Agriculture's Effect on Global Warming and Global Warming's Effect on Agriculture
Agriculture and climate change is a two-way street.
Modern agriculture uses quite a lot of fossil fuels to power machinery. But when a full life cycle analysis is applied to modes of farming the carbon footprint is expanded. Fertilizer and pesticide-intensive farming techniques - along with the geographic dispersal of production sites, processing facilities, and ultimate consumers - the carbon footprint and the impact on climate change appear much larger.
When agricultural production is accompanied by deforestation and destruction of grasslands in order to open up new lands to farming and grazing, there is an accompanying loss of carbon sinks that would have captured some of the added carbon produced by carbon-intensive modes of production and distribution of agricultural products.
Global warming in turn accelerates existing problems in agriculture, especially in the hottest, most arid regions of the world. In regions where agriculture is rainfall-dependent, there are greater vulnerabilities to crop failure when rainfall becomes more scarce and unpredictable because of climate change-induced weather pattern alterations. Increased heat in the already hottest regions of the world further robs the land of available surface water and ultimately depletes deep aquifers that feed whatever lakes and streams that are available. As land becomes more arid both through the effects of global warming and as a consequence of chemically intensive agricultural techniques, the nutrients in the soil are further diminished, and agricultural productivity over the longer term declines further. In terms of carbon-intensity of agriculture production, as well as the longer-term effects on soil quality and nutrient availability, much depends on what types of agricultural products are produced.
The positive and negative feedback loops whereby climate change affects agriculture and agricultural practices in turn affect climate change are far more numerous than mentioned thus far. The graphic on the right (from the Ministry of the Environment, Government of Japan) portrays some of the feedback loops that are characteristic of extreme climate change scenarios in which desertification is a major factor. The entries on this page explore some of the evidence pertaining to what is known or predicted with regard to the interaction between agriculture and global warming in light of overarching concerns about their implications for global justice.
Modern agriculture uses quite a lot of fossil fuels to power machinery. But when a full life cycle analysis is applied to modes of farming the carbon footprint is expanded. Fertilizer and pesticide-intensive farming techniques - along with the geographic dispersal of production sites, processing facilities, and ultimate consumers - the carbon footprint and the impact on climate change appear much larger.
When agricultural production is accompanied by deforestation and destruction of grasslands in order to open up new lands to farming and grazing, there is an accompanying loss of carbon sinks that would have captured some of the added carbon produced by carbon-intensive modes of production and distribution of agricultural products.
Global warming in turn accelerates existing problems in agriculture, especially in the hottest, most arid regions of the world. In regions where agriculture is rainfall-dependent, there are greater vulnerabilities to crop failure when rainfall becomes more scarce and unpredictable because of climate change-induced weather pattern alterations. Increased heat in the already hottest regions of the world further robs the land of available surface water and ultimately depletes deep aquifers that feed whatever lakes and streams that are available. As land becomes more arid both through the effects of global warming and as a consequence of chemically intensive agricultural techniques, the nutrients in the soil are further diminished, and agricultural productivity over the longer term declines further. In terms of carbon-intensity of agriculture production, as well as the longer-term effects on soil quality and nutrient availability, much depends on what types of agricultural products are produced.
The positive and negative feedback loops whereby climate change affects agriculture and agricultural practices in turn affect climate change are far more numerous than mentioned thus far. The graphic on the right (from the Ministry of the Environment, Government of Japan) portrays some of the feedback loops that are characteristic of extreme climate change scenarios in which desertification is a major factor. The entries on this page explore some of the evidence pertaining to what is known or predicted with regard to the interaction between agriculture and global warming in light of overarching concerns about their implications for global justice.
Estimating the Agricultural Sector's Contribution to Greenhouse Gases
The question of how much each economic sector contributes to the stock of greenhouse gases (GHG) and ultimately, to global warming, is not as easily answered as one might imagine. The pie chart at the right produced by the World Resources Institute is perhaps one of the most familiar and most widely cited estimates. Three points are crucial.
- First, estimates of historical contributions of each sector and current estimates of annual percentages of GHG contributions may vary across nations and within nations over time, especially as developing economies transition from heavy reliance on subsistence farming to more energy-intensive industrial as a larger proportion of their productive output. While agriculture on this chart appears as a relatively small proportion of overall contribution (14%), similar sectoral estimates within particular nations can differ substantially.
