GLOBAL MAP OF HOTSPOTS OF LAND COVER AND LAND USE CHANGE
Purpose: The goal of this project is to present examples of current hot spots of land cover and land use change around the globe, through an interactive online map. This project was a collaboration between graduate students in the Department of Geography at the University of Maryland, College Park, and was completed in late 2009. The site is periodically updated as new hotspots are identified by scientists from NASA’s Land-Use Land-Cover Change Program.
Hotspot Definition: For the purposes of this project, a "hotspot" is defined as existent or potential change to a region or area through land cover and land use change that has regional to global implications. The hotspots were also considered within the context of pressing environmental and social issues such as climate change, biodiversity, human health, and sustainability. Primary considerations were to identify areas of change within the last five years and areas of continued or potential future change.
Hotspot Categories: Seven broad categories of land-cover land-use change were identified for this project. In some cases the categories are related to one another, and other hotspots can be added as needed.
Afforestation / Reforestation
Agricultural Expansion / Abandonment
Afforestation / Reforestation
In the present era, where the vast majority of instances of LCLUC are negative in nature, afforestation and reforestation stand as important exceptions with positive impacts on the environment. Afforestation/reforestation can improve soil quality, reduce run off and minimize erosion, and enhance biodiversity (Allen and Chapman 2001). While rates of deforestation far outpace afforestation/reforestation efforts, these two mechanisms do serve to mitigate the negative impacts for example through carbon sequestration (Levy and Milne 2004). Large scale afforestation/reforestation projects include the Green Wall of China, which will eventually lead to nine million new acres of forest cover, or the Brazilian plan to plant one billion trees in the Amazonian state of Pará (Malagonoux, Sene, and Atzmon 2007; Xinhua 2009).
While often treated in the same manner, afforestation and reforestation differ subtly. Afforestation is defined as the planting of new trees in areas which were previously not forested, or at least within the last 50 years (Verchot et al 2007). By contrast reforestation is the replacement of trees in locations where they have traditionally been found in the past 50 years, but have been removed by human or natural forces (Zomer et al 2008). It is also important to note that neither tree plantations nor monocultures are regarded here as either afforestation or reforestation as they have minimal species composition, simple structure, a high degree to disturbance vulnerability, and a specified economic purpose (Lugo 1997).
Large-scale afforestation/reforestation requires a directed and concerted effort. Initiatives to afforest and reforest areas typically have backing from both national and local government, as well as the support of international NGO's and local community organizations. The rationale for these programs typically stem from desires to control storm surges, limit desert encroachment or improve the aesthetic value of a given landscape. While there has been some limited success in afforestation/reforestation projects to-date, there is considerable opportunity for larger scale projects in the context of carbon offsets.Afforestation References:
- Allen, Alistar, and Chapman, Deborah. 2001. Impacts of afforestation on groundwater resources and quality. Hydrogeology Journal 9 (4): 390-400.
- “Brazil Launches Program to Plant 1 Billion Trees in the Amazon.” 2008. Xinhua News Agency, CEIS. 30 May. http://www.redorbit.com/news/science/1409361/brazil_launches_program_to_plant_1_billion_trees_in_the/index.html (last accessed 20 October 2009)
- Levy, P.E., and R. Milne. 2004. Estimation of deforestation rates in Great Britain. Forestry 77(1): 9-16.
- Lugo, Ariel E. 1997. The apparent paradox of reestablishing species richness on degraded lands with tree monocultures. Forestry Ecology and Management 99:9-19.
- Malagonoux M., Sene E.H., and Atzmon N. 2007. “Forests, trees and water in arid lands: a delicate balance.” Food and Agriculture Organization of the United Nations. http://www.fao.org/ docrep/010/a1598e/a1598e06.htm (last accessed 20 October 2009).
- Verchot, Louis V., R. Zomer, O.V Straaten, and B. Muys. 2007. Implications of country-level decisions on the specification of crown cover in the definition of forests for land area eligible for afforestation and reforestation activities in the CDM. Climate Change 81:415-430.
- Zomer, Robert J., A. Trabucco, L.V. Verchot, and B. Muys. 2008. Land area eligible for afforestation and reforestation within the Clean Development Mechanism: a global analysis of the impact of forest definition. Mitigation and Adaptation Strategies for Global Change 13:219-239.
