After conservatives and industry raised a fuss, President Bush reversed a campaign pledge for the first time yesterday and said he would not seek reductions in carbon dioxide emissions from power plants. A statement by his campaign last September promised Bush would set “mandatory reduction targets” for emissions of CO2, the main gas contributing to global warming, and in recent weeks, U.S. EPA Administrator Christie Todd Whitman has pledged that Bush would stick by the promise. But in a letter yesterday to four Republican senators, Bush said that he wouldn’t keep his word out of concern that mandatory limits would lead to higher electricity prices. While industry folks cheered the news, enviros and others cried betrayal. A group led by moderate Republicans had been preparing to introduce a bill later this week to follow through on the campaign promise.