Total area deforested and deforestation rate in the Brazilian Amazon, 1988-2017. Data: Satellite Monitoring Project for the Amazon Forest (PRODES) (INPE/PRODES 2017). Graphic: Imazon

By Oliver Milman
4 October 2018

(The Guardian) – The role of forests in combating climate change risks being overlooked by the world’s governments, according to a group of scientists that has warned halting deforestation is “just as urgent” as eliminating the use of fossil fuels.

Razing the world’s forests would release more than 3 trillion tons of carbon dioxide, more than the amount locked in identified global reserves of oil, coal, and gas. By protecting and restoring forests, the world would achieve 18% of the emissions mitigation needed by 2030 to avoid runaway climate change, the group of 40 scientists, spanning five countries, said in a statement.

“We must protect and maintain healthy forests to avoid dangerous climate change and to ensure the world’s forests continue to provide services critical for the well-being of the planet and ourselves,” the statement reads.

The intervention comes as the UN’s Intergovernmental Panel on Climate Change gathers in South Korea ahead of Monday’s release of an eagerly awaited report on how the world can avoid warming of 1.5C (2.7F) beyond pre-industrial levels, an aspirational target of the landmark Paris climate deal in 2015.

It is expected the report will focus on required changes to the energy system, rather than forests. “In responding to the IPCC report, our message as scientists is simple: Our planet’s future climate is inextricably tied to the future of its forests,” the scientists’ statement pointedly concludes.

Trees and other vegetation currently absorb around a quarter of the CO2 humans are adding to the atmosphere, softening the potential impact of climate change.

While the world won’t lose all of its trees, large tracts of tropical forests, which hold a vast amount of carbon, are still being lost in the Amazon, central Africa and Indonesia. Warming temperatures are also fueling huge fires in forests in higher latitudes, as witnessed this summer when much of northern Sweden was aflame.

Deforestation in the Brazilian Amazon, 2012-2017. The average rate (6,325 km2) of deforestation between 2013 and 2017 was 38 percent larger than in 2012, when the lowest rate since the beginning of measurements was recorded. Graphic: Imazon

“The forest piece of the conversation is often lost and I don’t think the IPCC report will highlight it enough,” said Deborah Lawrence, a professor of environmental sciences at the University of Virginia and a signatory of the statement. “We almost take forests as a given but we lose forest every year, which means we are diminishing them as a carbon sink.

“Deforestation has been massively reduced in the Amazon, but that hasn’t happened elsewhere. As countries get more peaceful in Africa we could lose more tropical forests, which really worries me.”

The IPCC’s report is expected to mention the need for as-yet unproven technology to burn vegetation and bury the resulting emissions underground or directly suck carbon from the air as a way to meet the 1.5C target.

The statement by Lawrence and other scientists warns the former strategy, known as bioenergy with carbon capture and storage (Beccs), is untested and risks wiping out huge areas of rainforest in order to make way for plantation timber for energy.

“It breaks my heart to think we’d lose half our tropical forests for plantations just to save ourselves,” Lawrence said. “It’s horrifying that we’d lose our biodiversity to avert climate change. Losing tropical forests is not somehow cheaper than putting up wind farms in the U.S. or Sahara.” [more]

Scientists say halting deforestation 'just as urgent' as reducing emissions


Illustration showing how forests and oceans absorb carbon released by burning fossil fuels. Graphic: Climate and Land Use Alliance

Illustration showing how forests enhance rainfall. Graphic: Climate and Land Use Alliance

Statement from Scientist Signatories

“The Intergovernmental Panel on Climate Change (IPCC) will issue a new report soon on the impacts of 1.5°C of global warming. Limiting average temperature rise to 1.5°C requires both drastic reduction of carbon dioxide (CO2) emissions and removing excess carbon dioxide from the atmosphere. While high-tech carbon dioxide removal solutions are under development, the “natural technology” of forests is currently the only proven means of removing and storing atmospheric CO2 at a scale that can meaningfully contribute to achieving carbon balance.

In advance of the IPCC report, we highlight five often overlooked reasons why limiting global warming requires protecting and sustainably managing the forests we have, and restoring the forests we’ve lost.

1.  The world’s forests contain more carbon than exploitable oil, gas, and coal deposits, hence avoiding forest carbon emissions is just as urgent as halting fossil fuel use. Recent research suggests that, in order to have a chance of limiting warming to 1.5°C, we cannot emit more than about 750 billion tons of CO2 in the coming century[i]. The carbon in readily exploitable fossil reserves could release 2.7 trillion tons[ii] of CO2 up to 2100. By comparison, forests store enough carbon to release over 3 trillion tons[iii] of CO2 if destroyed. And climate change itself makes forests more vulnerable, including to uncontrollable wildfires.

2.  Forests currently remove around a quarter of the CO2 humans add to the atmosphere, keeping climate change from getting even worse. By destroying forests, we not only emit carbon dioxide but also lose the role forests play, through photosynthesis, in taking carbon dioxide out of the atmosphere. Of the 39 billion tons of CO2 that we emit into the atmosphere each year, 28%[iv] is removed on land (mostly by forests), and around a quarter by oceans. The remainder stays in the atmosphere. Maintaining and improving the management of existing forests is a critical part of climate change mitigation, with substantial additional benefits, including reducing air pollution, buffering against flooding, and conserving biodiversity.

