Former Massachusetts Gov. Bill Weld William (Bill) WeldRalph Gants, chief justice of Massachusetts supreme court, dies at 65 The Hill's Campaign Report: Biden visits Kenosha | Trump's double-voting suggestion draws fire | Facebook clamps down on election ads Biden picks up endorsements from nearly 100 Republicans MORE (R), who is challenging President Trump Donald John TrumpFederal prosecutor speaks out, says Barr 'has brought shame' on Justice Dept. Former Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick MORE for the GOP presidential nomination, said Friday that lawmakers should let the market decide when it comes to regulation on climate change.

Though Weld didn’t mention anyone by name, he criticized climate change proposals put forth by 2020 Democratic presidential contenders, arguing that a carbon tax is a much more feasible and economic alternative to address the the crisis.

He told Hill.TV that his proposal would not tell people what to do, which was an advantage to the other proposals. “They make their own decisions,” he said.

“That’s letting the market decide about carbon — that’s a much more powerful engine than just saying I’m going to spend $10 trillion dollars to promote clean energy,” he added. “You don’t know if you’re going to get there.”

A number of Republicans and Democrats in Congress have supported putting a tax on carbon.

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Weld’s comments come as he prepares to take part in a climate change forum hosted by MSNBC on Friday along with several other Democratic White House hopefuls.

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Presidential frontrunners former Vice President Joe Biden Joe BidenFormer Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick Bloomberg rolls out M ad buy to boost Biden in Florida MORE and Sen. Elizabeth Warren Elizabeth WarrenOvernight Defense: Appeals court revives House lawsuit against military funding for border wall | Dems push for limits on transferring military gear to police | Lawmakers ask for IG probe into Pentagon's use of COVID-19 funds On The Money: Half of states deplete funds for Trump's 0 unemployment expansion | EU appealing ruling in Apple tax case | House Democrats include more aid for airlines in coronavirus package Warren, Khanna request IG investigation into Pentagon's use of coronavirus funds MORE (D-Mass.) did not commit to being part of the forum.

Leading up to the event, Weld described his support for action on climate change as a “gamble” among Republican voters.

“The gamble is that Republican voters will agree with me that climate and environment are an important issue,” he told Hill.TV. “If they don’t then that’s bad news for me.”

Weld's challenge against Trump is a decided long shot. A new survey from the Economist and YouGov found Weld with 5 percent support among Republican voters, while Trump maintained his lead at 86 percent.

—Tess Bonn