The scope and cost of a PR campaign that would convince people to plant trees is staggering, and there's no single entity willing to pay for it. It's an issue of government taking action and extracting the money from the companies who have profited from pollution.
1. https://theconversation.com/government-action-isnt-enough-fo...
Americans have opportunities to vote on many levels of government. All those votes have a potential effect on policy. One woke vote for president is not going to counteract all the other bad votes or non-votes.
Obama would have done a lot more if his feet had been held to the fire by a more progressive Congress. But climate action opponents took control of the House in the very next election, effectively ending Obama's chance to take significant action.
My comment was about voting for your local, state, and congressional legislators, though. A president doesn't (and shouldn't) have unilateral power to mobilize the country against climate change. Congress controls the money and the laws, and it was never that liberal under Obama.