On almost every environmental issue I care about, in fact, I've been wrong at one point or another. I used to think that climate change was no big deal, that most environmental problems were massive exaggerations, that oil reserves were effectively unlimited, and more.

I think the environmental movement is now so large and diverse that it's hard to talk of it as a single entity.

I decided five years ago that I wanted to truly understand, for myself, what the state of the planet was, and when I dug into it, what I found was quite different than I'd imagined.

There are really two kinds of optimism. There's the complacent, Pollyanna optimism that says "don't worry - everything will be just fine" and that allows one to just lay back and do nothing about the problems around you. Then there's what we call dynamic optimism. That's an optimism based on action.

If the incentives are aligned right - towards better preservation and restoration of nature and natural resources - then you'll see a tremendous amount of activity in that direction.

Today, our incentives aren't set up well - you can make a lot of money burning fossil fuels, digging up wetlands, pumping fossil water out of aquifers that will take 10,000 years to recharge, overfishing species in international waters that are close to collapse, and so on.

Agriculture is the #1 source of deforestation. By some estimates it accounts for 80% of the forests chopped down in the tropics.