CLIMATE CONDITIONIN INDIA

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INTRODUCTIONOverwhelming scientific evidence has demonstrated that the earth is moving towards a point of no return, where ecological catastrophe brought about by climate change will be unavoidable. Climate change has the potential to undermine human development across many countries, including India, and may even lead to a reversal of current developmental progress. Actions taken, or indeed not taken, in the years ahead will have a huge impact on the future course of human development.

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India is confronted with the challenge of sustaining rapid economic growth amidst the increasing global threat of climate change. Evidence has shown that climate change will affect the distribution and quality of India's natural resources, which will ultimately threaten the livelihoods of the most poor and marginalised sector of the population who are closely tied to India's natural resource base. More than 56% of workers are engaged in agriculture and allied sectors, while many others earn their living in coastal areas through tourism or fishing; indeed most of the poorest people live in rural areas and are almost completely reliant on natural resources for their food and shelter (UN Human Development Report 2007/8). There is still opportunity to avoid the most damaging climate change impacts, but time is quickly running out: the world has less than a decade to change course and it is time to act.

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POPULATION DISTRIBUTION

Geographic factors Human Factors

Relief

Climate

Natural Resources

Social

Economic

Political

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EFFECTS OF CLIMATE ON HUMANS

Climate change has brought about severe and possibly permanent alterations to our planets’ geological, biological and ecological systems. The Intergovernmental Panel on Climate Change (IPCC) now contends that “there is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities ”. These changes have led to the emergence of large-scale environmental hazards to human health, such as ozone depletion, loss of biodiversity, stresses to food-producing systems and the global spread of infectious diseases. The World Health Organization (WHO) estimates that 160,000 deaths, since 1950, are directly attributable to climate change. Many believe this to be a conservative estimate.

Climate change poses a wide range of risks to population health - risks that will increase in future decades, often to critical levels, if global climate change continues on its current trajectory. The three main categories of health risks include: direct-acting effects (e.g. due to heat waves, amplified air pollution, and physical weather disasters), (ii) impacts mediated via climate-related changes in ecological systems and relationships (e.g. crop yields, mosquito ecology, marine productivity), and (iii) the more diffuse (indirect) consequences relating to impoverishment, displacement, resource conflicts (e.g. water), and post-disaster mental health problems.

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Beginning in the mid-70s, there has been an “emergence, resurgence and redistribution of infectious diseases”. Reasons for this are likely multicausal, dependent on a variety of social, environmental and climatic factors, however, many argue that the “volatility of infectious disease may be one of the earliest biological expressions of climate instability”. Though many infectious diseases are affected by changes in climate, vector-borne diseases, such as malaria, dengue fever and leishmaniasis, present the strongest causal relationship. Malaria in particular, which kills approximately 300,000 children annually, poses the most imminent threa.

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EFFECTS OF HUMANS ON CLIMATE

Human activities contribute to climate change by causing changes in Earth’s atmosphere in the amounts of greenhouse gases, aerosols (small particles), and cloudiness. The largest known contribution comes from the burning of fossil fuels, which releases carbon dioxide gas to the atmosphere. Greenhouse gases and aero -Sols affect climate by altering incoming solar radiation and out- going infrared (thermal) radiation that are part of Earth’s energy balance. Changing the atmospheric abundance or properties of these gases and particles can lead to a warming or cooling of the climate system. Since the start of the industrial era (about 1750), the overall effect of human activities on climate has been a warm-ing influence. The human impact on climate during this era greatly exceeds that due to known changes in natural processes, such as Solar changes and volcanic eruptions

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EFFECTS OF CLIMATE ON NATUREClimate change could magnify the cumulative impacts of other ecosystem stresses caused by human development, such as air and water pollution and habitat destruction. Natural systems, including glaciers, coral reefs, atolls, mangroves, boreal and tropical forests, polar and alpine ecosystems, prairie wetlands, and remnant native grasslands, are particularly vulnerable and may be damaged irreversibly.Considerable harm has already been done. For instance, according to the Millennium Ecosystem Assessment, in the last several decades of the twentieth century, about 20 percent of the world’s coral reefs were lost, and an additional 20 percent were degraded. This report also states that “by the end of the century, climate change and its impacts may be the dominant driver of biodiversity loss and changes in ecosystem services globally.

Causes of climate change

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AS SEEN IN THE UNDERSTANDING CLIMATE SECTION OF THIS WEBPAGE, THERE ARE MANY INFLUENCES OVER THE EARTH’S CLIMATE, WHICH CAN BE DISTINGUISHED INTO ‘NATURAL’ AND ‘ANTHROPOGENIC’ (HUMAN-INDUCED) FACTORS. SINCE THE BEGINNING OF THE 20TH CENTURY, SCIENTISTS HAVE BEEN OBSERVING A CHANGE IN THE CLIMATE THAT CAN NOT BE ATTRIBUTED TO ANY OF THE ‘NATURAL’ INFLUENCES OF THE PAST ONLY. THIS CHANGE IN THE CLIMATE, ALSO KNOWN AS GLOBAL WARMING, HAS OCCURRED FASTER THAN ANY OTHER CLIMATE CHANGE RECORDED BY HUMANS AND SO IS OF GREAT INTEREST AND IMPORTANCE TO THE HUMAN POPULATION. THE FOLLOWING SECTIONS LOOK AT THE MAIN CAUSES OF ANTHROPOGENIC (HUMAN CAUSED) CLIMATE CHANGE

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Aerosols in the AtmosphereAtmospheric aerosols are able to alter climate in two important ways:

1.They scatter and absorb solar and infrared radiation

2.They may change the microphysical and chemical properties of clouds and possibly their lifetime and extent.

