Glaciologists who study the seasonal growth and loss of the Greenland Ice Sheet have come to the startling conclusion that even if we stopped burning fossil fuels completely today, it would still lose enough mass on its own to raise global sea levels by at least a foot.
Snow that is sitting on top melts into ice during the colder months just like the Greenland ice sheet does as it gets warmer. The mass lost throughout the summer would be recovered over the winter in an equilibrium process in a stable environment. However, things are getting more out of balance as a result of climate change, which is making the globe hotter.
Computer simulations of ice movement and intricate climatic interactions are used by scientists to better understand how this glacier melting would affect sea levels all over the planet.
This approach, according to the authors of this new study, has flaws in that it is imprecise and neglects to take into account several factors that scientists are observing in the field. Increased precipitation that accelerates the melting of the ice on the surface, a surge of tropical ocean currents into Greenland’s fjords, and a darkening of the sheet surface that increases heat absorption are a few of these.
In a supplementary article for The Conversation, Alun Hubbard, Professor of Glaciology at the University of Tromsø, writes: “We’re observing many emerging processes that the models don’t account for that increase the ice sheet’s vulnerability.”
A new strategy, one that fully avoids computer models, has been adopted by Hubbard and his associates. The study is based on measurements made by meteorological stations over twenty years, data from satellites measuring the mass of the surface and the amount of bare ice, and a glaciological analysis method called volume-area power law scaling.
The team conducted analyses on how the Arctic’s climate has changed between 2000 and 2019 and how this has affected the annual imbalance between the ice sheet’s losses and growth. The boundary between the parts of the Greenland ice sheet that are prone to summer melting and those that are not as focused on is known as the changing snow line. This snow line may move to higher elevations during an unusually warm summer, exposing more ice to melting conditions and returning to lower elevations during an unusually cold winter.
Greenland’s Ice Sheet Currently in the State of Disequilibrium
According to researchers, Greenland’s ice sheet is currently in such a state of disequilibrium and has diverged so much from the Arctic climate that it won’t be able to support its mass.
The sheet will now have to rectify itself by losing an additional 3.3 percent of its volume for the physics to make sense. That is true even if the world immediately stopped burning fossil fuels. This is equivalent to 110 quadrillion tons of ice, which would raise sea levels worldwide on average by at least 27 centimeters (10 in).
Jason Box, the lead author from the National Geological Survey of Denmark and Greenland said: “It is a very conservative rock-bottom minimum. Realistically, we will see this figure more than double within this century. In the foreseeable scenario that global warming will only continue, the contribution of the Greenland ice sheet to sea level rise will only continue increasing. When we take the extreme melt year 2012…as a hypothetical average…, the committed mass loss from the Greenland ice sheet more than doubles to 78 cm (30 in).”
The US National Ocean and Atmospheric Administration (NOAA) estimates that since 1880, the sea has risen by eight to nine inches (21 to 24 cm) and that this rise is just continuing. It is alarming to see that Greenland alone is already anticipated to contribute more than this, most certainly before the turn of the century.
Coastal communities all across the world should expect a variety of new threats as a result of rising sea levels. These include wildlife dangers, infrastructural damage (from bridges to coastal residences), and shoreline erosion. Higher background water levels would result in destructive storm surges moving farther inland and far more frequent floods.
According to NOAA, high-tide flooding along a large portion of the US coastline has increased by three hundred to nine hundred percent in the past fifty years.