Amazon founder Jeff Bezos has pledged $2bn (£1.47bn) through his Bezos Earth Fund for land restoration in Africa.
The American billionaire previously indicated he would make investments worth $1bn (£732m) at an event with Prince Charles on Monday.
"We must conserve what we still have, we must restore what we've lost and we must grow what we need to live without degrading the planet for future generations to come," he says.
"Two-thirds of the land in Africa is degraded, but this can be reversed. Restoration can improve soil fertility, raise yields and improve food security, make water more reliable, create jobs and boost economic growth, while also sequestering carbon," Jeff Bezos said.
Bezos goes on to say his flight to space in July has changed his view of the world.
He says: "Looking back at Earth from up there, the atmosphere seems so thin, the world so finite and so fragile.
"Now, in this critical year and what we all know is the decisive decade, we must all stand together to protect our world."