Tom Perez: Climate Should Have Gotten More Time In 2016 Debates, But No Climate Debate In 2020
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DNC head Tom Perez also responded on Twitter, saying that “climate change is an existential threat” and that “it is an issue that should have been more prominent during the 2016 cycle.”
Ed. - Uh, yeah, no shit, Tom. 
Perez then reiterated the DNC’s comments to Inslee, saying the DNC “will not be holding entire debates on a single issue area — we want to make sure voters have the ability to hear from candidates on all the issues.”
Instead, Perez said, he would “do everything I can to make sure our candidates are able to debate all of the critical issues during this primary — and that we’re doing that as fairly as we can.” The DNC did not respond to a request for comment from ThinkProgress, but the committee has circulated Perez’s statement as its official stance.
Neither Perez nor the DNC confirmed whether candidates would in fact be barred from DNC debates if they participated in a separate climate debate. Both political parties traditionally sponsor a series of debates and require that any other events held and attended by candidates be considered “forums” that are not designated as formal debates.
But historically climate change has largely been left out of presidential debates, something a climate-focused debate would seek to rectify. According to Media Matters (MMFA), a nonprofit left-leaning organization that monitors the media, climate issues are routinely ignored during election cycles. Some 20 primary debates were held during the 2016 presidential cycle, but only 1.5% of all the questions referenced climate change. That percentage is better than the general election debates, which did not feature a single climate change question.
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https://thinkprogress.org/dnc-says-nope-to-climate-debate-inslee-warren-68966e2d3d96/