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Impacts of climate change

Climate change is a threat to mankind! Since the end of the 19th century the earth's average surface temperature has increased by 0.3-0.6 °C. Over the last 40 years, the rise has been 0.2-0.3 °C. Recent years have been the warmest since 1860, the year when regular instrumental records became available.

Some important aspects of our lives can be affected through changes in weather patterns and some of these are discussed here.

The steadily-increasing human population has led to a rise in the demand for food. As more land comes under agricultural cultivation there will be more pressure on natural ecosystems. Climate change will affect agricultural yield directly because of alterations in temperature and rainfall, and indirectly through changes in soil quality, pests, and diseases. In particular, the yield of cereals is expected to decline in India, Africa, and the Middle East. As the temperature rises conditions will become more favourable for pests such as grasshoppers to complete a number of reproduction cycles thereby increasing their population. In the higher latitudes (in the northern countries) agriculture will benefit with the rise in temperature as the winter season will be shorter and the growing seasons longer. This will also mean that pests that will move towards the higher latitudes as the temperatures rise. Extreme weather conditions such as high temperature, heavy rainfall, floods, droughts, etc. will also affect crop production.

A warmer climate will change rainfall and snowfall patterns, lead to increased droughts and floods, cause melting of glaciers and polar ice sheets, and result in accelerated sea- level rise. Rising warmth will lead to an increase in the level of evaporation of surface water; the air will also expand and this will increase its capacity to hold moisture. This, in turn, will affect water resources, forests, and other natural ecological systems, agriculture, power generation, infrastructure, tourism, and human health. An increase in the number of cyclones and hurricanes over the last few years has been attributed to changes in temperature.

Sea level rise
Coastal areas and small islands are among the most densely-populated parts of the world. They are also the most threatened because of rises in sea level that global warming may cause. The heating of oceans, and melting of glaciers and polar ice sheets, is predicted to raise the average sea level by about half a metre over the next century. Sea-level rise could have a number of physical impacts on coastal areas, including loss of land due to inundation and erosion, increased flooding, and salt-water intrusion. These could adversely affect coastal agriculture, tourism, freshwater resources, fisheries and aquaculture, human settlements, and health. Rising sea levels threaten the survival of many low-lying island nations, such as the Maldives and Marshall Islands.

There could be large decreases in the availability of water in many rivers because of rainfall and snow. The volume in others would increase due to glaciers melting, for example, the rivers originating in the Himalayas. Shifts in water availability could also affect hydropower generation, and industries such as paper, pharmaceutical, and chemical manufacturing, that use large quantities of water. Buildings and other infrastructure would be vulnerable to any increase in the frequency of storms and other extreme events, which could also disrupt transport routes.

Global warming will directly affect human health by increasing cases of heat stress.

Forests and wildlife
Ecosystems sustain the earth's entire storehouse of species and genetic diversity. Plants and animals in the natural environment are very sensitive to changes in climate. The ecosystems that are most likely to be affected by this change are the ones in the higher latitudes, the tundra forests. Polar regions will feel the impact of warming more than others. Interiors of continents will experience more warming than the coastal regions.

National parks are supposed to provide a sanctuary to wildlife from the ravages of humankind on nature. But no park boundary or conservation law can protect an ecosystem from climate change. A recent report by the WWF (The World Wide Fund for Nature) states that this invisible killer has entered the most cherished natural areas. The giant pandas of Wolong in China, the grizzly bears of America's Yellowstone National Park, and the tigers in Kanha National Park in India are some of the animals at risk from global warming. Mountain parks have been identified as being especially at risk from the environmental destruction caused by climate change. Species that live in the higher alpine zones, are forced to move higher up to find a suitable habitat thus reducing the area in which they can live. If the rate of climate change continues to accelerate, then the extinction of some mountain plants and animals is certain.

Migratory birds fly from the cold northern parts of the world to the warmer south. Factors such as the weather and food sources along the route are very important for the successful completion of their journey. Changes in climate may bring about a shift in their feeding points and disruptions to their flight patterns.

Marine life
Corals are known as the tropical forests of the oceans and sustain diverse life forms.

As ocean waters in the tropics become warmer, the damage to coral reefs seems to be increasing. These corals are very sensitive to changes in water temperature, which causes bleaching. Large stretches of the Great Barrier Reef in Australia have been damaged by bleaching.

Zooplanktons, small organisms that float on the sea surface are declining in numbers, reducing the number of fish and sea birds that feed on these organisms.

There is still a great deal that we do not understand about our climate, and about how our activities will change it. But one thing can be said loud and clear: if we wait to get answers to these questions, it will probably be too late!

Recent revelations on Global warming affecting India……

A new report by the country’s scientists has revealed that India has almost consistently experienced more than normal annual mean temperatures for the past 14 years, with 2006 being the warmest recorded so far. The statistics contained in the “Annual Climate Summary 2006”, a report produced by the National Climate Centre Office of the Additional Director General of Meteorology (Research) Meteorological Department, Pune revealed warming at the rate of 0.48 degrees Celsius over 100 years.The report clearly demonstrated that since 1993, there had not been a single year when annual mean temperature was less than the normal, remaining towards the higher side for all the years. Records show that prior to 1991, the annual mean temperatures were more than the normal in some years while in others, these were less than normal. Between 1901 and 1941, annual average temperatures were below normal for many years while since then, years with annual average temperature anomalies towards the higher side of the normal became more frequent. The year 2006 was the warmest year on record since 1901, according to the report. It was characterized by annual mean temperature over the country as a whole being 0.59 degrees celsius above the average calculated during 1961-1990.Minimum temperatures were more than two degrees Celsius above normal over northern parts of the country.
Source: Times of India and Tribune- April 2007

The report says during 2006, a number of cyclonic storms and depressions formed over the Indian seas. Severe cold wave conditions over northern and eastern parts of the country claimed more than 80 lives. Heat wave events over northern and some western parts of the country claimed close to 100 lives and as many as 1500 persons were killed in floods during the monsoon season.

