But if the world can limit future warming to just a few tenths of a degree and meet international climate targets, then just under half of the world’s glaciers will disappear, the same study says. Glaciers, mostly small but known, are heading towards extinction, according to their authors. The study notes that in the worst-case scenario of a few degrees of warming, 83 percent of the world’s glaciers are likely to disappear by 2100.
The study, published Thursday in the journal Science, examined the world’s 215,000 terrestrial glaciers, excluding those in Greenland and Antarctica, in a more comprehensive way than previous studies. The scientists then used computer simulations to calculate, using different levels of warming, how many glaciers will disappear, how many trillion tons of ice will melt, and how much this will contribute to sea level rise.
The world is currently on track to increase temperatures by 2.7 degrees Celsius above pre-industrial times, meaning the loss of 32 percent of the world’s glacier mass, or 48.5 trillion metric tons of ice, by 2100, and 68 percent disappearance of glaciers This would increase sea level rise by 115 millimeters, plus the fact that seas are already rising due to melting ice sheets and warming water, according to the study’s lead author, David Rounce.
Projected ice loss for 2100 ranges from 38.7 trillion metric tons to 64.4 trillion tons, according to the study, depending on how much the planet warms and how much coal, oil and gas is burned. The researchers calculated that all this melting ice would add between 90 millimeters at best and 166 millimeters at worst to global sea levels, 4 to 14 percent more than previous forecasts.
The rise means more than 10 million people around the world will be living below the high tide line that would otherwise be above it, researcher Ben Strauss, chief executive of Climate Central, told ABC News. Sea level rise in the 20th century due to climate change added about 10 centimeters to the surge from Hurricane Sandy in 2012, which caused about $8 billion in damage to the US economy, he said.