To prevent irreversible acceleration of sea level rise due to melting sea ice, Antarctic and Greenland, the increase in global average temperature must fall short of the maximum value set by Paris Agreement2 degrees Celsius, an international team of researchers says in the journal Nature communications.
The scientists used three of the scenarios, developed by the Intergovernmental Commission on Climate change (IPCC), which detect the possible evolution of the Earth’s temperature depending on the emissions of gases with the greenhouse effect are more or less controlled together with various simulations of the Earth system with an influence on the glacier melting process.
In the published article In connection this Tuesday, presented a new climate model that allows for the study of the complex relationships between ice shelves, the oceans, the atmosphere, and applied it to the study of how melting Antarctica and Greenland will contribute to sea level rise .
For example, in Antarctica, rising temperatures can cause deeper cracks in submerged ocean ice shelves on which surface ice rests. This can cause these plates to break up, which will cause ice that melts at the surface to slide faster into the ocean.
What they report in the article first authored by Jun-Young Park, from the Physics Center of Climate from the Institute of Basic Science in Busan, South Korea, is that only the SSP1-1.9 scenario, which envisages more ambitious cuts in carbon dioxide emissions, carbonand predicts a 1.5 degree rise in average global temperature by 2050 – the main goal of the Paris Agreement – is to avoid the impact of accelerating sea level rise for the next 130 years.
The Paris Agreement’s cap of two degrees Celsius above pre-Industrial Revolution values ”is insufficient to prevent an acceleration of sea-level rise over the next century,” the researchers write.
Uncertainties in Antarctica
The scientists present a longer-term analysis of what might happen under the IPCC’s Middle Path scenario (SSP2-4.5), in which emissions from greenhouse gases they only start to decrease from 2050 onwards and the average global temperature could increase by 2.7 degrees by the end of this century.
Sea level rise has been accelerating due to the melting of Greenland for 250 years and will peak in 2300 at a rate of 0.3 cm per year. The Antarctic contribution ranges between 0.2 and 0.3 cm per year between 2200 and 2500. “This indicates an even larger response and implies a commitment to sea-level rise due to warming in the 21st century,” the researchers write.
In the most pessimistic scenario (SSP5-8.5), which predicts that carbon dioxide (CO2) emissions will double by 2030 and that the global average temperature will be 4.4 degrees above what it was before the Industrial Revolution in 2100, ice loss is drastic. The Ross Ice Shelf in Antarctica – about the size of France – is simply disappearing from 2100 onwards, for example.
The most optimistic scenario (SSP1-1.9), in which the average global temperature does not exceed 1.5 degrees and greenhouse gas emissions are reduced to almost zero by 2050, “is enough to avoid significant ice loss in Antarctica in the next few . centuries,” says the team.
Global sea level rise in the last century has been about 20 cm, due to thermal expansion of seawater, melting glaciers and ice shelves, for example, and this trend is expected to accelerate because of global warming.
Satellite observations show that Greenland ice lost mass at a rate of 286 gigatons (Gt) per year between 2010 and 2018, while Antarctic ice lost 252 Gt per year between 2009 and 2017.
But there are many uncertainties about how the ice will develop on a warmer planet, and this team is trying to create a more effective forecasting model. The greatest uncertainty concerns the behavior of the Antarctic ice sheets. The South Pole ice, along with Greenland, is the biggest contributor to sea level rise – which will have a huge impact on the many cities and infrastructure built along the coast.
Recent studies show that global sea levels could rise by about 1.4 meters by 2150, under a scenario of high greenhouse gas emissions. In the new study, each of these ice sheets, Antarctica and Greenland, is predicted to contribute 60 to 70 centimeters to sea level rise over the next 130 years, which gives values similar to existing predictions.