- For example, a New Zealand Ministry for the Environment report, citing data from the 1990s, showed that 75% of carbon dioxide production in Brazil in 1994 was due to deforestation, 40% of carbon dioxide in Argentina in 1997 was due to agriculture, and 90% of carbon dioxide in China in 1994 was due to energy production.
Conceptual Problems in Sector Classification
- Second, any estimate of sectoral contribution depends on certain assumptions about how sectoral boundaries are conceptualized. For example, in many countries, the major reason for deforestation is conversion of forests to arable land for agricultural uses such as widespread soy production in Brazil. Similarly, while energy production may account for large reported percentages in China and elsewhere, some of the energy accounted for from the production side of the ledger can be accounted for differently were it broken out in terms of ultimate uses, such as agriculture or transportation or manufacturing.
- Moreover, transportation as in this United States Environmental Protection Agency (EPA) chart on your right, is not, for all imaginable analytic purposes, properly conceptualized as a discrete sector unto itself. For example, we might want to know how much GHG is produced by the process of transporting people versus how much is used in transporting diverse goods such as agricultural and manufactured goods. The proportion of GHG reasonably attributable to agriculture within any nation can thus vary considerably, depending on whether we focus on the production or consumption side of the equation. In this way of classifying sector contribution, agricultural contribution appears relatively minor.
Source: U.S. Environmental Protection Agency (EPA), Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2009, Table ES-7, 2011. http://www.epa.gov/climatechange/emissions/usinventoryreport.html
Direct and Indirect Accounting of Carbon Contributions
- A more specific example of the problem of conceptualization of sectors can be seen in the EPA table on the right, showing what it includes as agricultural sector contributors. It estimates that only 7% of agricultural-related carbon dioxide is produced by the consumption of fossil fuels. All indirect consumption in the form of fossil fuels used in the transportation of agricultural products or in the manufacture of fertilizer and pesticides is omitted. The fossil fuel emissions figures are primarily based on estimates of onsite combustion of gasoline and diesel fuel. If the purpose of classification is to identify opportunities for substituting renewable fuels in order to reduce the carbon dioxide emissions from agriculture production on the farm, the EPA's classificatory scheme fulfills a plausible analytic purpose.
- However, if the purpose is to get a better understanding of the GHS contributions of each economic sector in meeting various human resource needs, the inclusion of indirect carbon dioxide contributions may illuminate the true environmental cost of our consumption. The central point is that technological opportunity for mitigation of GHGs may not be identical with sectoral opportunity for mitigation. We might either focus our attention on the common, cross-sectoral technologies used in transportation for all sectors of the economy or focus on the sectoral opportunities for reducing GHGs in agriculture, for example, by identifying strategies to reduce reliance on carbon-intensive transportation. We need a form of accounting of the first sort in order to evaluate regulation of carbon-intensive technologies while the latter accounting illuminates opportunities to alter carbon-intensive forms of social organization.
Applying Life Cycle Analysis
- The suggestion that for some analytic and policy purposes we may need multiple, alternative ways of classifying carbon contributions by source is exemplified in the chart on the right. The chart comes from a study published in the International Journal of Life Cycle Assessment. The aim of life-cycle analysis, or life cycle assessment, is to pinpoint more precisely carbon contribution (or carbon footprint) in each of the stages of production and distribution of a loaf of bread. Assessments of various products under differing models of production and distribution will reveal wide variations in the primary sources of carbon. Here again, the carbon footprint may be as much a function of the form of social and economic organization as it is a function of the available technology. In this particular case, the production of the raw materials was the primary contributor to GHGs.
Differences in the Environmental Impact of GHGs
- Third, not all GHGs are equal in their global warming effects. Carbon dioxide may be the main culprit in many nations, but other GHGs may figure more prominently in others, and some GHGs tend to stay in the atmosphere for much longer periods of time and have greater radiative forcing effects. The graph on the right shows annual contributions by type of GHG, adjusted to reflect carbon dioxide equivalents. The 15% of emissions due to methane comes primarily from agriculture, and the 7% of emissions due to nitrous oxide is produced mostly from industry and agriculture, but the relative contributions are not indicated.
