Indicators of Biodiversity and Ecological Services

CO2 Fluxes from Forests

NOTE: This indicator will be updated with the latest data and analysis of Carbon Fluxes from Harris et al. 2021 soon.  

This indicator aims to monitor the amount of carbon dioxide (CO2) released into or absorbed from the atmosphere. As forests grow, they reduce the level of CO2 in the atmosphere by absorbing CO2 through photosynthesis and storing the carbon in vegetation and soil. When trees are cut, cleared, or burned and forest soils are tilled or drained for agriculture, CO2 is released back into the atmosphere. The net sum of CO2 that is released (emissions) versus absorbed (removals) is the “flux.”  

At this time, Global Forest Watch monitors CO2 emissions related to annual tree cover loss in tropical forests using spatially explicit data. More comprehensive estimates of global forest carbon fluxes based on spatial data are currently not available due to a lack of data and more complex processes influencing carbon dynamics in temperate and boreal forests (e.g., forest management, fire), although other estimates have been produced using nongeospatial approaches (see the Limitations section).  

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How much CO2 is emitted due to tree cover loss in the tropics?

Thanks to the recent availability of 30-meter resolution maps of aboveground biomass and annual tree cover loss, it is now possible to map annual gross emissionsSee <a href="/gfr/data-and-methods#co2-flux">Data and Methods</a>. from tropical tree cover loss. These emissions have increased significantlySee <a href="/gfr/data-and-methods#co2-flux">Data and Methods</a>. since the turn of the century, from 2.4 gigatons (Gt) of CO2 in 2001 to 4.2 Gt of CO2 in 2020. If tropical tree cover loss were a country, it would rank third in CO2 equivalent emissions, behind only China and the United States. Emissions from tree cover loss within tropical primary forests, which typically store more carbon and are irreplaceable when it comes to sustaining biodiversity, have also been on the rise, more than quadrupling since 2001. Brazil, the Democratic Republic of the Congo, and Indonesia were responsible for 61 percent of total CO2 emissions from tropical primary forest loss between 2001 and 2020, primarily due to expanding agricultural commodity production. 

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Carbon emissions from tropical tree cover loss have increased since 2000

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Areas of forest acting as sources and sinks of carbon

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Limitations and Future Prospects

Understanding the extent to which global forests and land-use change activities increase or reduce CO2 concentrations in the atmosphere is challenging because net flux is not directly observable across large scales; instead, it must be inferred from models. Recent satellite observations and advances in machine learning algorithms have resulted in better maps of tree cover loss and forest biomass density. Carbon storage in forest biomass and gross emissions from tree cover loss can therefore be mapped relatively easily and at relatively high spatial resolution. But accurately mapping all sources and sinks of carbon associated with the world’s forests, and understanding the human and natural factors driving these fluxes, requires more than this. Better spatial information is needed about management practices involving forest degradation, fire, and the draining of peatlands; about how relatively slow rates of forest carbon sequestration vary spatially across a landscape in response to both biophysical and management factors; and how management practices affect other carbon pools, including soil carbon, dead organic matter, and wood products. Improvements in both field estimates of biomass change and remote sensing technologies in the coming years may lead to more spatially explicit estimates of all forest carbon fluxes.  

Using nonspatially explicit data, the Global Carbon Project estimates that forests absorbed about 30 percent of annual fossil fuel emissions (an average of 11.6 Gt of CO2 per yearFriedlingstein et al. 2018, https://doi.org/10.5194/essd-11-1783-2019 .) every year between 2008 and 2017.Friedlingstein et al. 2018, https://doi.org/10.5194/essd-11-1783-2019 . In spite of rising fossil fuel emissions over time, forests continue to absorb this share, meaning that CO2 absorption from standing and regenerating forests continues to outpace CO2 emissions resulting from forest loss. The latest scientific evidence also broadly suggests that established temperate and boreal forests are responsible for about half of the global net forest carbon sink, and tropical intact forests are responsible for the other half.Pan et al. 2011, https://doi.org/10.1126/science.1201609 . Because these estimates are not based on spatially explicit data, we know much less about how forests in different regions are contributing locally to the net global carbon sink, although this continues to be an area of active research.  

