Reforestation: A greener future for planet Earth?

Up until the 20th century, "progress" was synonymous with "destruction of nature".

Across the developed world, we chainsawed and bulldozed the ancient old-growth forests. In their place, we put industrial farms to grow endless seas of corn, or cookie-cutter subdivisions with streets named after the trees that once grew there.

That's the story of the past—but it doesn't have to be the future. As technology improves, we can produce more while reducing our impact on the planet. We might still be headed for a solarpunk world where futuristic skyscrapers rise amidst lush garden cities.

There's no better proof than this: throughout much of the world, the forests are regrowing. Places once dominated by humans are returning to woodland.

Reforestation—yes, really

Earth-observing satellites and aerial drone photography, as well as ground-level forest surveys, allow scientists and planners to estimate how much of Earth's land area is wooded.

The results, as Max Roser writes on Our World in Data, are hopeful. In North and Central America, Europe and East Asia, forest cover has increased since 1990. And not by trivial amounts, either.

In Europe, a land area the size of Sweden has been reforested. In East Asia, regenerated forests cover land twice the area of Japan.

Unfortunately, it's still the case that Earth is losing more forest than it's gaining. The places where deforestation is still happening are mostly in South America and Africa. But even there, the pace is slowing and may already have peaked.

This isn't because of population decline, although that might be a factor in the future. The most important reasons are urbanization and better technology.

An ever-greater percentage of people are living in dense cities, rather than on farms or in rural villages. As agriculture gets more mechanized and efficient, it takes up less land and becomes concentrated in the most productive areas. In both cases, the result is the same: people move away, thinly-populated areas become completely depopulated, and marginal land is allowed to revert to wilderness.

What does this look like on the ground level? In the United States, in places like New England and rural Appalachia, abandoned fields and pastures are returning to native forest. So far, this mostly consists of fast-growing pioneer species like pine, maple, black cherry and aspen. These new woodlands tend to be simpler in structure and have fewer species than precolonization old growth, but we can expect this to change gradually through normal succession.

Besides natural regeneration, some governments are directly replanting forests to reverse environmental degradation. During the New Deal era, the U.S. did this with the Great Plains Shelterbelt, successfully combatting the Dust Bowl.

In the modern era, China's Grain for Green program pays rural farmers to restore natural vegetation. Other countries, like Japan and South Korea, have planted fast-growing species like larch, cedar and pitch pine to control soil erosion. These plantation forests are less biodiverse than woodlands created by natural regeneration, but they still store carbon and prevent further degradation of the land.

The good news is that nature is resilient. In spite of all the damage we've done, it can regenerate quickly if we just leave it alone. We've seen this natural rewilding happen in places like the Kocevski Rog in Slovenia. In less than a hundred years—a geological eyeblink—the forests have returned so completely, it's hard to tell that humans ever set foot there, as George Monbiot writes:

So tall and impressive are the trees now and so thickly do they now cover the hills that when you see the old photos — taken, in ecological terms, such a short time ago — it is almost impossible to believe that you are looking at the same place. I have become so used to seeing the progress of destruction that scanning those images felt like watching a film played backwards.

Are we just exporting deforestation?

There's an important footnote to this hopeful story.

A cynic might say that wealthy nations are restoring their own forests, while hypocritically consuming products that require deforestation elsewhere. In effect, rich countries are exporting their deforestation to poor countries.

There's some truth to this. Some of the worst deforestation still ongoing is in countries like Brazil and Indonesia, which are cutting down tropical forests to raise cattle for beef, or to grow crops like soybeans and palm oil, for buyers in Western markets. However, even in these countries, the majority of deforestation is driven by domestic demand:

Today, most deforestation occurs in the tropics. 71% of this is driven by demand in domestic markets, and the remaining 29% for the production of products that are traded. 40% of traded deforestation ends up in high-income countries, meaning they are responsible for 12% of deforestation.

This is encouraging, because it means there's more progress to be made. While Western-style consumption on a mass scale is unsustainable for the planet, it's also true that more advanced economies have less environmental impact.

As technology continues to improve, we can adopt more planet-friendly methods—like vertical farming, or agrivoltaics that provide both food and renewable energy, or even precision fermentation and other advanced biotechnology to grow meat substitutes.

These green technologies are a step above fossil-fuel-driven industrial agriculture, which is a step above slash-and-burn farming or subsistence agriculture that requires cutting down trees for firewood. As societies move up this technology curve, their impact on the planet decreases.

If we disseminate these technologies to countries that haven't yet adopted them—and especially if all us privileged Westerners eat a few less hamburgers—it's very possible that global deforestation will slow to a halt and then go into reverse. We may well see reforestation on a planetary scale occurring within our lifetimes.

Reforesting the Earth would be a true win-win. All those growing trees would take up and store carbon on a massive scale, slowing down climate change. They'd create oases of biodiversity and supply precious habitat for threatened and endangered species. And, harder to quantify but no less important, they'd bring natural beauty and majesty back to once-ravaged landscapes, bringing humans all the benefits that we can only find by immersing ourselves in nature. It's a future that we should all want to work towards.