Livestock: Still More Complications in Estimating the Greenhouse Gas Impact of Agriculture
A 2006 UN Food and Agriculture Organization report by FAO livestock specialists estimates that about 18% of human-caused global-warming greenhouse gas is attributable to livestock production. (See especially, chapter 3 of Livestock's Long Shadow).
But the FAO estimate, while much higher for that one segment of other estimates of the proportion of the GHG contribution from the overall agricultural sector, is still far less than other reputable estimates. The World Bank and the International Finance Corporation have developed an assessment indicating that at least 51 percent of human-caused greenhouse gas is attributable to livestock.
Robert Goodland, one of the experts contributing to the estimates relied upon by the World Bank and the International Finance Corporation argues that "the key difference between the 18 percent and 51 percent figures is that the latter accounts for how exponential growth in livestock production (now more than 60 billion land animals per year), accompanied by large scale deforestation and forest-burning, have caused a dramatic decline in the earth’s photosynthetic capacity, along with large and accelerating increases in volatilization of soil carbon."Indeed, the FAO and many others assumes that meat production worldwide will “more than double” from 1999 to 2050. Given what we know from recent experience, these predictions are not implausible. From 1961-2002, global annual meat consumption rose from 71 million metric tons to 247 million metric tons. This represents an almost fourfold increase while the global population roughly doubled. (Source: World Resources Institute Database).
But the FAO estimate, while much higher for that one segment of other estimates of the proportion of the GHG contribution from the overall agricultural sector, is still far less than other reputable estimates. The World Bank and the International Finance Corporation have developed an assessment indicating that at least 51 percent of human-caused greenhouse gas is attributable to livestock.
Robert Goodland, one of the experts contributing to the estimates relied upon by the World Bank and the International Finance Corporation argues that "the key difference between the 18 percent and 51 percent figures is that the latter accounts for how exponential growth in livestock production (now more than 60 billion land animals per year), accompanied by large scale deforestation and forest-burning, have caused a dramatic decline in the earth’s photosynthetic capacity, along with large and accelerating increases in volatilization of soil carbon."Indeed, the FAO and many others assumes that meat production worldwide will “more than double” from 1999 to 2050. Given what we know from recent experience, these predictions are not implausible. From 1961-2002, global annual meat consumption rose from 71 million metric tons to 247 million metric tons. This represents an almost fourfold increase while the global population roughly doubled. (Source: World Resources Institute Database).
World Development Report 2008: Agriculture for Development
The 2001 World Bank report cited by Goodland preceded the FAO report's estimates. But the World Bank report provides a detailed overview of the main trends in livestock anticipated over the next decades. It discusses the environmental, social, and health repercussions of those trends with a much more focal concern for the implications for poverty alleviation. A key recommendation is that the Bank and its allied regional lending institutions should “avoid funding large-scale commercial, grain-fed feedlot systems and industrial milk, pork, and poultry production.”
The Bank's annual World Development Report for 2008 follows up on the earlier work. The central question is "how agriculture can be an effective instrument for economic development, especially development that favors the poor?"
The Bank's annual World Development Report for 2008 follows up on the earlier work. The central question is "how agriculture can be an effective instrument for economic development, especially development that favors the poor?"
- How has agriculture changed in developing countries in the past 20 years?
- What are the important new challenges and opportunities for agriculture?
- Which new sources of agricultural growth can be captured cost effectively in particular in poor countries with large agricultural sectors as in Africa?
- How can agricultural growth be made more effective for poverty reduction?
- How can governments facilitate the transition of large populations out of agriculture, without simply transferring the burden of rural poverty to urban areas?
- How can the natural resource endowment for agriculture be protected? How can agriculture's negative environmental effects be contained?
