There are two numbers you need to know about climate change. The first is 51 billion. The other is zero. Fifty-one billion is how many tons of greenhouse gases the world typically adds to the atmosphere every year.

Climate change is a terrible problem, and it absolutely needs to be solved. It deserves to be a huge priority.

By the time we see that climate change is really bad, your ability to fix it is extremely limited... The carbon gets up there, but the heating effect is delayed. And then the effect of that heat on the species and ecosystem is delayed. That means that even when you turn virtuous, things are actually going to get worse for quite a while.

In other words, by mid-century, climate change could be just as deadly as COVID-19, and by 2100 it could be five times as deadly.

The climate is like a bathtub that's slowly filling up with water. Even if we slow the flow of water to a trickle, the tub will eventually fill up and water will come spilling out onto the floor. That's the disaster we have to prevent. Setting a goal to only reduce our emissions-but not eliminate them-won't do it.

Haiti should remind us all that there is an immediate need to invest in and promote long-term development projects that are sustainable, scalable, and proven to work.