Musk putting his fortune on the line and trying colonize Mars offers a win-win for everyone.

If people want to keep expanding as well as having more individual freedoms, we must get ourselves more room and resources.

If environmentalists want to keep planet Earth safe, having a place to send people and begin colonizing off-planet will in the long-term be best for Earth.

Lovelock is too close-minded in this case. Staying on Earth forever means the death of the human race and most likely the Earth's environment.