Earth Point

Environmental Pollution Through Emission of Harmful Gases: Greenhouse Effect, Ozone Depletion and Carbon Credit.Greenhouse Effect on environment & global warming VP Srivastava The writer is former additional commissioner, Commercial Tax UP; member, Commercial Tax Tribunal (Retd.) and President, C-CARBONS After rapid pace of industrialization and unsystematic urbanization, the global environment is deteriorating day by day especially due to emission and discharge of harmful and dangerous gases from industries, transportation, refrigeration, air-conditioning, manmade greenhouses and solid wastes as well as due to deforestation and loss of biodiversity. The greenhouse effect is a natural process that warms the earth’s surface. The earth is wrapped in a blanket of air called the atmosphere which is made-up of several layers of gases. When the sun’s energy reaches the Earth’s atmosphere, some of it is reflected back from earth’s surface and atmospheric gases in to the space and the rest is absorbed (in the form of heat-called trapping of the heat) and re-radiated by the so called Greenhouse gases (GHG’s). These gases trap some energy (i.e. heat) and become an additional source of energy (other than the sun) and emit infrared radiations to make the surrounding warmer. Greenhouse gases include water vapors (36% - 70%) carbon-dioxide(9% - 26%), methane (4% - 9%), ozone (3% -7%), nitrous oxide and some other gases. Of these, methane has 23 times the warming potential of carbon-dioxide while the remaining major gases in the atmosphere i.e. Nitrogen and Oxygen are not able to directly absorb or emit the infrared radiations, and their radiative effect on temperature is so weak that their contribution in temperature is negligible. The absorbed energy warms the atmosphere and surface of the earth. This process maintains the Earth’s temperature at around 330 c warmer than it would otherwise have been – at about freezing – 180 c rather than the palmy 150c as it is now, allowing life on Earth. In the normal scheme of things, greenhouse gases (GHG), which make up less than 1% of the atmosphere, are benign and useful for life. Their levels in the atmosphere are determined by a balance between ‘sources’ that release these gases and ‘sinks’ that absorb or remove them such as photosynthesis and carbon fixing. But the modern human activity has disrupted the optimal balance. Such disruption may happen by way of more generation of these gases or introduction of new sources of GHG such as CFC (chlorofluro carbons) and their substitutes or by interference with the natural sinks such as deforestation. One hectare of tropical forest, eg, is estimated to store 445 tonne of carbon in its biomass and soil. When a forest is cleared and replaced by agriculture or human settlements, much of the stored carbon is released into atmosphere as carbon-dioxide. With the forest gone, fewer plants are left to remove carbon-di-oxide from the atmosphere through photosynthesis. The enhanced level of GHGs accumulation in the atmosphere results is causing an increase in the temperature of the earth, referred to as the global warming which in turn leads to ‘climate change ‘. The name greenhouse effect derives its termname from thea man-made greenhouses to develop plants in nursery. In a greenhouse, energy from the sun passes through the glass as a ray of light. This energy is absorbed by plants, soils and other objects in the greenhouse. Much of this absorbed energy is converted into heat which warms the greenhouse. The glass helps to keep the greenhouse warm by trapping this heat. The earth’s atmosphere acts somewhat like the glass of a greenhouse. About 31% of the incoming radiation from the sun is reflected directly back into space by the earth’s atmosphere and surface (particularly by snow and ice) and another 20% is absorbed by the atmosphere. The rest of the incoming radiation is absorbed by oceans and land where it is converted into heatt warming the surface of the Earth and the air above it. Particular gases in the atmosphere – the greenhouse gases – act like the glass of a greenhouse – preventing the heat from escaping. These greenhouse gases absorb heat and re-radiate some of it back to the earth’s surface, causing surface to be warmer than that would otherwise be. This natural trapping of heat or the greenhouse effect has made the earth habitable. Without it the earth would have been a cold, lifeless planet. Earlier thisThis term Greenhouse Effect had been used to describe the naturally occurring function of traces of gases in the atmosphere and did not have any negative connotation. It was not until mid-1950 that the term-greenhouse effect -was coupled with concern over climate change. and in recent decades we often hear about the greenhouse effect in negative sense. The negative concerns are related to the possible