Deforestation: Before and After Facts

Deforestation involves clearing trees and other vegetation from a forested or wooded area.¹ Removing trees fundamentally changes the land. It affects wildlife, ecosystems, weather patterns and even the climate.² The effects of deforestation, before and after it takes place, are dramatic and often tragic.

Deforestation increases the Earth’s temperature 

The severity of the annual average hottest day in Europe, North America and Asia has significantly increased due to deforestation.³ Razing forests often increases both land-surface and near-surface temperatures.⁴ 

For instance, trees’ foliage blocks heat from the sun. This has a cooling effect.⁵ Planting more trees can therefore help to prevent any further increase in the hottest days’ temperatures.⁶

Another vital way trees help to cool down their local climate is through evapotranspiration.⁷ This is the process by which water transfers from the ground to water vapour.⁸ 

Trees and other plants play a significant role in the water cycle. They take up water in their roots, and it evaporates through their leaves.⁹ A large oak tree can transpire 151,000 litres of water per year.¹⁰ The moisture has a cooling effect on the air above.¹¹

Forests and rainfall

Forests also produce rainfall.¹² As they release water vapour through their leaves, trees create clouds.¹³ The destruction of tropical forests subsequently disrupts the movement of water in the atmosphere.¹⁴ This can reduce rainfall and even cause droughts.¹⁵

The Sahel region of Africa provides an example of this. Between the Sahara desert and the Sudanian savanna, this area has been affected by droughts for decades.¹⁶ One of the leading causes is vegetation and land degradation.¹⁷ Deforestation has helped to reduce the amount of rainfall across the Sahel.¹⁸ It has prevented food crops from growing, leading to famine.¹⁹ 

To combat this, the African Union is planting a Great Green Wall of trees.²⁰ It will be 10 miles wide and 4,350 miles long.²¹ The Great Green Wall will span the entire continent and necessitate planting in 20 countries.²² Regenerating 100 million hectares of degenerated land by encouraging vegetation to grow will prevent desertification from the Sahara.²³ It will also create some 10 million green jobs.²⁴

Moreover, the Great Green Wall will absorb about 250 million tons of carbon dioxide (CO2).²⁵

Deforestation before and after: Effects on CO2

Deforestation causes 10 per cent of all greenhouse gas emissions.²⁶ Removing forests has a two-fold effect on CO2. 

Firstly, trees naturally absorb and store large quantities of CO2.²⁷ Through photosynthesis, they use sunlight, carbon and water to produce food.²⁸ In the process, carbon is sequestered in the tree itself and the surrounding soil.²⁹ By destroying our forests, we are preventing trees from removing CO2 from the atmosphere.

Secondly, chopping trees down, burning them or letting them rot releases the carbon they have stored.³⁰ It combines with oxygen in the air to form carbon dioxide. In this gaseous form, it enters the Earth’s atmosphere. There, it prevents heat from escaping into space.³¹ 

This is “the most important long-lived ‘forcing’ of climate change”, according to NASA.³²

Deforestation before and after in the Amazon rainforest

The Amazon rainforest is the largest in the world. It covers 6.9 million square kilometres (2.72 million square miles).³³ However, it is also suffering considerable and unsustainable rates of deforestation. 

Tree cover losses in 2020 were 11,088 square kilometres.³⁴ This is the highest rate in the past decade.³⁵ The forest’s average temperature has risen by 1 to 1.5°C in the past century as a result.³⁶

Ability to absorb CO2

Deforestation has severe consequences for the Amazon. For instance, it currently absorbs two billion tons of CO2 per year.³⁷ This represents five per cent of all yearly emissions.³⁸ Yet, its ability to soak up carbon is being severely weakened by deforestation.

In the past decade, the amount of carbon absorbed by the Amazon rainforest has fallen by about a third. It now stores one billion tonnes of CO2 less than it did in the 1990s. This equates to twice the UK’s annual emissions.³⁹

There is a serious risk that deforestation will soon cause the Amazon to become a net source of carbon.⁴⁰ The forest degradation taking place under Brazilain President Bolsonaro could push it over the brink.⁴¹ The rate of deforestation has increased by as much as 92 per cent since Bolsonaro’s inauguration.⁴² Between March and May 2020 alone, his government passed 195 executive acts to directly or indirectly dismantle or bypass environmental laws.⁴³ 

The Amazon’s tipping point

Scientists predict that if deforestation affects 20 to 25 per cent of the Amazon, about 60 to 70 per cent of the rainforest will transform into savanna.⁴⁴ The process will take less than 50 years.⁴⁵ We are already close to this tipping point. 

Parts of the Amazon forest experiencing droughts

The Amazon basin has experienced severe droughts three times since 2005.⁴⁶ Fires burned through the region throughout 2019 and 2020.⁴⁷ Since 2000, rainfall has declined across 69 per cent of the Amazon rainforest.⁴⁸

Two years ago, an estimated 17 per cent of the rainforest had already been lost.⁴⁹ Losing much more would be disastrous for the one in 10 known species on Earth that reside there.⁵⁰ It would also be catastrophic for the entire planet’s climate.

Unless we protect and enhance our remaining forests now, we will lose these unique and biodiverse places forever.

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