Chapter 8. Restoring the Earth: Planting Trees to Sequester Carbon
In recent years the shrinkage of forests in tropical regions has released 2.2 billion tons of carbon into the atmosphere annually. Meanwhile, expanding forests in the temperate regions are absorbing close to 700 million tons of carbon. On balance, therefore, some 1.5 billion tons of carbon are being released into the atmosphere each year from forest loss, contributing to climate change. 22
Tropical deforestation in Asia is driven primarily by the fast-growing demand for timber and, increasingly, by the soaring use of palm oil for fuel. In Latin America, by contrast, the growing market for soybeans, beef, and sugarcane ethanol is deforesting the Amazon. In Africa, it is mostly the gathering of fuelwood and the clearing of new land for agriculture as existing cropland is degraded and abandoned. Two countries, Indonesia and Brazil, account for more than half of all deforestation and thus have the highest potential for avoiding emissions from clearing forests. The Democratic Republic of the Congo, also high on the list, is considered a failing state, making forest management there particularly difficult. 23
The Plan B goals are to end net deforestation worldwide and to sequester carbon through a variety of tree planting initiatives and the adoption of improved agricultural land management practices. Today, because the earth’s forests are shrinking, they are a major source of carbon dioxide (CO2). The goal is to expand the earth’s tree cover, growing more trees to soak up CO2.
Although banning deforestation may seem farfetched, environmental reasons have pushed three countries—Thailand, the Philippines, and China—to implement complete or partial bans on logging. All three bans were imposed following devastating floods and mudslides resulting from the loss of forest cover. The Philippines, for example, has banned logging in most remaining old-growth and virgin forests largely because the country has become so vulnerable to flooding, erosion, and landslides. The country was once covered by rich stands of tropical hardwood forests, but after years of massive clearcutting, it lost the forest’s products as well as its services and became a net importer of forest products. 24
In China, after suffering record losses from several weeks of nonstop flooding in the Yangtze River basin in 1998, the government noted that when forest policy was viewed not through the eyes of the individual logger but through those of society as a whole, it simply did not make economic sense to continue deforesting. The flood control service of trees standing, they said, was three times as valuable as the timber from trees cut. With this in mind, Beijing then took the unusual step of paying the loggers to become tree planters—to reforest instead of deforest. 25
Other countries cutting down large areas of trees will also face the environmental effects of deforestation, including flooding. If Brazil’s Amazon rainforest continues to shrink, it may also continue to dry out, becoming vulnerable to fire. If the Amazon rainforest were to disappear, it would be replaced largely by desert and scrub forestland. The capacity of the rainforest to cycle water to the interior of the continent, including to the agricultural areas in the west and to the south, would be lost. At this point, a fast-unfolding local environmental calamity would become a global economic disaster, and, because the burning Amazon would release billions of tons of carbon into the atmosphere, it would become a global climate disaster. 26
Just as national concerns about the effects of continuing deforestation eventually eclipsed local interests, deforestation has become a global challenge. It is no longer just a matter of local flooding. Because it drives climate change, deforestation is a matter of melting mountain glaciers, crop-shrinking heat waves, rising seas, and the many other effects of climate change worldwide. Nature has just raised the ante on protecting forests.
Reaching a goal of zero net deforestation will require reducing the pressures that come from population growth, rising affluence, growing biofuel consumption, and the fast-growing use of paper and wood products. Protecting the earth’s forests means halting population growth as soon as possible. And for the earth’s affluent residents who are responsible for the growing demand for beef and soybeans that is deforesting the Amazon basin, it means moving down the food chain and eating less meat. Ending deforestation may require a ban on the construction of additional biodiesel refineries and ethanol distilleries.
