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We’re picking up right where we left off in last week’s Climate Focus on melting glaciers and rising temperatures.
Water temperatures in and around Australia’s Great Barrier Reef have risen to their warmest in 400 years over the past decade, whilst melting glaciers continue to wreak havoc in Alaska.
The rising water temperatures are placing the world’s largest reef under threat, according to recent research by scientists.
The reef, the world’s largest living ecosystem, stretches for around 1,500 miles (2,400 km) off the coast of the northern state of Queensland. The research is rare in putting the effects of man-made climate change into historical context, as other surveys on damage to the reef have a shorter time frame.
A group of scientists at universities across Australia drilled cores into the coral and, much like counting the rings on a tree, analyzed the samples to measure summer ocean temperatures going back to 1618.
Combined with ship and satellite data going back around a hundred years, the results show ocean temperatures that were stable for hundreds of years began to rise from 1900 onwards as a result of human influence, the research concluded.
From 1960 to 2024, the study’s authors observed an average annual warming for January to March of 0.12°C (0.22°F) per decade.
Speaking of warming waters, more than 100 homes in Alaska’s capital Juneau have been damaged by a glacial dam outburst north of the city, an increasingly frequent phenomenon exacerbated by climate change.
The flooding began on Monday night after water spilled out from the glacial lake at Suicide Basin, which annually fills with rainwater and meltwater and is usually dammed by the retreating Mendenhall Glacier. If enough water fills the basin, it can burst through or overtop the ice damming it in.
Local authorities had warned residents near the river to take precautions and opened a local school as a shelter. City officials said no injuries have been reported.
The flood came almost exactly a year after a record-breaking glacial dam outburst at Suicide Basin caused similar flooding. In 2023, the Mendenhall River crested at 14.82 feet, the National Weather Service said.
The risk of glacial dam outbursts has been exacerbated by man-made climate change, which causes glaciers to retreat and has increased the number and size of glacial lakes, scientists say.
