New research sees accelerated melting of ice shelves in West Antarctica inevitable, even if the use of fossil fuels is greatly reduced and ambitious policies are implemented to reduce emissions of warming gases. This is indicated by the study carried out by the British Antarctic Survey and published in the journal Nature Climate Change.
The melting of the polar ice sheets and the resulting rise in sea levels are a consequence of alarming human-induced climate change. West Antarctica does not stop losing ice and is the main focus of Antarctica that contributes to the rise of the sea.
The interest of this type of study lies in the fact that the collapse of the West Antarctic ice sheet is a climatic turning point and has the potential to raise (within centuries) the global sea level of up to 5.3 meters.
These West Antarctic ice shelves play an important role in containing or slowing land-based ice sheets, as they can slow the flow of ice into the ocean and prevent further melting.
That this containment capacity on the ice sheet could give way or cease and it could quickly collapse is a cause for concern.
Recent estimates suggest that this tipping point can be reached with global warming of between 1.5°C and 3°C.
While there is growing evidence that ice loss in West Antarctica is irreversible, scientists have run simulations on the UK's national supercomputer to learn to what extent ice loss can be prevented through global emissions reduction policies. .
The new research, led by researcher Kaitlin Naughten, points out as the most worrying element that accelerated rates of melting of ice shelves are inevitable, regardless of future climate policies.
The scenarios analyzed range from those referring to the most demanding emissions reductions included in the Paris Agreement (a limitation of warming to 1.5 °C compared to pre-industrial times) to the most extreme emissions projections. Even in the best case scenario with a global temperature increase of 1.5ºC, melting will increase three times faster than in the 20th century.
Predicting the future melting of these ice shelves is considered a complex task, as melting rates largely depend on complex and variable ocean processes around Antarctica.
Furthermore, warming in the Amundsen Sea is highly uncertain, partly due to the influence of large-scale modes of climate variability such as El Niño.
However, based on a new high-resolution climate simulation model for the Amundsen Sea, the study argues that accelerated rates of ice melt are likely to occur under all emissions scenarios up to and beyond 2045. in the most extreme scenarios.
Kaitlin Naughten, lead author of the study and researcher at the British Antarctic Survey, notes that "it appears that we have lost control of the melting of the West Antarctic ice sheet." In her opinion, to "preserve it in its historical state we should have acted on climate change decades ago."
The positive side, he comments, is that, by recognizing this situation in advance, the world will have more time to adapt to the coming sea level rise. "If a coastal region has to be abandoned or substantially remodeled, having 50 years' notice is going to make a difference," he says.
"We must not stop working to reduce our dependence on fossil fuels," Naughten warns. "What we do now will help slow the rate of sea level rise in the long term. The slower sea level changes, the more It will be easy for governments and society to adapt to it, even if it cannot be stopped.
The research indicates that the accumulation of warm, salty water is the main mechanism driving melting at the base of the West Antarctic ice shelves. And the same mechanism will also be responsible for future warming trends.
In this sense, it is highlighted that the acceleration of currents along the edge of the Antarctic continental shelf activates a greater volume of warm water flowing towards the shelf in all emissions scenarios.
In the most extreme emissions scenario, not only does more warm water flow toward the continental shelf, but it also does so for longer, leading to higher rates of basal warming.
For their part, forecasts of sea level rise due to future melting remain very uncertain; and this study cannot directly quantify that impact.
However, the authors identify the critical melting points in Western Antarctica and where the greatest impact will occur on the anchoring point of the platform - that is, on the base from where the glacier takes off from the rocky bed and enters the ocean. as a floating ice shelf.
As warm water flows toward the continental shelf, it floods the deep ice shelves, which are most instrumental in supporting the ice.
On the other hand, in a scenario of greater warming emissions, the warm flow reaches the shallower ice shelves.
This study by Naughten represents the most complete set of future projections of Amundsen Sea warming to date.
The work specifies that although it is likely no longer possible to prevent the melting of ice shelves in West Antarctica, the impacts of climate change on sea level depend on a wide range of factors.
And the West Antarctic Ice Sheet represents just one of the factors contributing to global sea levels.
And in this sense, it is noted that the fate of the melting ice sheet of East Antarctica, for example, still depends on the ambition of world governments when it comes to applying warming mitigation policies.
The study adds that the climate variability in this region is large and that it is therefore essential to carry out more research to quantify the exact contribution of this ice sheet to sea rise.
Naughten's study was carried out with a single simulation model, so new work will be required. "For policymakers, the key question now is not only how to mitigate climate change, but also, increasingly, how to adapt to the inevitable effects of climate change," says a commentary on the journal article.
