Earth could lose half its glaciers — even if climate targets are met: report

On Friday, The Washington Postreported that a new study suggests the planet could lose around half of its glaciers, even if the globally recognized climate target of 1.5 degrees Celsius of warming is met.

"The study, published Thursday in the journal Science, finds that even with just 1.5 degrees Celsius (2.7 degrees Fahrenheit) of warming above preindustrial levels, some 104,000 of the world’s more than 215,000 mountain glaciers and ice caps will melt, raising global sea levels by a little shy of 4 inches," reported Chris Mooney. "A rise of 1.5 degrees Celsius beyond preindustrial temperatures is now extraordinarily difficult to avoid, suggesting that a change of this magnitude may be nearly unstoppable. With every additional increment of temperature increase, the study finds, the outlook becomes worse. Three degrees C (5.4 degrees F) of warming, the research finds, would translate into a loss of over 70 percent of global glaciers and result in about 5 inches of global sea-level rise. So, even if many losses are baked in, the authors say, it is still worth trying to avoid whatever warming we can."

Modern global warming is driven largely by human activity, including emissions from fossil fuels and agriculture. Countries around the world are working to reduce emissions, as well as other projects like reforestation and ecosystem restoration that could absorb greenhouse gases like carbon dioxide more efficiently.

"Human societies rely on these ice masses for water supplies, often heavily, as in the case of the thick glaciers of the high mountains of the Hindu Kush-Himalayan region, sometimes called the planet’s 'third pole.' Glaciers in this region feed water into massive river systems including the Indus and Ganges. An estimated 1.9 billion people worldwide depend on glaciers for water, the research notes," said the report. "In many cases, mountain glaciers also have great cultural and tourism significance — an example being Glacier National Park in the United States. The glaciers in this Montana region are in severe trouble, their size and number having plummeted since 1850, according to surveys and mapping by the U.S. Geological Survey. A 2017 study of the park by the agency showed that its remaining 37 named glaciers had shrunk by 68 percent."

"Larger glaciers and more densely glaciated regions, in the Arctic and Antarctic, will be more resilient as the century wears on and temperatures continue to rise, the research finds, melting and contributing to sea level rise but not necessarily disappearing," said the report. "The glaciers of Alaska, for instance, are a leading contributor to sea-level rise. This will continue, but some of the ice deposits are vast enough, and in cold enough places, that they are projected to withstand even 4 degrees C (7.2 degrees F) of warming. But that’s not always true of many smaller glaciers in the middle latitudes — in regions including the Alps in Europe, the Peruvian Andes and the peaks of New Zealand’s South Island."

In the previous decade, scientists finally announced some victories in the fight to mitigate climate change. For one thing, the Montreal Protocol — the global agreement that phased out aerosol components depleting the ozone layer — was largely successful, and some studies suggest this has made plants capable of absorbing far more industrial CO2 than they would have otherwise, preventing 0.5-1.0 degrees of warming. Additionally, economic data shows that many countries have successfully "decoupled" emissions from growth, meaning that their energy sources are clean enough that more production doesn't directly translate to more emissions.