of it is covered in ice, known as the Greenland ice sheet.

Although it's well known that this ice has been gradually melting over time — adding 1.3 millimeters (about .05 of an inch) to global sea levels each year — researchers have now confirmed that the melt is accelerating at an alarming rate.

The new report, published on Wednesday in Nature, maps the pace of the melting ice over 350 years. It shows that melting has rapidly increased over the last few decades — it is 50 percent faster today than it was in the preindustrial era.

Read more: Arctic warmer than much of Europe is a worrying sign of climate change

Nature and Environment | 31.10.2018

Using drills, researchers extracted ice cores from the Greenland ice sheet

'Unprecedented' melt

While we know that Earth is warming and its frozen regions are melting, so far it hasn't been clear whether or not the rate at which specific regions like Greenland are melting is unusual; records simply don't go back far enough. 

Read more: Sea level rise is real and accelerating: PNAS study

Our understanding of Greenland's melting has largely been based on satellite observations and has lacked a historical long-term perspective, Luke Trusel, the lead author of the study, told DW.

"We have a great understanding of how it's changing today, but we needed to put these observations in a longer-term context," Trusel said.

Using a drill to extract core samples from the ice sheet itself, the research team was able to extend records for Greenland ice melt back to 1650. They found that melt and runoff from the ice sheet have recently accelerated beyond the range of past variability.

As Trusel explained, this means melting of the ice sheet has been relatively steady in the past, and has only rapidly increased over the past few decades.

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"It's now increased to levels we haven't seen before, at least in the last few centuries and probably not in the last 8,000 years," he said.

"The changes we're seeing today are exceptional and unprecedented in a longer-term context."

Conservative estimates of global sea level rise predict an increase of half a meter by the end of the century

Read more: Germany's coastal lowlands under the shadow of climate change

Runaway melting a serious concern

Researchers have described this rise in melting as "nonlinear," because for every degree of global warming melting increases at a disproportional rate. Greenland ice sheet melt is now "outpacing" warming, Trusel said.

For example: in the past, 1 degree Celsius (1.8 degrees Fahrenheit) of warming might have had little or no impact on the ice sheet, but today the same amount of warming produces twice as much melt, or more.

Alun Hubbard, a professor of glaciology at Aberystwyth University, said researching these trends over the long term is incredibly important to understanding global warming.

It's also particularly valuable in combating climate change skepticism, he added. "It's really important to show that what's happened in the last couple of decades is something very different and very new," he said.

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Eco Africa | 19.01.2018

Photographing Greenland's vanishing glaciers

Greenland key for sea level rise

The Greenland ice sheet is as big as the US state of Alaska and now melting at an unprecedented rate; if it were to melt away, it could raise global sea levels by 7 meters (23 feet).

At the moment, conservative estimates of global sea level rise predict an additional half a meter or more by the end of the century. According to Hubbard, even an increase of half a meter is "a terrible disaster for humanity — especially coastal regions of the planet."

"Perhaps in the developed world we have the ability to mitigate it, but for the less developed world it's a complete and utter tragedy," he said.

But sea level rise wouldn't be the only consequence. The vast expanse of ice also moderates temperatures by reflecting a significant amount of the sun's energy back into space. And because of its position in the North Atlantic, its meltwater runoff regulates ocean circulation patterns.

Read more: How a warmer Arctic could lead to more extreme weather

A rapid melting of the ice sheet and the subsequent release of large amounts of freshwater would likely change the circulation system of the North Atlantic, having a huge impact on Europe's climate and global ocean circulation patterns.

"Warming means more today than it did in the past," Trusel said. "What we do now and in the future is critically important for how much Greenland will melt and how quickly it will contribute to sea level rise."

Solomon Islanders face rising sea levels

Life on the water

At high tide, Lau Lagoon's manmade islands barely rise above the waterline. During king tides and
 strong winds, which are becoming increasingly frequent, some islands are now completely submerged.

Solomon Islanders face rising sea levels

People of the sea

According to oral history, and "wane i asi," or people of the sea, have been living on manmade islands in Lau Lagoon for 18 generations. They are said to have come here to be closer to the sea that provides them with a bountiful supply of fish, and respite from mainland's mosquitoes.

Solomon Islanders face rising sea levels

The only way is up

As the sea level rises, more and more of the lagoon's residents are building their homes on stilits for a few extra feet of grace.

Solomon Islanders face rising sea levels

Water babes

Children are raised to feel at home with the ocean lapping at their feet. The only school is on the mainland, so they're used to making daily the journey back and forth across the lagoon.

Solomon Islanders face rising sea levels

Born sailors

Navigating between the islands and the mainland in tiny dugout canoes with plastic sails is a skill gained early in life and quickly becomes second nature.

Solomon Islanders face rising sea levels

Stormy weather

Living on the lagoon means being completely exposed to tropical storms. And this one came during what was traditionally the dry season. Lau Lagoon islanders are being forced to contend with increasingly unpredictable weather.

Solomon Islanders face rising sea levels

Times of change

John Kaia, 52, is chief of the Aenabaolo tribe on the island of Tauba1. He says that over his lifetime he has seen dramatic changes to the climate - and his people's way of life.

Solomon Islanders face rising sea levels

Swept away

Homes lie ruined in the wake of a large wave event. Here, the community decided to not rebuild - the destruction now comes too frequently and on too great a scale to make it worth while.

Solomon Islanders face rising sea levels

Fight against time

Living with rising sea levels is an uphill struggle. Essential structures such as this outhouse, only accessible by bridge, require constant maintenance.

Solomon Islanders face rising sea levels

Abandoned to the waves

The struggle to maintain this outhouse has long since been abandoned. What was once a part of a family home is now an occasional perch for seabirds.

Solomon Islanders face rising sea levels

New neighbors

Many of Lau Lagoon's people of the sea are tying to relocate to the mainland of Malaita. But they are not always welcome. Land disputes mean construction is halted by court order - as with this church.

Solomon Islanders face rising sea levels

Fresh start

While some wane e asi struggle for space on the mainland, others are unable to find land there at all, and are building new islands in the lagoon, like this one - still very much a work in progress.

Solomon Islanders face rising sea levels

Keeping the faith

Religion plays a central role in daily life in Solomon Islands. Prayer and devotional rituals provide solace in trying times. Many have also relied on the church to help them relocate, as state programs fail to get off the ground.

Solomon Islanders face rising sea levels

Saying goodbye

As Lau Lagoon's islands are abadoned, a way of life that has existed in harmony with nature for generations may be lost forever because of the damage industrialized nations have inflicted on our shared planet.

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