By Alex Morales

The loss of food and water security is one of the most immediate threats posed by global warming, the head of a United Nations panel said before publication of the most detailed report ever on the subject. The greatest risks include ``irreversible'' and ``abrupt'' changes such as the melting of the Greenland ice sheet and an interruption of the ocean circulation that drives the Gulf Stream, Rajendra Pachauri, who leads the UN Intergovernmental Panel on Climate Change, said late yesterday in an interview from New Delhi. Those are ``highly unlikely but very high-impact events,'' he said. The panel this year is issuing its first assessment of changing weather patterns since 2001, in four parts. Next week it will publish a study on the visible and predicted effects around the world, including shifting rain patterns, droughts, rising sea levels, melting glaciers, damaged ecosystems and the spread of some diseases.

``We're talking about developing countries and we're talking about the most densely populated regions of the world,'' Pachauri said. Concern about food and water security is ``more immediate, and the impacts on society could be really profound.'' There is now ``in general'' more confidence in the observations and forecasts, in comparison with 2001 and ``a little more regional detail,'' Pachauri said.

Regional Concerns

``When you're talking about the impacts, it's one thing to talk about global-level changes that are going to take place, but what's of much more direct concern to people is what's going to happen in their backyard,'' Pachauri said.

The 2001 document details observed and predicted regional effects as a result of global warming, including an increase in floods, droughts and cyclones in temperate and tropical parts of Asia, the melting of glaciers in the Alps in Europe, a loss of coastal wetlands in Florida and less reliable crop yields in parts of Africa and Latin America. In many tropical and sub-tropical parts of the world, where the poorest people are found, rainfall is forecast to diminish in quantity and increase in intensity, making water scarcer and harming agriculture, according to Pachauri. The panel chairman said that more research into the effects of climate change is needed in developing countries, which are expected to bear the brunt of global warming's worst effects.

``While we will have greater regional detail, it's certainly nowhere near what is desirable: we need much more work on a location-specific and regional basis,'' Pachauri said. ``The areas where you need the maximum amount of research have probably the least capacity to carry out this kind of work. I'm talking about the developing countries: Africa, south Asia, parts of China, parts of Latin America.''

More Study Needed

More research also needs to be conducted into the economic effects of climate change, Pachauri said. ``I don't think we would be able to give ourselves a pat on the back for coming out with some of the economic effects of climate change,'' the chairman said. ``There's a paucity of literature.''

An Oct. 30 report commissioned by the U.K. Treasury said spending 1 percent of economic output now on fighting global warming could avert future expenses of 5 to 20 percent of gross domestic product. The UN panel has studied the report, though it has ``limitations'' on the ability to use its findings because the report wasn't peer-reviewed, Pachauri said. Next week's report will be published on April 6 in Brussels, and on May 4, a third installment will detail ways in which people can mitigate climate change. The fourth volume, due in November, will summarize the other three.

Publication Delay

On Feb. 2, the panel said in its first of the four reports temperatures have risen by 0.76 degrees Celsius (1.37 Fahrenheit) since the 19th century, and will rise by another 1.1 to 6.4 degrees this century. It also said global warming is ``very likely'' caused by people, based on scientific evidence. The panel has yet to release the full scientific report that forms the basis of the ``summary for policymakers'' issued last month, leading to charges that the process is politicized and the science is being amended to conform to the policy document. The process is ``transparent,'' and the report will likely come in the next two weeks, Pachauri said.

``The draft that was submitted to the plenary and what came out of it are not substantially different, but we necessarily have to ensure that the underlying report conforms to the refinements,'' Pachauri said, adding that scientists were present and able to comment at the meeting of government officials that negotiated the summary's wording.

``That's the strength of the IPCC: really it would mean that one particular country or a group of countries would have to bamboozle everybody else to bring about radical changes that don't have a basic rationale behind them,'' Pachauri said. Still ``this point is well taken, and in the next two reports you won't see this kind of delay,'' he said.