World's glaciers melting at accelerating rate

The world's glaciers are melting at an accelerating rate, BBC News reports, citing a comprehensive new study.

A French-led team assessed the behaviour of nearly all documented ice streams on the planet.

The researchers found them to have lost almost 270 billion tonnes of ice a year over the opening two decades of the 21st Century.

The meltwater produced now accounts for about a fifth of global sea-level rise, the scientists tell Nature journal.

The numbers involved are quite hard to imagine, so team member Robert McNabb, from the universities of Ulster and Oslo, uses an analogy.

"Over the last 20 years, we've seen that glaciers have lost about 267 gigatonnes (Gt) per year. So, if we take that amount of water and we divide it up across the island of Ireland, that's enough to cover all of Ireland in 3m of water each year," he says on this week's edition of Science In Action on the BBC World Service.

"And the total loss is accelerating. It's growing by about 48Gt/yr, per decade."

The worldwide inventory of glaciers contains 217,175 ice streams.