Agricultural Expansion / Abandonment
Expansion of agricultural areas is increasing as the demand for agricultural land and products increases due to population growth and economic globalization. With concerns about climate change, attention must be directed to greenhouse gas (GHG) emissions related to agricultural expansion associated with forest loss (See Deforestation) and fossil fuel burning. Mechanized and intensified “agriculture consumes fossil fuels during the manufacture of equipment, fertilizer and other chemical inputs, as well as during machinery and grain handling operations,” showing agriculture has a net “global warming potential,” even before considering the amount of greenhouse gasses emitted through forest to cropland conversion (Johnson et al 2007, p. 109).
Climate change forcing is not the only detriment associated with forest to cropland conversion; rather, it also poses a significant threat to regional biodiversity with the destruction and fragmentation of habitat. Intensive use of fertilizer often impacts aquatic systems and water quality. The demand for agricultural land also drives expansion into marginal lands that are often poorly suited for cultivation. If these lands are poorly managed or subject to prolonged drought they become degraded (See Dryland Degradation) and are often abandoned. Expansion into marginal lands can also present a considerable threat to biodiversity.
The global increase in fuel prices has initiated a new type of land use change: from food cultivation to fuel cultivation. Large areas of land which traditionally produce wheat or soybeans are now being used for corn-based ethanol production. If the demand for food is to be met then compensatory lands need to be converted for food-producing agriculture, while additional lands are being converted for fuel production. One example of this is the tropics where forest or woodlands are being converted to agriculture for the production of sugar-cane based ethanol.
Economic development and the rising value of land is resulting in a decline in traditional small holder farming in more developed countries. In former communist countries large areas of previously subsidized mechanized farming are no longer economically viable . In both cases agricultural land is being abandoned. In some regions where population density is high, these abandoned lands are being used for residential development (e.g. the mediterranean) with implications for fire risk . In other less populated areas natural vegetation is regrowing (e.g. in Russia, resulting in increased biodiversity and a change in fire regime.Agricultural Expansion and Abandonment References:
- Johnson, J.M.F., A.J. Franzluebbers, S. Lachnicht-Weyers, and D.C. Reicosky. 2007. Agricultural opportunities to mitigate greenhouse gas emissions. Environmental Pollution 150: 107-24.
Deforestation is the loss or continual degradation of forest habitat due to either natural or human related causes. It occurs when forest is converted to another land cover or when the tree canopy cover falls below a minimum percentage threshold: 10 percent for the United Nation’s Food and Agriculture Organization (UNFAO) definition (Lepers et al 2005). Forests play an important role in the Earth System, and consequently, deforestation is significant for understanding global change. Deforestation has great impacts on the atmosphere (Carbon Cycle and Climate Change), hydrosphere (water loss), soil (soil loss and erosion), lithosphere (landslides), and biosphere (biodiversity loss). Tropical deforestation is currently contributing to the massive and permanent loss of biodiversity.
During the past several decades, economic development in the developing World has significantly impacted forest-cover change at the global level (Masek et al 2008). Research in deforestation “hot spots” has also been highlighted during the last two decades, especially in tropical and boreal forests (Myers 1988; Achard et al 2002; Hansen et al 2008). Direct causes of deforestation include agricultural expansion, wood extraction (logging or wood harvest for domestic fuel or charcoal), and infrastructure expansion such as road building and urbanization (Lindsey 2007). Indigenous populations are often marginalized in the process of deforestation. Many international organizations as well as local projects, such as those by the UNFAO, UNEP, the World Resources Institute, World Wildlife Fund, and Greenpeace have raised attention to the problem of deforestation. National governments are attempting to better manage deforestation and in the context of climate change international programs are being developed to reduce emissions from deforestation and degradation (e.g. UN REDD).Deforestation References:
- Achard, F., H. D. Eva, H.-J. Stibig, P. Mayaux, J. Gallego, T. Richards, and J.-P. Malingreau. 2002. Determination of Deforestation Rates of the World's Humid Tropical Forests. Science 297 (5583):999-1002.
- Hansen, M. C., D. P. Roy, E. Lindquist, B. Adusei, C. O. Justice, and A. Altstatt. 2008. A method for integrating MODIS and Landsat data for systematic monitoring of forest cover and change in the Congo Basin. Remote Sensing of Environment 112 (5):2495-2513.
- Hansen, M. C., S. V. Stehman, P. V. Potapov, T. R. Loveland, J. R. G. Townshend, R. S. DeFries, K. W. Pittman, B. Arunarwati, F. Stolle, M. K. Steininger, M. Carroll, and C. DiMiceli. 2008. Humid tropical forest clearing from 2000 to 2005 quantified by using multitemporal and multiresolution remotely sensed data. Proceedings of the National Academy of Sciences 105 (27):9439-9444.
