The melting of glaciers in high mountain areas such as the Alps seems unstoppable and in many cases becomes catastrophic due to climate change. Despite the fact that the environmental and social damage (loss of water resources, landslides...) are enormous on a global scale, the areas occupied for thousands of years by ice are now turning into open land where, in In some cases, new habitats for vegetation and fauna are formed.
A team of geologists and ecologists from various institutions in Switzerland and France have now created a computer model to predict the extent of glacial melt through the year 2100 and the ecosystems that will emerge in its place. The system could be used in affected areas such as the Alps or the Himalayas and in the future also in large extensions affected by melting ice such as Greenland and Antarctica, as indicated by the authors of this work in an article presenting the results published this week in the journal Nature. In a second article published on the same subject, also in this prominent scientific journal, the paradox is exposed that the melting of glaciers will cause the formation of new unprotected ecosystems.
"The emerging habitats that will form as the ice recedes present challenges, as well as opportunities, for conservation efforts," says Jeff Tollefson in the same magazine. Without counting Antarctica or Greenland, alpine glaciers currently cover some 650,000 square kilometers and supply water to almost 2,000 million people, as well as being of great importance for ecosystems in very diverse areas of the planet.
The researchers modeled the future of those glaciers, as well as the terrain they would leave behind, under scenarios of low and high greenhouse gas emissions. The results now published in Nature suggest that even in the most optimistic scenario, an area twice the size of Ireland could be exposed by the end of the century. That exposure more than doubles in a high emissions scenario, with the largest observed area impacts in Alaska and the high mountains of Asia.
"This could be one of the biggest ecosystem changes on our planet," says lead author Jean-Baptiste Bosson, a glaciologist at the Haute-Savoie Conservatory of Natural Areas (ASTERS), a conservation group based in Annecy, France.
Bosson and colleagues project that about 78% of the newly exposed terrain would be on land, while 14% and 8% of the ice-free areas would occur in marine and freshwater regions, respectively. In a curious twist, Bosson says, many of these areas could provide crucial new habitat that must be protected: Colonization by plants could lead to increased carbon storage at a time when forests elsewhere are being destroyed. , while also providing new habitats for animals threatened by climate change at lower elevations.
Previous research has shown that glaciers around the world are slowly melting due to global warming. Now the research team has attempted to estimate the global extent of the problem, while noting that the land beneath the glaciers will become new ecosystems and should be protected, if possible.
To create their model, the team used global glacier evolution data that is based on historical expansion data and estimated increases in temperatures to make predictions about the future amounts of glacier melt worldwide, excluding those in the Antarctica and the Greenland ice sheets.
Their goal was to predict how much change might occur in mountain and wetland glaciers. They were able to model areas of deglaciation that, they say, will develop into new ecosystems over the years leading up to the turn of the century. In developing their model, they took into account the different degrees of global warming.
Their model showed that, in the worst case, about half of all glacier mass will have disappeared by the year 2100. In the best case, the model showed a loss of about 22% of global glacier mass. Under this scenario, the area of loss would still be between the size of Nepal and that of Finland.
The researchers note that when glaciers melt, they reveal the land below, land that may have been covered in ice for thousands of years. Said land, they further point out, will naturally evolve into new ecosystems. And because so little research has been done on the fate of such areas, little is known about their characteristics. They suggest that surveys of such areas be carried out and that action be taken if they are found to be in need of protection.
