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A new study in the journal Geophysical Research Letters forecasts a massive reduction in Arctic sea ice over the next three decades, predicting that the North Pole will experience its first ice-free summer before 2050. What’s particularly disquieting is that this eventuality appears likely for all climate models, including those that factor in rapid reductions in carbon dioxide emissions.
The study takes into account data from the Shared Socioeconomic Pathways (SSPs) and Coupled Model Intercomparison Project (CMIP), which predict how the Earth’s climate will change depending on what climate policies are adopted and how greenhouse gas emissions are managed.
It is estimated that the world has a remaining carbon budget of around 1,000 gigatonnes of carbon dioxide, meaning that this is the absolute limit to our future emissions if we want to prevent a 2°C rise in global temperatures compared to pre-industrial levels. Yet after analyzing more than 40 different climate models, the study authors found that the Arctic will sometimes be ice-free in summer even if we stick to this budget.
"If we reduce global emissions rapidly and substantially, and thus keep global warming below 2°C relative to preindustrial levels, Arctic sea ice will nevertheless likely disappear occasionally in summer even before 2050. This really surprised us," said study author Dirk Notz, from the University of Hamburg in Germany, in a statement.
Of the 128 simulations that involved future cumulative carbon dioxide emissions of less than 1,000 gigatons, 101 saw levels of summer Arctic sea ice drop to below 1 million square kilometers (386,000 square miles) before 2050.
It’s important to note, however, that this annual disappearance occurs much more frequently in models based on high carbon dioxide emissions, which means that we can keep these ice-free summers to a minimum by reducing our output of greenhouse gases.
Sea ice plays a crucial role in supporting Arctic ecosystems and in regulating planetary weather cycles and other processes by providing a hunting ground for animals like polar bears while keeping the Earth’s extreme north cool.
It increases in volume each winter and decreases in the summer, although an acceleration in summer melt has been observed in recent years. While this study seems to suggest that we are inevitably heading towards a temporary loss of Arctic sea ice, it also brings home the importance of taking measures to reduce carbon dioxide emissions in order to ensure that a total summer melt becomes an occasional – rather than an annual – event.
