The Canopy Project
How Deforestation Affects The Water Cycle
February 8, 2023
Updated March 21, 2025 by Emma Holm-Olsen
South America’s Amazon Rainforest is a lush, tropical rainforest filled with trees larger than life and beautiful wildlife you won’t find anywhere else in the world. If deforestation levels continue to rise, the Amazon, like every other rainforest around the world, will dry up, becoming a lifeless, flat, and barren wasteland with no evidence of the once thriving rainforest. Cutting down trees decreases our source of oxygen, increases atmospheric carbon dioxide concentrations, and directly impacts the water cycle.
The water cycle, also known as the hydrological cycle, is the continuous circulation or movement of water between Earth’s surface and atmosphere. Liquid water evaporates into water vapor, condenses to form clouds, and then precipitates back to land in the form of rain and snow.
Other major processes within the water cycle include infiltration, runoff, groundwater, and transpiration: all different ways in which water moves across and through the ground. This cycle is important because it supplies water to all living organisms and regulates the planet’s weather patterns. Only 3% of all water in the world is freshwater, meaning 97% is unfit for consumption and irrigation. The water cycle circulates and transports freshwater, delivering clean water for drinking and agriculture.
The hydrological cycle heavily relies on trees to absorb the water in the atmosphere. Trees act as water reservoirs, taking in water from the soil and releasing it through its leaves, a process known as transpiration. The added moisture in the air results in cloud formation, leading to rainfall and the continuation of the water cycle. Transpiration also helps cool the surrounding air, just as humans sweat to cool down.
As more and more trees get cut down, evaporation levels are disrupted, drying up the moisture in the air and throwing off the balance of the water cycle. A continual cycle of dry air, low humidity, and decreased precipitation will inevitably lead to a drought-prone, desert-like climate.
Infiltration and runoff are additional components of the water cycle impacted by deforestation.
Normally, tree leaves and roots soak up rainwater, ensuring an adequate amount of infiltration and reduced levels of water runoff. However, deforestation results in the opposite: decreased infiltration and higher amounts of runoff. Without trees, there is nothing to hold the soil cover. Soil erosion rates are increased, leading to more frequent flooding and higher likelihoods of pollutants sweeping into nearby water reservoirs.
The ways in which deforestation is altering the water cycle in real time are perhaps most apparent in the Amazon. The Amazon’s climate, and that of surrounding regions, is heavily influenced by the considerable levels of moisture in the atmosphere, which provides high amounts of rain (hence the term “rainforest.”) Unfortunately, in the last 50 years, around 20% of the Amazon has been lost due to deforestation. If current trends continue, it is predicted that the Amazon will reach an irreversible tipping point by 2050, leading to rapid, large-scale ecosystem collapse.
These massive changes to our planet’s forests pose significant risks to communities all over the world, including higher urban temperatures, more frequent wildfires and degraded air quality, but are having particularly devastating impacts on cities which are relatively close to deforested areas. São Paulo, the largest city in Brazil and just a four-hour plane ride from the Amazon Rainforest, has recently been suffering from one of the worst droughts in the country’s recent history, a direct effect of deforestation in the Amazon.
Trees are the backbone of life. EARTHDAY.ORG’s campaign, The Canopy Project, plants trees to manage biodiversity, decrease carbon levels in the atmosphere, and fix the balance of the world’s essential hydrological cycle. Through The Canopy Project, we have rehabilitated heavily deforested areas, such as Cape Town, South Africa, by planting trees to restore the climate, increase rainfall, and preserve water in local aquifers.
Your donations to The Canopy Project help safeguard critical environments struggling under the weight of deforestation by growing trees and protecting the balance of the water cycle.
