The words of climate change and climate crisis are mentioned often when warning us of the impact of human actions on the environment. On one hand, we are urged to adopt mitigation strategies to slow down climate change, save wildlife, and feed eight billion people on the planet.
On the other hand, the problem of cutting down large areas of forests keeps going on without the sign of stopping, even though we know that deforestation only makes things worse. Trees help us tackle climate change by reducing the amount of greenhouse gases in the atmosphere.
This means we are giving up the long-term benefits that trees perform for us in exchange for quick benefits of obtaining fuel and building materials.
How does deforestation contribute to climate change?
Deforestation is the result of the growing human population that demand more timber for products such as paper or furniture, and the conversion of forest for settlements, crops and livestock.
According to the Environmental Defense Fund (EDF), one of the world’s largest environmental organizations, 32 million acres of tropical rainforest were cut down every year between 2000 and 2009.
Unless we change the present system that rewards forest destruction, forest clearing will put another 200 billion tons of carbon into the atmosphere in coming decades…
The Amazon, Earth’s largest rainforest, lost 20% of its forest in the last 40 years due to human activity. The island of Sumatra (Indonesia) lost 85% of its forests – mainly because of conversion for oil palm and pulp plantations. Many other forest areas across the planet are in the same danger (Russia’s boreal forest, Congo basin).
It is now widely accepted among scientists that increasing concentrations of greenhouse gases are causing changes in the climate patterns, leading to extreme events like heat waves, wildfires, droughts, floods, hurricanes, and threatening many animals and plants which are struggling to adapt to new conditions.
Forests play a crucial role in regulating Earth’s climate patterns. Mature forests absorb and store enormous quantities of CO2 (a greenhouse gas), within trees, vegetation itself, as well in the form of decaying plant matter in the soil.
Forests in regions like the Congo and the Amazon represent some of the world’s largest natural reservoirs for greenhouse gases on land.
In fact, the Earth’s vegetation and soils consist of around 7,500 Gigatonnes (Gt) of CO2 – that is more than double the amount of carbon from the atmosphere.
When forests are converted to agricultural land or logged on a massive scale, large quantities of CO2 and other greenhouse gases are released into the atmosphere, contributing to climate change. According to the IPCC report, cutting down forests and damaging peatlands contribute a big part of the 13% of human-made CO2 emissions. If you add it together with activities like agriculture, which is actually one of the main reasons of deforestation taking place, and land use changes, the number of emissions increases to 23%.
In the recent decades, deforestation became an urgent environmental issue that gradually threatens environment, biodiversity, people’s livelihoods, and intensifies climate change. All this despite the fact that the potential of forests to absorb carbon as they grow comes close to countering the total emissions from all land-based activities, accounting for about one-third of global emissions.
How exactly does deforestation affect climate? What processes happen?
There are numerous ways in which deforestation affects climate directly and indirectly because many processes on Earth are interconnected and work in natural harmony. That is until imbalance appears. In this case, the imbalance is represented by the inconsiderate removal of trees from areas that have been forested for hundreds of years. Here are processes that take place when forest ecosystems get permanently destroyed.
Changes to carbon sequestration
Reduced carbon sequestration happens when there is less capacity for trees and other natural systems to soak up carbon dioxide from the air. As trees grow, they act like nature’s vacuum cleaners, pulling carbon dioxide out of the atmosphere and storing it within their wood, plant parts, and the soil. This process transforms trees into “carbon sinks,” a term used by scientists to describe their role in capturing and locking away carbon.
The capacity of trees to store carbon is a vital part of the global carbon cycle, as they help keep a substantial amount of carbon dioxide that would otherwise stay in the air. However, when forests are cut down or degraded, this natural carbon storage ability is diminished and the opposite happens – carbon that has been stored within the plant material is released in the air.
Increased greenhouse gas emissions
Deforestation is one of the key drivers of increased greenhouse gas emissions. As trees are cut down and the integrity of the natural forests disappears, their capacity to capture and store carbon dioxide is severely compromised. This disruption leads to a surge in the release of stored carbon, primarily in the form of carbon dioxide, into the atmosphere.
A concerning example is seen in the Amazon rainforest, a colossal natural reservoir for carbon sequestration. Destruction of the rainforest alone stands as the largest contributor to greenhouse gas emissions in Brazil, accounting for a staggering 44 percent of the nation’s total emissions. Brazil ranks as the world’s sixth-largest emitter of greenhouse gases, with its contribution to global warming being a cause for growing concern.
Another problem that is seen in the Amazon is the declining state of the rainforest health itself. The delicate balance that sustains this vital ecosystem is teetering on the edge, nearing a tipping point beyond which the rainforest’s regenerative capacity will be compromised. Such a scenario would entail the release of even larger volumes of carbon dioxide into the atmosphere, exacerbating the challenges of climate change.
