Climate change concern builds

Pete Hodgson

Government polling is finding more public awareness and concern about climate change, Climate Change Minister Pete Hodgson says.

"But people are still not sure at all about what to do about it or how to adjust to it personally," he said.

Hodgson was opening a two-day climate change conference in Wellington, at which scientists warned of the potential extent and impact of man-made global warming.

He said it was an area bedevilled by free-rider problems.

"Everyone has a reason not to do anything. New Zealanders say we don't need to do anything because we are so small. The United States says it doesn't need to do anything because it is so big. India because it is so poor. Russia because it is so cold."

Hodgson said it was human nature to want to do things later rather than sooner, especially when the effects of climate change could not be seen now because of the long lags in the systems involved. But that amounted to inter-generational theft.

Professor Peter Barrett, a Victoria University geologist and director of its Antarctic Research Centre, said that if present trends in greenhouse gas emissions continued unchecked to 2100, carbon dioxide levels in the atmosphere would be double pre-industrial levels and the average global temperature was likely to rise by 3 degrees Celsius.

This level would not fall far short of the 4 degrees difference between now and 40 million years ago when Antarctica was free of ice and New Zealand was under water.

Barrett studies the fossil air trapped in bubbles in ice cores drilled in the Antarctic. They go back a million years, during which there have been several ice-age cycles.

He said carbon dioxide levels now were already outside the range prevailing through that period.

"We know that CO2 levels are higher than at any time in the past 800,000 years, and possibly the past 20 million years," he said.

"So we should not expect there to be no consequences."

David Lowe, of the National Institute of Water and Atmospheric Research (Niwa), said atmospheric CO2 levels had risen from around 320 parts per million in the 1950s to 380 ppm now - 100 ppm above pre-industrial levels.

About 40 per cent of that gets taken up by growing plants or is dissolved in the ocean. But the other 60 per cent remains in the atmosphere, contributing to the greenhouse effect.

The rate of increase is accelerating as about 7 billion tonnes a year is emitted from fossil fuel combustion and a further 2 billion as a result of land-use change.

But land-use change can also be part of the solution.

David Whitehead, of Landcare Research, spoke about the scope for substantial carbon sequestration from planting pine forests and turning marginal farm land to shrubland, initially manuka and kanuka.

Possibly as much as 1.5 million hectares - an area not much smaller than the plantation forest estate - was available for that form of "carbon farming", especially in the east coast of the North Island.

He said it would also offer benefits in water quality and preventing erosion and help the country reduce its net greenhouse gas emissions.

Hodgson said the hopes - now dashed - of having an excess of forest sink credits to sell had been only one of the reasons the Government had ratified the Kyoto Protocol.

The others were that New Zealand saw itself as a good international citizen, normally part of any multilateral effort.

It was especially reliant on having a reliable, equable, mid-latitude climate, as farming was, and would remain, the bedrock of the economy.

And it would have been damaging to the clean, green national image not to have taken part in an agreement that included all but two developed countries.