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{"Glossary":{"51":{"name":"agricultural tree crops","description":"Trees cultivated for their food, cultural, or economic values. These include oil palm, rubber, cocoa, cashew, mango, oranges (citrus), plantain, banana, and coconut.\r\n"},"94":{"name":"biodiversity intactness","description":"The proportion and abundance of a location\u0027s original forest community (number of species and individuals) that remain.\u0026nbsp;\r\n"},"95":{"name":"biodiversity significance","description":"The importance of an area for the persistence of forest-dependent species based on range rarity.\r\n"},"1":{"name":"deforestation","description":"The change from forest to another land cover or land use, such as forest to plantation or forest to urban area.\r\n"},"77":{"name":"deforested","description":"The change from forest to another land cover or land use, such as forest to plantation or forest to urban area.\r\n"},"76":{"name":"degradation","description":"The reduction in a forest\u2019s ability to perform ecosystem services, such as carbon storage and water regulation, due to natural and anthropogenic changes.\r\n"},"75":{"name":"degraded","description":"The reduction in a forest\u2019s ability to perform ecosystem services, such as carbon storage and water regulation, due to natural and anthropogenic changes.\r\n"},"79":{"name":"disturbances","description":"A discrete event that changes the structure of a forest ecosystem.\r\n"},"68":{"name":"disturbed","description":"A discrete event that changes the structure of a forest ecosystem.\r\n"},"65":{"name":"driver of tree cover loss","description":"The direct cause of forest disturbance.\r\n"},"70":{"name":"drivers of loss","description":"The direct cause of forest disturbance.\r\n"},"81":{"name":"drivers of tree cover loss","description":"The direct cause of forest disturbance.\r\n"},"2":{"name":"forest","description":"Forests include tree cover greater than 30 percent tree canopy density and greater than 5 meters in height as mapped at a 30-meter Landsat pixel scale.\r\n"},"3":{"name":"forest concession","description":"A legal agreement allowing an entity the right to manage a public forest for production purposes.\r\n"},"90":{"name":"forest concessions","description":"A legal agreement allowing an entity the right to manage a public forest for production purposes.\r\n"},"53":{"name":"forest degradation","description":"The reduction in a forest\u2019s ability to perform ecosystem services, such as carbon storage and water regulation, due to natural and anthropogenic changes.\r\n"},"54":{"name":"forest disturbance","description":"A discrete event that changes the structure of a forest ecosystem.\r\n"},"5":{"name":"forest fragmentation","description":"The breaking of large, contiguous forests into smaller pieces, with other land cover types interspersed.\r\n"},"6":{"name":"forest management plan","description":"A plan that documents the stewardship and use of forests and other wooded land to meet environmental, economic, social, and cultural objectives. Such plans are typically implemented by companies in forest concessions.\r\n"},"62":{"name":"forests","description":"Forests include tree cover greater than 30 percent tree canopy density and greater than 5 meters in height as mapped at a 30-meter Landsat pixel scale.\r\n"},"69":{"name":"fragmentation","description":"The breaking of large, contiguous forests into smaller pieces, with other land cover types interspersed.\r\n"},"80":{"name":"fragmented","description":"The breaking of large, contiguous forests into smaller pieces, with other land cover types interspersed.\r\n"},"74":{"name":"gain","description":"The establishment of tree canopy in an area that previously had no tree cover. Tree cover gain may indicate a number of potential activities, including natural forest growth or the crop rotation cycle of tree plantations.\r\n"},"7":{"name":"hectare","description":"One hectare equals 100 square meters, 2.47 acres, or 0.01 square kilometers and is about the size of a rugby field. A football pitch is slightly smaller than a hectare (pitches are between 0.62 and 0.82 hectares).\r\n"},"66":{"name":"hectares","description":"One hectare equals 100 square meters, 2.47 acres, or 0.01 square kilometers and is about the size of a rugby field. A football pitch is slightly smaller than a hectare (pitches are between 0.62 and 0.82 hectares).\r\n"},"67":{"name":"intact","description":"A forest that contains no signs of human activity or habitat fragmentation as determined by remote sensing images and is large enough to maintain all native biological biodiversity.\r\n"},"78":{"name":"intact forest","description":"A forest that contains no signs of human activity or habitat fragmentation as determined by remote sensing images and is large enough to maintain all native biological biodiversity.\r\n"},"8":{"name":"intact forests","description":"A forest that contains no signs of human activity or habitat fragmentation as determined by remote sensing images and is large enough to maintain all native biological biodiversity.\r\n"},"55":{"name":"land and environmental defenders","description":"People who peacefully promote and protect rights related to land and\/or the environment.