On “Late Show with David Letterman” on Tuesday, the late-night host suggested that Al Gore was “enabling” the continued use of fossil fuels by selling Current TV to Al Jazeera, financed by an emirate that reaps a windfall from oil and gas.

But Gore said that Qatar has “ambitious plans” for developing renewable resources, and praised Al Jazeera’s news coverage and its stories on climate change.

Letterman’s questioning was similar to that of Matt Lauer, who grilled Gore on “Today” earlier this week about the sale of Current, reportedly for $500 million.

Letterman highlighted a problem that Current had all along with the cable lineup: “I never could find it.”

“It turns out to be very difficult for an independent network to compete in a world of conglomerates,” Gore said.

A video of the interview is below.