Climate Change & Deforestation

Climate Change & Deforestation

Find out how deforestation and climate change are linked in this short video

There is a close link between climate change and deforestation. Greenhouse gases, most notably carbon dioxide (CO2), are the most important driving force behind global warming.1 Forests remove about 30 per cent of man-made carbon dioxide emissions from the atmosphere.2 We must be more mindful about land use, especially precious land like our rainforests.

Cutting down trees prevents them from mitigating climate change by absorbing and storing carbon dioxide. Carbon dioxide is one of the most harmful greenhouse gases. Greenhouse gases absorb and also emit infrared radiation.

Deforestation and carbon dioxide stored in trees

Deforestation also releases trees’ stored carbon dioxide into the atmosphere. As such, the practice is responsible for 10 per cent of all emissions.3 To prevent climate change, deforestation around the world must be massively reduced.

Modern deforestation and climate change

An area of forest the size of the UK is being cut down every year.4 The majority of tree loss occurs in tropical forests.5 In 2018, 3.6 million hectares of primary rainforest were razed.6 That is equivalent to the land area of Belgium.7

Forests are home to 80 per cent of all land-based plants and animals.8 Deforestation is responsible for the extinction of an estimated 137 species of plants, animals and insects every day.9 A mere four commodities – beef, soy, palm oil and wood products – drive the majority of tropical deforestation.10

If deforestation continues at the present rate, all the world’s rainforests will be gone by 2100.11 It will be impossible to prevent global warming without leaving our existing forests standing.

How does deforestation cause global warming and climate change?

Photosynthesis and carbon

All plants absorb carbon dioxide directly from the air through photosynthesis.12 They combine it with energy from the sun and water from the ground to create their own food.13 Trees store large quantities of carbon in their biomass for centuries.14 Forests also help the surrounding soil to capture significant amounts of carbon.15

In this way, a mature tree captures on average about 22 kilograms of carbon dioxide per year.16 A native UK broadleaf tree is estimated to take up one tonne of carbon dioxide during its lifetime of about 100 years.17 Without trees participating in the carbon cycle, the atmospheric concentration of CO2 would be significantly higher.

Scientists have found that 97 per cent of tropical and temperate tree species absorb more carbon as they grow.18 It takes a long time for a sapling to capture and store significant amounts of carbon.19 Cutting down old-growth or primary forest is, therefore, worse for the environment – even if new trees are planted to replace them.

Carbon emissions of deforestation

Deforestation is not merely removing the best climate mitigation technology at our disposal. It also produces vast quantities of greenhouse gas emissions. Clearing or burning forests releases the carbon trees have stored back into the atmosphere. Subsequently, between 2015 and 2017, global tropical forest loss accounted for 4.8 billion tonnes of carbon dioxide per year.20 We must lower the amount of this greenhouse gas in our atmosphere.

Deforestation and global warming

Carbon absorption

As forests are degraded, their ability to absorb carbon decreases. For instance, the Amazon rainforest has lost up to 17 per cent of its tree cover.21 The amount of CO2 it is absorbing and storing has fallen by about a third between 2005 and 2015.22 It is now taking up one billion tonnes of CO2 less than it was sixteen years ago.23 This equates to over twice the UK’s annual emissions.24

What happens when forests are cleared

Losing carbon sinks, such as the Amazon rainforest, has severe consequences for plants and animals, as well as mankind.

The Intergovernmental Panel on Climate Change (IPCC) has said that to avoid climate-related risks for natural and human systems, planetary temperatures must not exceed 1.5°C.25 Consequently, 196 international Parties have agreed to limit global warming to well below 2°C, preferably to 1.5°C.26 Peaking global greenhouse gas emissions and protecting forests are indispensable to achieving this target.27

desertification and climate change

Precipitation, desertification and climate change

Forests also create weather systems.28 They regulate local, regional and even continental climate.29 Trees produce atmospheric moisture and control temperature.30 Vegetation, especially trees, circulate water and create clouds and rain.31 Their roots absorb moisture in the ground, and their foliage releases it as water vapour.32 The water vapour forms clouds and creates rainfall up to thousands of miles away.33

deforestation and desertification

Rainfall has a cooling effect on the planet. Deforesting the land leads to droughts.34 Large-scale deforestation can even cause desertification and climate change.35

Just 11,000 years ago, the Sahara desert was a lush landscape of grassland and forests. Minute changes to the tilt of the Earth’s orbital axis and human activities, such as clearing vegetation with fire, converted it into the world’s largest desert.36

The Amazon rainforest’s tipping point

There are concerns that a similar fate could befall the Amazon rainforest. The forest’s average temperature has risen by 1–1.5°C over the past century. Severe droughts have hit the basin three times since 2005. In some areas, the dry season has enlarged over the past 50 years from four months to almost five.37

Science has shown that if deforestation reaches 20–25 per cent of the rainforest, a dangerous tipping point will be reached. At this point, vast areas in eastern, southern and central Amazonia will flip to non-forest ecosystems.38

deforestation and forest fires

Widespread forest fires throughout 2019 and 2020 indicate that the Amazon is already nearing this tipping point.39 Fire damages the surrounding forest and makes it more vulnerable to fire the following year.40 Widespread deforestation in 2020 increased the likelihood that 50 to 70 per cent of the Amazon rainforest will be transformed into savanna in less than 50 years.41

Future of climate change and deforestation

The connection between deforestation and climate change is clear. Curtailing deforestation is crucial for our planet’s future. Trees are the best technology we have to remove carbon dioxide from the atmosphere and prevent global warming.42 However, they can only provide half the solution.

A massive reduction in fossil fuel emissions is also necessary to avoid an environmental catastrophe.43 Forests are capable of absorbing vast quantities of carbon and stimulating continent-wide rainfall. However, burning fossil fuels is the key driver of climate change and requires an immediate resolution.44

Sources

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