Trees are an answer
Trees are not the entire answer, but they are a big part of the answer to the climate breakdown now in progress.
Massive replanting of trees would do a lot to help us. They would remove carbon from the atmosphere, and restore gravely threatened ecosystems.
But beyond that, the positive transformation of our societies -- moving from one of extraction, to one of replenishing and restoration -- is the real positive effect of a human focus on reforestation.
At minimum, we need a massive, massive reforestation effort that crosses borders and connects continents.
But ideally, we go beyond that and create a vast Global Commons, protected by international treaty, that keeps 50% of the world off limits to human exploitation. Fifty percent of the world free of humanity is a concept that increasingly appears in the scientific literature as an ideal. It seems radical today, but it is far less radical than a world that has been broken down and destroyed by a runaway climate breakdown, and by the ongoing extinction event now in process.
Finally, we should focus our scientific research on creating technologies to sequester carbon and cool the oceans. The great Global Commons, and billions of new trees, still won’t be enough. We will need to augment those natural solutions with human ingenuity. This means creating technologies at scale that can sequester carbon and also cool the oceans. The amount of warming in the oceans may already be enough to trigger Arctic sea ice collapse. We absolutely do need to figure out a way to cool the oceans.