methane on the rebound

The melting of glaciers driven by global warming portends a seismically turbulent future.

When glaciers melt, the massive weight on the Earth’s crust is reduced, and the crust “bounces” back in what scientists call an “isostatic rebound.”

This process can reactivate faults, increase seismic activity, and lift pressure on magma chambers that feed volcanoes.

This has happened several times throughout Earth’s history, and the evidence suggests that it is starting to happen again. Of course, not every volcanic eruption and earthquake in the years to come will have a climate-change link.

“A particular worry,” writes Bill McGuire in New Scientist, is that such seafloor landslides could “contribute to large-scale releases of methane gas from the solid gas hydrate deposits that are trapped in marine sediments.

Gas hydrates have been identified around the margins of all the ocean basins, and outbursts of gas may occur as sea temperatures climb or as rising sea levels trigger underwater quakes in the vicinity.”

World Watch Institute, 31 July 2006