Study: Tropical forests now release twice as much carbon than they absorb

Study: Tropical forests now release twice as much carbon than they absorb


A new ‘Study‘ from ‘Woods Hole Research Center‘ and Boston University reveals tropical forests now emit twice as much carbon than they capture. This is alarming news, since forests are the only carbon capture and storage “technology” that is safe, inexpensive and immediately available.

New approach to measuring forest carbon density using 1) satellite imagery 2003-2014, 2) laser remote sensing technology and 3) field measurements, were able to capture aboveground losses in forest carbon from full-scale deforestation as well as fine-scale degradation and disturbance. The latter has previously been a challenge to the scientific community over large areas. According to the study tropical forests in Americas, Africa and Asia are now releasing 425 (± 22%) teragrams (million tons) of carbon annually¹, equivalent to more than 4% (calculated by me) of global CO2 Emissions from Fossil Fuels and industrial processes. For perspectivation, global CO2 Emissions dropped 0.34% in 2016 compared to 2015.

Throughout the tropics selective logging and smallholder farmers removing individual trees for fuel wood adds up across large areas and become considerable. The research went further than previous studies in measuring the impact of disturbance and degradation (thinning of tree density and loss of biodiversity due to selective logging, forests fires, droughts and hunting) within apparently protected forests. Such fine-scale degradation can reduce biomass by up to 75%. Lead author Alessandro Baccini said. “If we’re to keep global temperatures from rising to dangerous levels, we need to drastically reduce emissions and greatly increase forests ability to absorb and store carbon (..) As always, trees are removing carbon from the atmosphere, but the volume of the forest is no longer enough to compensate for the losses. The region is not a sink anymore.”

Carbon losses from tropical forests result from:

  • Full-scale deforestation accounting for 31.1%
  • Degradation and disturbance within standing forests accounting for 68.9%

Carbon emissions from tropical forests are coming from:

  • Americas 76.4%
  • Africa 17.0%
  • Asia 6.6%

The article: ‘We are destroying rainforests so quickly they may be gone in 100 years‘ (Guardian, January 2017) suggests that: “If countries stick to their pledges and let damaged forests recover, annual global greenhouse gas emissions could be reduced by as much as 24 to 30% – an enormous step.”

In ClimatePositions area-changes of ‘Forest Cover‘ since 1990, and area-changes of ‘Primary Forest‘ since 2000, are (inadequate but worldwide available) ‘Indicators‘, when calculating national Climate Debts.

Read also Greenpeace’s report on Swedish boreal forests: ‘How Europe’s tissue giant is wiping away the boreal‘ (pdf 84 pages, September 2017), saying: “Since the 1950s, in Sweden’s portion of the Great Northern Forest, large areas of old-growth forest have been clearcut and the wider forest landscape fragmented. This has led to population declines in hundreds of forest species, with logging currently believed to be having significant negative impacts on over 1,300 red-listed plants, animals, fungi and lichens.”


¹Study ‘Abstract‘: Annual changes in the aboveground carbon density of tropical woody live vegetation, providing direct, measurement-based evidence that the world’s tropical forests are a net carbon source of 425.2 Tg C (± 22%). This net release of carbon consists of losses of 861.7 Tg C (± 9%) and gains of 436.5 Tg C (± 7%).


Study: ‘New approach to measuring forest carbon density shows tropics now emit more carbon than they capture‘ (‘Abstract‘ and ‘Summary, 2 pages‘). September 2017.
Video about the research: ‘Weighing the Rainforest (2:20)‘, April 2016.
The Guardian: ‘Alarm as study reveals world’s tropical forests are huge carbon emission source‘. September 2017.
The Guardian about a relating project: ‘New ‘disturbance map’ shows damaging effects of forest loss in Brazilian Amazon‘. June 2017.
The Guardian: ‘We are destroying rainforests so quickly they may be gone in 100 years‘. January 2017.

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