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The Greenhouse Effect: Economic Impacts and Policy Options

by Fahmida Akter
THE gtohal climate Is changing. this change threaten* the humanity with a major environmental impact The late 1980* have seen an unprecedented but growing concern about global warring or greenhouse effect Greenhouse effect 1* often perceived aa a problem of carbon dioxide emission Yet several different gaaea. arising from a wide range of human acttvttte*. make significant contributions
To understand the green house effect we have to know a little bit of science The earth receives moat of Its energy from the suns radiation The wavelength of the radiation emitted by a body varies with its absolute temperature. The warmer a body ts the shorter will be the wavelength of Its radiation The sun has an ap proximate temperature of about 0000 k and radiate* cn ergy mostly tn the form of vial bk- light and ultraviolet rays.
However, solar radiation forms only a part of the total radiation received by objects on the earth. Stxtyetghl per cent of the radiation they re cene ts from the earth (which has an approximate temperature of 2R5k) and atmosphere and consists largely of Infrared • waves
Some of the Infrared radiation escapes from the earth Into the troposphere. The proportion that so escapes Is reduced by the presence of certain gases in the atmosphere principally carbon dioxide (coj. 50 per cent), nitrous oxide (NjO. 8 per cent), methane |CH^. 18 per cent) chlorofluorocarbons (CFCs. 14 per cent). Troposp herlc ozone, stratospheric water vapour and other gases comprise the rest 12 per cent. Thus the greenhouse effect’ I* created In the troposphere, on' account of the presence of these gases which are termed as greenhouse gases.
The anthropogenic sources of these gases are many and varied Sources of the main gases are summed up in the table.
Atmospheric CO- concentration has Increased phenom enally from the pre-tndustrtal level of about 280 parts per million by volume (PPMV) tn 1750 to about. 315 ppmb tn 1958 and to about 380 today Recent evidence suggests that the Increased emission of trace gases will significantly add to any CO2 greenhouse cf feet
A* a result of Increases In those economic activities which emit greenhouse gases, the concentration of these gases are projected to increase quickly. Thus within the next
50 years, the radiative effect of the trace gases may exceed that of the increasing CO2 concentration. CFCs in particular will have an tncreas tngly important Impact, second only to CO2. on the greenhouse effect.
By adding to the waning effect of trace gases, the equivalent of such a doubling tn CO2 would occur as early aa 2030. By then, aa a best ^aes. we could experience an actual
2 warmer man today. ana because of the lag effect due to the thermal inertia of the ocean, we could be committed to an eventual temperalure change of 1 5°C 3. 1>C
warmer than today
If the above scientific con senaus ts accurate, there will
be some economic and envl ronmental consequences. To date, most attention has been focused on the effects on agri culture, as this activity Is directly altered by changes tn climate. This Is rather a shortterm effect. But increasingly concern has been expressed about the possible Implications for forest zones and about the effects of a sea-level rise which may occur in the long run.
The regions which are at risk from global warning resulting from a greenhouse effect include :
— the irrigated semt arid areas of northern mid-tail tudes. particularly In the US Midwest.
— the lowland areas and Island countries of the humid tropics in Asia, the Pacific and the Caribbean that are susceptible to excessive preciplta tton. violent storms and flood 'ng
—the arid and semi arid tropic of Africa. South Asia and the Mediterranean climate of West Asia and the North Africa that are already vulnerable Io climate variability;
ralnfed upland and highland regions, particularly with poor soil conditions; and
—livestock raising In ex treme northern latitudes.
Global warming may also cause change In some of I he world » major river systems (Brahmaputra 1n case of Bangladesh) Changes In the flow* or storage capacities of these river* would result In cl ther less surface and under ground flow or more frequent flooding which could be dlsas trous for irrigated agriculture In many countries irrigated agricultural systems haw been Intensively developed tn correspondence with the precise seasonal variations of delta flooding and run-off.
