Carbon dioxide is one of the main culprits for greenhouse gases and the reduction of emissions of this toxic substance has become the topic of the agenda. Greenhouse gases are released into the atmosphere by burning fossil fuels. Accelerated industrial activity in many developed and developing countries has dramatically increased the levels of these emissions in the air. Mass deforestation has also cut the globe’s ability to absorb these gases. The dilemma is how to find ways that permit the economic growth without jeopardising the environment. Canada along with other 37 countries has ratified the 1997 Kyoto protocol according to which the emissions of greenhouse gases must be reduced significantly by year 2012. It has adopted the policy of private-enterprise solutions to the global warming problem.
As the date of reducing significantly the emissions of greenhouse gases is approaching, many wonder whether governments would ever consider the adoption of some measures to reduce the accelerated deterioration of the atmosphere. It is feared that the uncontrolled industrial activity may lead to a situation where further economic development would be impossible. Greenhouse gases believe to cause warming of the Earth’s climate, leading to erratic whether, melting polar caps and drought in already warm regions. The ecological equilibrium is in jeopardy. From a policy perspective the radical plan hammered out by politicians in Kyoto is the first concrete initiative to fix targets for a significant reduction of greenhouse gases. Although the timetable set for gases emissions reductions is considered by some too long and by others too short, the fact of the matter is that the countries which ratified the Kyoto protocol have not taken, as yet, any concrete measures to the application of the agreement. Plausible questions arise as to the seriousness of politicians and policy makers to tackle this problem.
Canada is a case in point. It has pledged, under the Kyoto agreement, to cut greenhouse gas emissions by 6 per cent from 1990 levels by 2012. It has opted to use a market where every ton of carbon dioxide that is removed from the atmosphere or prevented from being emitted is bought and sold on an exchange like the one that already exists in the U.S. for sulphur dioxide emissions – a market that is now worth an estimated $500-million (U.S.) in trade a year. Under such a regime overpolluters could offset their reduction obligations with credits. Demand and supply for credits would provide the appropriate incentives for reducing emissions. Actually, prices, as determined in the auction exchange market, would provide the appropriate signals for emissions reduction. A strong demand for market credits would push up the price of the units and create a powerful incentive for others to create more credits by devising innovative means of cutting emissions. Such an environmental regulation provides incentives for technological change and better environment.
The Kyoto accord has set the bases for a cleaner environment and the participating countries are currently trying to develop the necessary means for attaining the targets established. The most favoured approach is the use of trading permits. This private-firm solution is debated by many as far as its efficiency is concerned. Economists, however, demonstrate the superiority of this approach compared to most direct ones such as taxes and direct penalties. Little progress has been done though world wide even in the use of this approach. The apparent difficulty lies in the uncertainty surrounding the real threat emanating from the presence of sulphur dioxide and the sheer size of costs associated with the reduction or the curtailment of the emissions of gases. Given that the costs are ten times higher than the estimated benefits little interest exists from private firms and governments to implement the necessary measures for cleaner environment. The estimated costs and benefits, although valid in a strict economic sense, neglect some important facets that can make an important difference in the outcome. The benefits arising from the reduction of CO2 emissions are calculated as the environmental damages that are avoided by preventing rising concentrations of gases. Although costs are calculated in a more direct way the benefits are at best uncertain. Even the direct benefits are really difficult to calculate, never mind the indirect ones. Cleaner environment and better standards of living arising out of emissions curtailment are difficult to quantify accurately. Should such comprehensive calculations were possible we would have a more balanced picture of the true costs and benefits. The international trade in emission rights reduce the calculated costs without altering drastically the ecological capital. Weak sustainability is possible and it can be achieved by relying on the market mechanisms, such tradable pollution permits.
In an ever increasing competitive environment firms have a particular interest and incentive to comply with the Kyoto accord first before their competitors do so. The competitive advantage thus gained makes them more efficient and financially stronger, not weaker. The very recent experience with an ever increasing number of firms seeking to strike deals in getting trading permits is an evidence in point. Such a market is worth more than $60 billion-a-year in the U.S. alone. If politicians agree on clear rules for international trading, the global market could in time reach a trillion dollars a year. Such a growth in the market of tradable permits is quite promising as far as weak sustainability is concerned. Governments should abide to concrete and permanent rules on trading of pollution permits so that polluters and non polluters find the way to trade their permits and reduce the pollution of the environment. By rendering markets more perfect (information becomes more symmetric) the quality of the environment in the future can only get better.
