Sen. Al Franken (D-Minn.) has returned to his roots in comedy to join David Letterman in a new web series that puts the spotlight on climate change, and the various political interests stalling environmental progress in Washington.

The project is aptly titled “Boiling the Frog,” a reference to the myth of a frog in a pot of cool water on a stove, unaware that it was slowly boiling to death as the water temperature rises. The series, which debuted Monday, includes six digital installments in which the two comedy giants discuss different aspects of the climate change debate—the far-reaching influence of the Koch brothers, coral reef destruction, the melting of ice caps, and so on. Their intent is to “offset the pessimism,” as Letterman puts it, of political inaction and encourage people to take active roles in fighting global warming.

But it’s not all earnest pessimism, With their banter and trademark humor, Franken and Lettterman turn “Boiling the Frog” into a refreshing addition to the fight against climate change.

In the first episode in the series, Franken takes on climate change deniers with a story about an overweight, heavy smoker desperately seeking a doctor to sanction his unhealthy lifestyle. Watch below:

Boiling the Frog with Senator Al Franken: Episode 1 If just 1 out of 33 doctors told you smoking was healthy would you listen? What if 1 out of 100 Senators told you to watch a video? If the answer to either of these questions is yes, you’ll love Boiling the Frog with U.S. Senator Al Franken. Our new series collaborates with Funny Or Die to address one of the greatest challenges of our time with some much needed humor. You’ll laugh, you’ll cry, and you just might learn something. #YEARSproject Posted by The Years Project on Monday, July 10, 2017

To watch the entire series, head over to Funny or Die.