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Rethinking Reforestation: Degradation as a Carbon Source in Tropical Forests

Monday, December 18, 2017
Lovinia Reynolds

Lovinia Reynolds

Research Associate

Tropical forest ecosystems are globally recognized for their carbon sequestration capacities. Past research has estimated that tropical forests on average sequester a net 1400 teragrams of carbon per year, the equivalent of taking approximately 1 billion passenger vehicles off the road. International governing bodies, national governments, and nonprofit organizations have attempted to capitalize on the carbon sequestration services provided by tropical forests in an increasingly carbon rich atmosphere.  Programs such as REDD+ (Reducing Emissions from Deforestation and forest Degradation + enhancing forest carbon stocks) have resulted in significant expenditures of efforts and resources into developing frameworks for preserving tropical forests.

The Brazilian Amazon (Wikimedia Commons)

However, a report by the Woods Hole Research Center (WHRC) released in September 2017 added a wrinkle to the discussion about forests and climate change. The authors found that despite these efforts, tropical forests may now be a carbon source as opposed to a carbon sink. In other words, more carbon is leaving tropical forests than is being brought into tropical forests. Analysis of satellite images of tropical forests across the globe suggest that tropical forests may have lost approximately 425 teragrams of carbon per year between 2003 and 2014. According to EPA’s Greenhouse Gas Equivalency Calculator, this approximately equals the annual emissions of 334 million passenger vehicles.

The report led by Andrew Baccini found that patterns of loss and gain varied by country as opposed to ecosystem, suggesting that governance plays a significant role in ensuring forest conservation. Moreover, carbon loss was not distributed equally across the globe: 58% of carbon loss occurred in the Americas; 24% of loss occurred in Africa; and 16% of loss occurred in Asia.

Countries with borders encompassing large forested areas, such as Brazil, the Democratic Republic of Congo, and Indonesia, were particularly influential in shaping patterns of loss and gain. In Brazil, the national forest code requires private landowners to maintain 80% of their property as native forest and to obtain permits for deforestation. However, the size of the Brazilian Amazon makes this code difficult to enforce. In the Democratic Republic of Congo, the 2002 forest laws aim to achieve state control over the tropical forest while improving revenue from forest economy and protecting local communities’ rights. Still, extractive companies have found loopholes that allow them to escape strict anti-logging laws. Improving the enforcement and implementation of these laws will be crucial in preserving tropical forests as a carbon sink.

In addition to highlighting the areas where the most carbon loss is occurring, this report made a significant contribution to forest management policy by focusing on the mechanisms of deforestation. 

Many reports quantify the change in carbon flux (carbon uptake and carbon lost) in forests. However, few determine how this change occurs. This report differentiated between carbon lost due to stand removal, like clearing a forest for pasture or agriculture, and degradation or disturbance losses. Researchers found that degradation and disturbance accounted for roughly 69% of all carbon losses. To arrive at this number, researchers subtracted the total carbon lost due to land cover change from the total carbon lost.

This suggests that while curbing deforestation is important, so is ensuring healthy, intact forests. Forests can be degraded through the loss of biodiversity or the reduced capacity to provide ecosystem services such as carbon sequestration or water filtration. Human causes of degradation can include timber harvesting in native forests, the collection of wood for fuel where removal of trees exceeds growth, and fires that do not result in a change in land use. Indirect anthropogenic drivers of degradation include forest exposure to harsh conditions such as drought and wind shear. A shift in ecosystem composition toward species with reduced carbon sequestration capacities can also degrade forests.

The recent 2017 United Nations Climate Change Conference in Bonn, Germany, reaffirmed the global commitment to conserving tropical forests. Many nation-states and global nongovernmental organizations pledged significant efforts to restoring carbon sequestering capacities to tropical forests through differing methods. Ecuador pledged to reduce 15 million metric tons of emissions in the forest sector (equivalent to removing approximately 3 million passenger vehicles) by reducing deforestation. One of their initiatives, “Socio-Bosque,” pays communities and private landowners with native forests to conserve their land. The World Resources Institute announced $2.1 billion to restore 50 million hectares in Latin America and the Caribbean as part of their 20x20 initiative originally founded at the 2014 United Nations Climate Change Conference in Lima, Peru. The initiative has already restored 10 million of the  20 million hectares originally promised. The director of Gabon National Park Services, which comprise 26,000 square kilometers of tropical forest, in their 13 parks plans to reduce 20 million metric tons of carbon emissions by halting illegal logging.

While these efforts are significant, most do not directly address degradation. Efforts to preserve forests often focus on deforestation because it is easy to measure and track using satellite images.  Degradation is more localized, not easy to track, and can be caused by a variety of environmental and social factors. However, the results of the WHRC report and other research highlights that more needs to be done to protect healthy forests.

Future initiatives should invest resources into what types of forest best provide carbon sequestration and what factors may be degrading their sequestration capacity. The WHRC results are an urgent reminder that current frameworks of conservation may need rethinking if tropical forests are to aid in carbon mitigation. Past frameworks of conservation have not been successful in maintaining tropical forests as a carbon sink, and focusing on deforestation without considering degradation may not be the most efficient approach toward tropical forest conservation. The World Bank’s Carbon Fund, implemented through REDD +, requires degradation to be accounted for in forest emissions reductions programs when degradation accounts for over 10% of forest emissions. This report suggests degradation is far past the 10% limit, reinforcing the notion of degradation as the “the forgotten D of REDD +.”

This research should kick-start a conversation about conservation frameworks, sources of carbon emissions, and the institutional methods we use to tackle forest conservation.  As report author Baccini notes, “Forests are the only carbon capture and storage 'technology' we have in our grasp that is safe, proven, inexpensive, immediately available at scale…” in the fight against climate change. This research suggests that in addition to anti-deforestation and reforestation efforts, addressing forest degradation is just as important to tropical forest carbon storage.

Moreover, tropical forests are more than just the carbon they store. Due to its localized and contextual nature, a focus on degradation could reinvigorate and prioritize the role that tropical communities play in forest conservation. Forests prove innumerable social, economic, and medicinal benefits that we can only protect by focusing on the health of forest ecosystems as whole.