Tropical forests could avert dangerous climate change by reducing annual carbon emissions by 5 billon tonnes

A quartet of scientific studies provides compelling evidence that feasible improvements in tropical forest management could bridge the gulf between today’s rampant fossil fuel emissions and a sustainable future, and that indigenous forest peoples have a crucial role to play.


A Xingu village in the Amazon region – photo by Chris Linder

PARIS/FALMOUTH – Scientists have estimated that reducing tropical deforestation, expanding the tropical forest estate and restoring degraded tropical forests could cut net carbon emissions by 5 billion tonnes per year, the equivalent of nearly half current annual global emissions. Combined with urgent efforts worldwide to reduce and then eliminate the burning of fossil fuels, they say it could be enough to prevent dangerous climate change.

According to Richard Houghton, lead author of the paper and a senior researcher at the Woods Hole Research Center (WHRC), this finding adds to a growing body of scientific work indicating that a greater focus on tropical forests could be one of the world’s best chances of averting dangerous climate change. WHRC scientists and collaborators recently published four papers that make a convincing case for greater focus on tropical forests in mitigating climate change.

“Combined, the four papers provide powerful evidence that tropical forests can absorb and store huge quantities of carbon, that these quantities can be reliably measured, and that such quantities can offset a large percentage of global greenhouse emissions,” said Houghton. “The research also identifies a key way to make it happen – supporting indigenous forest peoples in their guardianship of their ancestral forests.”

In one of the four papers, published in the December 2015 edition of Nature Climate Change, Houghton and his colleagues estimated that 1 billion tons of annual carbon emissions could be eliminated by stopping tropical deforestation, 1-3 billion tons of carbon are already being sequestered in regrowing tropical forests, and another 1 billion tons of carbon could be removed from the atmosphere each year by expanding the tropical forest estate. Phased in over ten years, this reduction, combined with a strategy to hold fossil fuel emissions constant for the next ten years and then reduce them linearly to 20% of 2014 emissions by 2050 (before further reduction to zero by 2100) would have a 75% likelihood of avoiding warming in excess of 2°C.

The ambition of halting deforestation is realistic, according to another of the four WHRC papers, published in the December 2015 edition of the scientific journal Global Change Biology. It found that, between 2004 and 2009, Brazil cut its annual forest emissions by over 1 billion tons of carbon through a combination of public policy changes, increased transparency, improved law enforcement and voluntary actions in the private sector.

“Brazil shows it can be done, and done quickly,” said Alessandro Baccini, a WHRC scientist and one of the study’s co-authors. “It requires strong political will, however, and that’s an ingredient that too often is missing, not only in tropical countries but also in developed countries, which need to help finance the effort.”

Another of the four papers, published as a stand-alone report, found that the carbon contained in tropical forests in indigenous territories in the Amazon Basin, Mesoamerica, the Democratic Republic of the Congo, and Indonesia is equivalent to 168.3 gigatonnes of carbon dioxide. This is 20.1% of the carbon stored aboveground in all the world’s tropical forests – a conservative estimate because it does not consider carbon stored in indigenous territories in other parts of tropical Asia and the Congo Basin. Importantly, nearly half (45%) of this carbon is stored in forests claimed by indigenous peoples but to which they have no legal rights.

“It’s difficult to overstate the importance of this finding for combating climate change,” said the WHRC’s Wayne Walker, the lead contributor to the report. “It shows that countries with indigenous territories could increase their Intended Nationally Determined Contributions to climate change mitigation simply by establishing strong tenure rights for indigenous peoples. This single measure would go a long way to maintaining and expanding the tropical forest carbon store and thereby mitigating climate change.”

The fourth of the quartet of papers demonstrates that technological developments are fast overcoming one of the barriers to the inclusion of forest carbon in global agreements on climate change. The combination of satellite imagery, such as that produced by Landsat, as well as data produced by light detection and ranging (LiDAR) and field measurements make it possible to accurately calculate forest carbon emissions and sequestrations due to deforestation, forest degradation, forest restoration and forest management and how they change over time.

“There is a revolution in the way we measure and monitor tropical forests and the carbon they contain,” said Scott Goetz, a WHRC scientist and lead author of the paper. “It is enabling us to accurately measure changes in forest carbon, monitor environmental safeguards, and provide real-time information to inform law enforcement and deforestation alert systems.”

The concept of REDD+, as laid out in decisions under the UN climate change convention, involves payments based on emission reductions that have been measured, reported and verified relative to baselines and subject to various safeguards to, for example, protect indigenous rights and biodiversity. One of the issues debated over the large-scale implementation of REDD+ is perceived uncertainty in monitoring capabilities, but this is no longer an issue, according to Goetz. “We can already measure forest change and carbon emissions with sufficient accuracy, and such measurements will become even more accurate very quickly,” he said.

Walker believes that the four WHRC papers, in combination, have immense implications. “They encapsulate a huge global research effort to apply hard science to the proposition that tropical forests can be a major factor in averting dangerous climate change,” he said.

“The case for that proposition is now clear. Bringing it to reality will require improved governance, especially with respect to the rights of indigenous peoples and local communities. It will require considerable political will, and it will require a significant flow of money from developed countries. But we know it can be done, we can measure it being done, and we know that, if it is done, it will make a big difference in the world.”

“The four WHRC papers are welcome additions to the growing body of evidence that tropical forests are an undervalued asset in the fight against climate change,” said Frances Seymour, Senior Fellow at the Center for Global Development and author of Why Forests? Why Now? “Recognizing that forests are a safe and natural technology for carbon capture and storage, that tools for measuring forest carbon are available now, and that indigenous peoples provide essential forest stewardship would go a long way towards achieving climate stability.”

Link to all four studies and related press releases »

WHRC is an independent research institute where scientists investigate the causes and effects of climate change to identify and implement opportunities for conservation, restoration and economic development around the globe.