Climate science

Factcheck: Will climate change lead to giant, man-eating snakes, tiny horses and shrunken goats?

  • 22 Oct 2014, 14:01
  • Robert McSweeney

Rising temperatures have caused mountain goats in the Alps to 'shrink' by up to 25 per cent, according to new research . The news follows on from recent stories of how climate change could bring us huge spiders, tiny horses and giant snakes.

Despite the slightly ridiculous headlines such research prompts, there is actually some science behind it all.

Behavioural change

So, first things first; rising temperatures haven't actually caused any goats to shrink per se. Rather the research, published in the journal Frontiers in Zoology, finds that young goats aren't as big as they were 30 years ago.

Scientists analysed records of the Alpine Chamois goat in the Italian Alps and found they were as much as 25 per cent smaller than goats of the same age in the 1980s.

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Worst case scenarios of sea level rise, and why scientists and policymakers consider them

  • 21 Oct 2014, 17:52
  • Robert McSweeney

Sea levels could rise by a maximum of 190 centimetres by the end of the century, according to a new study, which examines a worst case scenario for sea level rise.

In reality, the amount of sea level rise we get is likely to be less than that. But scientists and policymakers examine such 'worst case' scenarios to safeguard against climate risks.

Upper limit

With 10 per cent of the world's population living less than 10 metres above sea level, the threat of  coastal flooding is significant. The Intergovernmental Panel on Climate Change (IPCC) expects sea level rise to cause a ' significant increase' in sea levels extremes and the risk of coastal flooding.

The new study, published in  Environmental Research Letters, considers the assessment of 13 ice sheet experts. They conclude that the contribution from ice sheets is likely to be greater than projected by the IPCC. The paper suggests that sea levels could rise by as much as 190 cm this century.

Projections of sea level rise are typically constructed by working out the contribution to sea level rise from different  factors. The biggest contribution is from water expanding as it warms, followed by melting glaciers, then melting ice sheets on Greenland and Antarctica.

The crucial question for sea level rise this century is how much ice will be lost from the ice sheets, the authors argue. But it remains one of the largest uncertainties. In its Fifth Assessment Report (AR5), the IPCC says there isn't sufficient evidence for them to give probabilities of large-scale losses of ice sheets.

The new study uses expert judgement to consider areas of ice sheet loss that are often not included in the sea level  models that the IPCC bases its assessment on. They then combine these judgements with the methods used in AR5 to produce their upper-limit figure of 190 cm.

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New study maps countries most at risk from El Niño flooding

  • 20 Oct 2014, 20:00
  • Roz Pidcock

From South America to the Sahel, scientists have for the first time mapped how flood risk rises and falls across the world each time the extreme weather phenomenon known as El Niño hits.

With an El Niño brewing in the Pacific right now, being prepared for flooding can help protect vulnerable communities and curb damages, say the researchers.

Changing rainfall

Every five years or so, a change in the winds in the  equatorial Pacific  causes a shift to warmer than normal ocean temperatures - known as El Niño, or cooler than normal - known as La Niña.

The warm and cool phases, together known as the El Niño Southern Oscillation (ENSO) affect  rainfall patterns worldwide.

While scientists have looked before at the consequences for specific countries, such as Australia, the new study is the first to take a global view, mapping flood risk right across the world.

Flood _volume (Ward Et Al)

Percentage of land experiencing changes in flood volume with return periods of 100 years, during El Niño years (top) and La Niña years (bottom). Source: Ward et al. (2014)

 

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