Expansionary Institute

Michael Zey
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AMSTERDAM, July 13 (Reuters) - United Nations' talks on the Kyoto Protocol on climate change are set to resume in Bonn next week.

The talks, which focus on cutting carbon dioxide emissions from industrialised states to help slow global warming, will take place largely in the political arena.

But they are driven by the science behind global warming and the uncertain predictions about the changes that may follow. Following are some key climate change questions.

IS GLOBAL WARMING REAL?

A report issued earlier this year by a United Nations scientific body, the Intergovernmental Panel on Climate Change (IPCC), said it was very likely that the 1990s were the hottest decade in history and 1998 the warmest year since reliable records began in 1861.

Global average temperatures in the 20th century rose by 0.6 degrees Celsius plus or minus 0.2 degrees, mostly between the years 1910-1945 and 1976-2000.

Since 1950, according to the IPCC, minimum nighttime air temperatures over land have increased by 0.2 degrees Celsius per decade, and the average maximum daytime temperatures by 0.1 degree Celsius per decade. The increase in sea surface temperatures is roughly half those levels.

DO ALL SCIENTISTS AGREE?

No. Reliable long-term records of temperature change are hard to find.

Some critics of the IPCC report say the temperature changes from the 20th centruy are within the bounds of normal variability. Others cite faulty research data, and believe surface temperatures alone do not provide the best gauge of climate change.

WHAT IS "THE GREENHOUSE EFFECT?"

The greenhouse effect is based on physics models showing that concentrations of certain gases, including carbon dioxide, methane, nitrous oxide, water vapour and chloroflorocarbons (CFCs), help trap the sun's heat in the Earth's atmosphere.

The IPCC has said that all carbon dioxide emissions, some natural and some caused by mankind's burning of fossil fuels, are increasing and will heighten the greenhouse effect.

Critics say the correlation between atmostpheric carbon dioxide and temperature is unproven.

WILL TEMPERATURES CONTINUE TO RISE?

The IPCC predicts the global average surface temperture will rise by 1.4 to 5.8 degrees Celsius in the period from 1990 to 2100. Those projections are based on estimated growth in greenhouse gas concentrations and computer climate models.

However, researchers point out that climate modelling is an inexact science, since many aspects of weather are not fully understood, including the impact of clouds, which can have both warming and cooling effects.

Also unclear is the role of ocean currents, as well as the reflective nature of ground cover, since dark ground cover such as forests absorbs more of the sun's heat than snow or ice cover, which reflect it back into space. Critics point to the wide range of temperature estimates as a sign of the inexactitude of the science, as well as to probability studies that indicate the temperature change will likely be at the low end of the range.

ARE OTHER CHANGES EXPECTED?

The IPCC also expects sea levels to rise by 0.09 to 0.88 metres by 2100, as ice caps and glaciers melt and increasing temperatures cause water to expand. Rising sea levels will put numerous small island states at risk and threaten heavily-populated coastal areas.

Incidence of severe weather is expected to rise sharply, making hurricanes and monsoons more devastating and raising the threat of heavy flooding.

The change in climate is also expected to hit agricultural production near the equator as water supplies come under increased strain. But more northern countries, including the United States, Canada and Russia, could see farm output rise.

Climate change is also expected to increase the extinction of animal species as the Earth's biodiversity suffers.

CAN WE PREVENT THE CHANGES?

The Kyoto Protocol is an attempt to rein in human-related carbon dioxide output, although even supporters of the pact acknowledge that it will have little impact on climate change, and that carbon dioxide output may have to fall by as much as 60 percent to stabilise global warming.

But proponents say the protocol is a first step toward reducing pollution and decoupling economic growth from the use of fossil fuels and moving towards renewable energy sources.

Scientists also say use of natural depositories, or "sinks," such as forests and farmlands, could at least temporarily store atmospheric carbon, although the long-term viability of these sinks remains in question.

Opponents say the treaty is an overly expensive insurance policy that will damage the international economy, which is heavily dependent on coal and crude oil, and that renewable energy technology is not advanced enough to support global needs.

09:26 07-13-01

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