(MCT) — WASHINGTON — Democrats in Congress wasted no time in taking up President Barack Obama’s challenge Tuesday night that lawmakers take a “market-based” approach to addressing climate change, even if their effort has little hope of success.

Within hours of the president’s State of the Union address, two Democratic senators announced that they would introduce a climate-related bill that would include a tax on carbon emissions. The legislation would tax the source of about 85 percent of U.S. greenhouse gas emissions, and would invest heavily in energy efficiency and renewable-energy research.