In some regions, the balance has tipped, with parts of the rainforest emitting more carbon dioxide than they are able to absorb. This alarming situation, particularly prominent in the southeastern part of the Amazon, which is concurrently a hotspot of deforestation, underscores the urgency of addressing deforestation’s far-reaching consequences.
Altered local and regional climate
Deforestation has a notable impact on the local climate. Intact forests affect temperature, rainfall patterns, humidity levels and air quality. You can easily imagine some of the impacts yourself.
Just think of a walk in the forest on a hot summer day. How does it feel compared to walking on a paved street between the buildings? Or when a short-overcast catches you outdoors without a jacket? You feel much better under the cover of the trees, right?
Trees provide shade and cool the air through a process called evapotranspiration, where certain percentage of water evaporates from leaves during the day. Without evaporation and the protective canopy cover of trees, the soil underneath is fully exposed to the sun and temperature of the surrounding environment increases faster for longer periods of time.
Additionally, even erosion takes place easier on soils without the protective cover of organic material. Eroded soils on their own are vulnerable to becoming too dry and compacted, not allowing any rainwater to infiltrate and nourish plant roots, neither replenish groundwater reservoirs.
Trees also play a role in the water cycle by contributing to the formation of clouds and precipitation. It is, for example, known that the Amazon generates half of its own rainfall from the humidity it releases into the atmosphere.
When deforestation happens, the amount of rain in the area decreases. This leads to a second unwanted effect that many of us may not take into consideration. Drier climate with less annual rainfall slowly dries out remaining trees and vegetation, further contributing to changes in the regional dynamics.
Loss of biodiversity of species
Forests cover 31 percent of earth’s land surface and house a majority of the plants and animals found on Earth. It is estimated that these diverse ecosystems house 80 percent of the world’s terrestrial biodiversity.
These plants and animals are integral to forest ecosystems and provide countless ecosystem services to humans and climate.
Biologically diverse ecosystems serve as buffers to climate change by absorbing the excess greenhouse gas emissions (yes, the processes are so connected that we nearly always circle back to the delicate balance of greenhouse gases concentration in the atmosphere). When forested areas get cleared for different land use activities, parts of their biodiversity sustaining services are lost, and with them even the benefits for the healthy planet.
But the word biodiversity means even more than that. It supports even complex nutrient cycling processes that help maintain soil fertility and water regulation. Biodiverse ecosystems are more resilient to disturbances such as extreme weather events and disease outbreaks.
Read more on the topic in our article: Why Is Biodiversity Important?
Deforestation also initiates a feedback loop that exacerbates its impact on both local environments and the broader global climate. As trees are cleared, their ability to capture and store carbon dioxide is compromised.
The rise in atmospheric carbon dioxide levels contributes to a warmer climate, affecting the delicate balance of ecosystems and further jeopardizing the very forests that were initially cleared. As temperatures climb, remaining forests become more vulnerable to wildfires, invasive species, and diseases, potentially triggering additional deforestation.
This vulnerability of forests to changing climate creates a concerning feedback loop. As deforestation renders ecosystems more susceptible to disturbances, the cycle intensifies. Weakened forests release more carbon dioxide into the atmosphere through various mechanisms, including increased decay of organic matter and heightened susceptibility to wildfires.
This vicious cycle continues to worsen the global climate crisis.
How does deforestation contribute to the greenhouse effect?
Deforestation amplifies the greenhouse effect by disrupting the intricate balance of greenhouse gases within the atmosphere. As we discussed in the previous section, the consequences of deforestation extend far beyond the act of clearing trees, with cascading effects on climate dynamics and carbon sequestration capacity of the forest. The complex interactions between deforestation and atmospheric chemistry set many processes in motion.
One example is the destruction of wetlands and soil compaction resulting from logging activities. These changes lead to emissions of nitrous oxide, a potent greenhouse gas. Additionally, deforestation-linked practices such as land-clearing fires release black carbon, small soot particles that not only absorb sunlight but also contribute to atmospheric warming.
Deforestation and associated land use changes lead to emissions of methane. Agricultural expansion and large scale cattle farming release large concentrations of methane, a potent greenhouse gas that has a much higher heat-trapping potential than carbon dioxide.
In essence, deforestation acts as a catalyst for a complex web of changes. Its contribution to the greenhouse effect is far-reaching, extending beyond the loss of carbon-absorbing trees. The consequences of this disruption are evident not only in the immediate local environment but also in the broader context of global climate change.
Acknowledging the intricate relationship between deforestation and the greenhouse effect underscores the urgency of adopting sustainable practices and forest conservation measures.