Despite its small concentration, CO2 is a very important component of Earth's atmosphere, because it traps infrared radiation and enhances the greenhouse effect of water vapor, thus keeping the Earth from cooling down. The initial carbon dioxide in the atmosphere of the young Earth was produced by volcanic activity; this was necessary for a warm and stable climate conducive to life. Volcanic activity now releases about 145-255 million tons of carbon dioxide each year. Volcanic releases are about 1% the amount which is released by human activities. Atmospheric CO2 has increased about 30 percent since the early 1800s, with an estimated increase of 17 percent since 1958 (burning fossil fuels such as coal and petroleum is the leading cause of increased man-made CO2 , deforestation the second major cause).
Global warming findings predict that increased amounts of CO2 tend to increase the greenhouse effect and thus cause a man-made global warming. The widespread opinion that there is currently a warming phase and that the increased carbon dioxide amounts are a major contributor to it has led to widespread support for international agreements such as the Kyoto Protocol which aim to regulate the release of CO2 into the atmosphere.
Various scenarios of future emissions due to human activities predict that increased atmospheric concentrations equivalent to a doubling of CO2 by 2100 is unavoidable, and a tripling or greater by that time is a distinct possibility.
The magnitude of the natural greenhouse effect can be determined by observations of the atmosphere's radiation balance and surface temperatures. Both the atmospheric concentrations and current anthropogenic emissions of other greenhouse gases are orders of magnitude smaller than that of carbon dioxide. However, per unit of emission, these gases have a much larger climatic effect than carbon dioxide. Each kg of CFCs and fully fluorinated compound emitted today, for example, can have an accumulated global warming potential (GWP) over the next century many thousands times greater than that of a kg of CO2. Global increases in concentrations of methane, nitrous oxide, ozone, CFCs and other minor gases have added about 70% to the climatic effects of CO2 increases alone. Continued emissions of these gases in the future will significantly advance the timing of climate forcing equivalent to a doubling of CO2, perhaps before 2050.
Oceans add considerable inertia to the climate system, slowing it down, and hence increase the time it takes the system to respond to change. Responsive change in ocean circulation patterns, such as the thermohaline circulation system that controls the behaviour of the Atlantic Gulf Stream, can also significantly modify the primary changes in atmospheric circulation.
Greenland ice cores and ocean sediments confirm that such modifications can have dramatic effects on regional climates, effects that may occur within the space of decades, and can last for centuries. Hence oceans add an additional major element of irreversibility, on human time scales, to global climate change. The Earth's oceans dissolve a major amount of carbon dioxide. The resulting carbonate anions bind to cations present in sea water such as Ca2+ and Mg2+ to form deposits of limestone and dolomite. Most carbon dioxide in the atmosphere eventually undergoes this fate.
Oceans represent a major sink for carbon. Oceans take CO2 up through chemical and biological means. Chemically, ocean waters absorb CO2 by the formation of carbonic acid:
CO2 + H2O ========= H2CO3
The double-headed arrow on this equation indicates that this is an equilibrium reaction. Hence, as CO2 in the atmosphere increases, more is taken up by the oceans, "pushing" the reaction towards formation of H2CO3 (carbonic acid). Cold water holds more CO2 in solution than warm water. This cold, CO2-rich water is then pumped down by vertical mixing to lower depths.
Oceans also take up CO2 biologically, largely through photosynthesis of plankton and other algae. This "fixed" carbon is eventually removed from the water by biochemical processes (for example, the algae are eaten by shell fish, which die and sink to the ocean floor, eventually forming carbonates and entering the long term geochemical cycle.
Oceans hold 50-60 time more carbon in various forms than does the atmosphere, which holds it mostly as CO2. The ratio is about 50 molecules of CO2 in the ocean for every one in the atmosphere. Some parts of the ocean are major sinks; such as the North Atlantic during the spring plankton bloom (population explosion). On the other hand, some areas of the oceans are net sources, such as the equatorial Pacific. On balance, however, oceans are net sinks for carbon.
Temperature increases may have caused CO2 concentrations to increase. This is because of effects of temperature increases on biological processes and changes in ocean circulation (or vice versa).
The oceans are currently taking up more carbon than they are releasing, but we don't know how rapidly they can take it up in response to increases in atmospheric CO2 concentration. There is much uncertainty in estimates of what fraction of extra CO2 emissions the oceans are really taking up. When CO2 dissolves in seawater, it forms an acid that eats away at the shells and skeletons of some marine organisms. With no end in sight to the greenhouse gases spewed out when humans burn fossil fuels, the oceans could become acidic enough to slash the growth of corals and plankton in half. Such a catastrophe would throw entire food chains out of whack, severely disrupting marine ecosystems. The study demonstrates that actively pumping CO2 into the oceans, a method suggested to combat global climate change, would have a major biological impact beneath the blue.
