WASHINGTON - Ditching its past cautious tone, the nation's top scientists urged the government yesterday to take drastic action to raise the cost of using coal and oil to slow global warming.
The National Academy of Sciences specifically called for a carbon tax on fossil fuels or a cap-and-trade system for curbing greenhouse gas emissions, calling global warming an urgent threat.
The academy, which advises the government on scientific matters, said the nation needs to cut the pollution that causes global warming by about 57 percent to 83 percent by 2050.
"We really need to get started right away. It's not opinion, it's what the science tells you," said academy panel vice chairman Robert Fri. The cap-and-trade idea would set overall limits on carbon dioxide pollution, but would allow companies to pollute more by paying for it and buying pollution credits from cleaner companies.