This has been studied. It is likely the most promising idea. The problem is scale in terms of both plants and time. And, of course, energy. Growing trees is

This has been studied. It is likely the most promising idea. The problem is scale in terms of both plants and time. And, of course, energy. Growing trees is precisely how the planet regulated CO2 levels over the 800,000 years of data we have. And we can see precisely how long it takes to come down by 100 ppm. The answer is 50,000 to 100,000 years. And so the question becomes: How are we going to deliver results 1000x faster than that? On a human time scale rather than a geological scale. We can't. Because of the third dimension: Energy. You can't get something for less energy than what it took to create the problem in the first place. The energy that created this problem is unimaginably large and it was deployed over a scale of millions to billions of years, consuming a staggering amount of material to store it in the form of petroleum. We can't magically grow enough trees to "fix" it 1000x faster without energy and resources we likely do not have. And then there's the question of what happens with so much vegetation. Which, again, is answered by the 800,000 year ice core record: Huge continental scale fires that load-up the atmosphere with CO2. Here in California we have probably put so much CO2 in the atmosphere in the last several months that you would have to shutdown the economy for a year to compensate. Nature is violently heartless. It does not care about us and our toys. Plant a trillion trees and see what happens when a major forest fire burns across thousands of miles without us having any ability to control it. Not a simple problem. EDIT: Here's a good article on the reforestation idea: https://www.livescience.com/65880-planting-trees-fights-climate-change.html https://www.livescience.com/65880-planting-trees-fights-clim...