A 2008 Report on Likely impacts on US Agriculture
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"The Effects of Climate Change on Agcriculture, Land Resources, Water Resources, and Biodiversity" is one of many reports prepared by the U.S. Global Change Research Program. Its website indicates that it "coordinates and integrates federal research on changes in the global environment and their implications for society." It was known formerly as the U.S. Climate Change Science Program from 2002 through 2008. The organization has links to 13 federal agencies and prepares reports to Congress annually regarding the full range of climate change issues affecting the US. one of their recent reports is Our Changing Planet. The U.S. Global Change Research Program for Fiscal Year 2012
Positive (Adverse) Feedback Loops: Livestock, Feedstock, and their Relation to Global Warming
One of the major negative consequences of global warming is loss of accessible groundwater and the progressive desertification of some of the least productive and most vulnerable agricultural lands on the planet. For more on livestock's role in depletion of water resources and increase in water pollution, see chapter 4 of the FAO report. The loss of water resources is in itself a serious environmental concern, but there is an important linkage even for those whose primary focus is global warming. Some observers, including James E. McWilliams (see citation below), have called attention to the “desertification-global warming feedback loop” whereby:
• (1) Animal grazing itself is an important cause of desertification
• (2) Which then increases global warming
• (3) Which, in turn, leads to further desertification
For more on the causes and extent of global desertification, see the brief summary produced by the International Center for Agricultural Research in the Dry Areas (ICARDA).
Loss of useable agricultural lands, of course, contributes to increased food security and risk of hunger. In nations where agricultural land is scarce already, the increased need to rely upon imported grains and other foods also means greater risk of food-price shocks when global grain prices rise and local capacities for agricultural self-sufficiency have eroded. Consider some of the trends. In 2006, over one-third of all grain produced in the world was used as animal feed for meat production. In the U.S., 80% of grain produced was used as animal feed for meat production. (Source: Food and Agriculture Organization. Livestock’s Long Shadow: Environmental Issues and Options. 2007. 87).
Conversion of crop lands to grazing is not the only problem of this kind. The conversion of farm land once used for staple crops meant for human consumption to the production of grains used as feedstock also undermines the ability of many regions of the world to adapt to the effects of global warming. Vaclav Smil estimates that it would require 67% more land than Earth has in order to allow the global population consumed as much meat as those in the developed world. (Source: Singer, Peter. “The Ethics of Eating.” Chinadialogue. 30 April 2006). While global warming robs countries of the quantity of overall farm land necessary for the basic grain-based support of human life, the parallel diversion of a dwindling mass of farmland fused or feedstocks only makes for decreased ability to adapt to the harsh agricultural impact of global warming.
• (1) Animal grazing itself is an important cause of desertification
• (2) Which then increases global warming
• (3) Which, in turn, leads to further desertification
For more on the causes and extent of global desertification, see the brief summary produced by the International Center for Agricultural Research in the Dry Areas (ICARDA).
Loss of useable agricultural lands, of course, contributes to increased food security and risk of hunger. In nations where agricultural land is scarce already, the increased need to rely upon imported grains and other foods also means greater risk of food-price shocks when global grain prices rise and local capacities for agricultural self-sufficiency have eroded. Consider some of the trends. In 2006, over one-third of all grain produced in the world was used as animal feed for meat production. In the U.S., 80% of grain produced was used as animal feed for meat production. (Source: Food and Agriculture Organization. Livestock’s Long Shadow: Environmental Issues and Options. 2007. 87).
Conversion of crop lands to grazing is not the only problem of this kind. The conversion of farm land once used for staple crops meant for human consumption to the production of grains used as feedstock also undermines the ability of many regions of the world to adapt to the effects of global warming. Vaclav Smil estimates that it would require 67% more land than Earth has in order to allow the global population consumed as much meat as those in the developed world. (Source: Singer, Peter. “The Ethics of Eating.” Chinadialogue. 30 April 2006). While global warming robs countries of the quantity of overall farm land necessary for the basic grain-based support of human life, the parallel diversion of a dwindling mass of farmland fused or feedstocks only makes for decreased ability to adapt to the harsh agricultural impact of global warming.
Avoiding Meat: Comparative Energy Efficiency of Foods and Ways to Mitigate Global Warming
Source: BBC 2011
Livestock production has other, more direct energy-related implications as well, apart from diversion of scarce land resources away from what is needed for better adaptation to global warming. Grains produce 1.5-2.5 food calories for every 1 calorie of fossil fuel burned, while meat production operates at a net energy loss. For example, range-fed beef produces 1 food calorie for every 3 calories of fossil fuel burned. Feedlot beef produces 1 food calorie for every 33 calories of fossil fuel burned. Pigs, chickens, lamb, and dairy products fall in between these two extremes.