negative impacts of an enhanced gGreenhouse effect, especially. It is the an increase in the concentration of especially carbon-dioxide that is the cause of concern that is being produced in plenty due to burning of fossil fuels (coal, natural gases as well as from some rainforest burning), cement production and land use change such as deforestation. Compared to pre-industrialization atmospheric concentration of around 270 ppm (parts per million) the average concentration has increased to 400 ppm in 2012. This causes the manmade portion of the greenhouse effect or the enhanced greenhouse effect and has beenis responsible for the global warming infor the plast 50 years or more, endangering life on earth. China is now estimated to be the largest emitter of greenhouse gases followed by European Union, Russian, Japan, Canada and India. Potent Green house Gases And their Contribution in Global warming Carbon dioxide or CO2 is responsible for more than 55% of the current global waorming from GHGs produced by human activities. Its concentration contributionconcentration contribution has increased by more than 30% since pre – industrial times ie within 100 years and currently increase by 1% every year. The main sources (75%) are the excessive burning of fossil fuels particularly coal and increasing motor vehicle exhaust. Deforestation and biomass burning contribute 25%. CO2 molecules remain in the atmosphere for around 200 years. CH4 (methane) accounts for 16% of the increase in GHGs. It can trap 23 times more heat than CO2. Its molecules remain in the atmospheres for 10-12 years . It is produced by decomposition of organic matter eg rice paddies, natural wetlands, sewage, landfills, intestines of cattlescattle, sheepssheep and termites. Its concentrationIts concentration has doubled since pre industrial times . A tTypical domestic cow maycow may produce 73,000 liters oflitres of methane per year. About 1/3 of humans have methane producing bacteria in their guts as well. The increasing amount of methane is linked to the world’s population growth-more people need more food and more cattle. The largest agricultural sources of methane production issource of methane production is linked with rice production. The warm water logged soil of paddy fields providesoils of paddy fields provide ideal conditions for methane production. The possible sources of methane emission from paddy fields are organic matter such as rice straw, soil, organic matter and carbon supplied by decaying rice plants. Nitrous oxide (NO2) accounts for 6% of human inputs of GHGs. It is released during nylon production, burning of biomass and fossil fuels like coal, deforestation, fertilizers, live stock wastes and nitrate contaminated ground water. Its life span is 120-190 yrs and traps heat 200 times more than CO2 molecule. Chlorofluorocarbons are responsible for 24% of human contribution of GHGs. They are entirely man made GHGs. They can trap 1500-1700 times more heat than CO2 mol. Its sources are refrigerants, industrial solvents, aerosol propellants and products of plastic foam. Effect on Effects of Global Warming (or Greenhouse Effect) There are plenty of ill-effects of global warming due to greenhouse effect, some of which may be summarized as follows:- Effects on weather – The normal temperature will increase. It is projected that by 2100, the normal temperature will increase by 30C. It will disturb the cycle of rains, there will be untimely rains. The increase in temperature may bring unusual storms, floods, and droughts and so on. Rise in Sea level – The enhanced temperature will cause melting of glaciers, ice and snow causing increase in sea level which will in turn threaten low lying coastal areas, their population, flooding the farm land and a decrease in habitable land. Effect on crops – It is projected that when by 2100, the normal temperature would increase by 30C. by the rise of that temperature, rice and maize yields in the tropical area are expected to decrease by 20 to 40% and there would be reduction in global food production while the population would naturally grow which may lead to malnutrition. DIn damage to, plants and animals – It has taken millions of years for life to become used to conditions on earth. As weather and temperature changes, the homes of plants and animals will be affected all over the world, e.g. polar bears and Seal will have to find new land for hunting and living if ice in the arctic melts. Many plants and animals may not be able to cope with these changes and could die causing loss of bio-diversity. BOX The Greenhouse effect is a natural process that warms the earth’s surface. The earth is wrapped in a blanket of air called the atmosphere which is made-up of several layers of gases. When the sun’s energy reaches the Earth’s atmosphere, some of it is reflected back from earth’s surface and