A new threshold has been crossed. On January 6, NASA [National Aeronautics and Space Administration] measured a rise in the oceans of more than 10 centimeters since 1993. This is just the beginning, as the increase in greenhouse gas (GHG) emissions in recent years amplifies warming. In fact, 90% of this excess heat is absorbed by the oceans, one of the main responses being rising sea levels. Thus, this phenomenon is accelerating: it was 2.9 millimeters per year between 2001 and 2010, a rate that nearly doubled to reach 4.5 millimeters per year between 2011 and 2020, according to the European Copernicus program.
The rise in sea level has three sources: the expansion of water due to temperature, the melting of continental glaciers, and the melting of polar ice sheets. The latter component has only been triggered since the 2000s, but it is the fastest-growing and will determine the course of future events.
These glaciers have seen their melt rate double in less than twenty years. The situation is even evolving more rapidly, and glaciologists have recently expressed concern about a very rapid acceleration in the melting of the main glaciers in West Antarctica. One of them, as large as England, could disappear in just a few years, leading to a rise in sea levels of 60 centimeters by itself. Even though West Antarctica and Greenland will not completely disappear in a century, their melt is accelerating rapidly and will be the primary cause of sea level rise in the future. Projections for 2035-2040 are more than 0.5 centimeters per year, and the increase could exceed 1 centimeter per year before the end of the century, according to NASA.
Source: Le monde