And note also that these figures do not include the energy required for: (1) Transportation and (2) Preparation and cooking. Livestock production thus not only contributes disproportionately to desertification, leading to more global warming, and hence, to a further reduction in capacity for adaptation, but to more carbon-intensive ways of meeting our caloric requirements, leading to still more global warming. For more on the relative energy efficiency of production of various foodstuffs see, this chart from the truecosts blog.
For an intriguing, 360 degree brief against reliance upon livestock as a source of human calories, see. McWilliams, James E. “Meat: The New Caviar.” in Just Food: Where Locavores Get It Wrong and How We Can Truly Eat Responsibly. New York: Little, Brown and, 2009. 117-154.
Also see McWilliams' op-ed in the New York Times, "The myth of sustainable meat." Consider the following claim from there:
"It requires 2 to 20 acres to raise a cow on grass. If we raised all the cows in the United States on grass (all 100 million of them), cattle would require (using the figure of 10 acres per cow) almost half the country’s land (and this figure excludes space needed for pastured chicken and pigs). A tract of land just larger than France has been carved out of the Brazilian rain forest and turned over to grazing cattle. Nothing about this is sustainable."
And note also that these figures do not include the energy required for: (1) Transportation and (2) Preparation and cooking. Livestock production thus not only contributes disproportionately to desertification, leading to more global warming, and hence, to a further reduction in capacity for adaptation, but to more carbon-intensive ways of meeting our caloric requirements, leading to still more global warming. For more on the relative energy efficiency of production of various foodstuffs see, this chart from the truecosts blog.
For an intriguing, 360 degree brief against reliance upon livestock as a source of human calories, see. McWilliams, James E. “Meat: The New Caviar.” in Just Food: Where Locavores Get It Wrong and How We Can Truly Eat Responsibly. New York: Little, Brown and, 2009. 117-154.
Also see McWilliams' op-ed in the New York Times, "The myth of sustainable meat." Consider the following claim from there:
"It requires 2 to 20 acres to raise a cow on grass. If we raised all the cows in the United States on grass (all 100 million of them), cattle would require (using the figure of 10 acres per cow) almost half the country’s land (and this figure excludes space needed for pastured chicken and pigs). A tract of land just larger than France has been carved out of the Brazilian rain forest and turned over to grazing cattle. Nothing about this is sustainable."
Still Another Potentially Adverse Feedback Problem: Biofuels
Photo: Stephanie Says, Flickr, CC
To what sector do we attribute the production of GGHs in creating biofuels as energy alternatives to fossil fuels? In the EPA chart above, should it fall under energy production or agriculture? Clearly, it is not for food, and yet it is an agricultural product.
Either way the contribution of biofuels to GGHs is significant and growing. There are differences in the carbon footprint of so-called first generation biofuels - corn, rapeseed, wheat, palm oil - and second generation cellulosic ethanol made from plants not used for food - e.g., switchgrass. In other words, there may be significant differences among biofuels when a comprehensive life cycle analysis is employed. Such an assumption underlies a legislated life cycle GHG assessment under the US Energy Independence and Security Act (EISA) of 2007. The aim was to restrict the kinds of fuels that could be counted as part of a mandate to switch 7.5 billion gallons of fossil fuels to renewable fuels by 2012. The law requires the EPA to do a full life cycle analysis extending from every stage of production and distribution - unlike the chart above in which the EPA's method for classifying carbon contributions attributable to industry sectors omits life cycle analysis. But there is reason for further caution about the carbon benefits of biofuels in general.
Many observers doubt whether any biofuels can offer a net carbon reduction once the contributions from the entire life-cycle analysis from production to consumption are counted. For example, one study in Science looked at the conversion of rainforests and grasslands in Brazil and Southeast Asia and found that in various sites, biofuel conversion could result in the release of between 17-420 times more carbon dioxide than the carbon reductions achieved by replacing a like quantity of fossil fuel. If the aim is carbon stocks mitigation, biofuels may be a self-defeating strategy. The legislative provisions in EISA reflect worries of just this sort. More importantly, perhaps, is the fact that relying on biofuels as a carbon mitigation strategy involves another possible adverse feedback loop. We not only expend more energy than is made available to substitute the biofuel for traditional fossil fuels - that's bad enough - but, in the process, we decrease the extent of farmland available for food production, already made more scarce by the effects of global warming. The net result is a loss of the very resources we need for adaption to the negative effects of global warming on our ability to feed the planet.
