Antarctic ice-loss: a 25-year-long look from space.

BBC has, courtesy of the Fall Meeting of American Geophysical Union (AGU), a quarter-century of satellite images of Antarctica showing how the ice is shrinking, and where the melted water is flowing:

Scientists have combined nearly a quarter of a century of observations to show how the region’s great glaciers are losing height by up to 7m per year.

The satellite data also traces the way this thinning behaviour has spread up the length of the ice streams.

Right now, they are dumping some 120 to 140 billion tonnes of ice a year into the ocean, which is sufficient to push up global waters by between 0.34mm and 0.40mm per annum – more than 10% of the total worldwide trend.

The glaciers’ reduction in height is likely the result of the warm seawater recorded around Antarctica in recent decades.

“As the glaciers accelerate, they have to take ever more ice from the interior to compensate for the speed-up. This means they thin; they lose height, which we can detect from space,” explained Dr Hannes Konrad from the UK’s Centre for Polar Observation and Monitoring (CPOM).

“And if there is no increase in snow and ice in the interior then this thinning will just migrate further and further upstream,” the Leeds University researcher told BBC News.

It seamlessly ties together for the first time the altimetry observations from five different satellites operated by the European and American space agencies from 1992 to the present day.

What is interesting in the data is the individual responses of the glaciers to the melting assault.

They all show thinning over the period, but the behaviours are far from uniform.

Pictures and maps at the link.