Climate change increasing freak weather

SIMON DAY
Last updated 05:00 02/12/2012
Hurricane Michael
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Hurricane Michael threatened the eastern seaboard of the US in September. Sandy, which followed, caused widespread damage costing over US$50 billion.

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Climate change is increasing far faster than the world has been willing to admit, and New Zealand could face increased flooding and drought while large areas of coastline could be inundated by the rising sea and coastal erosion.

As another round of global climate talks began last week in Doha, a member of the generation that will face the effects of climate change, 18-year-old Ben Dowdle, believes those with the power to do something are not concerned about his future.

Dowdle was a Unicef youth ambassador at the climate change negotiations in Rio de Janeiro in June and witnessed the political inaction firsthand.

"It is definitely frustrating, we are the generation that have inherited the biggest issues of our time. Young people are getting more of a voice but politics doesn't think long term. It's why Rio+20 failed and it's why the talks in Qatar won't achieve anything," he said.

Fellow United Nations Children's Fund ambassador Rachael Hodge, 17, watched how people worked together when her home city of Christchurch was flattened by the 2010 and 2011 earthquakes.

Hodge hopes it won't take a climate change-induced natural disaster to make New Zealand aware of the effects of climate change.

"If we rely on a natural disaster to get people mobilised, everything is going to be a short-term response," she said.

Extreme weather events are going to become larger and more frequent in New Zealand and around the world as scientists begin to acknowledge that the more severe predictions of climate change are on course to become reality.

Last week the World Bank released a grave assessment of the potential effects of climate change.

A two-degree global temperature increase is generally regarded as dangerous climate change. The report, 'Turn Down the Heat', says that under current emissions levels the Earth will warm by an average of 4C by 2100, with dramatic consequences.

"To prevent the 2C rise is virtually impossible with our current rate of emissions. Of the climate models we use to predict warming, the ones that predict the higher levels are probably more accurate," said Professor Tim Naish, director of Victoria University's Antarctic Research Centre and lead author of the Intergovernmental Panel on Climate Change's fifth assessment report due next year.

The World Bank report forecasts droughts that will destroy agriculture, the flooding of coastal cities, unprecedented heatwaves and increased frequency and intensity of tropical cyclones, unless drastic action is taken to reduce the greenhouse gas emissions.

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Dr Jim Yong Kim, the president of the World Bank, hopes the report will "shock" the world into action.

But policy makers have been surprised by the extent of the onset of climate change and now adaptation is taking priority over prevention, says Naish.

"The conversation has changed from mitigating, to how to cope living in a warmer world."

This year the world witnessed how difficult and expensive it is to cope with the effects of extreme weather.

There is no denying Hurricane Sandy was a monster of mother nature. But the influence of man-made climate change fuelled the storm, say many scientists.

The north Atlantic was unseasonably warm, sea surface temperatures were 3C higher than normal, (0.6C can be attributed to global warming) magnifying the storm by 5-10 per cent, according to New Zealand scientist, Dr Kevin Trenberth, senior scientist at the US National Centre for Atmospheric Research.

"The environment in which all these storms form is different than 20 to 30 years ago. Where they form is warmer and moister."

Which means more destruction.

"Ninety-five per cent of the time they look like storms we had before but they are really not. All of the storms that come through pick up those effects and can develop somewhat stronger."

As the water warms and sea levels rise, the increased frequency of extreme weather events is already being felt in New Zealand. Sea level rises will occur naturally, but New Zealand's low-lying areas will be vulnerable to the increased storm surges and rainfall of a warmer climate.

Last week Dunedin City Council responded to the effect by annoucing new homes would have to be built 1.2 metres higher off the ground.

"A 10-centimetre sea level rise increases the frequency of flooding in coastal regions by a factor of three. So a half-metre rise will increase the frequency of flooding by 300," said Naish.

"We are already getting to see that in Nelson where we are getting the one-in-100-year floods happening every few years now. That's not just because of sea level rise, that is because of extreme climate change."

If the climate continues to trend towards a 4°C increase, the West Coast is expected to get much wetter while the east of New Zealand will be much drier.

In the worst-case scenario, climate change will lead to highly drought-prone areas in the key eastern agricultural regions by 2050, according to a report on climate change and drought by the National Institute of Water and Atmospheric Research (Niwa).

And it is drought, not Hurricane Sandy, that will be the most destructive weather event to hit the US this year. Millions of hectares in the Midwest have been scorched by drought at an estimated cost to the economy of US$77 billion ($93.6b), the third costliest natural disaster in the country's history.

But the effects of 4 degrees of warming will not be evenly distributed around the world.

New Zealand's coastal climate and isolation mean it could be relatively well off. But if parts of Australia experience extreme drought and heatwaves, and the warming oceans fuel tropical cyclones and rising sea levels displace thousands of Pacific Islanders and South Asians, New Zealand will become a destination for climate migrants.

"There is growing recognition that climate change will exacerbate both the sudden and gradual environmental events and processes driving current patterns of migration and displacement," said Philippe Boncour and Bruce Burson in the paper Climate Change and Migration in the South Pacific.

New Zealand has already seen environmental migrants arrive from Australia after the Queensland floods and the Pacific archipelago Kiribati is looking to relocate its entire 103,000 population.

Hodge thinks Kiwis should be prepared.

"I hope that it is not just a lesson about being prepared for natural disasters it is about being prepared for a world that is always changing."

- © Fairfax NZ News

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