The debate was a mess as moderator Chris Wallace struggled with President Trump's interruptions. But let's analyze the climate parts anyway without normalizing the whole thing.

Why it matters: The contest provided a collision over the topic between Trump and Joe Biden, and underscored the two candidates' immense differences.

Here are a few takeaways...

1. Surprise! Climate wasn't on the list of topics Wallace planned, and his multiple questions, beginning about 75 minutes in, provided a lengthy exchange.

2.Biden has a complicated relationship with the climate left. The former VP said "the Green New Deal is not my plan" and "I don't support the Green New Deal."

• But his online climate platform unveiled last year called the GND a "crucial framework for meeting the climate challenges we face" without endorsing it outright.
• And more recent changes have moved his plan closer to what activists want, notably a 2035 target for reaching 100% carbon-free power and a proposal of $2 trillion in climate investments over his first four years.
• Still, there are limits. For instance, Biden recently emphasized that he's not seeking to ban fracking.
• It's part of a delicate balance to keep his coalition together, and key GND backers are willing to give him some space for now.

3. Trump still rejects consensus science. Asked whether human-induced emissions fuel climate change, Trump said, "I think a lot of things do, but I think to an extent, yes."

• That's a tad different than his past rejection of global warming as a hoax. But still at odds with the scientific consensus that humans are the dominant driver of ongoing warming.
• Anyway, the slight change in posture didn't come with a pivot away from rolling back climate rules or any policy shifts (with a small asterisk I'll get to next).

4.Trump muddied his position on EVs. Trump said "I think I’m all for electric cars" and "I’ve given big incentives for electric cars."

• In fact, the White House has previously proposedending tax credits for EV purchases, but Congress has not gone along.

5. Trump made other questionable or inaccurate statements. For instance, he claimed the Green New Deal would cost $100 trillion.

• The conservative group American Action Forum has offered an estimate of up to $93 trillion over 10 years (while acknowledging it's steeped in uncertainty).
• Useful long-term estimates are impossible because the GND is a vague, sweeping set of concepts, not a piece of legislation.

6. Biden took too much credit for renewable cost declines. Touting the Obama-era stimulus he helped oversee, Biden said he was able to "bring down the cost of renewable energy to cheaper than, or as cheap as, coal and gas and oil."

• In truth a whole suite of forces — including, but not limited to, federal investments in the stimulus and elsewhere — have led to huge cost declines over the last decade.

One interesting moment wasn't in the climate section.

Driving the news: Earlier in the debate, Biden flatly refused to say whether he supports ending the Senate filibuster.

Why it matters: If he wins and Democrats gain the Senate, ending the super-majority requirement would lower the immense hurdles in front of energy and climate legislation to some degree.