Recently, the issue of Climate Change has been explored in sub-Saharan countries even though it appears to have no widespread impact in these countries. Climate change means big changes in the Earth’s weather patterns over time, including temperature, rain, wind, and more. It’s mainly caused by things people do, such as burning fossil fuels (coal, oil, gas), cutting down trees (deforestation), and industrial activities. These actions release bad chemicals into the air, like carbon dioxide, methane, and nitrous oxide. These chemicals trap heat and make the earth get warmer, resulting in a phenomenon called the Greenhouse effect.
One key element of this change is global warming. The average temperature of the globe has gone up a lot in the last 100 years, especially in the polar regions. It also results in extreme weather. There are more frequent and intense natural disasters like hurricanes, heatwaves, droughts, and heavy rainfall. Then, there are the melting ice and expanding seawater which cause sea levels to rise, threatening coastal areas and ecosystems. As well, climate changes disrupt the natural balance, affecting where species live, when plants grow, and putting many species at risk of extinction.
Sector at risk from rising temperatures and acidification.
Nigeria, as part of the global community, is not immune to the impacts of this occurrence. The country’s climate ranges from the arid north to the tropical rainforest in the south. This makes it particularly vulnerable to a variety of climate change effects. An example is in the fisheries sector which is essential to the country’s economy, food security, and livelihoods, especially in coastal and riverine communities. Climate change severely threatens this sector, affecting fish populations, habitats, and the overall Sustainability of fisheries. Rising water temperatures alters fish metabolism, growth rates, and reproductive cycles. Warm-water species may benefit from higher temperatures up to a point, while cold-water species may suffer. For instance, tilapia, a popular fish in Nigeria, may experience faster growth but also higher susceptibility to diseases in warmer waters.
As a result, fish species may migrate to cooler waters if temperatures exceed their tolerance limits. This can lead to shifts in species distribution. Local fisheries that rely on specific fish populations will be affected this way. Coastal and estuarine fisheries might witness a decline in traditional fish stocks as species move deeper or farther from shore. Further, increased carbon dioxide (CO₂) levels lead to ocean acidification, which affects shell-forming species such as oysters, clams, and certain types of plankton. Acidic waters hinder Shell formation and reduces the survival rates of these species. Shellfish are important both ecologically and economically in Nigeria, particularly in the Niger Delta region where they are a staple food source and income provider.
Droughts and reduction in water may occur as a result.
Again, ocean acidification impacts the availability of plankton, a primary food source for many fish. A decline in plankton populations can disrupt entire marine food webs, leading to lower fish production. Then, one must consider changes in precipitation and hydrology. Increased rainfall and extreme weather conditions cause flooding and lead to higher sediment loads in rivers and coastal areas. Sedimentation can smother fish habitats, reduce water quality, and impact breeding grounds. For example, flooding in the Niger Delta not only damages Infrastructure but also alters the delicate balance of freshwater and saltwater ecosystems, such that species like catfish and shrimp are affected.
Still, the phenomenon causes droughts and reduced water availability. Droughts reduce water levels in rivers, lakes, and reservoirs. This impacts fish habitats and reduces the availability of aquatic plants and insects that fish feed on. Lake Chad, once a thriving fishing ground, has dramatically shrunk. The livelihoods of communities dependent on its fish resources are severely affected. Rising sea levels and Coastal Erosion are other areas of impact. They threaten mangrove forests, which are vital nurseries for many fish species. Mangroves also protect coastlines and support biodiversity. In the Niger Delta, mangroves provide essential habitat for fish species like the West African croaker. The loss of mangroves due to sea-level rise and human activities undermines fish populations and the resilience of coastal fisheries.
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Intrusion of saltwater into freshwater systems due to sea-level rise and reduced river flows can alter the salinity of estuaries and rivers, affecting fish that are not tolerant of higher salinity levels. This salinization impacts freshwater species and can lead to a decline in fish stocks that are vital for inland fisheries. Essentially, many Nigerian communities, particularly in coastal and riverine areas, depend on fisheries for their livelihoods. Climate change-induced declines in fish populations threaten these communities’ Economic Stability and food security. Fishers need to adapt to changing conditions, which may require new fishing techniques, equipment, and knowledge about different fish species. This transition can be costly and challenging, especially for small-scale fishers with limited resources.