Because of the importance of forests in modulating climate, the Intergovernmental Panel on Climate Change (IPCC) has examined the potential for tree planting and improved forest management to sequester CO2. Since every newly planted tree seedling in the tropics removes an average of 50 kilograms of CO2 from the atmosphere each year during its growth period of 20–50 years, compared with 13 kilograms of CO2 per year for a tree in the temperate regions, much of the afforestation and reforestation opportunity is found in tropical countries. 27
Estimates vary widely on the full potential for tree planting to sequester carbon. Looking at global models, the IPCC notes that on the high end, tree planting and improved forest management could sequester some 2.7 billion tons of carbon (9.8 billion tons CO2) per year by 2030 at a carbon price of less than $367 per ton ($100 per ton of CO2). Nearly two thirds of that potential—or roughly 1.7 billion tons per year—is thought to be achievable at half that carbon price. Plan B, with its 2020 timeline, cuts the IPCC sequestration figure in half, to get 860 million tons of carbon sequestered per year by 2020 at a carbon price below $200 per ton. 28
To achieve this goal, billions of trees would need to be planted on millions of hectares of degraded lands that had lost their tree cover and on marginal cropland and pastureland that was no longer productive. Spread over a decade, to reach annual sequestration rates of 860 million tons of carbon by 2020, this would mean investing $17 billion a year to give climate stabilization a large and potentially decisive boost.
This global forestation plan to remove atmospheric CO2, most of it put there by industrial countries, would need to be funded by them. In comparison with other mitigation strategies, stopping deforestation and planting trees are relatively inexpensive. They pay for themselves many times over. An independent body could be set up to administer and monitor the vast tree planting initiative. The key is moving quickly to stabilize climate before temperature rises too high, thus giving these trees the best possible chance of survival. 29
There are already many tree planting initiatives proposed or under way that are driven by a range of concerns, from climate change and desert expansion to soil conservation and making cities more habitable.
Kenyan Nobel laureate Wangari Maathai, who years ago organized women in Kenya and several nearby countries to plant 30 million trees, inspired the Billion Tree Campaign that is managed by the United Nations Environment Programme (UNEP). The initial goal was to plant 1 billion trees in 2007. If half of those survive, they will sequester 5.6 million tons of carbon per year. As soon as this goal was reached, UNEP set a new goal of planting 7 billion trees by the end of 2009—which would mean planting a tree for every person on earth in three years. As of July 2009, pledges toward the 7 billion plantings had passed 6.2 billion, with 4.1 billion trees already in the ground. 30
Among the leaders in this initiative are Ethiopia and Turkey, each with over 700 million trees planted. Mexico is a strong third, with some 537 million trees. Kenya, Cuba, and Indonesia have each planted 100 million or more seedlings. Some state and provincial governments have also joined in. In Brazil, the state of Paraná, which launched an effort to plant 90 million trees in 2003 to restore its riparian zones, committed to planting 20 million trees in 2007. Uttar Pradesh, India’s most populous state, mobilized 600,000 people to plant 10.5 million trees in a single day in July 2007, putting the trees on farmland, in state forests, and on school grounds. 31
Many of the world’s cities are also planting trees. Tokyo, for example, has been planting trees and shrubs on the rooftops of buildings to help offset the urban heat island effect and cool the city. Washington, D.C., is in the early stages of an ambitious campaign to restore its tree canopy. 32
An analysis of the value of planting trees on the streets and in the parks of five western U.S. cities—from Cheyenne in Wyoming to Berkeley in California—concluded that for every $1 spent on planting and caring for trees, the benefits to the community exceeded $2. A mature tree canopy in a city shades buildings and can reduce air temperatures by 5–10 degrees Fahrenheit, thus reducing the energy needed for air conditioning. In cities with severe winters like Cheyenne, the reduction of winter wind speed by evergreen trees cuts heating costs. Real estate values on tree-lined streets are typically 3–6 percent higher than where there are few or no trees. 33
Planting trees is just one of many activities that will remove meaningful quantities of carbon from the atmosphere. Improved grazing practices and land management practices that increase the organic matter content in soil also sequester carbon.
22. Vattenfall, Global Mapping of Greenhouse Gas Abatement Opportunities up to 2030: Forestry Sector Deep-Dive (Stockholm: June 2007), p. 1.
23. “Forest Area and Area Change,” in FAO, op. cit. note 3, pp. 109–15.