- Lepers, E., E. F. Lambin, A. C. Janetos, R. DeFries, F. Achard, N. Ramankutty, and R. J. Scholes. 2005. A synthesis of information on rapid land-cover change for the period 1981-2000. BioScience 55 (2):115-124.
- Lindsey, Rebecca - NASA Earth Observatory, 2007. http://earthobservatory.nasa.gov/Features/Deforestation/deforestation_update3.php (last accessed 2 Nov, 2009)
- Masek, J. G., C. Huang, R. Wolfe, W. Cohen, F. Hall, J. Kutler, and P. Nelson. 2008. North American forest disturbance mapped from a decadal Landsat record. Remote Sensing of Environment 112 (6):2914-2926.
- Myers, N. 1988. Threatened biotas: "hotspots" in tropical forests. The Environmentalist 8 (3):187-208.
With increasing human population pressure, land degradation is occurring at unprecedented rates. Drylands are particularly susceptible to degradation and, although they cover about 41 percent of Earth's land surface (Safriel & Adeel, 2005), estimates of the extent and severity of degradation vary greatly (Lepers et al., 2005). Best estimates indicate that degrading areas currently support 1.5 billion people (Bai et al., 2008). Often these populations are rural and underdeveloped and subject to the larger and more imminent threats of hunger, poverty and conflict. Local livelihoods are jeopardized by soil erosion, salinization, vegetation loss, water scarcity, and air pollution. Moreover, regional and global ecosystem services rendered by drylands, such as carbon cycling, make it a cumulative problem that is not limited to the developing world (Reynolds and Stafford Smith, 2002).
Definitions of land degradation, dryland degradation and desertification have never reached a consensus in the scientific community (Glantz and Orlovsky, 1983; Veron et al., 2006). However, if we consider it to be the semi-permanent degradation of land in terms of a loss of productivity that does not return with rain, then we capture the essence of the problem in most situations (Prince et al., 1998). Including droughts is a controversial issue, given their natural cycle and inter-annual variability. However, in searching for hotspots we cannot turn a blind eye to drought emergencies such as the current one in East Africa; which naturally exacerbate land degradation in low productivity ecosystems (Prince et al., 2009). While such droughts might not be caused by land degradation itself, there is very likely to be a drought to land degradation feedback mechanism (Prince et al.,1998), which needs to be understood and addressed.Dryland Degradation References:
- Bai, Z.G., Dent, D.L., Olsson, L. & Schaepman, M.E. 2008. Global assessment of land degradation and improvement. 1. Identification by remote sensing. Report 2008/01, ISRIC – World Soil Information, Wageningen.
- Glantz, M.H., Orlovsky, N.S. 1983. Desertification: a review of the concept. Desertification Control Bulletin 9:12–22.
- Lepers, E., Lambin, E.F., Janetos, A.C., DeFries R., Achard F., Ramankutty, N., Scholes, R.J. 2005. A Synthesis of Information on Rapid Land-cover change for the Period 1981-2000. Bioscience. 55(2):115-124.
- Prince, S. D., Brown de Colstoun, E., & Kravitz, L. 1998. Evidence from rain use efficiencies does not support extensive Sahelian desertification. Global Change Biology (4):359−374.
- Prince, S.D., Becker-Reshef, I., Rishmawi, K. 2009. Detection and mapping of long-term land degradation using local net production scaling: Application to Zimbabwe. Remote Sensing of Environment. 113 (2009):1046–1057.
- Reynolds, J. F., & Stafford Smith, M. (2002). Global desertification: Do humans create deserts? Berlin: Dahlem University Press.
- Safriel, U., & Adeel, Z. 2005. Dryland systems. Ecosystems and human well-being: Current state and trends (pp. 948). Washington, D.C.: Island Press.
- Veron, S.R., Paruelo, J.M., Osterheld M. 2006. Assessing Desertification. Journal of Arid Environments (66):751-763.
Beginning in the early 1980s, a significant global warming trend has led to glacial retreat, so much so that some glaciers have disappeared completely with many more threatened (IPCC 2001). For example, sixty-seven percent of glaciers are retreating in the Himalayas with climate change identified as the major causal factor (Ageta and Kadota 1991). Melting of glaciers, while leading to increased run off in the near term, will have serious impacts on future water supplies and other important hydrologic assets (UNEP 2002). This is particularly the case where agriculture is maintained by glacial melt-water and where a reduction in summer streams affects both the ability to irrigate crops and keep dams and reservoirs replenished. Several large agricultural areas of the World are irrigated by rivers that are fed by mountain meltwater.
