Norway. I stand on the edge of the Greenland ice sheet, mesmerized by the breathtaking view of natural destruction. A mile-wide portion of the face of the glacier has broken off. A huge iceberg is breaking and falling into the sea. Huge columns of ice, the height of a three-storey building, are swaying from side to side. A huge piece of this glacier falls into the sea – several tons of snowflakes can be seen flying in the air. After this, high waves rise and drown everyone in their path.
Luckily, I’m seeing all this from a cliff a few miles away. But even here I can feel the tremors. Despite the spectacle, I am well aware that this is bad news for the world’s bottom beaches. As a field glaciologist, I have worked on ice sheets for more than 30 years. In that time I have seen some amazing changes. The last few years have been particularly important because of the rapid rate and magnitude of changes taking place. My books taught me that ice sheets react on millennium time scales, but that’s not what we see today.
A study published on 29 August 2022 suggests that the current Arctic climate has caused the Greenland ice sheet to be so out of balance that it can no longer maintain its current shape. It is irreversibly committed to at least 59,000 square kilometers (22,780 sq mi), an area much larger than the Danish protected area of Greenland.
Even if all greenhouse gas emissions contributing to global warming were eliminated, we find that the loss of the Greenland ice sheet would raise global sea levels by at least 10.8 inches (27.4 cm) under current temperatures . This is higher than the current model forecasts. If every year was like 2012, when Greenland experienced a heat wave, the irrevocable commitment to sea level rise would triple. This is an ominous sign, given that these are climate conditions we’ve seen before, not a hypothetical future scenario.
2100. By the time extreme heat will make most of the earth dangerous
Our study takes an entirely new approach – it is based on observation and glacial theory rather than on sophisticated numerical models. The current generation of coupled climate and ice sheet models used to predict future sea level rise have failed to capture the emerging processes we see driving Greenland ice loss.
How did Greenland reach this point?
The Greenland ice sheet is a huge, frozen reservoir that looks like an inverted bowl. The ice is in constant flux, flowing from within – where it is more than 1.9 miles (3 kilometers) thick, cold and icy. Overall, the ice sheets hold enough fresh water to raise global sea levels by 24 feet (7.4 meters).
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Greenland’s land ice has existed for about 2.6 million years and expanded and contracted with two dozen ‘ice age’ cycles, lasting 70,000 to 100,000 years, punctuated by a roughly 10,000-year warm interglacial. Each glacier is driven by changes in Earth’s orbit that control how much solar radiation reaches Earth’s surface. These variations are then reinforced by snow reflectance, the albedo; atmospheric greenhouse gases; and the ocean circulation that redistributes that heat around the planet.
We are currently passing through an interglacial period – the Holocene. For the past 6,000 years Greenland, like the rest of the planet, has benefited from a mild and stable climate with ice sheets – until recently. Since the 1990s, as the atmosphere and oceans have warmed under rapidly rising greenhouse gas emissions, Greenland’s mass balance has deteriorated. Snow loss is now more than snow accumulation due to more snowfall, rain, snow drift etc.
what does the future hold?
The important questions are, how fast is Greenland losing its ice, and what does this mean for future sea level rise? The loss of the Greenland ice sheet is contributing about 0.04 inches (1 millimeter) per year to global sea level rise over the past decade. This net loss is split between surface melting and the dynamical processes that accelerate outward glacier flow and are greatly increased by atmospheric and ocean warming, respectively. Define it in simple words, he can say that ice sheets do not like hot weather or water flow, and there is heat.
Models used by the Intergovernmental Panel on Climate Change project a sea level rise of about 4 inches (10 cm) over Greenland by 2100, with a worst-case scenario of 6 inches (15 cm). But this prediction is different from what field scientists are seeing from the ice sheet.
According to our findings, Greenland will lose at least 3.3% of its ice, more than 100 trillion metric tons. This damage has already been done – ice must melt and glaciers break in order to re-establish Greenland’s equilibrium with the current climate.
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it’s not too late
The consequences of catastrophic coastal flooding in the form of sea level rise are still unimaginable for the billions or more people living in the low-lying coastal regions of the planet. Personally, I hope we can get back on track. I don’t think we’ve overstepped the limits of improvement, but it’s not too late to act on what we understand about the ice sheet and the insights our new studies provide. But fossil fuels and emissions must be reduced now, as time is short and water levels are rising – faster than anticipated. (agency input)
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First Published: August 30, 2022, 23:03 IST
