Denying climate change is dangerous and unreasonable in the year 2020, according to billionaire Amazon founder Jeff Bezos.

Speaking at Amazon’s Smbhav summit for small and medium-sized enterprises in New Delhi, India, Bezos described climate change as a big problem and warned that Earth is “a finite planet.”

“You can go back 10 years or 20 years and there were people who just did not acknowledge that climate change is real,” he said. “Anybody today who is not acknowledging that climate change is real — that we humans are affecting this planet in a very significant and dangerous way — those people are not being reasonable.”

“This is a big problem and it’s going to take collective action all over the world if we are going to make progress on that problem,” he added.

Amazon unveiled its “climate pledge” last year, which aims to reach the goals of the Paris Agreement 10 years early, and commits the retailer to operate on 100% renewable electricity by 2030. Other climate initiatives the tech giant has committed to include being plastic-free in India by June and acquiring 100,000 electric delivery vehicles.

“When a large company like Amazon with 700,000 employees and a big global footprint does something like the climate pledge, it really can be a needle mover,” Bezos said on Wednesday. “Because it’s not just Amazon, it’s our supply chain. For us to meet that pledge, they have to meet that pledge.”

He added that he was using his own connections to work with CEOs around the world on climate change policies.