Glaciers grow and shrink naturally in pace with the climate's natural variations. But the ongoing global warming, which is mainly caused by human combustion of fossil fuels, has increased the melting at a pace never seen before.
A new American study published in Science Advances shows that the glaciers in Sierra Nevada in American California have never melted away during at least 11,700 years. Probably they were in place for more than 20,000 years ago, thus a time before humans settled on the continent.
But by the next turn of the century, the already heavily affected glaciers are expected to be completely gone, if the emissions continue as expected.
The researchers examined, among other things, the isotopes in the bedrock that have recently been exposed under the melting glacier to see when it was last ice-free. They also looked at when the glacier was at its largest by examining rocks and gravel that the glacier had pushed in front of it.