There is little that can be done to reduce global warming on the timescales needed. At best all efforts at mitigation will only lead to a stabilization of current carbon dioxide levels (IPCC 2001). There is therefore a need for scientific research on high-risk areas to develop realistic projections of water supply and mid-term land use planning on how to adapt to these changes.Glacial Retreat References:
- Ageta, Y. & T. Kadota (1991) Predictions of changes of glacier mass balance in the Nepal Himalaya and Tibetan Plateau: a case study of air temperature increase for three glaciers. Annals of Glaciology 16: 89-94.
- IPCC, Intergovernmental panel on climate change. "188.8.131.52 Mountain glaciers". Climate Change 2001 (Working Group I: The Scientific Basis).
- UNEP, United Nations Environment Programme. 2002. "Global Warming Triggers Glacial Lakes Flood Threat. April 16. UNEP News Release 2002/20.
For the first time in history, over half the human population now lives in urban areas. Urbanization refers to the process by which an increasing proportion of the world's population lives in and around cities. Driven in part by the doubling of global population in the last 50 years and unprecedented era of economic development, the urban footprint in developed and developing cities continues to grow and intensify. By 2030 nearly five billion people will live in urban areas, primarily concentrated in Africa and Asia (UNFPA 2007). This growth is connected with rapid economic development in places as diverse as Lagos, Nigeria, Manaus, Brazil, Dubai, UAE, and cities in central China. While the developed world’s cities are experiencing urban renewal and suburban sprawl, the developing World’s mega-cities are being formed by the in-migration of rural populations in search of work.
The rural to urban conversion, often referred to as urban sprawl, has become a focus area for the scientific community as well as policy-makers. Poor infrastructure and public transport leads to traffic jams and automobile pollution in most big cities. Often economic forces such as the labor market and land availability drive immigrants into urban areas. The rate of urban population growth often outpaces the rate of infrastructure revitalization degrading the quality of life and in extreme cases leading to the development of slums or shanty towns. The promise of sustainable urban development requires a framework of sound land use and transportation planning, floodplain safety regulations, and health and waste management strategies.
Although information is available for some cities, the true extent and rate of urban land expansion worldwide remains unknown. The resulting impact on biodiversity, local climate, and global change processes is an areas for research. While geographic information systems and other quantitative data tools on urbanization will assist decisions on smart growth, equitable development, infrastructure management, and public health public and governmental will remain the most significant factor in mitigating urbanization’s negative externalities.Urbanization References:
- UNFPA. 2007. State of World Population 2007: United Nations Population Fund. http://www.unfpa.org/swp/swpmain.htm (last accessed 5 November 2009).
Wetland ecosystems comprise some of the most biologically diverse systems in the world, exhibiting complex ecosystem processes and nutrient flows. Naturally-functioning wetlands provide a range of benefits and services for people's livelihoods and well-being, including food, fiber, flood protection, water purification and water supply. Wetlands include marsh, swamp, lakes, rivers, fen, peatland, coral reef, mangrove, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water with a depth of less than six meters. Wetlands may also incorporate riparian and coastal zones adjacent to the wetlands (RAMSAR Convention 1971).
Wetlands can be extremely vulnerable to damage from humans and their land use practices. It has been estimated that anthropogenic land use change has eliminated 50 percent of the Worlds wetlands since 1900 (OECD 1996). The anthropogenic threats to wetland ecosystems include dumping of waste or water extraction or diversion, conversion to agriculture, residential or other land uses, or overuse of the sensitive ecosystem. Wetlands can also be lost by modifying or damming rivers or building levees. The increasing demand for land throughout history has led to successive draining or infilling of wetland areas, which is continuing to this day, despite our current understanding of the critical role that these ecosystems play in the web of life.
These existent or potentially complete changes to wetlands, possibly irreversible, often have both local and global implications and are some of our most pressing environmental and social issues. Extensive research is necessary to understand the relationships, roles, both physical and social, within, and surrounding wetland loss. Further investigations are needed to implement comprehensive national inventories and developing the appropriate planning and management techniques that can adequately protect wetland resources for the future.Wetlands Loss References:
- OECD/IUCN. 1996. Guidelines for aid agencies for improved conservation and sustainable use of tropical and sub-tropical wetlands. OECD, Paris.
- Ramsar Convention, 1971. International Agreement for the Protection of Wetlands. Ramsar, Iran, 2 February.
The project would like to acknowledge the previous work of Erica Lepers in identifying hotspots, the various sources of information used to summarize the hotspots, all those who provided photos and Enrique Montaño for helping develop the web site.