24. Johanna Son, “Philippines: Row Rages Over Lifting of Ban on Lumber Exports,” InterPress Service, 17 April 1998; John Aglionby, “Philippines Bans Logging After Fatal Floods,” Guardian (London), 6 December 2004; Republic of the Philippines, “President Okays Selective Lifting of Log Ban,” press release (Manila: 7 March 2005).
25. “Forestry Cuts Down on Logging,” China Daily, 26 May 1998; Erik Eckholm, “China Admits Ecological Sins Played Role in Flood Disaster,” New York Times, 26 August 1998; Erik Eckholm, “Stunned by Floods, China Hastens Logging Curbs,” New York Times, 27 September 1998; Chris Brown, Patrick B. Durst, and Thomas Enters, Forests Out of Bounds: Impacts and Effectiveness of Logging Bans in Natural Forests in Asia-Pacific (Bangkok, Thailand: FAO Regional Office for Asia Pacific, 2001); John Aglionby, “Philippines Bans Logging After Fatal Floods,” Guardian (London), 6 December 2004.
26. Geoffrey Lean, “A Disaster to Take Everyone’s Breath Away,” The Independent (London), 24 July 2006; Daniel Nepstad, “Climate Change and the Forest,” Tomorrow’s Amazonia: Using and Abusing the World’s Last Great Forests (Washington, DC: The American Prospect, September 2007); S. S. Saatchi et al., “Distribution of Aboveground Live Biomass in the Amazon Rainforest,” Global Change Biology, vol. 13, no. 4 (April 2007), pp. 816–37.
27. Intergovernmental Panel on Climate Change (IPCC), Climate Change 2007: Mitigation of Climate Change. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (Cambridge, U.K.: Cambridge University Press, 2007), pp. 541–84; Vattenfall, op. cit. note 22, p. 16; sequestration per tree
calculated assuming 500 trees per hectare, from U.N. Environment Programme (UNEP), Billion Tree Campaign, “Fast Facts,” at www.unep.org/billiontreecampaign, viewed 10 October 2007; growing period from Robert N. Stavins and Kenneth R. Richards, The Cost of U.S. Forest Based Carbon Sequestration (Arlington, VA: Pew Center on Global Climate Change, January 2005), p. 10.
28. Carbon sequestration potential based on IPCC, op. cit. note 27, pp. 543, 559.
29. Johan Eliasch, Climate Change: Financing Global Forests (London: The Stationary Office Limited for Her Majesty’s Stationery Office, 2008), pp. xvi–xvii, 69–80; McKinsey & Company, Pathways to a Low Carbon Economy: Version 2 of the Global Greenhouse Gas Abatement Cost Curve (London: 2009).
30. UNEP, Billion Tree Campaign, at www.unep.org/billiontreecampaign, viewed 13 July 2009; carbon sequestration assuming that three fourths of trees will be in tropics and one fourth in temperate regions, using sequestration rates in Vattenfall, op. cit. note 22, p. 16; UNEP, “Tree Planting Campaign Hits Four Billion Mark,” press release (Nairobi: 10 June 2009).
31. UNEP, “The State of Paraná in Brazil Undertakes a Major Reforestation Project,” at www.unep.org/billiontreecampaign/CampaignNews, viewed 12 October 2007; UNEP, “31 July—The Greenest Day of the Calendar in India and a Tree Planting Record by 600,000 Volunteers,” at www.unep.org/Documents.Multilingual, viewed 12 October 2007.
32. Chang-Ran Kim, “Tokyo Turns to Rooftop Gardens to Beat the Heat,” Reuters, 7 August 2002; Washington, D.C., program from Casey Trees, at www.caseytrees.org, viewed 17 June 2009.
33. Kathy Wolf, “Urban Forest Values: Economic Benefits of Trees in Cities,” fact sheet (Seattle, WA: Center for Urban Horticulture, November 1998); Greg McPherson et al., “Municipal Forest Benefits and Costs in Five US Cities,” Journal of Forestry, December 2005, pp. 411–16.
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