By John Fischer

We are facing a big problem — climate change. Fortunately, we have an easy solution available, and to implement it, all we have to do is nothing. There are two ways to change the concentration of CO2 in the atmosphere: emit less, and absorb more. And while the “emit less” part of the solution has been slow and spotty to materialize, the “absorb more” side is easy and is happening right now.

Trees are the answer. And we only need about a trillion more of them. That number seems large, but the amount of land needed is only about a quarter of what is currently being used to raise livestock, and as soon as we stop keeping trees from growing on current farmland, the forest will return. Planting the trees is usually not necessary, because letting trees reclaim their former forests naturally provides a more wildlife- and ecosystem-friendly forest than putting in long rows of the same tree.

A squirrel used to be able to go from the Atlantic Ocean to the Mississippi River without touching the ground. That vast forest has been largely removed to allow industrial-scale agriculture to raise corn and soybeans to feed to livestock. The overuse of fertilizer is polluting water, large amounts of fossil fuels are burned, pesticides poison good and bad bugs alike, and a thousand acres of corn has less diversity of wildlife than a single acre of woodland. Farmers who currently receive subsidies on their crops (including indirect subsidies like cheap water) could be given larger payments to do nothing and let the trees grow back. Much of New England was deforested for farming, but after better land was cleared out West, the rocky soils of Vermont and New Hampshire went from marginal fields to flourishing forests in short order.

Of course, it’s a good idea to plant more trees in your own yard, for the carbon capture, for the summer shade, and for the wildlife habitat. But because urban land covers only 3% of the habitable land in the U.S. and 1% worldwide, most of the new trees will have to grow on formerly forested land currently used for agriculture. Growing trees does not mean that no food can be produced. Shade-grown crops, fruits, and nuts can all be part of the forest renewal.

And what you see above the ground is only half of the picture. The community beneath the surface is a world of its own, an ecosystem that takes years to develop and thrive, and a carbon sink. Disturbed soils often hold less carbon, and are always less biologically diverse than those in mature forests. With proper management, a forest can produce wood, food, clean water, carbon sequestration, recreational opportunities, and peace of mind.

While environmental groups often focus on stopping deforestation overseas, the U.S. has cut a higher percentage of its trees than most other countries. Eighty percent of the Amazon rainforest is still intact, and while cutting there is continuing and should be contained for planetary health, in the U.S., three quarters of our original forests have been completely removed, and only 5% of the forested lands in the U.S. have never been cut. While working to reduce further cutting in the tropics is an important pursuit, undoing what we have done here would have more impact, and show the world how serious we are about seeing the forest again — for more than just the trees.