WASHINGTON – Climate change is suddenly a hot topic again. The issue is resurfacing in talks about a once radical idea: a possible carbon tax.

On Tuesday, a conservative think tank held discussions about it while a more liberal think tank released a paper on it. And the Congressional Budget Office issued a 19-page report on the different ways to make a carbon tax less burdensome on lower income people.

A carbon tax works by making people pay more for using fossil fuels like coal, oil, and gas that produce heat-trapping carbon dioxide.