We could stop greenhouse gases from rising for up to 20 years if we restored around five billion acres of degraded land, according to UN climate scientists. That would cost around $300 billion, which is less than what China is investing in renewable energy.

Barron J. Orr, lead scientist for the UN Convention to Combat Desertification, told Bloomberg that it’s about restoring soils and planting crops and trees.

“We have lost the biological function of soils. We have got to reverse that,” Orr said. “If we do it, we are turning the land into the big part of the solution for climate change.”

The land that has been degraded has often been overgrazed or deforested, the scientists claim. Basically, humans need to rejuvenate the land they have damaged. If we did that, carbon levels would stop rising, and we could focus on transitioning to renewable energy.

The scientists claim about a third of all land has been degraded to some extent. This is largely due to human activity.

“The idea is to put more carbon into the soil,” Orr told Bloomberg. “That’s not going to be a simple thing because of the natural conditions. But keeping the carbon in the soil and getting that natural vegetation, grazing land etc. thriving again — that’s the key.”

In order to restore vegetation on degraded land, the scientists claim the right amount of quality fertilizer will do the trick. They warned against using too much fertilizer or using harmful chemicals on the land.

Though climate scientists say reducing greenhouse gas emissions is the most important thing to focus on when it comes to fighting climate change, they also claim that stopping deforestation and planting more trees is an important factor. The key is to plant large trees that will not be harvested for log, pulp or paper.

Unfortunately, many powerful countries are moving in the wrong direction. Trump has allowed logging to increase significantly on public lands, and Brazil President Jail Bolsonaro is decimating the Amazon rainforest. It helps if the leader of your country actually thinks the thing that’s threatening human existence is a real problem.

A study from earlier this year found targets to reduce greenhouse gas emissions that were put in the Paris Agreement will not be met due to deforestation around the globe. Though the Paris Agreement was a good start when it comes to fighting climate change, even that plan doesn’t go far enough to avoid the catastrophic effects climate change will bring.