Climate Change is a shift in the “average weather” that a given region experiences.
This is measured by changes in all the features we associate with weather, such as temperature, wind patterns, precipitation and storms. Global
climate change means change in the climate of the earth as a whole. Global change does occur naturally, the ice age is an example. The Earth’s natural climate has always been, and still is, constantly changing. The climate change we are seeing today differs from previous climate change in both its rate and its magnitude.
The temperature on earth is regulated by a system known as the “greenhouse effect”. Greenhouse gases primarily water vapour, methane, carbon dioxide and nitrous oxide traps the heat of the sun, preventing radiation from dissipating into space. Without the effect of these naturally occurring gases, the average temperature on the earth would be -18°C, instead of the current average of 15°C.
The cause of these increases has been human activities related to our increasingly sophisticated and mechanized lifestyle, in particular the burning of fossil fuels such as coal, oil and natural gas to generate electricity and in factories and cars. As well, we have the past 100 years than in all of prior human history. This has resulted in the loss of forests and wetlands, which absorb and store greenhouse gases and naturally regulate the atmosphere.
Raising the global temperature may trigger a series of changes within the overall global climate system. For instance, global sea levels have rise 10 – 25 on over the past 100 years, and are expected to continue to rise due to increase in temperature. We are also seeing in increases in severe weather events. Such impacts of climate change could have far-reaching and/or unpredictable environmental, social and economic consequences. Indeed, the climate change problem and the related changes it may bring about are among the most serious of the environmental issues that we face today.
Potential Impact of Climate Change. Around the world, climate change is projected to:
· Threaten the world’s boreal forests with an increased fire risk because of the drying climate;
· Cause water needs to outstrip supply;
· Cause severe water loss due to changes in evaporation and precipitation patterns;
· Cause flood damage to low-lying countries and islands states, including loss of coastal land to rising sea levels;
Global warming is neither temporarily nor spatially uniform. Warming will be more intense over land than sea and will be particularly marked in the high northern high latitudes in winter. The energy gradient from equator to pole will also diminish.
Agriculture vs. Climate Though there is no definite evidence to show any direct impact of changes in climatic parameters on Indian agriculture, some trends would affect food production considerably. The recent IPCC report indicates high probability of food losses with increase in temperature in the tropical regions. Studies do confirm this trend, though there is considerable disagreement on the magnitude of loss.
Among cereal crops important for food security, wheat is most sensitive to even small increases in temperature. Relatively, rice has greater tolerance to temperature increases. It is, however, possible for farmers to adapt to a limited extent and reduce the losses. Increasing climatic variability cloud, nevertheless, result in considerable seasonal/annual fluctuation in food production. All agricultural commodities are sensitive to such variability.
Glacier retreat
Glaciers have been retreating world wide and average global temperatures are expected to rise between 1 – 4 and 5.8°C by the end of 21st Century. Simulation projects that a 4°C rise in temperature would cause nearly all the world’s glaciers to melt. These glaciers are extremely important because they are susceptible to climatic changes and their directly loss affects human population and ecosystems. Continued and widespread melting of glaciers during this century will lead to floods and water shortages for millions of people. As sea levels rise, coastal communities and habitats will destroyed.
It is projected that global warming will cause sea level to rise by as much as 5mm per year over the next 100 years. This rise threatens entire notions on low-lying islands in the Pacific and Indian Oceans. The rise in temperature will lead to more absorption of heat from atmosphere by seas causing them to expand and rise.Glacier melting has accelerated in Alaska, Northern Andes and in European alps (loss of 10-20% ice in last two decades) and in India too.
Coral Reefs Bleaching
Coral reefs are extremely important for biodiversity providing a home to 25% of all marine life. They provide nurseries for many species of commercially important fish and protect coastal area from storm waves and are significantly important for tourism industry. However, they are very fragile ecosystems that can tolerate only a narrow range of temperature.
Health
The most direct effect of climate change would be the impacts of hotter temperatures themselves. The number of deaths under extreme temperature conditions increases due to many reasons. People with heart problems are vulnerable because one’s cardiovascular system must work harder to keep the body cool during hot weather heat exhaustion and some respiratory problems increase. According to doctors the global warming could mean more cardiovascular diseases. Higher air temperature also increases the concentration of ozone at ground level, which acts as a pollutant in the lower atmosphere. Ozone damages lung tissue, and cause particular problems for people with asthma and other lung diseases.