atmospheric gases in to the space and the rest is absorbed (in the form of heat-called trapping of the heat) and re-radiated by the so called Greenhouse gases (GHG’s). These gases trap some energy (i.e. heat) and become an additional source of energy (other than the sun) and emit infrared radiations to make the surrounding warmer. Greenhouse gases include water vapors (36% - 70%) carbon-dioxide(9% - 26%), methane (4% - 9%), ozone (3% -7%), nitrous oxide and some other gases. Of these, methane has 23 times the warming potential of carbon-dioxide while the remaining major gases in the atmosphere i.e. Nitrogen and Oxygen are not able to directly absorb or emit the infrared radiations, and their radiative effect on temperature is so weak that their contribution in temperature is negligible. The absorbed energy warms the atmosphere and surface of the earth. This process maintains the Earth’s temperature at around 330 c warmer than it would otherwise have been – at about freezing – 180 c rather than the palmy 150c as it is now, allowing life on Earth. In the normal scheme of things, GHG’s ,which make up less than 1% of the atmosphere are benign and useful for life. Their levels in the atmosphere are determined by a balance between “ Sources” (that release these gases) and sinks (that absorb or remove them such as photosynthesis and carbon fixing). But the modern human activity has disrupted the optimal balance. Such disruption may happen by way of more generation of these gases or introduction of new sources of GHG’s such as CFC’s (chlorofluro carbons) and their substitutes or by interference with the natural sinks such as deforestation. One hectare of tropical forest, eg, is estimated to store 445 tonne of carbon in its biomass and soil. When a forest is cleared away and replaced by agriculture or human settlements, much of the stored carbon is released into atmosphere as carbon-dioxide. With the forest gone fewer plants are left to remove carbon-di-oxide from the atmosphere through photosynthesis . The enhanced level of GHGs accumulation in the atmosphere results is causing an increase in the temperature of the earth ,referred to as the global warming which in turn leads to ‘climate change’. OZONE DEPLETION The atmosphere of Earth is divided into five layers. From closest and thickest to farthest and rarest the layers are: troposphere, stratosphere, mesosphere, thermosphere and exosphere. The majority of the atmosphere’s ozone resides in stratosphere which extends from 10Km above the Earth’s surface to 50 km. the stratospheric ozone plays a critical role in absorbing ultraviolet B (UVB) radiation emitted by the sun which is harmful for human body and other organisms and plants. It has been discovered that stratospheric ozone is depleting as a result of anthropogenic pollutants and foam blowing agents (CFC’s, HCFC’s, freons, halons etc.) for the last four decades. These compounds are transported into the stratosphere with the passage of time. CFC’s (chlorofluorocarbons), HCFC’s (hydrochlroflurocarbons) and other contributory substances are reffered to as ozone-depleting substances ODS). Ozone depletion process begins when CFC and other ODS are emitted into the atmosphere. CFC’S are extremely stable and they do not dissolve in rain. When these substances reach stratosphere, strong UV light breaks apart the ODS molecules. CFCs, HCFCs, Carbon tetrachloride, methyl chloroform and other substances release chlorine atom and halons and methyl bromide release Bromine atoms. It is these atoms that destroy ozone causing ozone depletion or ozone hole. It is estimated that one chlorine atom destroys over one lakh ozone molecules before it is removed from the stratosphere. Reaction Process of Ozone Depletion by CFCs may be understood as under- CFC uvrays/ free chlorine atom. (cl) Free cl. Atom (cl)+O3 ClO + O2 A free O atom from the atmosphere attacks ClO, releasing a free Cl atom and forming an oxygen molecule O+ClO+O2 Cl+2O2 Chain reaction starts again with free Cl atom Extent of ozone Depletion:- From 1970 onwards there has been a steady decline of about 4% per decade in the total volume of ozone in Earth’s stratosphere and a much larger springtime decrease in stratospheric ozone (ozone hole) over Earth’s polar regions. The ozone depletion has been predicted to be roughly 7% per decade over a 60 year period. This sounds the grave concern over ozone depletion. Consequences of ozone layer depletion:- Ozone, while a minority constituent in Earth’s atmosphere, is responsible for most of the absorption of ultraviolet B radiation. Ultra-Violet B radiations (UVB) are the higher energy UV radiations which are generally accepted to be a contributory factor to skin cancer, cataracts, skin burn, harm to marine organisms and damages to materials like plastics. A number of economically important species of plants such as rice