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Why the Mail's claim that 'There is more ice at the South Pole than ever' only tells half the story

• 16 Oct 2012, 11:30
• Roz Pidcock

Based on mainstream media coverage from recent months, you'd be forgiven for being a little confused about what's going on with melting ice in the poles. Last week, the Daily Mail quoted scientists saying that sea ice is at record high levels in the Antarctic and calling the science of manmade climate change into question. We take a look at how the Mail has, once again, cherry-picked climate data to tell half of the story.

Half-truths

The Mail article explains, quite correctly, that the amount of ice that floats on the water around Antarctica - known as sea ice - is on the increase. The US National Snow and Ice Data Centre (NSIDC) confirmed that Antarctic sea ice reached a record extent - a measure of sea ice cover - of 19.44 million square kilometres on 26 September this year. The graph below shows the extent of sea ice this winter relative to the average between 1979 and 2008.


Source: Cryosphere Today

But the article neglects to mention that sea ice is only a small part of the story in Antarctica. Most of the freshwater held in the region is actually contained within an expanse of ice that covers the land mass and extends into the surrounding ocean - known as the Antarctic ice sheet. We explained more about the difference between sea ice and ice sheets in a blog last year after skeptic journalist Christopher Booker got his facts very publicly wrong on the same topic.

The recent Mail article ignores the fact that just as scientists found an increase in the amount of Antarctic sea ice, measurements from the Gravity Recovery and Climate Experiment (GRACE) satellite since 2002 have shown very clearly that the mass of the Antarctic ice sheet - on land - is decreasing rapidly.

Sea ice vs land ice

Contrary to the Mail's claim that "there's more ice at South Pole than ever", this summer ice loss from the ice sheet dwarfs the gradual increase in sea ice that occurred this winter. Overall, satellite observations show that the Antarctic is losing ice mass, as the graph below shows. The blue crosses are satellite observations of ice mass, while the green line is the trend calculated over the 17-year time period.


Source: Velicogna et al. (2009)

Misleading headlines

When the story was originally published on Thursday it was under the headline ' Scientists find Antarctic ice has reached record HIGH levels: just weeks after Arctic ocean hits new low'.

Not too terrible, but the headline is still misleading because it ignores the distinction between land ice and sea ice.

But by Friday things had moved on and the same link led to a new article, by the Mail's former environment correspondent David Derbyshire, under a new headline: 'Now there's more ice at South Pole than ever (So much for global warming thawing Antarctica)'.

As well as being entirely misleading - there is not more ice than ever at the South Pole - this headline echoes stories from some skeptic outlets by suggesting the new record for Antarctic sea ice proves climate models wrong. In fact, they do no such thing.

Overall, climate models predict a loss of ice in Antarctica over the next few decades, albeit at a slower rate than in the Arctic. But scientists have known about the subtle increase in Antarctic sea ice since satellite measurements began in 1979, so this year's record has come as no particular surprise.

Poles Apart - Arctic vs Antarctic

The Mail article is also a little confusing about temperature trends in the Antarctic. It says:

"While the rest of the world has been getting warmer over the last 50 years, large parts of the Eastern Antarctic have been getting cooler".

This may refer to the fact that scientists first thought that Eastern Antarctica was so cold that it resisted ice melt. But recent research shows that since 2006, it has been losing mass along with western Antarctica.

The average atmospheric temperature over Antarctica has risen by 0.5 degrees Celcius in the last 50 years. The Southern Ocean that surrounds Antarctica has been warming faster than the rest of the world's oceans, at a rate of 0.17 degrees Celsius between 1955 to 1995 compared to a global average of 0.1 degrees. So the Antarctic is warming, not cooling.

The article says, quite correctly, that the maximum in Antarctic sea ice comes hot on the heels of the NSIDC's announcement in September that Arctic sea ice reached the lowest extent since satellite records began in 1979, which we wrote about here.

The article goes on to explain that unlike the Arctic, where warming seawater leads directly to sea ice melt, the wind plays more of a role in the Antarctic. Scientists say that ozone loss above Antarctica - related to human activity - has led to a strengthening of the winds that encircle the continent, increasing the area that sea ice covers by pushing it further out to sea.

Last week, a team of scientists produced the first three-dimensional map of the underside of Antarctic sea ice, made using a robot submarine. This will help scientists to better understand how climate change may be affecting the thickness of sea ice as well as the area it covers.

Giving the full picture

You don't have to wade through the scientific literature to get a good idea of what is going on at the poles - there are some very accessible internet resources to keep up to date with the latest changes in polar ice cover. These include the excellent National Snow and Ice Data Center (NSIDC) website, and Cryosphere Today.

This context is important: it's only by considering sea and land ice in both hemispheres can we get a full picture of how the planet is responding to global warming. Picking one convenient fact and ignoring everything else doesn't give an accurate picture.