Glaciers

Antarctica’s Thwaites Glacier got its nickname the “Doomsday Glacier” for its potential to flood coastlines around the world if it collapsed. It is already contributing about 4% of annual sea-level rise as it loses ice, and one theory suggests the glacier could soon begin to collapse into the ocean like a row of dominoes. But is that kind of rapid collapse really as likely as feared? A new study of Thwaites Glacier’s susceptibility to what’s known as marine ice cliff instability offers some hope. But the findings don’t mean Thwaites is stable. Polar scientist Mathieu Morlighem, who led the study, explains the results. Why is the Thwaites Glacier so important? Thwaites Glacier drains a huge area of Antarctica’s ice sheet – about 74,000 square miles (192,000 square kilometers), an expanse bigger than Florida. If a snowflake falls within that drainage system, it will eventually end up as part of an iceberg in the ocean off Thwaites....

As humans alter the planet’s climate and ecosystems, scientists are looking to Earth’s history to help predict what may unfold from climate change. To this end, massive ice structures like glaciers serve as nature’s freezers, archiving detailed records of past climates and ecosystems – including viruses. We are a team of microbiologists and paleoclimatologists that studies ancient microorganisms, including viruses preserved within glacier ice. Along with our colleagues Lonnie Thompson, Virginia Rich and other researchers at the Ice Core Paleoclimatology group at The Ohio State University, we investigate interactions between viruses and their environment archived in ice cores from the Guliya Glacier on the Tibetan Plateau. By linking the genomes of ancient viral communities to specific climate conditions preserved in glacier ice, our newly published research offers insights into how these viruses have adapted to Earth’s shifting climate over the pas...

My favorite place in the world isn’t a fixed location. It’s the JOIDES Resolution, an internationally funded research ship that has spent its service life constantly on the move, from deep in the Antarctic to high in the Arctic. Since 1985, scientific expeditions on this one-of-a-kind oceangoing laboratory have drilled 230 miles (370 kilometers) of sediment and rock cores – long cylindrical samples that provide a unique view of the ocean floor. The cores come from a thousand different locations, enabling scientists from many universities around the world to explore changes within the Earth. They also provide a window into our planet’s history. The ocean floor preserves a geological library that documents millions of years of climate change and evolution. The JOIDES Resolution leaves Honolulu in 2009. IODP/Wikipedia, CC BY Sadly, the JOIDES Resolution, also known as the JR...

Superstorms, abrupt climate shifts and New York City frozen in ice. That’s how the blockbuster Hollywood movie “The Day After Tomorrow” depicted an abrupt shutdown of the Atlantic Ocean’s circulation and the catastrophic consequences. While Hollywood’s vision was over the top, the 2004 movie raised a serious question: If global warming shuts down the Atlantic Meridional Overturning Circulation, which is crucial for carrying heat from the tropics to the northern latitudes, how abrupt and severe would the climate changes be? Twenty years after the movie’s release, we know a lot more about the Atlantic Ocean’s circulation. Instruments deployed in the ocean starting in 2004 show that the Atlantic Ocean circulation has observably slowed over the past two decades, possibly to its weakest state in almost a millennium. Studies also suggest that the circulation has reached a dangerous tipping point in the past that sent it into a precipitous, uns...

In August 2023, residents of Juneau, Alaska, watched as the Mendenhall River swelled to historic levels in a matter of hours. The rushing water undercut the riverbank and swallowed whole stands of trees and multiple buildings. The source for the flood was not heavy rainfall – it was a small glacial lake located in a side valley next to the Mendenhall Glacier. Glacier-dammed lakes like this are abundant in Alaska. They form when a side valley loses its ice faster than the main valley, leaving an ice-free basin that can fill with water. These lakes may remain stable for years, but often they reach a tipping point, when high water pressure opens a channel underneath the glacier. The rapid and catastrophic drainage of lake water that follows is called a glacial lake outburst flood, or GLOF for short. The flood waters race downstream over hours or days and often hit unexpectedly. Suicide Basin, a glacier-dammed lake, has flooded the Mendenhall River...