The closing statements from the candidates in a debate are entirely freestyle. They don’t have to respond to a question. They don’t have to worry about what some other candidate just said about them. For one minute, it’s a chance to tell the country what they think truly defines them.
FWIW, that doesn’t appear to be climate change. Of the ten candidates on the stage last Wednesday, eight didn’t mention it at all. Elizabeth Warren mentioned it in passing as part of a laundry list, and even Tom Steyer only gave it a single sentence. Roughly speaking, the main topic the ten candidates addressed went like this:
race, business background, race, technology, decency, race, race, race, corruption, US is greatest country in the world