The "Once Upon a Time in Hollywood" star cruised around L.A. Tuesday like a real champion of climate change ... not in some roadster or gas-guzzling monstrosity but in a this-ain't-your-mom's-regular Volvo. Leo's behind the wheel of a Volvo XC90 T8 Plug-In Hybrid.

The SUV ain't cheap ... it goes for around $70k. It seats 7, so there's plenty of space to pick up MILFs on the way home. But, we know he likes 'em young, which might explain why in the past he went with an Escalade here, here and here.