Why does deforestation increase carbon dioxide in the atmosphere

Each year, 46 to 58 million square miles of forest are lost due to deforestation -- the removal of trees from the land by man-made and natural events. Deforestation is caused by land-clearing for urban development and agriculture, tree harvest for wood products, and forest fires. The loss of trees has an adverse affect on the air.

Table of Contents Show

Fewer Trees to "Clean" the Air
Less Oxygen Produced
Less Carbon Dioxide Is Removed
Temperatures Are Rising
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TL;DR (Too Long; Didn't Read)

Deforestation has an adverse affect on air by reducing the amount of oxygen and increasing the amount of carbon dioxide as well as contributing to global warming.

Fewer Trees to "Clean" the Air

Trees and plants, in general, produce energy for growth using a process known as photosynthesis. Using light, water and carbon dioxide, a plant produces energy in the form of sugar and releases oxygen into the air. Forests cover approximately 30 percent of the land on earth and sustain nearly 80 percent of the world's terrestrial organisms. It is estimated that one acre of trees in urban forests can produce enough oxygen for eight people and remove 188 pounds of carbon dioxide from the air.

Less Oxygen Produced

Oxygen comprises only about 21 percent of air's chemical component. Yet, it is extremely important to life on earth. Living organisms, from single-celled animals to humans, use oxygen to produce the energy required to sustain them. Since trees are larger plants, their production of oxygen is significant. It is estimated that tropical rainforests, produce 40 percent of the earth's oxygen even though they cover only about 6 percent of the land. Rainforests in the Amazon have declined by 17 percent in the last 50 years as a result of deforestation.

Less Carbon Dioxide Is Removed

Carbon dioxide is one of the greenhouse gases that help to hold heat in the atmosphere. Trees remove some of this carbon dioxide from the air through photosynthesis and store that carbon in their tissues and in the soil. This process is known as carbon sequestration. Since the industrial revolution began in the mid-1700s, more greenhouse gases have been released than removed from the air. In 2011, forests in the United States removed only about 14 percent of the carbon dioxide emitted into the air. Deforestation reduces the removal component of this cycle, further increasing the carbon dioxide in the air. This results in an increase in temperature, an effect known as global warming.

Temperatures Are Rising

Not only does deforestation contribute to global warming by increasing the amount of carbon dioxide in the air but it also directly increases the temperature radiating from the land. The forest canopy shades the ground, absorbs the sun's rays for photosynthesis, and reflects about 12 to 15 percent, cooling the land beneath. This holds moisture in the soil that carries nutrients through the roots into the plant. Plants then release water vapor into the air through their leaves in a process known as transpiration. A single leaf can release more water into the air than its own weight. Water vapor in the air accumulates and falls as rain, cooling the land and carrying nutrients back to the plants. Without forests, the land would radiate and reflect heat back into the air, adding to global warming. It is estimated that trees in tropical rainforests lower the temperature by 3.6 to 6.3 degrees Fahrenheit. In the past century, the average temperature around the world has increased by 1.4 degrees Fahrenheit.

What, exactly, is the relationship between deforestation and climate change? The Rainforest Alliance breaks down the numbers for you—and explains our innovative approach to keeping forests standing.

Among the many gifts forests give us is one we desperately need: help with slowing climate change. Trees capture greenhouse gases (GHGs) like carbon dioxide, preventing them from accumulating in the atmosphere and warming our planet.

When we clear forests, we’re not only knocking out our best ally in capturing the staggering amount of GHGs we humans create (which we do primarily by burning fossil fuels at energy facilities, and of course, in cars, planes, and trains). We’re also creating emissions by cutting down trees: when trees are felled, they release into the atmosphere all the carbon they’ve been storing. What the deforesters do with the felled trees—either leaving them to rot on the forest floor or burning them—creates further emissions. All told, deforestation on its own causes about 10 percent of worldwide emissions.

Healthy forests and vibrant communities are an essential part of the global climate solution. Sign up to learn more about our growing alliance.

Knowing that deforestation robs us of a crucial weapon in the battle against climate change—and creates further emissions—why on Earth would anyone clear a forest? The main reason is agriculture. The world’s exploding population has made it profitable for big business to raze forests so it can plant mega crops like soy and oil palm; meanwhile, on a much, much smaller scale, subsistence farmers often clear trees so they can plant crops to feed their families and bring in small amounts of cash.

But there’s a tragic irony to clearing rainforests for agriculture: their underlying soils are extremely poor. All the nutrient-richness is locked up in the forests themselves, so once they are burned and the nutrients from their ashes are used up, farmers are left with utterly useless soil. So on they go to the next patch of forest: raze, plant, deplete, repeat. All told, agriculture is responsible for at least 80 percent of tropical deforestation.

Not surprisingly, agriculture causes emissions, too—in fact, farm emissions are second only to those of the energy sector in the dubious contest for the emissions title. In 2011, farms were responsible for about 13 percent of total global emissions. Most farm-related emissions come in the form of methane (cattle belching) and nitrous oxide (from fertilizers and the like).

All told, deforestation causes a triple-whammy of global warming:

We lose a crucial ally in keeping excess carbon out of the atmosphere (and in slowing global warming),
Even more emissions are created when felled trees release the carbon they’d been storing, and rot or burn on the forest floor, and
What most often replaces the now-vanished forest, livestock and crops, generate massive amounts of even more greenhouse gases. Taken together, these emissions account for a quarter of all emissions worldwide.

Our accounting of the ugly impacts of deforestation only considers emissions and doesn’t even touched on how the lives and traditions of forest communities are ruined when forests are razed, or how many species of plants and animals are lost, upsetting the delicate balance of ecosystems. The uptick in mosquito-borne diseases, for example, or the rapid spread of roya, an insidious plant disease that threatens our supply of coffee are all indirect consequences of deforestation and global warming.

There’s no doubt about it: the best thing we can do to fight climate change is keep forests standing. Yet the need to feed a rapidly growing global population—projected to reach 9 billion by 2050—is urgent. That’s why the Rainforest Alliance works with farmers to advance a variety of strategies, such as crop intensification (growing more food on less land), and with traditional forest-dwellers to develop livelihoods that don’t hurt forests or ecosystems. We stand more of a chance in this fight with forests standing strong.