Either way the contribution of biofuels to GGHs is significant and growing. There are differences in the carbon footprint of so-called first generation biofuels - corn, rapeseed, wheat, palm oil - and second generation cellulosic ethanol made from plants not used for food - e.g., switchgrass. In other words, there may be significant differences among biofuels when a comprehensive life cycle analysis is employed. Such an assumption underlies a legislated life cycle GHG assessment under the US Energy Independence and Security Act (EISA) of 2007. The aim was to restrict the kinds of fuels that could be counted as part of a mandate to switch 7.5 billion gallons of fossil fuels to renewable fuels by 2012. The law requires the EPA to do a full life cycle analysis extending from every stage of production and distribution - unlike the chart above in which the EPA's method for classifying carbon contributions attributable to industry sectors omits life cycle analysis. But there is reason for further caution about the carbon benefits of biofuels in general.
Many observers doubt whether any biofuels can offer a net carbon reduction once the contributions from the entire life-cycle analysis from production to consumption are counted. For example, one study in Science looked at the conversion of rainforests and grasslands in Brazil and Southeast Asia and found that in various sites, biofuel conversion could result in the release of between 17-420 times more carbon dioxide than the carbon reductions achieved by replacing a like quantity of fossil fuel. If the aim is carbon stocks mitigation, biofuels may be a self-defeating strategy. The legislative provisions in EISA reflect worries of just this sort. More importantly, perhaps, is the fact that relying on biofuels as a carbon mitigation strategy involves another possible adverse feedback loop. We not only expend more energy than is made available to substitute the biofuel for traditional fossil fuels - that's bad enough - but, in the process, we decrease the extent of farmland available for food production, already made more scarce by the effects of global warming. The net result is a loss of the very resources we need for adaption to the negative effects of global warming on our ability to feed the planet.
Deforestation: What is it? Where is it most prevalent?
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David Allen of the Global Change Program at the University of Michigan follows the general view of the FAO in defining deforestation as follows:
"Deforestation: The conversion of forest to another land use or the long-term reduction of the tree canopy cover below a 10 percent threshold. Deforestation implies the long-term or permanent loss of forest cover and its transformation into another land use."
The FAO's explanatory note says that "the term specifically excludes areas where the trees have been removed as a result of harvesting or logging, and where the forest is expected to regenerate naturally or with the aid of silvicultural measures." Obviously, there is room for disagreement regarding whether and when some heavily cleared forest land is likely to regenerate, given the practices and uses involved.
Moreover, it is important to distinguish the FAO definition from that used by the UNFCCC under the terms of the Marrakech Accord (MA). The FAO definition includes losses of forest land from both natural and anthropogenic causes in order to produce a comprehensive assessment of the state of global forests, while the MA definition considers only a directly human-induced transition from forest to non-forest as deforestation of the sort potentially subject to regulation under the Kyoto protocols. Information below utilizes the comprehensive FAO definition and the data are from the 2011and 2012 FAO reports.
The assessment of the state of the world's forests requires a regional approach, but an overarching point from the 2012 report is the following: "According to the Millennium Ecosystem Assessment (MEA, 2005), more than 60 percent of the world’s major ecosystems are now degraded or used unsustainably. More than 50 percent of all types of forest, agricultural land and wetlands surrounding urban and semi-urban areas have been lost through conversion to other land uses." (p. 24).
The regional analysis is found in the FAO's 2011 State of the Forests Report. Below are some highlights.
Latin America, along with the Caribbean, holds almost one quarter of the world’s forests, with thirteen percent of the world’s forests found in Brazil alone.The leading cause in this region is conversion of land for agriculture and urbanization, although deforestation rates have decline slightly in the past few years. (For data on Brazil's declining rates of deforestation and its 2012 revisions to the 1965 Forest Code, see one of the many news items generated by the process between 2011 and the present).
