When it comes to the causes of global warming, fossil fuel burning from cars, homes and industry gets most of the attention. You may not have heard quite as much about the role of deforestation. But disappearing forests and other land-use changes (urban sprawl, agriculture) contribute a staggering 20% to 25% of human-caused carbon emissions.
Here are a few things you need to know about forests. Trees and soil absorb and store carbon (they “sequester” it, to use the scientific term). That means that they are actually removing carbon dioxide from the air, which helps to slow global warming. When we cut down trees or pave over farms and fields, we lose in two ways. First, we lose those carbon storehouses—all that carbon that would have been tucked away in a tree or in the soil stays in the atmosphere.
And here is the worst part: When we cut down a tree, it sends all that carbon it had been storing right back into the air, increasing total carbon emissions in the atmosphere. Two points for global warming with one swing of the ax.
According to the Union of Concerned Scientists:
“Deforestation, urban sprawl, agriculture, and other human influences have substantially altered and fragmented our landscape. Such disturbance of the land can change the global atmospheric concentration of carbon dioxide, the principal heat-trapping gas, as well as affect local, regional, and global climate by changing the energy balance on Earth's surface.
Current efforts to combat global warming focus on reducing the emission of heat-trapping gases, but do not fully address the substantial contribution of land use to climate change. Since even small changes of 100 square kilometers in urban development or deforestation can change local rainfall patterns and trigger other climate disruptions, science and public policy must evolve to factor in all of the components of human-induced climate change.”1
Tropical deforestation is responsible for approximately 20% of total human-caused carbon dioxide emissions each year. Source: IPCC, U.S. Department of Energy, courtesy of Union of Concerned Scientists.
For more information on forests’ role on climate change, visit the Union of Concerned Scientists.