Global warming is a kind of harmful climatic change resulting from an increase in average temperature of the earth. Global warming has been particularly pronounced since early 1990s and its thought to likely due to the intensification of green house gases which are often released to the atmosphere. Green house gases include majorly carbon dioxide and other oxides of carbon, nitrogen, sulphur, methane chlorofluorocarbons. It has been observed that higher concentration of carbon dioxide in the atmosphere is automatically accompanied by higher temperature.
Also, human activities like the use of firewood to cook, coal, kerosene, stoves and other solid fuels have contributed greatly to the emission of green house gases which cause global warming. Green house gases and other materials emitted to the atmosphere cause global warming where they depleted the ozone layer.
OZONE
Ozone is a bluish pungent gas which is often described as the earth's natural sunscreen because, it normally forms a blanket sheet/layer in the stratosphere where it absorbs the sun solar radiation (Ultraviolet radiation) thereby, reducing the scourging effects of sun on earth. Therefore, ozone acts as the umbrella that protects living things against the harmful effect of the UV radiation of the sun.
Ozone is formed when oxygen molecules (O2) absorbs UV light and split the molecule into individual atoms (O) which then combine with other oxygen molecules (O2) to form a trivalent oxygen(O3) that is referred to as OZONE. Radiation in the form of energy emitted as rays, waves or particles by radioactive substances from nuclear power plant also contribute to ozone depletion also radiation emitted by various electronic devices such as lacers, X-ray machine, colour television set and microwave oven also consume ozone layers.
EFFECTS OF GLOBAL WARMING
The effect of global warming is highly pronounced on biodiversity and ecosystem. Ozone layer in the stratospheric region of the atmosphere acts as a blanket sheet or umbrella that shields life against harmful and deadly effects of UV radiation from the sun. This shielding prevents and protects living organisms from the scourging effects of exposure to solar UV radiation. This scourging effects in most organism comes in form of pains or discomfort, disease and even death. Anything that cause destruction to the ozone layer automatically create avenue for the penetration of UV radiation down into the earth thereby causing unbearable warming. The spread of this intensive warming across all continents of the globe result in what is known as GLOBAL WARMING.
The adverse consequence of global warming is a change in climate which causes rise in temperature. Rise in temperature causes rise in sea level which forces hundreds of millions of organisms around the world to be exposed to increased water stress, decreased air quality, increased oceanic acidification leading to massive destruction of marine life. A thin layer of ozone indicate that more UV radiation is reaching the earth surface and which causes a great danger to the environment because, it may cause unfavourable alteration to the ecosystem and climatic condition.
Ecologically, global warming affects both terrestrial and aquatic ecosystem thereby altering growth, reproductive and distribution pattern of many floral (plant) and fauna (animal). Global warming also has a negative impact on farming and fisheries. It increases the livelihood and severity of wildfire and mortality rate resulting from drought and heat waves. Hurricanes and cyclones are empowered by warm water on the surface of the ocean. Thus, as global warming heat the water surface, hurricanes and cyclones increase in speed, power and severity. Severe and powerful cyclones most often leads to crop damage, power outage increase the risk of food and water borne diseases, population migration and loss of properties.
Both the biotic and abiotic components of an ecosystem are tempted by global warming i.e producer (green plant) use the sun's energy and some inorganic nutrients to manufacture foods. However, exposure of these plant to high UV radiation destroy the mesophyll tissue of the leaves which are responsible for the photosynthetic activities of these plants. Aquatic life occurring just below the surface of water where plants species forming the basis of food chain are mostly abundant, they are also affected by increasing levels or UV radiation in terms of growth, reproduction and distribution pattern. Also, increase in carbon dioxide causes acid rain which may lead to acidification of the soil all of which have adverse effect on forest vegetation including land crops and aquatic lives.
On human health, ozone depletion causes increased UV radiation level at the surface of the earth. These results in increased incident of certain type of skin cancer, cataract, immune deficiency disorder, clouding of eye lens resulting in blurred vision. Ozone depletion also causes severe sun burn, chest pain, respiratory and cardiovascular diseases, throat inflammation and decreased resistance to infectious diseases.
MEASURES TO REDUCE GLOBAL WARMING
Any measure to reduce global warming should be first geared towards protecting the ozone layer from being depleted and to protect the ozone layer, all efforts must be directed towards reducing the release or emission of toxic or harmful materials into the atmosphere. These measures are;
- Industries and factories should incorporate processing unit that will help to clear up their effluents before being discharged into the environment.
- The ban on used refrigerator and air conditioner which contain chlorofluorocarbons should be strictly enforced and when these products are faulty, the technicians repairing them should ensure that they recover and recycle the old chlorofluorocarbons so that they are not released into the atmosphere. Also, vehicle air conditioning unit must be regularly checked for detection of leakages.
- Importation of second hand vehicles popularly called 'Tokunbo vehicles' that are above 8years old should be banned. This is because these used vehicles release pollutants like carbon dioxide, sulphur dioxide, and other oxides of hydrocarbon into the atmosphere where they destroy ozone layer.
- Irregular power supply has prompted many residence to turn to the use of generator, diesel fired electricity generator whose thick and dark smoke containing carbon dioxide contribute greatly to destroy ozone layer.
To reduce these problems, efforts must be geared by government to ensure constant and uninterrupted power supply so as to reduce importation of generators. - Farmers especially the illiterates ones should be enlightened on the moderate application of nitrogen-base fertilizer which are responsible for substantial increase in the release of oxides of nitrogen from the soil into the atmosphere where they damage the ozone layer.
- Forest clearing, bush burning and fossil fuel combustion are the major sources of carbon dioxide emission which contribute to the planetary green house effects. These gases especially carbon monoxide(CO) often raise the planetary surface temperature to about 40°c which may be harmful to the environment especially to living organisms. Thus, deforestation in the form of bush burning, tree felling and forest clearing should be discouraged.
- Also, the use of cooking gas and stove should be encouraged especially among village people so as to discourage the uncontrollable use of forest trees as firewood.
REFERENCES
Global warming: Definition, facts, causes and effects
Ozone: Definition, properties, structure