Africa accounts for 17 percent of global forest area, the majority being found in southern and central Africa. Roughly ninety percent of wood removals are for fuelwood, and deforestation has risen in this region as a result of the rising population and increased demand for fuelwood.
Asia and the Pacific account for about 18 percent of the world’s forests, with the largest forested areas being China, Australia, Indonesia, India, and Burma. Rapid deforestation in countries such as Indonesia for land conversion to agricultural monocrops has recently been offset by massive aforestation efforts in China, India, and Vietnam.
North America accounts for 17 percent of global forests and one quarter of the world’s primary forests. Approximately 85-90% of North American wood removals are for "industrial roundwood" for wood processing and pulp industries. In the past decade, the region has seen an annual increase in forest, as has the Asia and Pacific region.
"Deforestation: The conversion of forest to another land use or the long-term reduction of the tree canopy cover below a 10 percent threshold. Deforestation implies the long-term or permanent loss of forest cover and its transformation into another land use."
The FAO's explanatory note says that "the term specifically excludes areas where the trees have been removed as a result of harvesting or logging, and where the forest is expected to regenerate naturally or with the aid of silvicultural measures." Obviously, there is room for disagreement regarding whether and when some heavily cleared forest land is likely to regenerate, given the practices and uses involved.
Moreover, it is important to distinguish the FAO definition from that used by the UNFCCC under the terms of the Marrakech Accord (MA). The FAO definition includes losses of forest land from both natural and anthropogenic causes in order to produce a comprehensive assessment of the state of global forests, while the MA definition considers only a directly human-induced transition from forest to non-forest as deforestation of the sort potentially subject to regulation under the Kyoto protocols. Information below utilizes the comprehensive FAO definition and the data are from the 2011and 2012 FAO reports.
The assessment of the state of the world's forests requires a regional approach, but an overarching point from the 2012 report is the following: "According to the Millennium Ecosystem Assessment (MEA, 2005), more than 60 percent of the world’s major ecosystems are now degraded or used unsustainably. More than 50 percent of all types of forest, agricultural land and wetlands surrounding urban and semi-urban areas have been lost through conversion to other land uses." (p. 24).
The regional analysis is found in the FAO's 2011 State of the Forests Report. Below are some highlights.
Latin America, along with the Caribbean, holds almost one quarter of the world’s forests, with thirteen percent of the world’s forests found in Brazil alone.The leading cause in this region is conversion of land for agriculture and urbanization, although deforestation rates have decline slightly in the past few years. (For data on Brazil's declining rates of deforestation and its 2012 revisions to the 1965 Forest Code, see one of the many news items generated by the process between 2011 and the present).
Africa accounts for 17 percent of global forest area, the majority being found in southern and central Africa. Roughly ninety percent of wood removals are for fuelwood, and deforestation has risen in this region as a result of the rising population and increased demand for fuelwood.
Asia and the Pacific account for about 18 percent of the world’s forests, with the largest forested areas being China, Australia, Indonesia, India, and Burma. Rapid deforestation in countries such as Indonesia for land conversion to agricultural monocrops has recently been offset by massive aforestation efforts in China, India, and Vietnam.
North America accounts for 17 percent of global forests and one quarter of the world’s primary forests. Approximately 85-90% of North American wood removals are for "industrial roundwood" for wood processing and pulp industries. In the past decade, the region has seen an annual increase in forest, as has the Asia and Pacific region.
The Major Causes of Deforestation
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It remains controversial just how much various factors figure in causing deforestation. For example, there is debate regarding the contribution of traditional swidden agriculture - which involves slashing and burning forests to create fields for agriculture - especially the magnitude of effects of swidden techniques as part of indigenous, subsistence farm practices as compared to its role within large-scale clearing of forests for cattle production as global meat consumption rises.
There are those who argue that the traditional swidden techniques are environmentally sustainable forms of land management (USAID-sponsored surveys from many years ago). Others argue that poverty, rapid population growth, and ignorance are among the biggest threats to forests insofar as the poor and the hungry destroy their immediate environment to survive. Just fly over the island of Hispaniola that is home to both Haiti and the Dominican Republic and the difference is stunning.
