Published on International Journal of Forestry & Plantation
Publication Date: September, 2019
Isese, M. O. O.
Forestry Research Institute of Nigeria
P.M.B Jericho Hills, Ibadan, Nigeria
Journal Full Text PDF: Deforestation and its Health Implication.
Deforestation gives rise to climate change which negatively impact on the immediate environment and health of human. Sub-Saharan African countries are experiencing population growth most especially Nigeria which has led to uncontrolled and unsustainable exploitation of natural resources, especially the forests resources. Through the process of tree falling, deforestation has alters every element of local ecosystems most especially temperature changes which has negative effects on health. Deforestation is associated with life threatening consequences such as global warming and climate change, this is because trees produce oxygen which humans depend and any attempt to remove trees without replacement could lead to negative implications. Between 1990 and 2015, Nigeria lost over 17 million hectares of forest and other wooded land area, with an average annual loss of 3.5 percent for forests and 5 percent for wooded land areas, due to agricultural encroachment, infrastructure development, excessive official and unofficial logging, firewood collection, and urbanization (FAO 2015). Over 90 percent of Nigeria’s forest has been lost to deforestation. Over 70% percent of Nigerians still live below poverty line which encourages more of deforestation activities.
Keywords: Deforestation, Health, Climate change & Diseases.
Deforestation has been found to lead to heightened health risk through both ecological and socio-economic mechanisms. Relative to forests, deforested lands have higher temperatures (Lindblade, 2000), more sunlight (Yasuoka and Levins, 2007), and more standing water (Patz et al., 2000), resulting in accelerated life cycles (Afrane et al., 2005). Relative to forests, cleared lands also have fewer insectivores, more species competing for ecological niche, and arguably fewer “dead-end hosts” to dilute malaria (LaPorta et al., 2013, Wood et al., 2014). Additionally, “frontier malaria” can result from unstable socio-economic conditions commonly associated with deforestation, including rapid in-migration, new human exposure (e.g., Friedrich, 2016) and low immunity, poor housing quality, and sparse availability of health services, (de Castro et al., 2006). Singer and de Castro (2006) suggest that these “frontier malaria” effects last for 6-8 years. Deforestation alters every element of local ecosystems such as microclimate, soil, and aquatic conditions, and most significantly, the ecology of local flora and fauna, including human disease vectors 11 . Of all the forest vector species that transmit diseases to humans, mosquitoes are among the most sensitive to environmental changes because of deforestation: their survival, density, and distribution are dramatically influenced by small changes in environmental conditions, such as temperature, humidity, and the availability of suitable breeding sites (Marten, 1998).
According to the Union of Concerned Scientists (2013), tropical deforestation accounts for about 10 percent of the world’s heat-trapping emissions. They reported that tropical deforestation contributes about 3.0 billion tons of CO2 a year to global warming pollution (Union of Concerned Scientists, 2013).
Health is the total wellbeing of any individual; it refers to a perfect functioning of all the body organs. However, the ultimate impact of deforestation is on human health. Social and economic
implications are not left out. For instance, deforestation increases the vulnerability to landslides which are capable of causing loss of lives and property. Health is an inevitable requirement for optimal functioning. Without health nothing can be achieved.
Despite the high rates of health related issues associated with deforestation in Nigeria, the relationships between the two challenges have not been comprehensively elucidated. The objective of this report therefore is to evaluate the relationship between deforestation and health in Nigeria with the view to providing information that has health remedial policies and sustainable forest resource management in Nigeria.
2. Deforestation a transmitter of diseases in Nigeria
The world’s forests cover almost four billion hectares or about 31 percent of the land surface. They are a source of timber and food, provide habitat for numerous species, and supply essential ecosystem services such as climate regulation, filtration of water, and protection of soils. While the annual rate of global deforestation has slowed since its highest of 16 million hectares in the 1990s, it is still high in many regions. Nigeria has experienced one of the greatest net losses in Sub-Saharan Africa. Between 1990 and 2015, Nigeria lost over 17 million hectares of forest and other wooded land area, with an average annual loss of 3.5 percent for forests and 5 percent for wooded land areas, due to agricultural encroachment, infrastructure development, excessive official and unofficial logging, firewood collection, and urbanization (FAO 2015). Uncoordinated land use policy, weak enforcement and inadequate funding of existing conservation policies and programs, as well as poor data quality (the last national forest inventory dates back to 1997) remain the major impediments to forest conservation (Usman and Adefalu 2010). Figure 1 presents our estimates of tree loss in Nigeria between 2000 and 2012.
At the same time, Nigeria is home to one-fifth of Africa’s population with some of the highest disease burdens on the continent. Despite significant progress in health outcomes since the 1990s, in 2013 the under-five mortality rate remained at 117 deaths per 1,000 live births and there were 560 maternal deaths per 100,000 live births (WHO 2015). Among children under five, 21 percent of deaths are attributed to malaria, 15 percent to acute respiratory infections, and 10 percent to diarrhea.
The direction of the impact of environmental degradation such as tree loss on the incidence and severity of infectious diseases is not clear a priori. Forests and wooded areas are a source of fuel for more than 50 percent of Nigeria’s population that relies on solid biomass for cooking. Forests regulate temperature and rainfall that affect the breeding and survivorship of malaria-carrying vectors.
3. Deforestations in Nigeria: Causes and Implication
Deforestation is inevitable when about 90% of a population is depending on wood as fuel for cooking and heating. Poor agricultural practices such as slashing and burning also contribute to deforestation (Terminski 2012). Study shows that about 60% of Nigerians use firewood for cooking because of the high cost of kerosene (Akinbami 2003). Some persons ignorantly set fire on forests thereby contributing to deforestation. According to FAO, developing countries from the tropics suffer most from deforestation between 2000 and 2005.