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The scattering of solar radiation acts to cool the planet, while absorption of solar radiation by aerosols warms the air directly instead of allowing sunlight to be absorbed by the surface

of the Earth.

>Human activity contributes to the amount of aerosols in the atmosphere in several ways.>Dust is often a bi-product of agricultural processes.>Biomass burning produces a combination of organic droplets and soot particles.>Industrial processes produce a wide variety of aerosols depending on what is being burned or produced in the manufacturing process.>Exhaust emissions from transport generate a rich cocktail of pollutants that are either aerosols from the outset, or are converted by chemical reactions in the atmosphere to form aerosols.

The concentrations of aerosols are about three times higher in the Northern Hemisphere than in the Southern Hemisphere. This higher concentration is estimated to result in radiation forcing that is about 50 per cent higher for the Northern Hemisphere.

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Land use changeLand-use changes (e.g. cutting down forests to create farmland) have led to changes in the amount of sunlight reflected from the ground back into space (the surface albedo). The scale of these changes is estimated to be about one-fifth of the forcing on the global climate due to changes in emissions of greenhouse gases. About half of the land use changes are estimated to have occurred during the industrial era, much of it due to replacement of forests by agricultural cropping and grazing lands over Eurasia and North America. The largest effect of deforestation is estimated to be at high latitudes where the albedo of snow-covered land, previously forested, has increased. This is because snow on trees reflects only about half of the sunlight falling on it, whereas snow-covered open ground reflects about two-thirds.

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Overall, the increased albedo over Eurasian and North American agricultural regions has had a cooling effect. Other significant changes in the land surface resulting from human activities include tropical deforestation which changes evapotranspiration rates (the amount of water vapour put into the atmosphere through evaporation and transpiration from trees), desertification, which increases surface albedo, and the general effects of agriculture on soil moisture characteristics. All of these processes need to be included in climate models. Except for climate change studies there are few reliable records of past changes in land use. One way to build up a better picture of the effects of past changes is to combine surface records of changing land use with satellite measurements of the properties of vegetation cover. Such analyses show that forest clearing for agriculture and irrigated farming in arid and semi-arid lands are two major sources of climatically important land cover changes. The two effects tend, however, to cancel out, because irrigated agriculture increases solar energy absorption and the amount of moisture evaporated into the atmosphere, whereas forest clearing decreases these two processes.

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Greenhouse gasesThe Earth has a natural greenhouse effect where certain gases (known as greenhouse gases) in the atmosphere allow the sunlight to enter but absorb the heat radiation. Because these gases absorb the heat, they keep the average surface temperature on Earth around 14°C. Without the natural greenhouse effect, the Earth’s average surface temperature would be around -19°C.

Since the industrial revolution, human activity has increased the amount of greenhouse gases in the atmosphere (shown in the graph to the right). The increased amount of gases which absorb heat, has directly lead to more heat being retained in the atmosphere and thus an increase in global average surface temperatures. This change in temperature is known as global warming. The increase in temperature is also leading to other effects on the climate system. Together these affects are known as anthropogenic (human caused) climate change.

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The main Greenhouse gases include:Water vapour - The most abundant greenhouse gas (GHG), however because it spends just a short time in the atmosphere, and humans have a very impact on the amount of water in the atmosphere, it is not considered the most important GHG.

Carbon dioxide (CO2) - Is actually only a small part of the atmosphere, but one of the most important GHGs. CO2 is released naturally into the atmosphere through volcanic eruptions

and animal respiration but it is also released through human activities such as deforestation and the burning of fossil fuels for energy. CO2 also spends a long time in the atmosphere increasing its impact. Since the industrial revolution, humans have increased atmospheric

CO2 concentration by 30%.

Methane - The second most important GHG, is produced both naturally and through human activities. The most significant sources of Methane come from the decomposition of organic matter e.g. in landfills and in agriculture. Another large source is from the digestion of ruminants (cows, goats etc). Methane is a stronger GHG than CO2 because it can absorb more heat, however it is much less abundant in the atmosphere.

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Nitrous oxide - A very powerful greenhouse gas which is heavily produced in the agriculture sector, specifically in the production and use of organic fertilizers. It is also produced when burning fossil fuels.

Chlorofluorocarbons (CFCs) - These man-made compounds were produced for industrial use, mainly in refrigerants and air conditioners. They are now regulated under the Montreal Protocol due to their adverse affect on the Ozone Layer.

Since the beginning of the 20th century industrial acti vity grew 40-fold, and the emissions of greenhouse gases grew 10-fold.

The amount of CO2 in the air increased from some 280 parts per mill ion by volume (ppmv) at the beginning of the century to 389 ppmv at the end of 2010. The amount of CO2 varies throughout the year as the result of the annual cycles of photosynthesis and oxidati on, i l lustrated in the graph. Similarly, methane (CH4) rose from a preindustrial atmospheric concentrati on of around 700 parts per bil l ion by volume (ppbv) to about 1,789 ppbv by 2007.

The overal l warming from 1850 to the end of the 20th century was equivalent to about 2.5 W/m²; CO2 contributed around 60 per cent of this fi gure and CH4 about 25 per cent, with N2O and halocarbons providing the remainder. This has resulted in Earth’s average temperature increasing from 15.5°C to 16.2°C in the last 100 years. The warming eff ect that would result from a doubl ing of CO2 from pre- industrial levels is esti mated to be 4 W/m².

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