depends on cynobacteria residing in their roots for retention of nitrogen. Cynobacteria are sensitive to UV radiation and would be affected by its increase thus affecting production of such crops. Global concerns about ozone Depletion:- After detecting loss of ozone in stratosphere and its consequences, the developed countries like the US and Europe started thinking over it since 1970’s. In 1985, 20 nations including most of major CFC producers signed the Vienna Convention for protection of ozone layers which established a framework for negotiating inter-national regulations on ozone depleting substances. Then in 1987 representatives of 43 nations signed the Montreal protocol in which participants agreed to reduce production of CFC’s y 50% by 1999. The protocol was further strengthened later on. U.N. General Assembly has proclaimed 16 Sept as International Day for Preservation of ozone layer. It was on this day in 1987 that the Montreal Protocol was signed by various countries at Montreal Canada. Carbon Credit A carbon credit is a tradable certificate or permit representing the right to emit one tonne of carbon-dioxide or the mass of another greenhouse gas (GHG) equivalent to one tonne of carbon-dioxide. Such credits are awarded to countries or groups that have reduced their green house gas emission below their emission quota. Its goal is to stop the increase of carbon dioxide and other greenhouse gases which are responsible for greenhouse effect leading to global warming. The approach can be understood through an example. If an environmentalist or a group plants enough trees to reduce emission of carbon-dioxide by 1 tonne, it will be awarded one carbon credit. At the same place if a steel producer has emission quota of 10 tonnes but expecting to produce 11 tonne of carbon-dioxide, it could purchase one carbon credit from the above environmentalist or the group. The Carbon Credit system looks to reduce emission by having countries honour their emission quotas and offer incentives for being below them. Carbon Credit creates market for reducing greenhouse emission by giving a monetary value to the cost of polluting the air such as carbon emitted by burning of fossil fuels such as coal and natural gases. This means that carbon becomes a cost of business for those creating more carbon than authorized by norms and is seen like other inputs such as raw material and labour. Many types of activities can generate carbon credits (or carbon offsets). Renewable energy such as wind farms, or installation of solar, small hydro, geothermal and biomass energy can all create carbon offset by displacing fossil fuels. Others include those resulting from energy efficiency projects or carbon-dioxide saving projects such as use of renewable energies, methane capture from landfills or livestock, destruction of potent greenhouse gases such as halocarbons, and carbon sequestrian projects such as aforestation and reforestation that absorbs carbon-dioxide from the atmosphere. Carbon credits are a part of international emission trading norms. They incentivize companies or countries that emit less carbon. The total annual emission is capped and the market allocates a monetary value to any shortfall through trading. Businesses can exchange, buy or sell carbon credits in international markets at the prevailing market price. India and China are likely to emerge as the biggest sellers and Europe is going to be the biggest buyer of carbon credits. Carbon, like any other commodity has begun to be traded with Europe through European Climate Exchange. Value of one carbon credit has been up to roughly 22 Euro i.e. Rs. 1800/- (cost of one tone of carbon-dioxide) Many types of activities can generate carbon credits (or carbon offsets). Renewable energy such as wind farms, or installation of solar, small hydro, geothermal and biomass energy can all create carbon offset by displacing fossil fuels. Others include those resulting from energy efficiency projects or carbon-dioxide saving projects such as use of renewable energies, methane capture from landfills or livestock, destruction of potent greenhouse gases such as halocarbons, and carbon sequestrian projects such as aforestation and reforestation that absorbs carbon-dioxide from the atmosphere. Carbon credits have been created through Kyoto Protocol, an international agreement between more than 170 countries and only those companies that meet the UNFCCC (United Nations Framework Convention on Climate Change) norms can sell the carbon credits. Any company, factory or farm owner or any entrepreneur in India can get linked to the UNFCCC and know the standard level of carbon emission allowed for any country or allowed for its outfit or activity. The extent to which one emits less Carbon (as for standard fixed by UNFCCC) one gets credited in a developing country. That is carbon credit.