Oceans were estimated to be taking up about half of the excess CO2 put into the atmosphere by human activities.
14.4 trillion kg of CO2/year input to the atmosphere from ALC + fossil fuel burning, and
8.6 trillion kg of CO2/year as net ocean net uptake
(ALC = anthropogenic land conversion)
In year 2005, fossil fuel burning and land conversion will contribute to CO2 emissions and the oceans were estimated to be taking up about 38% of the human-influenced flux into the atmosphere.
Estimates put the net input to the atmosphere at 30 trillion kg of CO2 (from ALC and fossil fuel burning). Of that, about half (14.4 trillion kg) are estimated to stay in the atmosphere, with a net influx into the oceans of 8.6 trillion kg. (Net influx means ocean uptake in excess of its giving off of CO2 back to the atmosphere).
Notice anything wrong here? 30 trillion kg into the atmosphere and only a total of 23 trillion kg accounted for! The remaining 7 trillion kg represents the "missing carbon mystery!" If 40-50% of the carbon emissions stay in the atmosphere and 15-30 % go into the oceans, what happens to the remaining 20 - 35%?
There are several ways the oceans can take CO2. Mixing and the biological pump are two of them. For now let us focus on how CO2 is taken by the terrestrial system. through the biological carbon cycle.
Historically, CO2 taken up in the biological carbon cycle was approximately equal to the CO2 released. The global production of carbon fixed by plants was then equal to the global ecosystem respiration that comprised respiration by plants plus respiration by all other living things on land. On a global basis, there was no net flux of carbon to or from the atmosphere, and there was not net change in carbon storage in terrestrial ecosystems (globally). Unfortunately, human activities have recently been converting forested landscapes to grazed, cultivated, or urban landscapes.
The biological carbon cycle on Earth was then balanced.
No net gain or loss of CO2, and the biomass of the Earth was constant.
However, during the carboniferous era, a net increase in biomass (carbon storage). Much of the biomass became our fossil fuels.
Today there is a net loss of biomass through:
a) deforestation and land use conversion
b) worldwide burning of fossil fuels
Photosynthesis, is the process by which green plants and certain other organisms use the energy of light to convert carbon dioxide and water into the simple sugar glucose. In so doing, photosynthesis provides the basic energy source for virtually all organisms. An extremely important byproduct of photosynthesis is Oxygen, on which most organisms depend.
Photosynthesis occurs in green plants, seaweeds, algae, and certain bacteria. These organisms are veritable sugar factories, producing millions of new glucose molecules per second. Plants use much of this glucose, a carbohydrate, as an energy source to build leaves, flowers, fruits, and seeds. They also convert glucose to cellulose, the structural material used in their cell walls. Most plants produce more glucose than they use, however, and they store it in the form of starch and other carbohydrates in roots, stems, and leaves. The plants can then draw on these reserves for extra energy or building materials.
Virtually all life on earth, directly or indirectly, depends on photosynthesis as a source of food, energy, and Oxygen, making it one of the most important biochemical processes known. It is a part of the global life-support systems and is a right that needs protecting at all costs. The right and responsibility that human beings have in protecting photosynthesis has the highest importance on the Scale of Human and Earth Rights.
Forests contribute to absorbing carbon dioxide and act as CO2 sinks. Conversely, deforestation largely in tropical countries is a source of CO2 to the atmosphere. CO2 releases from deforestation are about 1/6 of sources from fossil fuel combustion. Not all the CO2 is absorbed by the atmosphere; part of the CO2 is absorbed by oceans, and part by forests through the process of photosynthesis.
Water vapour and clouds are some the most important atmospheric constituents of climatic significance that cause about two-thirds of the Earth's natural greenhouse effect. Changes in the concentrations of water vapour has major influences on the radiative fluxes of both incoming sunlight and outgoing heat radiation. Such changes are largely controlled by the response of the hydrological cycle to other forces upon the thermal properties of the climate system, and hence are not primary causes for change. Indeed, the most significant atmospheric components that can be changed by both natural and human influences external to the climate system are other greenhouse gases, particularly carbon dioxide and methane, and aerosols.
Many studies have been made on the change of the Earth’s climate. The above discussion has been useful in understanding the fundamentals of the models of climate change. Now is time to look at results obtained so far.
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