Amazon: Regrowing Forests Have Offset Less Than 10% of Carbon Emissions from Deforestation

By Charlotte Smith, PhD Candidate in Environmental Science, Lancaster University, Erika Berenguer, Senior Research Associate in Tropical Forest Ecology, University of Oxford, and Jos Barlow, Professor of Conservation Science, Lancaster University. Originally published at The Conversation.

Driven largely by the expansion of farm land to meet increasing global demand for products such as soya bean, over 810,000 km²of forest in the Amazon has been cleared – an area nearly as big as Norway and Sweden combined.

Deforestation is not only a tragedy for biodiversity, it also releases huge quantities of carbon dioxide (CO₂) into the atmosphere. Despite a glimmer of hope in the early 2010s, when deforestation rates plummeted to an all-time low, forest loss is once again on the rise.

The bulldozers aren’t always the end of the story. Nearly 30% of deforested land in the Amazon has been abandoned, giving the forest a chance to regrow – albeit with differing degrees of success, depending on how long and how intensely the land was used for agriculture. While these recovering habitats, known as secondary forests, are a poor substitute for the species-rich old-growth forests they replace, they can rapidly capture large quantities of CO₂ from the atmosphere.

But in a new study, we discovered that secondary forests across the Amazon are absorbing just 9.7% of the emissions created by the destruction of old-growth forests in the region. That’s despite these regrowing habitats occupying 28.8% of all deforested land.

Restoration Versus Deforestation

Although the Paris Agreement assumes that there will need to be some degree of tropical forest restoration to achieve emissions reduction targets, few studies have assessed how forest cover in the Amazon is changing. Research in the Amazon tends to focus on Brazil, which holds 60% of the basin, but fails to account for the eight other countries. Understanding how forests are recovering differently between countries and regions can help scientists and decision-makers understand which countries’ policies are helping to maintain the forest carbon sink, and which are not.

We set out to fill this void by mapping deforestation, recovery and carbon stocks from 1986 to 2017 across the entire Amazon, as well as individually for its nine constituent countries, and Brazil’s nine Amazonian states.

We used land cover maps built from high-resolution satellite imagery by the MapBiomas initiative to establish where, when and how much carbon has been lost to deforestation. We combined this with similarly generated maps of carbon gained by secondary forests to work out what proportion of these emissions have already been offset.

We found big differences between countries in the amount of emissions offset by secondary forest growth. As Brazil contains more than half of the Amazon basin, it is unsurprisingly responsible for more deforestation than any other country. However, Brazil’s contribution to overall Amazon deforestation (85%) and the associated CO₂ emissions (80%) went well beyond what would be expected from the country’s size.

The Brazilian state of Pará alone has seen more deforestation than the other eight Amazonian countries combined, a staggering 263,000 km² – an area larger than the UK. Brazil is also falling behind the other countries on the amount of deforested land that is recovering. Just a quarter of Brazil’s previously deforested land is occupied by secondary forest, with these new forests offsetting just 9% of CO₂ emissions from deforestation. Ecuador, on the other hand, has secondary forest growing on over half of its deforested land. In Guyana, where the recovering forests are older and so have had time to capture more CO₂, nearly a quarter of deforestation emissions have been offset, the highest of any Amazonian country.

These country-level patterns were underpinned by a trend that extended across the entire Amazon basin. Regions that have undergone the most extensive deforestation – and so have the greatest potential for large-scale forest restoration – currently have the lowest rates of recovery. To make matters worse, these highly deforested Amazonian landscapes show no sign of increasing forest cover, even 20 years after the land was initially cleared.

Large-scale forest restoration in the Amazon is an important nature-based solution to climate change. The latest findings from the Intergovernmental Panel on Climate Change indicate that reaching net zero emissions is essential for stabilising global warming and nature-based solutions will be at the forefront of discussions at the UN climate talks in November 2021, otherwise known as COP26, where governments from around the world will develop a plan to reach net zero emissions globally.

But unless drastic changes are made to halt deforestation and encourage forests to regrow, the Amazon cannot fulfil its potential to mitigate climate change.

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  1. Henry Moon Pie

    Earth’s forests constituted critical balancing loops as part of Earth’s huge and complex system of maintaining steady levels of CO2 and a climate in equilibrium. The Amazon is now a net emitter of carbon. The boreal forests of the north are at a tipping point. Melting permafrost and vast drought-induced fires are turning them into a net emitter as well. That leaves forests in the temperate zone, but they’re shrinking too before the bulldozers of the land developers and Big Ag.

    One “look over there” strategy of the Business as Usual types are carbon offset tree planting, but these monocultures are failures as carbon sinks and have little resilience when it comes to drought, fires and insects.

    As long as consumption patterns remain the same, the reinforcing loops driving increases in atmospheric carbon will continue to take us toward a climate that cannot support this many humans living at the levels some are clinging to.

    If you’d like to see what role forests play in climate, check out the EN-ROADS simulator that lets you play with various parameters to see their effect on climate change.

  2. Captain Obious

    I seem to recall that raising beef for USA’s fast food industry is a main use of deforested areas in South America. If I look at TV, it seems about half the ads are for fast food (the other half cars, beer and insurance), and I get the impression those restaurants are doing better than their struggling more traditional counterparts. I don’t notice much mention of any of this in mainstream media.

    1. drumlin woodchuckles

      The Superior Green Minority will have to model a lifestyle of zero fast food beef. If they ( we) can be satisfied that beef on multi-species pasture and range is as skycarbon-draining as its supporters and practitioners say it is, then we can make a point of making sure to eat some carbon capture Green-Ecobeef.

  3. Scott1

    Day after day there is bad news far as any hope that mankind will survive the bottleneck. The role of the Economists is as systems engineers with the goal of paying off those who attack the planets real assets with no regard for natural systems.
    I think out into the oceans and the food chain being wrecked.
    The extinctions continue apace. It is we who are at the top of the food chain.
    We have no effective enforcement of limits to ocean harvesting of fish. We cannot afford to go to war with China over their complete depopulation of fisheries.
    Hence whatever hopes we have for what would look like victory over the extinction of ourselves is simply wishful thinking.
    Crisis overload looks like this.
    What is happening is nothing less than terrible. It would be a service of some Hollywood disaster movie to show what the grand famine will be like.

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