Though climate change is a global phenomenon and no region of the world will be free of its impacts, the negative impacts are likely to affect developing nations especially those in the tropics. This post is a review on evidences of climate change impacts in Nigeria. Our findings indicate a rise in mean temperature (warming), reduction in amount of rainfall, desert encroachment, coastal floods, drying up of surface waters, and low agricultural productivity. In view of the negative impacts of climate change, there is the need to reduce greenhouse gas and take up adaptive measures.
Climate change can be defined as changes in the climate system that are attributable to human activities that alter the atmospheric composition of the earth and balance of the equilibrium between the natural greenhouse gases (GHGs) ultimately lead to global warming. Natural greenhouse gases are carbon dioxide (CO2), chlorofluorocarbons (CFCs), Methane (CH4) and nitrous oxide (N20) among others; whereas man-made GHGs include sulfur hexane fluoride-(SF); hydro-fluorocarbons-(HFCs); and perfluorocarbons (PFCs).
These activities either increase greenhouse gas emission or reduce earth’s ability to absorb the greenhouse gases. Some of these activities include: deforestation, urbanization, burning of fossil fuel, gas flaring, etc. In other words, the increased volume of CO2, and other GHGs released from the burning of fossil fuels, deforestation, agriculture and other human activities are sources of global warming that have occurred in the last four to five decades.
These human activities, contribute to alter the balance of the equilibrium between the natural GHGs ultimately lead to global warming. The increase of these gases in earth’s atmosphere promotes warming of both the atmosphere and the oceans since they are heat-trapping gases.
Global warming is the term used to describe the gradual increase in the average temperature of earth’s atmosphere and its oceans.
According to available reports, if the current trend of GHG emissions continues through 2030, the earth is likely to experience an average rise in temperature close to 5°C. This warming would impact earth’s environmental stability in various ways including: temperature rise, rainfall unpredictability, low-level harvests of crops, changes to land cover/vegetation, melting of polar ice-caps which will result in sea level rise that could lead to floods in coastal areas. These have severe implication for fresh water resources (fishes, etc.), agriculture, and food security, energy generation etc.
Farmers in Nigeria cultivate both annual and cash crops. Some of the annual crops include yam, cassava, melon, rice, onions, pepper, groundnuts, plantain, vegetables, etc. The cash crops include oil palm, cashew, cocoa, mango, rubber, coconut, cotton, pineapple, pawpaw, etc.
These crops depend on rainfall. Crops that require much rain are planted in the southern parts of the country where rain is abundant; whereas, crops that do not require much rain are cultivated in the northern part of the country.
Unfortunately, food production in Nigeria fails to keep pace with the country’s growing population. Climate change affects crop production in a number of ways. For example, uncertainties and variation in the pattern of rainfall, floods and devastated farmlands, adversely affects crop yield.
Available reports show that if the current trend of GHG emissions continues unchecked for the next ten years, the country (and the whole earth) would likely experience a rise in temperature of up to 4.5°C.
The rise in temperature would adversely affect crop yield because high temperatures smother crops. Furthermore, the temperature rise would result in melting of polar ice-caps, rise in sea level that could lead to coastal floods which further reduces crop yield.
All of these have grave implication for agriculture and food supply.
Global warming with regional variations has capacities for increases and decreases in rainfall, resulting in floods, and droughts, melting of polar ice-caps, thermal expansion, surges and acidification.
Irregular and unpredictable rainfall and sunshine hours has been largely responsible for the recently recorded low level harvests of rice, maize, cassava, melon, sorghum and yam.
Extreme weather conditions such as drought and floods feature prominently in the Northern region of the country. These affects crops, farming and harvests as well as livestock production since the feed are mostly crop-based.
Flooded farmlands cause arable land losses for cultivation and thus reduce root/tuber crops harvest (yam, cassava, sweet potatoes, etc.)
Climatic change has adversely affected feed, water intake, grazing time and hence rate of growth and productivity of livestock.
High temperatures have hindered livestock (sheep, and goat, cattle, poultry and piggery) production through reduced grazing land, retarded reproductive cycles, reduced meat and milk outputs, as well as their grazing lands.
Livestock mortalities have increased in poultry, piggery and rodentary production systems to the level of at least 15% per annum.
We are witnessing a nationwide flooding of fish ponds especially those sited in wetlands and farmlands. Flooding and erosion of Nigeria’s coastal areas and consequent losses of income are some of the effects of climate change on the population areas of Ondo, Bayelsa, Rivers, Akwa Ibom and Cross River States).
More than seventy percent of Nigeria’s population is engaged in agriculture as their major occupation and means of livelihood. Furthermore majority of them are small-scale, resource-poor farmers operating less than five hectares using traditional technologies.
Consequently, Nigeria’s agricultural activities are dependent on rain, and the farmers rely heavily on rainfall which is becoming increasingly unpredictable. Climate change and its attendant effect have brought untold hardship and crises to farmers.
Floods that occur with sea level rise sometimes with heavy rainfall become the cause of road tracks flooding, house losses, public health hazards and losses of potable water owing to saltwater intrusions into wells. This often results in farmland losses and population displacements and ultimate livestock mortalities.
Part of the impact of climate change in Nigeria is the loss of forest resources such as: medicinal plants, mushrooms, cane, etc. The loss have been directly attributed to storm surges, felling of trees and forest exploitation (including firewood procurement) which has been proceeding in Nigeria at the annual depletion rate of higher than 400, 000 hectares.
Nigeria, at present does not enjoy food security and therefore is more vulnerable to the effect of climate change. Climate change-induced threatens to food security in the the following ways:
a. Extreme weather events, e.g. drought, floods and erosion, all of which pose danger to farmlands and fisheries resources often become inundated with the intrusions of seawater with drastic salinity changes
b. Variability in the onset and cessation of rainfall and rainfall amounts, effects of high temperature which hinder livestock and fisheries production, reduce weight gains.
c. Proliferation of pests and diseases affecting agricultural production
Climate change impact on the farming communities in Nigeria has had to do with population displacements and relocations with immediate village abandonment (usually occasioning farmland losses) and hence farm occupation decline. At least, 32,000 farmers are affected annually in Nigeria’s farming communities.
Hydro electric power generation is most likely to be affected by climate change. It is sensitive to the pattern, amount, and timing of rainfall as well as temperature.
Low rainfall and high temperatures reduce energy generation and transmission capabilities of hydro-electric power stations nationwide.
Excessive drought adversely affects water volume and causes reduction in hydroelectric power generating capacities.
In view of the negative impacts of climate change, it is necessary to come up with strategies for limiting and adapting to the negative impacts of climate change in Nigeria.
There is the need for government, development partners, and private stakeholders to come together and make efforts towards mitigating the negative impacts of incessant climate change on the environment and the livelihoods of Nigerians.
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