Hamilton has been accused of hypocrisy over recent social media posts lambasting meat-eaters for their impact on the climate crisis, with his lifestyle and motor-racing career held up as something to beat Hamilton with.
The Mercedes star gave an impassioned defence of his views in the press conference before the Mexican Grand Prix, as well as detailing the efforts he has made in an attempt to go carbon neutral by the end of 2019.
Vettel backed Hamilton's crusade for a better planet, and called on F1 to ramp up efforts to make the sport more environmentally conscious.
"I'm not active on social media, but the point is very clear," Vettel said.
"You would be ignorant if you wouldn't look at it. As Lewis said, it's difficult for us to get acceptance from the outside because we don't have the smallest footprint.
"The races happen around the world, we have to travel so it's part of our jobs. But in general, F1 should do more. It's a worldwide operating platform, and I think we should send a much stronger message.
"I think everybody can do something. Contribute a little bit. If the whole world acted like that it would be a huge difference.
"I think it is inevitable that change is coming, hopefully sooner rather than later."
Other drivers at the press conference also defended Hamilton, Sergio Perez saying: "If we can impact the world, help a bit, we are obliged to do so. I don't see anything wrong with that."
Alexander Albon was also supporting, adding: "Just because we're in Formula 1 doesn't mean we can't care about the environment."
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