Consequences of Climatic Change
The consequences of global warming and climatic change are complex. It is difficult to forecast how this situation will affect thus since global climate is a function of physical, chemical, biological and social processes. If a key factor is altered, such as average global temperature, remiation from this change will have far-reaching consequences. Wind and precipitation patterns prevalent since thousands and millions of years could change; sea -level could rise and threaten islands, sea-beaches and low-lying coastal regions. This might result into famines, floods, landslides, avalanches, hurricanes, natural hazards and catastrophes unprecedented in their severity and also large scale migration of human population and plants and animal communities. According to the experts, there are likely regional climate responses expected, such as temperature, precipitation, soil moisture, and air-masses characteristics change.
While scientists are relatively confident that climatic change will lead to higher temperatures, they are less sure of how it will affect precipitation. Some of the possible consequences of climatic change are given in the following:
1. Sea Level Change
As a consequence of climatic change, the sea level may rise by about two to three metres by the end of 21 century. The sea-beaches, sea-ports, coastal urban centres and numerous islands will submerge under water. The worst affected may be the Islands of Maldives and the coral formations of the Pacific and Indian and Atlantic oceans. At present, nearly 50 per cent of the total urban population of the world is residing along the coastal areas that may be submerged under water. The submergence of the coastal urban ecosystems will be a great economic loss to the humanity.
2. Atmospheric Circulation and Changes
The ocean and the atmosphere are an extension of each other. Human activities have changed the atmosphere as well as the oceans. Pollutants injected into the air can have global consequences for the ocean and for all the living organisms on earth. Depending on the change in temperature and salinity of the oceans, the direction, velocity and patterns of ocean currents will also be changed.
Northward Movement of the Inter-Tropical Convergence Zone
The Inter-Tropical Convergence Zone may move northward, bringing more rainfall in the hot-desert of the world. The monsoon mechanism, and origin of tropical and temperate cyclones may become even more complicated. The deserts areas may move northward in the Northern Hemisphere and southward in the Southern Hemisphere. Consequently, the ecosystems (fauna, flora abiotic components) of tropical deserts and semi-deserts will get transformed.
Increase in the number of Tropic
Since the coastal areas will submerge and thereby the area of the oceans will increase, there will be more evaporation. The water vapor and latent heat reaching the troposphere will create favorable conditions for the origin, development and intensity of tropical cyclones. There will be intense rainfall with thunder and lightning in short duration which shall lead to deluges and floods.
Change in the Pattern of Precipitation
The precipitation belts tend to shift pole-ward, because the average temperatures are expected to increase more near poles than near the equator and lower latitudes. If there occurs a change in precipitation in the middle and higher latitudes (temperate zone), it will not be in the form of more rainy days, but rather a decrease in the number of rainy days and increase in the intensity of rain. In fact, the weather will be stormy even in the temperate latitudes. This will cause floods, landslides, avalanches and soil erosion.
Alteration in Vegetation and Soil Belts
The climatic belts and vegetation belts in general overlap each other. With the change in temperature and precipitation regimes, the vegetation belts will also undergo changes. The coniferous forest (Taiga) may push northward in the Northern Hemisphere by about 200 km within the 21st century and same may be the case with the temperate and tropical grasslands.
Change in Cryosphere, Arable Land and Cropping Patterns
In the snow covered and permafrost areas (cryosphere) the reflection of sunï¿½s rays (albedo) is upto 95 percent. The albedo increases the temperature of the atmosphere. Consequently, the snow and permafrost areas are exposed to the sun. Thus, the carbon trapped within the land and soils is released into the atmosphere. Moreover, melting of ice and reduction in snow covered area leads to sea-level rise and climate change. All crops need a minimum and maximum temperature and moisture under which they give optimum production per unit area.
Increase in the concentration of CO2 may enhance crop productivity. In principle, higher levels of CO2 should stimulate photosynthesis in certain plants, especially wheat, rice and legumes by about 30 to 100 per cent. Under the influence of global warming, the proportion of arable land and cropping patterns in Siberia, Canada and USA will change. The climate of these regions will become more favourable for crops like barley, oats, sugar-beet, fodder and pastures (Figs. 7.4 and 7.5).
The expansion of Deserts
Under the conditions of high temperature, there would be more evaporation from land and soils which may result into expansion of deserts and more desertification within the deserts.
The effect on Food Supply
At present, USA and Canada are the leading suppliers of food to many of the developed and developing countries of the world. If the frost free period in Siberia, Alaska (USA), Canada and Scandinavian countries increases, grain sales could shift in the other directions.
Fresh Water Supply
Climate change will have a serious impact on fresh water supply. This will affect the availability, quality, and distribution of fresh water. The impact of climate change on the Earthï¿½s fresh water resources have the potential of affecting the international relations, especially the country borders, where shared wetlands can generate local and international political and geographical disputes.
Increase in Poverty in Developing Countries
About 17 per cent of the total population of the world is below the poverty line. Most of the poor people are living in tropical and sub-tropical - developing countries. The change in climate may threaten their livelihood. In fact, climate change is thus a serious threat to poverty eradication.
Threat to Food Supply
In case of crop failure under the changed climatic conditions the price of food-grains will go up. According to the united nations World Food Programme (WFP) the cost of food production has gone up by about 60 per cent. As a matter of fact, the food supply is becoming increasingly short and expensive.
The effect on Human Health
According to E. Huntington, there is a direct co-relation between the prevailing temperature, humidity and weather conditions and the health and efficiency of people. Under the changed weather and climatic conditions, the health and efficiency of the people in tropical and temperate latitudes may be favourably and/or adversely affected. The land-based animals will have to adapt to changing patterns of available forage.
Impact on International Trade
Generally, the surplus countries supply the agricultural products to the food-deficit countries of the world. If the Siberian region started growing more cereal crops, Russia may become a surplus country in the production of cereals and dairy products. Same may be the case with Northern Canada, Finland, Norway, Sweden, Argentina and Chile. Consequently on the trade relations of international community and the present trade pacts will change.
Written by princy