Half of Earth’s mountain glaciers ‘doomed’ to melt by end of century

By Mark Waghorn via SWNS

Half of Earth's mountain glaciers are doomed to melt by the end of the century, warns new research.

The threat they pose to the planet due to global warming has been greatly underestimated, say scientists.

Even under the most optimistic scenarios, glaciers globally will lose substantially more mass and contribute to more sea-level rise than current predictions.

These include those published in the most recent IPCC (Intergovernmental Panel on Climate Change) report.

Lead author Dr. David Rounce of Carnegie Mellon University in Pittsburgh, Pa., said: "Every increase in temperature has significant consequences with respect to glacier contribution to sea level rise, the loss of glaciers around the world, and changes to hydrology, ecology, and natural hazards."

There are more than 215,000 glaciers in the world - excluding the Greenland and Antarctic ice sheets.

They cover 450,000 square miles. If they all melted they would raise sea levels by about 16 inches.

Rates of glacier melt have increased over the past few decades. The continued decline of these vulnerable features will also affect freshwater availability for nearly two billion people - and increase the risk of glacier-related hazards.

Projecting their loss is critical to future global climate adaptation and mitigation efforts.

Existing calculations are limited to regional scales and neglect key physical processes controlling glacier mass loss.

So Dr. Rounce and colleagues took advantage of new datasets that explicitly account for glacier dynamics.

They produced projections for all of Earth’s individual glaciers under +1.5°Celsius (C), +2°C, +3°C, and +4°C temperature change scenarios by 2100 relative to pre-industrial levels.

The findings suggest glaciers will lose 26 to 41 percent of their total mass by 2100 relative to 2015.

This is under temperature increases of 1.5°C to 4°C, respectively, compared to pre-industrial levels.

This means that even under the best-case scenarios, where the global average rise is limited to 1.5°C, as many as half of the planet's glaciers will be lost by 2100.

Recent climate pledges from COP-26 project an increase of 2.7°C over the next century,

Rounce said: "Earth will likely experience a near-complete deglaciation of entire mid-latitude regions, including Central Europe, Western Canada and the United States, and New Zealand.

"This will result in a much greater glacial contribution to sea-level rise than currently estimated."

The study in the journal Science represents "a substantial step forward in predictive modeling", said the researchers.

Melting glaciers contribute to rising sea levels, but almost three-quarters of this water comes from Greenland and Antarctica.

The Hindu Kush Himalayas, Patagonia and Iceland are also significant. The European Alps, which run through France, Switzerland, Italy, Austria and Germany, contribute less than one percent.

Cutting the emissions from fossil-fuel burning, deforestation and other polluting activities is the biggest factor in minimizing the melting of the ice.

Professor Gudfinna Adalgeirsdottir of the University of Iceland, who was not involved in the study, decribed it as a "stark warning about the consequences of insufficient action."

She added: "Although it is too late to avoid losing many glaciers, any effort to limit global mean temperature rise will have a direct effect on reducing how many glaciers will be lost."