How Exactly Do Trees Affect The Climate?

There has been a lot of talk about trees since the beginning of the new millennium. Discussions on their importance to human survival by aiding the maintenance of livable atmospheric conditions, providing shelter to a huge number of biological species, and being an immense source of food and energy have been swirling in all corners of the globe.

You will have certainly heard a lot about these topics, and have probably even been a part of some, but do you understand how trees actually affect the climate? Why are trees so often touted as the ‘saviors of humankind’ from its own unbridled industrial and technological advancements?

Forests Today

Credit: Paolo Bona/Shutterstock

Photo Credit: Paolo Bona/Shutterstock

Forests cover almost 30% of the land on our planet, but most of these forests are clustered in specific parts of the world. According to data from the United States, these countries include the United States, Canada, the Russian Federation, Brazil, China, India, Australia, the Democratic Republic of Congo, Indonesia and Peru.

Trees have an immensely positive impact on the climate of a region. They primarily affect the climate in three ways: by reducing temperature, decreasing energy usage and cleansing the air by removing a host of air pollutants.

Cooling Things Down

The cooling effect on the climate is facilitated by the leaves of trees, which is a process called evapotranspiration. Evapotranspiration occurs due to the combination of evaporation and transpiration, both of which are separate ways to release water into the air. Evaporation in trees involves the conversion of water to vapor and the release of this vapor through soil, lakes, and rivers.

Transpiration, on the other hand, involves the release of water, which was absorbed by roots, through leaves and into the air. This process can transfer a considerable amount of water in a tree’s lifetime. For example, a huge oak tree transfers almost 40,000 gallons (151,000 litres) of water into the atmosphere in one year. (Source)

Reducing Energy Usage

Beautiful Trees

Photo Credit: Sunny Forest/Shutterstock

Reduction in atmospheric temperature significantly impacts our energy usage on a daily basis. Think of how often you use air conditioning when the weather outside is already cool and pleasant. There are hundreds of thousands of other people who don’t use air conditioning on a pleasant day, but that is only one important aspect of energy saving. There are many other ways in which trees are able to reduce energy consumption. Strategically planted trees near buildings and residences not only cool them on warmer days with their shade, but also allow sunshine to pass through during winter to provide the much-needed warmth of the sun.

Cleansing the Air

This is one of the most crucial benefits of trees, especially in urban and industrial areas. Trees do a fantastic job of cleansing the air that we breathe through a number of processes. Photosynthesis, the process by which trees make food using sunlight and water, requires carbon dioxide (which is an air pollutant) to sustain. In turn, photosynthesis releases life-sustaining oxygen into the atmosphere. Trees can also absorb and store oxygen through a process called carbon sequestration.

Therefore, it is quite unfortunate that we are cutting down these life-sustaining agents of nature at such a rapid rate. An area of forest, equivalent in size to the country of Greece, is cut down every year to accommodate the demands of growing population and increasing agricultural and industrial advances. Unless we put an end to such indiscriminate decimation of forests to feed our greed, the future of life on Earth is going to be very bleak.


  1. Weather and Climate – Climate Education (National Science Education Standards)
  2. State of The Planet Earth Institute Columbia University
  3. HowStuffWorks
  4. USGS Water-Science School
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About the Author

Ashish is a Science graduate (Bachelor of Science) from Punjabi University (India). He spends a lot of time watching movies, and an awful lot more time discussing them. He likes Harry Potter and the Avengers, and obsesses over how thoroughly Science dictates every aspect of life… in this universe, at least.

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