Countries must settle their differences at climate talks later this year to minimize the impact of global warming, according to the head of a U.N. panel of climate change experts.

Citing statistics from reports recently released by the Intergovernmental Panel on Climate Change, which he chairs, Robert Watson warned that temperatures will rise on average between 1.4 and 5.8 degrees in the next 100 years, with countries in northern latitudes seeing as much as a 7 degree jump.

"In 1995 we said there was a discernible human influence (on the climate)," he told The Japan Times in an interview. "Now we have said that most of the observed warming over the past 50 years is due to human activities. That is a much stronger statement,"

Evidence indicates the warmer climate is also altering ecosystems.

"We have now observed changes, not only in physical systems, like sea ice and glaciers, but also in some ecological systems. We have started to see changes in the migration patterns of birds and butterflies, and early flowering seasons -- the first indications that ecological systems are changing.

"Policymakers cannot wait for perfect knowledge given the long time inertias in the climate system," warned Watson.

Even when greenhouse gases such as carbon dioxide are stabilized, temperatures will still rise for 100 to 200 years as will sea levels for a few thousand years, he added.

"The key message is that we are changing our environment and we need to learn how to manage it better."

Climate warming also has drastic implications for agriculture, he said.

"For almost any change in climate, agricultural productivity in developing countries is likely to go down. Agricultural production globally could well be threatened over most scenarios."

Watson said he was not surprised that the Sixth Convention of Parties (COP6) to the international climate pact, held in The Hague in November, broke down.

"We hoped that there would be an agreement, but we all realized that there were some very big issues to discuss."

While the issues that stalled talks in November remain as perplexing as ever, the new U.S. administration of George W. Bush will have a big, though unknown, influence on upcoming talks.

"What makes it more complicated is that there is a new U.S. administration with a whole new negotiating team. . . . None of us know what the Bush administration position will be."

Watson said that the U.S. Senate in recent years, when it was dominated by Republicans, "has been very negative toward the Kyoto Protocol and the climate change issue." Despite the question mark hanging over climate negotiations, Watson said voluntary efforts by corporations to reduce greenhouse gas emissions have buoyed his confidence.

He also predicted a carbon commodities market, where carbon can be traded like rice, will emerge and prove essential to paring greenhouse gas emissions and getting industrialized countries to commit to action. Despite the doom and gloom, global warming predictions also offer opportunities for business.

"I believe that industries that move quickest and develop more energy efficient products . . . could capture a fair part of the world market," Watson said. "Therefore, my comment to a country like Japan is to make those technological breakthroughs."