Changes In seasonal flows would mean severe disruptions
tn cultivation. Moreover, many river systems do not have adc quate water control and man-agement facilities to cope with any variations In flooding or underground storage. For example. tn the lowlands of the humid tropic, the result could be destructive flooding in the vast delta networks of Thailand. Laos. Cambodia. Vietnam. India. China and Bangladesh
So. the economic Impact of any greenhouse effect will most likely be In terms of the rising costs of agricultural displacement and adoption tn the face of climate Instability with potentially grave consc qurnres for the pattern and distribution of global food pro duction and for food security tn many developing countries.
As a result, sustaining even minimum nutritional standards for millions of people In the Third World will require a surplus In the world sgrlcul tural production and the availability of that surplus to the Third World In the form of food or aid Import.
The impact of climate change on the world s major ecosystem* would also affect human welfare This Is particularly true for major forest sys terns For example, the boreal forests found at higher northern latitudes may be pert ku larly vulnerable For the mid latitude temperate forests in the Northern Hemisphere, a high rate of warming of 0 8®-1°C per decade will have ma jor impacts — including large-scale forest dieback between 2000 and 2060. The result will be that more and more production forests would need replanting and increased management
Furthermore, there win also be Impacts on recreational values if Important national park* an wildlife habitat* are decimated. There could also be dramatic Impacts on the major rain forests of the world such as the extensive Indonesian. Amazonian and Central African tropical forest systems
In the long-run. the posai billtv of s rise In global sea levels has been accepted seriously by many sdentists. Even a one metre rise would require expenditures of between US dollars IO and US dollar* IOO billion to maintain threatened
beaches and coastal area* on the Eastern Conal of the USA. Low lying, densely populated countries — such as Bangladesh and the Netherlands — will be particularly after ted
The densely populated and mainly agricultural tow-lying Ganges Brahmaputra Meghna River Delta In Bangladesh has always been poorly protected from frequent tropical cyclones. storm surges and flooding A rise In sea level of 0.5 meter would also severely affect small oceanic Islands, particularly the tow reef Islands and atoll* of the Caribbean and Pacific ocean. This result could be a substantial reduction In Island *Ur and shifts and reductions in shoreline length.
Other direct impact* Include decreased availability of fresh water due to salt-water Intrusion, greater exposure to
of sea surge and storm damage.
A rise in sea-level mean* that less land would be avail able for food production which would result In extensive food shortage, greater risk of malnutrition and health problems Island population would most certainly have to be moved from coastline areas either by In — country migration from tow to high Islands or to urban centres or to continental countries
With such a potentially vital future problem, there is a call
for taking measure Two type* of measure* are suggested In this regard One ts adaptive and the other la preventive.
Adaptive measures Include I) development of a global food security system 2) provision of additional financial assistance to developing countries 3) allocation of development funds to Third World countries tn order to expand food production and to develop a sustainable agriculture 4) a greater in-ternatlonal effort to hall the trend of accelerating global desertification 5) a commit ment to humane method of curbing population growth
On the otherhand. proven Ove measures would Include 1) reducing burning of fossil fuel, particularly through the development of non fossil fuel energy sources and through 1m-extracting useful energy from fossil fuels 2) reducing emission o( trace gases from other anthropogenic sources 3)lncreaslng pollution control and developing technological and recycle the carbon and other trace residual* emitted when fossil fuels are burnt 4) halting unnecessary tropical tive development strategies and 1,-icentfves 5) Increasing the rate of replanting In defer ested areas, encouraging afforestation and improving forest management
To make any major impact on reducing carbon and trace gas emission* quickly would require rapidly Implementing the above measures and would necessitate diverting resources from economic activity This could result in some decrease in short term economic growth. But in the tong run It would save energy costs
One final point, the poten Hal of global warming Is plagued with uncertalntie* In terms of climate change and sea-level rise which calls for further research and is fol
the policy options This in turn requires the continuation of International co-operation if the world has to survive.
The u^tter I* a Research A>*rtal> BIDS. and Pvt Oro duate student of Enutron mental Economics at the Uni uersttp Cadsgs, London.