The 10 warmest years ever since the Met Department started keeping a record of temperatures since 1901 are 2006 (0.595), 2002 (0.59), 1998 (0.50), 2004&2001 (0.47), 2003 (0.45), 1958 (0.43), 1941 (0.41), 2005(0.40), 1999 (0.39), 1953 & 2000 (0.36) and 1980 (0.34).

An anomaly was that whereas traditionally dry areas like Saurashtra and Kutch and West Rajasthan, besides Gujarat, Madhya Maharashtra and Orissa, received excess rainfall, Himachal Pradesh, east and west U.P, Bihar, Jharkhand and Assam and Meghalaya remained deficient. But overall the country received 100% normal rainfall. During February, northern hilly regions, Uttrakhand, Himachal and parts of Jammu and Kashmir were abnormally warmer with maximum temperatures 6 to 8 degree above normal.

Health impacts of climate change

Climate change is a major problem caused by the increase of human activities leading to several direct and indirect impacts on health. The combustion of fossil fuels, increasing number of industries, and large-scale deforestation are some of the causes for the accumulation of GHGs (greenhouse gases) in the atmosphere. According to the IPCC (Intergovernmental Panel on Climate Change), an increase in carbon dioxide and other GHGs, like methane, ozone, nitrous oxide, and chlorofluorocarbons, in the atmosphere is expected to increase the average global temperature by 1.5 C to 4.5 C. This in turn will lead to changes in rainfall and snowfall, more intense or frequent droughts, floods, and storms, as well as a rise in sea level. These climatic changes will have wide-ranging harmful effects including increase in heat-related mortality, dehydration, spread of infectious diseases, malnutrition, and damage to public health infrastructure. Thus we should take appropriate measures to stop this climate change.

Direct impacts
The weather has a direct impact on our health. If the overall climate becomes warmer, there will be an increase in health problems. It is anticipated that there will be an increase in the number of deaths due to greater frequency and severity of heat waves and other extreme weather events. The elderly, the very young and those suffering from respiratory and cardiovascular disorders will probably be affected by such weather extremes as they have lesser coping capacity. An extreme rise in the temperature will affect people living in the urban areas more than those in the rural areas. This is due to the ‘heat islands’ that develop here owing to the presence of concrete constructions, paved and tarred roads. Higher temperatures in the cities would lead to an increase in the ground-level concentration of ozone thereby increasing air pollution problems.

Indirect impacts
Indirectly, changes in weather pattern, can lead to ecological disturbances, changes in food production levels, increase in the distribution of malaria, and other vector-borne diseases. Fluctuation in the climate especially in the temperature, precipitation, and humidity can influence biological organisms and the processes linked to the spread of infectious diseases.

Higher temperature will cause the sea levels to rise that could lead to erosion and damage to important ecosystems such as wetlands and coral reefs. Direct impact of this rise would include deaths and injury caused by intense flooding. Temperature rise would indirectly result in geohydrological changes along the coastline such as saltwater intrusion into the groundwater and the wetlands, coral reef destruction, and damage to the drainage in the low-lying areas. Climate change could increase air pollution levels by accelerating the atmospheric chemical reactions that produce photochemical oxidants due to a rise in the temperature.

The GHGs have been responsible for the depletion of stratospheric ozone, which protects the earth from the harmful direct rays of the sun. Depletion of stratospheric ozone results in higher exposure to ultra violet rays of the sun, leading to an increase in the incidents of skin cancer in light skinned people. It could also lead to an increase in the number of people suffering from eye diseases such as cataract. It is also thought to cause suppression of the immune system.

Due to global warming there will be an increase in the areas of habitat of disease-spreading insects such as the mosquito, causing an increase in the transmission of infection through these carriers.

Potential effects on health due to sea level rise include:
sqb.gif (46 bytes)death and injury due to flooding;
sqb.gif (46 bytes)reduced availability of fresh water due to saltwater intrusion;
sqb.gif (46 bytes)contamination of water supply through pollutants from submerged waste dumps;
sqb.gif (46 bytes)change in the distribution of disease-spreading insects;
sqb.gif (46 bytes)effect on the nutrition due to a loss in agriculture land and changes in fish catch; and
sqb.gif (46 bytes)health impacts associated with population displacement.

Preventive measures
sqb.gif (46 bytes)Reduction in the use of non-renewable sources of energy and increased use of renewable sources will undoubtedly decrease the emission of GHGs substantially. This decrease in the GHGs will have a positive affect on the health and well being of the people.
sqb.gif (46 bytes)Furthermore, switching to cleaner fuels and energy-efficient technologies will reduce local pollutants and therefore, have an added beneficial impact on health.



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