It's this on warming — or else

UNITED NATIONS -- Wrenching worldwide climate changes can no longer be avoided, but there is still time to stave off the worst consequences of global warming, an international research team said Tuesday.

The scientists from 11 countries urged sweeping conservation measures to hold the expected increase in temperatures to no more than an average of 3.6 degrees Fahrenheit globally -- less than half the expected increase if emissions of greenhouse gas and soot continue unabated.

Based on two years of study, the scientists called for dramatic actions ranging from carbon taxes and a ban on conventional coal-fired power plants to an end to all beachfront construction worldwide.

The researchers were funded by the nonprofit U.N. Foundation and the 60,000-member research society Sigma Xi.

With its emphasis on policy recommendations, the panel's effort marks a shift in the international politics of pollution and climate change, analysts said. Researchers are no longer debating whether human-induced global warming is genuine but have begun the painstaking process of negotiating international agreement on what to do about it.

Their effort comes on the heels of a landmark U.N. report last month that concluded rising temperatures would continue to increase even if greenhouse gas emissions could be held to current levels.

Global temperatures already have increased about 1.4 degrees over pre-industrial levels, the researchers reported. To meet the scientists' goal, global carbon dioxide emissions must level off by 2015 and drop by two-thirds of that level by 2100.

They urged stricter fuel efficiency standards, as well as fuel taxes, registration fees and rebates that favor more efficient transportation, which today is responsible for 40 percent of the world's carbon emissions. A 20-fold improvement in car efficiency is well within existing technology, they said. Moving freight by rail instead of truck could also cut emissions substantially

The researchers also recommended expanded use of biofuels, to reduce dependence on the oil that accounts for one-quarter of the world's carbon emissions. They endorsed broader use of nuclear power, if it can be made safer.

In addition, the scientists called for improved designs of energy-efficient appliances, office equipment and "greener" commercial and residential buildings. Taken together, heating, cooling and lighting buildings accounts for almost 30 percent of the world's greenhouse gas emissions.

Most tellingly, the panel also called for a ban on any new coal-fired power plants that cannot be equipped to capture and store the carbon dioxide they emit.

All told, the U.S., China and India currently plan to build nearly 850 new coal-fired plants over the next decade, which by environmentalists' calculations would pump up to five times more carbon dioxide into the atmosphere than current international control measures aim to eliminate.

No matter what people do to reduce soot or curtail emissions of carbon dioxide and other greenhouse gases, the world will continue to warm somewhat and people will have to adapt, the researchers said.

To minimize the hazards of rising sea levels and more powerful storms, the group called for a worldwide ban on costal construction near existing high-tide lines.

To reduce the effects of climate-related disasters, such as floods or prolonged droughts, the panel urged better international emergency response measures, warning that there may be as many as 50 million environmental refugees by 2010.