This suggests a relationship between poverty and deforestation. Poverty induced human activities are the major causes of deforestation in Nigeria (Terminski 2012).
Corruption is a serious issue in Nigeria and contributes immensely to illegal logging by companies and forest officials (Global witness 2013). Activities of illegal logging lead to deforestation. According to Goncalves, Panjer, Greenberg & Magrath (2012), an area of forest about the size of a foot ball field is clear-cut by illegal loggers every two seconds. Illegal trading in timber and its products lead to massive economic losses and environmental damages (Transparency international 2011).
The rising demand for wood products has made the forestry lucrative and this invariably promotes illegal logging (Transparency international 2011). Logging is said to be the first threat to existing tree population (Effects of Deforestation, 2010). Corruption is also observed at the level of government institutions, wealth and power due to harvesting of forest riches. Unfortunately all these are done on the platform of short term economic benefits (Effects of Deforestation, 2010). Lack of integrity in the judiciary to check illegal logging further promotes deforestation (Transparency International 2011).
Poverty is also a strong factor in the issue of deforestation. Poverty leads to the felling and burning of trees for fuel. Charcoal produced from the burnt trees is sold for money to make ends meet. At the other hand, the felled trees are also sold as timber; cleared land is used as pasture for livestock, plantations of communities and settlements (Terminski 2012). Increasing growth in population and demographic pressure contributes immensely to deforestation processes in Nigeria (Effects of Deforestation, 2010). The most populous country in Africa is Nigeria with the population rate of 162.5 million (World Bank, 2011).
This becomes a serious problem when increasing population combines with the high level of poverty. About 70 percent (105million) of Nigerians are now living below the poverty line (Central Intelligence Agency (CIA) 2012, Sanusi, 2011). Overpopulation causes a corresponding increase in the construction of residential and public areas. This causes the soil to become loose and more susceptible to the possibility of running off and flooding (Effects of Deforestation, 2010). The outcome can be devastating. United Nations Environmental programme (UNEP) posited that Africans are suffering deforestation at the rate of two times of that of the world.
Urbanisation process is another strong factor in the issue of deforestation. Lack of awareness on the adverse effects of deforestation has caused the destruction of over 8,5 million hectares of tropical forest permanently yearly for the construction of buildings and new urban areas. This leads to uncontrollable and continuous destruction of forest resources. In Nigeria, 81% of the original forest cover is removed (Effects of Deforestation, 2010). Other causes of deforestation in Nigeria include clearing of forest for logging, agricultural activities, felling of trees by rural dwellers for sales as a means of sustenance due to poverty and using of trees as wood for fuel which causes serious damages with an end result of desertification.
Fig 1: Map showing the forest classification of Nigeria
4. Effect of Deforestation on Temperature Change: Health Trend
Trees serve as cover to the soil thereby protecting the variety of life existing in it from extreme temperatures. They serve as carbon sink by absorbing CO2 which is a potent greenhouse gas that causes global warming. It is alarming that despite the importance and contribution of forests to global warming and climate change mitigation, many forests are being converted to agricultural lands, for industrialization and so on. This deforestation activities increase the amount of CO2 released into the atmosphere directly and indirectly. Directly in the sense that, all the uses except lumbering for which the products of deforestation (such as wood) are used release CO2 and sometimes CH4 (in the case of decay) into the atmosphere. Deforestation increases the amount of CO2 indirectly in the sense that there is greenhouse gas absorption deficit resulting from fewer carbon sinks thereby causing a surplus of CO2 emissions. Canziani and Benitez, (2012) investigated the climate impacts of deforestation/land-use changes in Central South America in the PRECIS regional climate model. They concluded from their research that for temperature, significant changes are found within deforested areas and beyond, with major temperature enhancements during winter and spring. Mi Zhang et al., (2014) reported in their research that along the North – South Transect of Eastern China (NSTEC) in Eastern China, deforestation caused cooling at the Changbaishan temperate mixed forest (CBS site) pair and warming at the subtropical and tropical site pairs.
They inferred that deforestation increased the diurnal temperature range (DTR), especially in the temperate area. They also reported that precipitation was an important driver of the latitudinal and inter-annual variations in the deforestation effect.
Fig 2: The effect of deforestation with respect to temperature on Climate change.
There is a law that borders on conservation and protection of forests. This law should therefore be properly implemented and enforced to the law with proper policing and monitoring and stringent punishment.
Afforestation and Reforestation programmes with incentives should be organized to recuperate the dwindling forests.
Moderate Resolution Imaging Spectrometer (MODIS) should be launched onboard Nigeria’s satellite so as to enable the monitoring of deforestation and necessitate quick action in case of unlawful deforestation.
Forest conservation efforts in Nigeria should focus on management interventions to secure the many values of standing forests, including carbon storage, biodiversity habitat, clean water provision, food provision, and other aspects of health.
More studies using advanced models should be carried out to investigate the actual impact deforestation has on global warming/temperature increase and climate change in Nigeria.
The problem of deforestation in Nigeria increases at an alarming rate and is fast becoming a major threat to human health. Immediate intervention measures are necessary to prevent it from getting worse. The role of forestry communities in forest management is presently almost non-existent in most parts of Nigeria. Communities around the forest should be empowered to ensure that the forest recourses are preserved. This strategy have the possibility of limiting the rate of tree cutting which can ultimately reduce all the effects of deforestation which include climate change, global warming, emission of carbon dioxide and monoxide, soil erosion, air and water pollution.