Blueprint for greenhouse gases

The latest report on global warming reveals the trade-offs and uncertainties in forcing changes.

Buy a fluorescent bulb and stop a hurricane? It's not that easy. A new climate-change report finds voluntary conservation and the use of clean energies together won't be enough to slow global warming. Rather, strict rules on greenhouse gases will need to pinch lifestyles. And the biggest price? A crimp on world economic growth.

These sober projections were issued last week by the Intergovernmental Panel on Climate Change in a consensus document written with input from more than 2,000 experts and approved by more than 100 governments.

This latest IPCC report should serve as an action plan for the planet. And in fact, a G-8 summit will take it up in June with hopes that rich nations can push for a post-Kyoto treaty this year. It should also guide legislation in Congress aimed at greater fuel efficiency in vehicles and investments in alternative energies.

The report's key projection is that the kind of tough emissions-reduction schemes to prevent a severe temperature rise of 3 to 4 degrees F. would result in 3 percent less global economic growth by 2030 (or 5.5 percent less by 2050).

Hold on, says the White House: Such a drop in GDP would amount to a recession. But IPCC economists – and it is far more difficult to get a consensus among economists than climate scientists – counter that this economic slowdown would be mild compared with the disasters that might be averted by the recommended mitigation steps.

Other experts, such as Yale economist Robert Mendelsohn, contend that the net economic impact of climate change will be surprisingly small over the next century. If true, then a 3 percent GDP reduction may be too much to pay.

Who's right? At the least, with this latest report, global citizens now have numbers on the table to make better political decisions.

Putting a price tag on the effects of global warming will narrow the choices. It helps reduce the emotional, Chicken-Little tone of this debate. And it should lead to wiser decisions on the difficult trade-offs.

The IPCC report is helpful on other points:

• Higher taxes on fuel won't significantly force drivers to cut emissions. Autos that get more miles per gallon are needed.

• With a stiff tax on fossil fuels, the share of electricity generated from renewables – dams, wind, etc. – can rise from 18 percent to between 30 to 35 percent by 2030.

• Technology alone, such as capturing carbon dioxide from coal-fired power plants, cannot solve the climate challenge.

A degree of humility is found in this report, as it should be. The severity of climate change remains uncertain. As a result, determining the size of a carbon tax or a cap on emissions is "not ... unambiguous." It's difficult to know when the costs of action will exceed the benefits.

If climate change is gradual, the world can take gradual steps. If sudden change such as an Arctic cap meltdown can be predicted, "earlier and more stringent mitigation is economically justified," the report states. A better alert system for climate change would help.

Used with care, this report can provide a blueprint for managing the risks of an emission-reduction system that does the least harm.

The cure should not be worse than the bite.

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