The second Democratic primary debates kick off tonight. Twenty candidates vying for the 2020 nomination will face off over two nights in Detroit. Senators Elizabeth Warren and Bernie Sanders will be among the 10 contenders facing off tonight.

In more 2020 news, CNN and MSNBC both announced last week they would hold town halls centered on the climate crisis. This comes after a sustained campaign by climate activists to include a climate-focused debate as part of the primaries. Democratic National Committee Chair Tom Perez has denied such demands, though the DNC is scheduled to vote on a resolution supporting the call next month. Activists celebrated the announcement by the networks but say a climate debate—not just the town halls—is needed. For CNN’s event, participants must meet the same eligibility requirements as the September debates, meaning they must meet certain polling and donation thresholds by August 28.