Forests are the unsung heroes in our struggle to address climate change. The IPCC has released a new report on what the world would be like if the earth warms by 1.5°C (2.7°F). Well, without forests, we’d already be past 1.5° and well on our way to 2° of warming. Standing forests take up a quarter of all the CO2 we pump into the atmosphere every year. Photosynthesis is a tried and true method by which plants remove CO2 from the atmosphere, use it to create sugars, and grow. Forests store large quantities of CO2 in tree trunks, leaves, roots and soils. When we cut forests down, we lose their ability to take CO2 out of the atmosphere. We lose the very thing that keeps the planet from warming faster. We also flood the atmosphere with all the CO2 that has accumulated in forests over centuries and, in some cases, millennia.
The IPCC report tells us that to keep warming below 1.5°, we cannot emit more than around 750 billion tons of CO2 in the coming decades. Exploitable fossil reserves hold 3.5 times that amount. But the world’s forests hold over 4 times that amount. At current emission rates, we’ll reach our limit in under 20 years. We must switch to clean energy to maintain a livable planet. It means leaving fossil fuel in the ground. To stay below 1.5°C, we also need to keep forest carbon rooted in the ground.
From a scientific perspective, forests are more than CO2. From a human perspective, too. They provide water filtration, flood prevention, soil maintenance, fiber, food, recreation and retreat — replenishing our bodies and souls and sustaining ecosystems on which we depend. Tropical forests are home to stunning biodiversity, a value we recognize in our hearts. Tropical forests also do something we cannot even see. They move water constantly. Water evaporates from the leaf surface of all plants. Tropical forests have the highest density of leaves, moving the most water. This process (called evapotranspiration) cools the atmosphere above the forest, cools the tropics, and cools the entire planet, acting as a global air conditioner. As we move from the 1.0° of warming we already have toward the 1.5° of warming we hope to avoid, tropical forests are doing double duty.
As the climate changes, we need our forests more and yet they are more vulnerable to loss—to disease, drought and fires. Large forested areas promote rainfall and create a moister, cooler environment, enhancing the resilience of the forest and the people nearby. Forests keep our climate stable, and preserving them is critical to solving our climate problem. To limit warming to 1.5° requires that we continue to take carbon out of the atmosphere for decades to come. We do not need to wait to develop technology for carbon removal. We have nature’s proven technology in forests—and that is why we must do everything possible to restore the forests we’ve lost and manage and conserve what remains.