\r\n"},"9":{"name":"loss driver","description":"The direct cause of forest disturbance.\r\n"},"10":{"name":"low tree canopy density","description":"Less than 30 percent tree canopy density.\r\n"},"84":{"name":"managed forest concession","description":"Areas where governments have given rights to private companies to harvest timber and other wood products from natural forests on public lands.\r\n"},"83":{"name":"managed forest concession maps for nine countries","description":"Cameroon, Canada, Central African Republic, Democratic Republic of the Congo, Equatorial Guinea, Gabon, Indonesia, Liberia, and the Republic of the Congo\r\n"},"91":{"name":"megacities","description":"A city with more than 10 million people.\r\n"},"57":{"name":"megacity","description":"A city with more than 10 million people."},"56":{"name":"mosaic restoration","description":"Restoration that integrates trees into mixed-use landscapes, such as agricultural lands and settlements, where trees can support people through improved water quality, increased soil fertility, and other ecosystem services. This type of restoration is more likely in deforested or degraded forest landscapes with moderate population density (10\u2013100 people per square kilometer). "},"86":{"name":"natural","description":"A forest that is grown without human intervention.\r\n"},"12":{"name":"natural forest","description":"A forest that is grown without human intervention.\r\n"},"63":{"name":"natural forests","description":"A forest that is grown without human intervention.\r\n"},"82":{"name":"persistent gain","description":"Forests that have experienced one gain event from 2001 to 2016.\r\n"},"13":{"name":"persistent loss and gain","description":"Forests that have experienced one loss or one gain event from 2001 to 2016."},"97":{"name":"plantation","description":"An area in which trees have been planted, generally for commercial purposes.\u0026nbsp;\r\n"},"93":{"name":"plantations","description":"An area in which trees have been planted, generally for commercial purposes.\u0026nbsp;\r\n"},"88":{"name":"planted","description":"A forest composed of trees that have been deliberately planted and\/or seeded by humans.\r\n"},"14":{"name":"planted forest","description":"A forest composed of trees that have been deliberately planted and\/or seeded by humans.\r\n"},"73":{"name":"planted forests","description":"A forest composed of trees that have been deliberately planted and\/or seeded by humans.\r\n"},"15":{"name":"primary forest","description":"Old-growth forests that are typically high in carbon stock and rich in biodiversity. The GFR uses a humid tropical primary rainforest data set, representing forests in the humid tropics that have not been cleared in recent years.\r\n"},"64":{"name":"primary forests","description":"Old-growth forests that are typically high in carbon stock and rich in biodiversity. The GFR uses a humid tropical primary rainforest data set, representing forests in the humid tropics that have not been cleared in recent years.\r\n"},"58":{"name":"production forest","description":"A forest where the primary management objective is to produce timber, pulp, fuelwood, and\/or nonwood forest products."},"89":{"name":"production forests","description":"A forest where the primary management objective is to produce timber, pulp, fuelwood, and\/or nonwood forest products.\r\n"},"87":{"name":"seminatural","description":"A managed forest modified by humans, which can have a different species composition from surrounding natural forests.\r\n"},"59":{"name":"seminatural forests","description":"A managed forest modified by humans, which can have a different species composition from surrounding natural forests. "},"96":{"name":"shifting agriculture","description":"Temporary loss or permanent deforestation due to small- and medium-scale agriculture.\r\n"},"17":{"name":"tree cover","description":"All vegetation greater than five meters in height and may take the form of natural forests or plantations across a range of canopy densities. Unless otherwise specified, the GFR uses greater than 30 percent tree canopy density for calculations.\r\n"},"71":{"name":"tree cover canopy density is low","description":"Less than 30 percent tree canopy density.\r\n"},"60":{"name":"tree cover gain","description":"The establishment of tree canopy in an area that previously had no tree cover. Tree cover gain may indicate a number of potential activities, including natural forest growth or the crop rotation cycle of tree plantations."},"18":{"name":"tree cover loss","description":"The removal or mortality of tree cover, which can be due to a variety of factors, including mechanical harvesting, fire, disease, or storm damage. As such, loss does not equate to deforestation. "},"19":{"name":"tree plantation","description":"An agricultural plantation of fast-growing tree species on short rotations for the production of timber, pulp, or fruit.\r\n"},"72":{"name":"tree plantations","description":"An agricultural plantation of fast-growing tree species on short rotations for the production of timber, pulp, or fruit.\r\n"},"85":{"name":"trees outside forests","description":"Trees found in urban areas, alongside roads, or within agricultural land\u0026nbsp;are often referred to as Trees Outside Forests (TOF).\u202f\r\n"}}}