Humanity injects an almost impossible level of understanding 42 billion tonnes of carbon dioxide (CO₂) into the atmosphere every year. This is mainly due to the burning of fossil fuels, but there are still significant amounts. about 16%The land we use is what makes us human. Deforestation is the main cause of land-use emissions, especially in the tropics.
To slow climate change, the international community must reduce these 42 billion tons to net zero. That is, any remaining emissions will be offset by other uptake. A tonne of CO₂ has the same impact on the climate whether it comes from fossil fuels or forest loss, so halting deforestation is a necessary part of tackling climate change.
As part of its push for a deal at COP26, the UK government is expected to announce a plan to “halt and reverse” global deforestation by 2030. How much would this reduce global warming?
This is why we need to understand carbon budgets. The 2015 Paris Agreement aimed to prevent the global average temperature rising more than 1.5°C above pre-industrial levels. The amount of warming is tightly linked to the amount of CO₂ in the atmosphere. This means that there is a fixed amount, or budget, of CO₂ that the world can emit without exceeding this target.
This budget is tight. Limiting future emissions of CO₂ to 460 billion tonnes, counting from the beginning of this year, will give a 50:50 chance of warming staying below 1.5°C. If emissions remain at 2019 levels, the budget would be exhausted in 11 years, or 2032. Deep cuts in emissions are required to ensure a fair chance of reaching the Paris goal. They must be reduced to zero by 2050.
Deforestation and carbon budget
Many countries, including the UK are striving for net zero by 2050. There are many benefits to pushing harder to stop deforestation before 2030. First, land-use emission are high. At the current rate of land-use change, they would consume 15% the global budget for the next decade. Each tonne less carbon from forests means less room for decarbonizing the rest of the world’s economy.
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Second, stopping deforestation will not immediately stop all past forest loss-related emissions. These emissions are largely released over the next decade, as carbon continues its loss. the soil. These delayed emissions will be reduced if deforestation is stopped earlier than 2050.
Third, the world’s forests are more than a store of carbon which needs protecting – they are also actively taking it up. According to our latest estimate, forests are removing approximately 20% of the emissionsEach year, the atmosphere is subject to the same amount of pollution as people. Trees can help. grow faster with more CO₂ and because many forests today are filled with trees which are relatively young and vigorousYou eat the emissions from older trees that were cut down in the past.
Calculations of the global carbon budget assume that this uptake continues. However, every bit of forest that is lost is an area that is no longer contributing to this uptake. The total area of forest that has been lost in the tropics since 1990 is almost two millionAn area of Mexico’s size, it covers a total of 2.4 million square kilometers. These losses could lead to catastrophic forest loss in some areas, like the Amazon. to releasing it.
What about the “reversing” component of the plan? This is less straightforward. It is impossible to reverse the loss of biodiverse and complex old-growth forest within our lifetimes. However, increasing the size of young forest can be done. if done properlyBy temporarily balancing emissions from industries that have low-carbon alternatives, such as aviation,, you can help reach net zero.
Reforestation is an effective tool to address climate change. It does not rely upon unproven technology. But it can only be a temporary fix. The land that could be reforested is finite. limited by competing demands, such as the production of food or the growth biofuels.
The science is clear: failing to rapidly reduce deforestation will make the enormous challenge of limiting climate change to 1.5° even tougher – perhaps impossible. The more carbon budget that is available elsewhere, the faster the world can reduce deforestation.
That is not to suggest that halting, or even reversing, deforestation will be plain sailing – far from it. It must be done in an equitable and sustainable manner. The vast majority of forest losses are occurring in the poorest countries. global southThese include the industrial-scale destruction of major agrobusinesses and the minor depletion of subsistence farmers. The livelihoods of many rural communities are intertwined with the forest – they must be genuine partners in efforts to protect them.
It may be as difficult as cutting emissions from the rest the world economy to decouple local economies from deforestation, but it will not cause harm to the people who live there. Deforestation can be stopped for many reasons, not just the climate. protecting biodiversity securing clean water. However, leaders around the world must not view it as a quick fix or an easy way to be less ambitious.
This story is part of The Conversation’s coverage on COP26, the Glasgow climate conference, by experts from around the world.
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