News: NZ faces triple climate threat

Wed, 26 Sep 07

Water security, natural ecosystems and coastal communities are the sectors most vulnerable to climate change in New Zealand, reports NZTV.com...

These were the findings of the latest report from the United Nations' Intergovernmental Panel on Climate Change (IPCC), a collaboration of over 2,500 climate change scientists and 130 governments.

National Institute of Water and Atmospheric Research (NIWA) scientist Dr Jim Salinger says the report is the result of a comprehensive survey of the science since 2001 and is based on over 550 research studies of what is happening in Australia and New Zealand.

Salinger says sea levels are expected to rise by half a centimetre a year, and by the year 2080 the average temperature may have also increased by up to 3.5 degrees.

He says eastern New Zealand will also be facing increased risk of fire, eventually sparking a decline in agriculture and forestry. The opposite problems are expected to affect the western side of the country, with increased floods and landslides forecast.

NIWA says changes already observed since 1950 include a warming in mean temperature for New Zealand of 0.4 degrees Celsius, a decrease in cold nights and frosts by 10-20 days a year, and a sea level rise of about 70mm.

Water security:  A major problem

The IPCC report highlights water security as a major problem - in particular ongoing coastal development and population growth in areas such as Northland and Bay of Plenty are projected to exacerbate risks from sea-level rise. There is expected to be an increase in the severity and frequency of storms and coastal flooding by 2050.

Many councils have identified areas sensitive to coastal hazards within the next 100 years but NIWA's Dr Dave Wratt says they have been repeatedly challenged by property developers, and individual homeowners with different interpretations of the risks.

"Some people try to emphasise it's all very uncertain, but there are many things that we do know. We know it's going to get warmer, the science is pretty adamant about the fact that we're going to get more heavy rainfall," he says.

The report also says while climate change may boost production in agriculture and forestry in western and southern areas due to a longer growing season, less frost, and increased rainfall, production is projected to decline by 2030 over parts of eastern New Zealand due to increased drought and fire.

Risk of biodiversity loss

A southward shift in agricultural pests and diseases is also likely with New Zealand becoming more susceptible to the establishment of new horticultural pests.

The report also highlights the risk of biodiversity loss including alpine areas and sub Antarctic Islands. Many ecosystems are not expected to survive, with up to 300 native plants expected to become extinct by 2080.

Salinger says that while New Zealand has the ability to cope with small amounts of climate change using its strong scientific and technical capabilities, there will be "major challenges" from changes in extreme events and larger amounts of changes in climate.

Pacific neighbours

Climate change is already impacting on some of New Zealand's smaller South Pacific neighbours according to the regional breakdown report.

New Zealand MetService international manager Pene Lefale is one of the authors of the section on small islands. He says air and sea temperatures have increased by up to one degree in the past 100 years and the sea level rose more than three millimetres a year between 1950 and 2000.

Temperatures and sea levels are expected to continue to rise and there could be fewer but much stronger cyclones and rainfall patterns will change.

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