Government bypasses doubts on road to Kyoto

By BRIAN FALLOW

Prime Minister Helen Clark is due to formally ratify the Kyoto Protocol on New Zealand's behalf tomorrow.

It is a watershed event.

Assuming Russia also ratifies as expected next year, the protocol will come into force and begin the transition from a world which runs on fossil carbon, and in which the right to emit greenhouse gases is untrammelled, to a world which relies on renewable energy sources and in which emissions will incur a cost.

However, it remains a divisive issue.

Critics regard Kyoto as a solution that won't work to a problem that is grossly exaggerated.

The Governments which are ratifying, on the other hand, consider there is enough agreement among climate scientists about enough of a risk to warrant an international policy response.

It is rare for policy so pregnant with economic and geopolitical consequences to be based on the projections of practitioners of what is still an immature and inexact science.

Unfortunately, the scientists are not singing in unison.

Among the sceptics is Dr Chris de Freitas, of Auckland University's school of geography and environmental science, who says the assumed consensus among climate scientists is unreal, imposed by ideologues.

"The valid message is that there are uncertainties and those uncertainties point to a very low risk, if any at all, of catastrophic change."

For the "official" scientific view journalists and politicians tend to cite the five-yearly reports of the United Nations' Inter-governmental Panel on Climate Change, written by a panel of 140 authors drawn from the ranks of the world's climate scientists and subject to layers of reviewing.

But de Freitas says that the summary for policymakers from IPCC's most recent (2001) report is a selective and biased account of the underlying scientific report, which more accurately reflects the inherent uncertainties of the science.

However, Dr Jim Salinger, senior climate scientist with the National Institute of Water and Atmospheric Research (Niwa), says the main scientific report from the IPCC contains "irrefutable backing" for the statements contained in the summary for policymakers (SPM).

"The IPCC summaries are by definition more conservative because under the United Nations system they have to be acceptable to all countries, including countries such as Saudi Arabia, the United States and Australia who have yet to ratify the Kyoto Protocol. The SPM is produced at a plenary where countries sign off the prose line by line. The SPM therefore has to accurately reflect the main report."

De Freitas says the average annual increase in COinf2 emissions arising from man's activities over the past 20 years has been something like 1 per cent, but the increase in COinf2 levels in the atmosphere has been less than half that. As a proportion of gross emissions, the net increase in COinf2 levels in the atmosphere was lower in the 1990s than in the 1980s.

Maybe the difference is explained, in part at least, by an increase in plant growth - no bad thing.

"Carbon dioxide is food for plants. The more there is the more they use," de Freitas said.

He cites research estimating that "biomass" may be able to absorb an extra 10 billion tonnes of carbon a year, over three times the net annual increase in atmospheric COinf2 from world fossil fuel combustion.

In any case, emissions caused by human activities are relatively small (less than 3 per cent) compared with the flows in the natural carbon cycle, de Freitas says.

Given the difficulties and uncertainties involved in measuring the latter accurately, no one can be sure that man's activities are what makes a difference to concentrations of greenhouse gases in the atmosphere or to climate change and its impacts.

Salinger agrees that emissions are growing faster than atmospheric COinf2 levels and that there are large year-to-year fluctuations in the rate of increase of atmospheric COinf2.

"The IPCC takes all these factors into account, and concludes that the COinf2 concentrations in the atmosphere have increased by 31 per cent since 1750," Salinger said.

There was irrefutable scientific evidence that the increase in carbon dioxide concentrations is caused by fossil fuel combustion and deforestation.

"The more carbon dioxide in the atmosphere, the warmer we can expect the planet to become. Quantities of carbon dioxide in the atmosphere have been rising steadily since the late 19th century. In addition several other gases such as methane which trap the sun's heat have also increased.

"Our climate is the product of a complex range of interlocking reactions between air, ocean, land and ice masses. A change in global temperature of the size expected as greenhouse gases continue to increase can spark a broad range of consequential changes. Some might be beneficial, but some might not be.

"The most serious negative effects will include sea level rise which will continue for many decades even if greenhouse gases were stabilised," he said.

While some processes, like the fertilisation effect of there being more COinf2 for plants to absorb, would mitigate global warming, others would reinforce and amplify it.

"For example, as the planet's snow and ice masses melt with warmer temperatures, global warming increases because there is no longer such a broad expanse of white ice to reflect the sun's incoming heat directly back to space," Salinger said.

De Freitas takes issue with the common claim that adverse weather events like droughts, floods, hurricanes and tornadoes have become more frequent or more extreme.

Salinger says that one of the greater certainties of climate science is that as temperatures rise so will the amount of water in the atmosphere.

"This is partly because more warmth means faster evaporation, and also because a warmer atmosphere can hold more water. This has been observed for many places in the 20th century record. Therefore the heaviest rainfall is expected to become heavier, except in those regions where substantial drying occurs because of climate change."

There would be important implications for flood protection, water supply, drainage, agriculture, horticulture, the hydroelectricity industry and a wide range of other sectors, he said.

"Extremes such a high temperatures can be expected. Because there is a lot of year-to-year and decade-to-decade natural variability there is not enough information to provide definitive conclusions on trends in cyclones or hurricanes. Climate models still have insufficient detail to provide definitive predictions."

De Freitas argues that IPCC's projections arise from mathematical models of the climate.

Climate modelling began in earnest in the 1980s. "Now we have 20 years of data to decide whether these models are capable of predicting future climate. All have failed badly," he said.

"The real climate is proving less sensitive to COinf2 increases than the models would have it."

But Salinger says climate models have greatly improved over the past decade. "

With this degree of disagreement among experts, what are policymakers to do?

Most developed countries - the United States and Australia being the conspicuous exceptions - have gone for the precautionary principle.

The argument is that because of the very long lags involved (a COinf2 molecule hangs around in the atmosphere on average for something like 100 years), no one can afford to wait decades for the science to harden up before deciding whether to do something about it, because of the potential damage associated with cumulative emissions in the mean time.

"I would agree, if that was the case," de Freitas said. "But the evidence is now there that there is no reason to believe the risk we are running is a big risk."

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