3.  Achieving the 1.5°C goal also requires massive forest restoration to remove excess carbon dioxide from the atmosphere. Reforestation and improving forest management together have large potential to remove CO2 from the atmosphere. These “natural climate solutions” could provide 18%[v] of cost-effective mitigation through 2030.

4.  Bioenergy is not the primary solution[vi]. Achieving significant amounts of carbon dioxide removal through use of wood for energy and capturing the resulting carbon in geological reservoirs requires technology that is untested at large scale. In some areas, such as high carbon tropical forests and peatlands—both of which continuously remove carbon from the atmosphere—conservation is the best option. Climate benefits could also come from increased use of sustainably produced wood in longer-lived products, such as buildings, where timber can store carbon and substitute energy-intensive materials like concrete and steel.

5.   Tropical forests cool the air around them and the entire planet, as well as creating the rainfall essential for growing food in their regions and beyond[vii]. Standing forests pull moisture out of the ground and release water vapor to the atmosphere, regulating local, regional and global precipitation patterns and acting as a natural air conditioner[viii]. In contrast, cutting down tropical forests increases local surface temperatures by up to 3°C[ix]. These “climate regulation” effects of tropical forests make their conservation essential to protect food and water security.

In sum, we must protect and maintain healthy forests to avoid dangerous climate change and to ensure the world’s forests continue to provide services critical for the well-being of the planet and ourselves. The natural technology forests provide underpins economic growth but, like crumbling infrastructure, we’ve allowed forests to be degraded, even as we know that deferring maintenance and repair only increases the costs and the risk of disaster. In responding to the IPCC report, our message as scientists is simple: Our planet’s future climate is inextricably tied to the future of its forests.”

Signatories:

  1. Paulo Artaxo, Physics Department, University of São Paulo
  2. Gregory Asner, Department of Global Ecology, Carnegie Institution for Science and US National Academy of Sciences
  3. Mercedes Bustamante, Ecology Department, University of Brasilia and Brazilian Academy of Sciences
  4. Stephen Carpenter, Center for Limnology, University of Wisconsin-Madison
  5. Philippe Ciais, Laboratoire des Sciences du Climat et de l’Environnement, Centre d’Etudes Orme des Merisiers
  6. James Clark, Nicholas School of the Environment, Duke University
  7. Michael Coe, Woods Hole Research Center
  8. Gretchen C. Daily, Department of Biology and Woods Institute, Stanford University and US National Academy of Sciences
  9. Eric Davidson, University of Maryland Center for Environmental Science and President of the American Geophysical Union
  10. Ruth S. DeFries, Department of Ecology, Evolution and Environmental Biology, Columbia University and US National Academy of Sciences
  11. Karlheinz Erb, University of Natural Resources and Life Sciences, Vienna (BOKU)
  12. Nina Fedoroff, Department of Biology, Penn State University
  13. David R. Foster, Harvard University
  14. James N. Galloway, Department of Environmental Sciences, University of Virginia
  15. Holly Gibbs, Center for Sustainability and the Global Environment, University of Wisconsin-Madison
  16. Giacomo Grassi
  17. Matthew C. Hansen, Department of Geographical Sciences, University of Maryland
  18. George Homberger, Vanderbilt Institute for Energy and Environment
  19. Richard Houghton, Woods Hole Research Center
  20. Jo House, Cabot Institute for the Environment and Department of Geographical Sciences, University of Bristol.
  21. Robert Howarth, Department of Ecology and Evolutionary Biology, Cornell University
  22. Daniel Janzen, Department of Biology, University of Pennsylvania and US National Academy of Sciences
  23. Carlos Joly, Institute of Biology, University of Campinas
  24. Werner Kurz, Canada
  25. William F. Laurance, College of Science and Engineering, James Cook University
  26. Deborah Lawrence, Department of Environmental Sciences, University of Virginia
  27. Katharine Mach, Stanford University Earth System Science
  28. Jose Marengo, National Centre for Monitoring and Early Warning and Natural Disasters (CEMADEN, Brazil)
  29. William R. Moomaw, Global Development and Environment Institute, Tufts University and Board Chair, Woods Hole Research Center
  30. Jerry Melillo, Marine Biological Laboratory, University of Chicago
  31. Carlos Nobre, Institute of Advanced Studies, University of São Paulo and US Academy of Sciences
  32. Fabio Scarano, Institute of Biology, Federal University of Rio de Janeiro, and Brazilian Foundation for Sustainable Development (FBDS)
  33. Herman H. Shugart, Department of Environmental Sciences, University of Virginia
  34. Pete Smith, FRS, FRSE, University of Aberdeen, United Kingdom
  35. Britaldo Soares Filho, Institute of Geosciences, Federal University of Minas Gerais
  36. John W. Terborgh, Nicholas School of the Environment, Duke University
  37. G. David Tilman, College of Biological Sciences, University of Minnesota
  38. Adalberto Luis Val, Brazilian National Institute for Research of the Amazon (INPA)
  39. Louis Verchot, International Center for Tropical Agriculture (CIAT)
  40. Richard Waring, Department of Forest Ecosystems and Society, Oregon State University

Five Reasons the Earth’s Climate Depends on Forests

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