- Global Warming is defined as the increase in the average global temperature of the earth’s atmosphere due to increased greenhouse effect, mainly due to human activities like burning of fossil fuels, deforestation, etc.
- The average global temperature is 15°C due to the normal greenhouse effect, to sustain life-forms on earth.
- The concentration of major greenhouse gases – carbon dioxide, water vapours, methane, nitrous oxide, chlorofluorocarbons (CFCs) have significantly increased over the past years in the earth’s atmosphere.
- These greenhouse gases, in turn, trap more incoming radiation containing heat and thus raise the average temperature of the earth’s atmosphere beyond 15°C.
- Change in the average temperature of the earth by 2°C over the next few years may prove detrimental for many living beings on earth including humans and may threaten their survival.
The contribution of major greenhouse gases to global warming and their sources are
Impact of Global Warming on Human Communities and Agriculture
Major ill-effect of global warming on humans’ are:
- Change in rainfall pattern, which in turn, may affect distribution of vector borne diseases and emergence of vector borne diseases like malaria, filariasis, elephantiasis etc. in new places like Ethiopia, Kenya and Indonesia & rise in global infectious diseases.
- Increase in heart problems, skin and respiratory diseases, especially affecting the vulnerable group of the population – elderly, sick and children.
- Abnormally high temperature variations due to heat waves, especially in tropical and subtropical regions. Sea level may rise by 0.2-1.5 meters due to a 3°C rise in average atmospheric temperature over the next 50-100 years.
- Rise in sea level due to melting of polar ice will cause flooding in low lying areas around the world and the livelihood of people living in those areas will be severely affected.
- Frequent drought and floods.
- Increase in forest wildfires and loss of biodiversity.
Impact on Agriculture
There are different views regarding the effect of global warming on agriculture. It may show positive or negative effects on various types of crops in different regions of the world.
- The crop yield will be reduced due to less growth period, due to more temperature and carbon dioxide which will also deteriorate the crop quality in terms of its sugar content, coloration, etc.
- Reduced nutritional value due to increased carbon dioxide levels in the atmosphere which reduces the concentration of protein and essential minerals in most plant species, including wheat, soybeans and rice.
- Drought and flooding will severely damage agricultural productivity and thus may cause food insecurity, especially for agriculture dependent and poor countries.
- Extreme weather events including heat waves may harm crops and reduce crop yields.
- Land fertility will degrade due to reduced soil moisture, accelerated decomposition of organic substances and increased soil erosion, which may affect wheat and maize production.
- Agriculture in tropical and subtropical regions will be affected badly because of the already higher temperature as compared to other regions.
- Increased weeds, pests and fungi may reduce crop productivity.
- Drought resistant, heat resistant and pest resistant varieties of crops need to be developed to enhance food production and thus ensure food security.