Warming oceans ‘will double cyclones’ in future

Image copyright AFP Image caption This is the tsunami-like debris in the Philippines after an 8.9-magnitude earthquake in April

Tropical cyclones in the central and western Pacific are likely to be twice as strong by the end of the century, say scientists.

Published in the journal Nature Geoscience, the research also predicts rising sea levels.

The strong tropical cyclones are “simply unrelated” to climate change, argue the authors.

They say a higher concentration of heat waves and heavy rains in regions will make them stronger and rainfall more extreme.

They also estimate that by 2100, the highest elevation reached by a storm would be 1,800m (5,827ft) – at the threshold of six metres (19ft) of sea level rise.

“It is quite evident that a strong tropical cyclone about five metres [18ft] above sea level could lead to significant damages,” said a University of New South Wales (UNSW) spokesman, Dr Rachel Swain.

Cyclones in the western Pacific generally weaken after crossing the South China Sea, while most tropical cyclones in the Indian Ocean range from Category 1 to 3 on the Saffir-Simpson scale.

In 2010, Typhoon Bopha killed thousands of people in the Philippines and China.

Image copyright AFP Image caption Cyclone Ita hit Madagascar in November 2013, with record-breaking wind speeds of 315km/h (195mph)

‘Politicians ignore research’

The researchers, from the US Geological Survey and UNSW, linked the expected increase in cyclones to rising ocean temperatures, increased rainfall and melting of ice sheets.

The average global sea level rose by 2.6cm a year between 1980 and 2011, following a levelling off in the mid-2000s. But the level is expected to continue to rise.

Scientists who analysed previous studies’ projections on the impact of climate change on storms concluded that nearly every hurricane category 4 or 5 would become a category 4 or 5 by the end of the century.

Although some cyclones are influenced by climate change, the study’s authors said they were susceptible to non-climate-change factors such as increased rates of wave and wind power.

However, the Tropical cyclone Research Collaboration – the ocean basins for 21 nations including Australia, Indonesia, Russia, Japan and the Philippines – said: “This is certainly an important observation and a welcome advance in climate science.”

Dr Grant Bigg, a marine scientist at UNSW, told the Guardian that politicians “don’t feel the need to listen to science any more” when researching disasters.

But the UN recognised the evidence for cyclones as the strongest in the atmosphere and oceans, he said.

“There has been a whole lot of efforts around bringing tsunamis to the Pacific, whether it be by sea-level rise, storm surge or nature changes that had nothing to do with climate change.”

Environmental activist Helen Szoke, head of the Institute for Energy Economics and Financial Analysis, said there was little benefit to scientists in discussing the risks of what climate change could bring.

“The issue is too politically charged and dangerous for any politician to take a stand against the science when they are in a position of power,” she said.

However, research published in the same journal on 11 August concluded that the ecological ramifications of a 2C rise in global temperatures have already been passed.

Image copyright AFP

“There is a simple, stark link between the extensiveness of our ecological effects and the warming we are collectively committing to,” concluded the scientists.

“In the 20th century, the planet warmed by 0.9C. Our carbon emissions had already trebled before the 20th century had ended,” they continued.

“When the original scientists predicted human activities would warm the earth at historically unprecedented rates, it seemed like the best and most-probable prediction.

“But not only have we tripled our carbon emissions; we have quadrupled the climate’s already devastating effects.”

They suggested that our current emissions would lead to a global average temperature rise of 3.8C by 2100.

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