"I think there will be a big fiscal impact," said Sen. Michael J. Hough, a Frederick County Republican. "Clearly this is a mandate, so I'm going to vote 'no.'"
But supporters said it's wise to reduce greenhouse gases, which contribute to climate change. Climate change change can cause expensive problems, said Sen. Paul Pinsky, a Prince George's County Democrat and sponsor of the bill.
"The question is: Do we pay the cost up front -- if there is in fact a cost -- or do we pay it later on?" Pinsky said.
The previous goal was to cut emissions by 25 percent by 2020 and was set six years ago. That law would expire if not reauthorized by lawmakers.