Half of the world's glaciers may thaw this century - study

Half of the world's glaciers may thaw this century - study

Even if civilization is ambitious with regard to climate change targets, the world’s glaciers will still have disappeared at unprecedented rates by the end of the century according to a recent study published in the journal, Science. This will lead to a significant increase in sea levels and may also deprive billions of people of their main water sources.

Over 215,000 glaciers among the mountains of the world benefit people by providing fresh water, with some sources putting the figure at about 2 billion people. On the other hand, the melting of these massive ‘ice rivers’, some of which are hundreds of thousands years old, will trigger a significant rise in sea levels and thus threaten billions of people who live along coastlines.

While it is no secret to scientists that glaciers are sensitive to temperature increases, it has not been evident in the past how these giant ice masses could respond to various climate change scenarios. The data previously used for analyses was mainly regional which made it difficult to evaluate the extent of the impact of temperature rises on the world’s glaciers. However, new high-resolution data currently available to scientists allows them to model different climate change scenarios and predict changes in glaciers around the world.

The recently published report reached some alarming conclusions. By 2100, almost half of the world’s glaciers risk disappearing under the best-case climate scenario. According to predictions, if the global temperature rises and reaches 4 degrees Celsius, glaciers are expected to melt and lose 41% of their mass before the end of the century. If the rise in global temperatures increases by between 2.1 and 2.9 degrees Celsius by the end of the century, a scenario projected by the United Nations, then glaciers are expected to almost fully disappear in regions such as western Canada and the United States, Central Europe, and New Zealand.

Regarding the report’s outcomes, David Rounce, a glaciologist at Carnegie Mellon University and lead author of the report, said:

“No matter what, we’re going to lose a lot of the glaciers. But we have the ability to make a difference by limiting how many glaciers we lose.”

Fig.1. Percentage of glaciers projected to vanish between 2015 and 2100 for global temperature change scenarios sorted by size.

Source: Science

The disappearance of these massive ice rivers risks significantly increasing global sea levels. According to the report, keeping the temperature rise below 1.5 degrees Celsius threatens to raise sea levels by 90 millimeters. If the temperature reaches 4 degrees Celsius, then sea levels will increase by around 154 millimeters.

The report also reached a vital conclusion, linking the loss of glaciers with global temperatures linearly. This means that any efforts that positively affect climate change will also have an impact on glaciers. Therefore, it is essential to put in place measures to lessen global warming and cool global temperatures.

“Even a small reduction in temperature change can have a really big impact,” David Rounce said.