CORRECTION: An earlier version of this op-ed said plans to reduce carbon emissions worldwide to avoid expenses associated with climate change could cost $46 trillion in 2100. That estimate is the total cost in net present value. The annual cost in 2100 would amount to about $40 trillion.
COPENHAGEN -- In speech after rousing speech at the United Nations summit on global warming last week, politicians emphasized the need to protect the world's most vulnerable, who will be hit hardest by climate change. The rhetoric did little to disguise an awful truth: If we continue on our current path, we are likely to harm the world's poorest much more than we help them.
Urged on by environmental activists, many politicians are vowing to make carbon cuts designed to keep expected temperature rises under 3.6 degrees (2.0 Celsius). Yet it is nearly impossible for these promises to be fulfilled.
Japan's commitment in June to cut greenhouse gas levels 8 percent from its 1990 levels by 2020 was scoffed at for being far too little. Yet for Japan -- which has led the world in improving energy efficiency -- to have any hope of reaching its target, it needs to build nine new nuclear power plants and increase their use by one-third, construct more than 1 million new wind-turbines, install solar panels on nearly 3 million homes, double the percentage of new homes that meet rigorous insulation standards, and increase sales of "green" vehicles from 4 percent to 50 percent of its auto purchases.