More or Less from the Eye of the Storm?

In a surprising finding from CSIRO research commissioned by the federal government, climate change could dramatically reduce the number of tropical cyclones in the Australian region and decrease wave heights on the nation’s east coast. Meanwhile Queensland climate change scientist and director of the Global Change Institute at the University of Queensland, Professor Ove Hoegh Guldberg, says the world has only another decade to reduce greenhouse gasses to save the Great Barrier Reef.

Ben Packham in The Australian (4 April 2011):

CSIRO research commissioned by the federal government suggests climate change could dramatically reduce the number of tropical cyclones in the Australian region and decrease wave heights on the nation’s east coast.

The surprise findings, which appear to contradict some common predictions about the impact of climate change, are contained in scientific papers on “Projecting Future Climate and its Extremes”, obtained under Freedom of Information laws by The Australian Online.

One paper, by CSIRO researcher Debbie Abbs, found rising temperatures could halve the frequency of tropical  cyclones.

“Climate change projections using this modelling system show a strong tendency for a decrease in TC numbers in the Australian region, especially in the region of current preferred occurrence,” Dr Abbs said.

“On average for the period 2051-2090 relative to 1971-2000, the simulations show an approximately 50 per cent decrease in occurrence for the Australian region, a small decrease (0.3 days) in the duration of a given TC and a southward movement of 100km in the genesis and decay regions.”

Another paper, by Mark Hemer, Kathleen McInnes and Rosh Ranasinghe, predicted small but significant falls in likely wave heights as temperatures rose.

Their June 2010 research said wave heights could fall by a “relatively robust” 5mm-10mm along the NSW coast by the end of the century.

“Projected changes are larger and significant on the northern coast,” it said.

“While projected changes are typically small, in some circumstances we project a large reduction in storm wave energy along the NSW coast of up to 50 per cent decrease.

“The potential impacts of such decreases in storm wave energy on the coastal environment are unknown.”

A third paper suggests an increase in frequency of intense rainfall events in most Australian regions by 2055.

The paper, by Tony Rafter and Ms Abbs, says the “magnitude of change varies widely”.

It says central Queensland could experience a 110 per cent rise in the frequency of one in 20 year rain events, while Victoria could experience between 21 per cent fewer and 25 per cent more one in 20 year events.

The findings highlight scientific indecision about some of the likely impacts of global warming.

The CSIRO paper on cyclones runs counter to warnings that such extreme events will increase in frequency, although it reflects several recent studies in other parts of the world.

Recent studies on wave heights have suggested ocean swells are getting bigger as ocean temperatures rise.

The CSIRO has meanwhile today called for a carbon price to be a key part of the nation’s overall climate action.

CSIRO chief Dr Megan Clark will today join 600 of Australia’s top climate change scientists at a meeting in Cairns to update the latest observations.

Dr Clark says global warming is one of the most challenging issues facing humanity and needs careful consideration.

“It’s an urgent issue, but it is also a very complex one and one that will affect us, not just in this country, in all aspects of society, but probably one of the most challenging issues we have ever faced as humanity,” she told the ABC.

“It does need careful consideration and it does need debate.

“We need to debate the issue, come to grips with the issue, and it’s an important part of us coming to grips with it and stepping forward.”

Source: www.theaustralian.com.au

By Kirsty Nancarrow on ABC Online (4 April 2011):

A Queensland climate change scientist says the world has only another decade to reduce greenhouse gasses to save the Great Barrier Reef.

The director of the Global Change Institute at the University of Queensland, Professor Ove Hoegh Guldberg, is addressing a climate change conference in Cairns in the far north today.

Professor Hoegh says coral bleaching events are becoming more frequent because of rising sea temperatures and levels.

He says good management and the low population along the Great Barrier Reef have helped it bounce back in the past, but it could be gone in 40 years if carbon emissions are not reduced.

“If we actually act today we can save the Great Barrier Reef and reefs around the world,” he said.

“What it’ll take is a very concerted global effort to remove these dangerous gasses from the atmosphere.”

He says climate modelling shows sea temperatures and ocean acidification will soon rise to levels that cannot sustain coral reefs.

“We’re really right at the crossroads right now,” he said.

“If we go another 10 years of pumping two parts per million or more CO2 into the atmosphere, we’ll pass a point at which we won’t be able to constrain further temperature increases and greenhouse gas concentrations that will allow reefs to persist.”

Source: www.abc.net.au