Climate science

Satellites reveal rapid acceleration of Antarctic glacier ice loss

  • 21 May 2015, 19:00
  • Robert McSweeney

Thinning of glaciers in one of the most vulnerable parts of Antarctica has accelerated at a "remarkable rate" since 2009, a new study finds.

Stable through the 2000s, the glaciers began losing large quantities of ice within just a year or two, the lead author tells Carbon Brief.

The study shows the surprising speed with which Antarctica's glaciers can react to rising ocean temperatures, and without warning, he says.

Remarkable acceleration

Glaciers are huge rivers of ice that ooze their way over land, powered by gravity and their own sheer weight. They accumulate ice from snowfall and lose it through melting.

In the new study, published today in  Science, researchers analysed changes to glaciers on the Southern Antarctic Peninsula in the last decade and a half.

For most of the 2000s, satellite data shows the glaciers lost about as much ice as they gained, meaning they stayed roughly stable. But around 2009 there was "a remarkable rate of acceleration" in ice loss, the study says.

more

Scientists warn against premature predictions of a "substantial" El Niño

  • 20 May 2015, 17:00
  • Roz Pidcock

It's too early to tell if the El Niño brewing in the Pacific will be a big event or how serious its impacts might be, scientists warned today.

Speaking at a press conference in London, scientists said they can't rule out an  El Niño as large as the one in 1997/8 - which raised global temperature by more than half a degree - but it's looking unlikely.

There's even a slight chance this year's event could be a false alarm, say the scientists. But their best current guess is that we should expect a "moderate" event in the coming months.

Forecast

Tropical Pacific surface waters are warmer than average for this time of year, and have been for several months - a sure sign that El Niño is  underway.

The  latest forecast from the US National Oceanic and Atmospheric Administration (NOAA) gave a strong chance of a "weak to moderate" event lasting through the Northern Hemisphere summer.

During Spring, there's still a lot of uncertainty about how El Niño could develop, and scientists are not ruling out the possibility of an event to rival the one the world experienced in the winter of 1997.

But based on current evidence, scientists are reasonably confident of a moderate strength event, Prof Adam Scaife, an expert on monthly and decadal prediction at the Met Office, told journalists today.

This would probably place this year's event somewhere between the 1997/8 and more recent 2009/10 event in terms of strength, said Scaife.

more

Mountain shape a key factor in species surviving climate change

  • 20 May 2015, 08:30
  • Robert McSweeney

One way animals and plants can cope with climate change is to relocate. Research shows some species are already shifting to higher ground or towards the poles in search of cooler climes.

But for creatures already living in mountains, the solution is not so simple. A new study of 182 high-altitude regions across the world shows how mountain shape is critical in determining whether a species will find refuge from rising temperatures further uphill.

This means the odds of survival are better for some species than others, say the authors.

Habitat range

The typical image of a mountain is a pyramid shape - a broad base that tapers to a peak. In theory, as species move upwards the habitat available to them shrinks, the paper explains.

But the study, published in Nature Climate Change, finds that over two-thirds of mountains don't follow this rule. In fact, mountains fall into one of four shapes: diamond, pyramid, inverse pyramid and hourglass, as the diagram below shows.   

Elsen & Tingley (2015) Fig1

 

Examples of four common mountain types. Colours indicate elevation, from low (blue and green) to mountaintops (yellow and orange) Source: Elsen & Tingley (2015)

more