Still others claim that much of the deforestation attributed to traditional agriculture that is widely cited is in fact caused by both legal and illegal logging and by commercial development schemes such as plantations, ranching projects, and dams. Along the lines of this latter view, are claims that corrupt governments and public industry-friendly government policies now pose one of the main threats, even in regions where burning and clearing for small-agriculture or fuelwood extraction has been among the major threats in the past. There are questions as well about the extent to which the primary causes vary from region and according to the timeframe of analysis. There are, in short, many unresolved empirical questions, and assessments even from a few years ago are unlikely to be reliable indicators of risk in a dynamic global marketplace and a context of persistent poverty.
Among the major types of human activities that cause deforestation are: logging, agriculture extension, firewood, charcoal production, cattle ranching, palm oil production, shrimp farming, road construction and mining. According to United Nations Framework Convention on Climate Change, subsistence farming accounts for 48% of human-induced deforestation, and commercial agriculture for a further 32%. In addition, 14% is caused by commercial logging, and fuel wood harvesting accounts for 5%.
There are those who argue that the traditional swidden techniques are environmentally sustainable forms of land management (USAID-sponsored surveys from many years ago). Others argue that poverty, rapid population growth, and ignorance are among the biggest threats to forests insofar as the poor and the hungry destroy their immediate environment to survive. Just fly over the island of Hispaniola that is home to both Haiti and the Dominican Republic and the difference is stunning.
Still others claim that much of the deforestation attributed to traditional agriculture that is widely cited is in fact caused by both legal and illegal logging and by commercial development schemes such as plantations, ranching projects, and dams. Along the lines of this latter view, are claims that corrupt governments and public industry-friendly government policies now pose one of the main threats, even in regions where burning and clearing for small-agriculture or fuelwood extraction has been among the major threats in the past. There are questions as well about the extent to which the primary causes vary from region and according to the timeframe of analysis. There are, in short, many unresolved empirical questions, and assessments even from a few years ago are unlikely to be reliable indicators of risk in a dynamic global marketplace and a context of persistent poverty.
Among the major types of human activities that cause deforestation are: logging, agriculture extension, firewood, charcoal production, cattle ranching, palm oil production, shrimp farming, road construction and mining. According to United Nations Framework Convention on Climate Change, subsistence farming accounts for 48% of human-induced deforestation, and commercial agriculture for a further 32%. In addition, 14% is caused by commercial logging, and fuel wood harvesting accounts for 5%.
Deforestation and Agricultural Conversion: Riding the Adaptation-Mitigation See-Saw
The UNFCCC (the Little REDD+ Book) estimates that roughly 18% of GHG emissions are due to human-induced deforestation. A comprehensive estimate of the net carbon increase in the atmosphere due to conversion of land such as rainforests and grasslands to some new agricultural purpose depends heavily on the carbon footprint of the prior land use. Forest destruction for the purpose of cattle grazing, soy production for animal feed used elsewhere, or for the production of biofuels can result in net carbon reduction failures of two sorts:
- First, there is the loss of carbon sinks that aid the carbon cycle by absorbing GHGs produced by other sources. This undermines mitigation efforts directed at stabilizing atmospheric GHGs.
- Second, if the cleared land is now dedicated to livestock production or biofuels, then still more GHGs would be produced than alternative agricultural uses that might enable countries hit hardest by by climate-change induced loss of arable land to adapt to the consequent loss of food security.
New NASA Estimates of the Carbon Contribution from Deforestation
Source: NASA, 2012
New estimates from NASA of the carbon contribution from deforestation during the early 2000's are sharply lower than previous estimates. The June 2012 NASA gross emissions estimate of 0.81 billion metric tons of carbon emitted per year is approximately one third of previously published estimates, and represents just 10 percent of the total global human-produced carbon emissions over the time period analyzed (2000 to 2005).
Carbon Sinks, Forests, and Climate Change
This Global Issues webpage offers more information on the relationship between deforestation and climate change, particularly in the form of regional case studies and analysis of recent trends and international policy (i.e. Kyoto Protocol). Although the article highlights the numerous benefits of re-forestation in this context, it also emphasizes that such measures do not represent a solution on their own. Rather, re-forestation often falls far short of necessary increases in carbon sinks while providing loggers and other perpetrators with a false sense of "sustainability."