What Might Man-Induced Climate Change Mean? [Excerpt]
Society, Science and Climate Change [Excerpt]
The Cost of Combating Global Warming
Toward a Real Global Warming Treaty
Stick with Kyoto: A Sound Start on Global Warming
What Makes Greenhouse Sense?
What to Do About Climate Change
Copenhagen's Inconvenient Truth
How to Salvage the Climate Conference
The Low-Carbon Diet
How the Market Can Curb Climate Change
Globalizing the Energy Revolution
How to Really Win the Clean-Energy Race
Tough Love for Renewable Energy
Making Wind and Solar Power Affordable
Cleaning Up Coal
From Climate Culprit to Solution
How Big Business Can Save the Climate
Multinational Corporations Can Succeed Where Governments Have Failed
How Washington Can Bolster a Stronger Climate Deal
Why Municipalities Are the Key to Fighting Climate Change
The Geopolitics of the Paris Talks
The Web of Alliances Behind the Climate Deal
The Problem With Climate Catastrophizing
The Case for Calm
Climate Catastrophe Is a Choice
Downplaying the Risk Is the Real Danger
Paris Isn't Burning
Why the Climate Agreement Will Survive Trump
Why Trump Pulled the U.S. Out of the Paris Accord
And What the Consequences Will Be
Trump's Paris Agreement Withdrawal in Context
The Polarization of the Climate Issue Continues
…A growing accumulation of evidence has persuaded most of the scientific community that human activity may be contributing to a substantial change in the Earth's climate on a global scale. In particular, large-scale consumption of fossil fuels (coal, petroleum and natural gas) is leading to an accumulation of carbon dioxide in the atmosphere, which if continued appears likely to increase the average surface temperature of the Earth by several degrees over the next 50 to 70 years. And the release into the atmosphere of other gases arising from human activity may add significantly to this overall "greenhouse effect."
There are, of course, many gaps in our understanding of how the climate system behaves, and hence many uncertainties in this prediction of the future. But few climatologists still doubt that there will be a gradual trend toward a warmer Earth in the decades ahead, assuming we continue to add enormous quantities of carbon dioxide to the atmosphere. By the same token, we can anticipate shifts in the current patterns of precipitation due to changes in atmospheric circulation, though the details of these shifts are still unclear.
Since this prospective global change is the result of human activities, we could in principle avert or at least defer it if we decided that the likely consequences were "unacceptable." Or we could accept their onset and take measures to mitigate the adverse effects of the change and to capitalize on its beneficial effects.
Four years ago an informative article in these pages undertook to examine what the broad impact of man-induced climate change might be, particularly in terms of food production and ecological systems. At that time the scientific community was more divided on the issue, but a great deal of research has now made some elements of the future picture more clear. There remains an important need for more organized and systematic analysis, especially in translating overall global trends into a more precise picture of what can be expected for the climate of specific regions of the world. But the trend itself is now so unmistakable that it is time to broaden the analysis and to unite the research and judgment not only of physical scientists but of a whole range of disciplines including history, geography, political science and economics.
To that end, the present authors-one a climatologist, the other a political scientist-published in early 1981 a book that sought to present an overview of the situation and the present state of knowledge concerning it. This article seeks to go further and to present, for what may be a wider audience, a more detailed picture of the possible shape of future climate change, followed by the implications of such change for the habitability of specific regions and nations of the earth in terms of three specific subjects: agricultural productivity, ecology, and human health and disease-which lead to a more speculative discussion of possible climate-influenced migration.
It used to be generally doubted that people, so insignificant in size compared to their planet, could have any real influence on the global environment. But for at least two generations it has been clear that human activity has significantly altered the climate of our large cities and the regions downwind, and that we have aided the spread of deserts and decimated large parts of the forests that used to cover vast areas of both the temperate zones and the tropics. Such actions have altered the heat and water balance on a regional scale. And now we are influencing the climate of the Earth on a truly global scale.
Burning fossil fuels converts carbon that has been locked in the Earth for tens of millions of years to carbon dioxide and water vapor. The result has been an increase of about 20 percent in the carbon dioxide content of the atmosphere since the start of the Industrial Revolution, most of it occurring in this century. Whereas the atmospheric fraction of carbon dioxide is estimated to have been approximately 280 parts per million prior to 1900, it is now reaching 340 parts per million, or 0.034 percent by volume.
Since 1900 the release of additional carbon dioxide from fossil fuel burning has risen inexorably. From 1900 to 1973 the average annual rate of increase was roughly four percent, but since that time the rate of increase has slackened to about 2.3 percent per year.
Even if there should be no further increases, present levels of release are bound to deposit a large fraction of the new carbon dioxide in the atmosphere. In aggregate terms, the world was releasing 1.6 billion tons of carbon per year (in the form of carbon dioxide) in 1950, and 5.3 billion tons in 1980. The resulting increase in atmospheric carbon dioxide during that period has averaged one part per million per year. Comparing the additional amount that can be accounted for in the atmosphere to the amount released, the airborne fraction has averaged about 60 percent of the total.
The other 40 percent of the added carbon dioxide must have been taken up mostly by the oceans. The oceans represent a sink for carbon dioxide that is some 60 times larger than the atmosphere; eventually almost all of the added carbon dioxide will end up in the oceans. However, the processes of removal from the atmosphere, limited by the rate of mixing of the large volume of deep ocean water with the surface mixed layer only a few hundred meters deep, are extremely slow and gradual, acting over a period of 500 years or more. Several studies have been made of the oceanic uptake and mixing processes and, while there remain a number of uncertainties, it seems likely that in the next 50 to 100 years the oceans will continue to take up a little less than half of the new carbon dioxide added each year.
One must also take account of the influence on carbon dioxide levels of the Earth's biosphere. Photosynthesis in the plants and trees of the world is a major sink for carbon dioxide; until the last century there was a rough balance between the take-up of carbon dioxide by photosynthesis and its return to the atmosphere by decay or burning. However, the forests of the world, especially those in the tropics that contain 80 to 90 percent of the living biomass, have been cut down rapidly in recent years, with further deforestation in prospect. There now rages a fierce controversy over whether this deforestation may be reducing the significance of the biosphere as a sink for carbon dioxide, and whether it may actually mean that the decay or burning of all that wood constitutes a net source of "new" carbon dioxide entering the atmosphere.
One widely quoted estimate placed the biospheric source as equal to or even larger than the fossil fuel source. It now seems, however, that estimates of current global deforestation were based on too scanty data and were probably exaggerated-though the problem is indeed very serious in some developing countries for other economic and environmental reasons-and that regrowth of forests and the sequestering of carbon in the form of charcoal (which lasts for a very long time) has been underestimated. The matter is still not settled, but we would probably not be making a significant error if we assumed that the oceans were the main sink and that fossil fuel burning was the main source.
This is the past and present situation regarding atmospheric carbon dioxide. Let us now address the question of its future levels and the effects of a continued rise on climate.
Just before the turn of this century a prominent American geologist and president of the University of Wisconsin, T.C. Chamberlain, and an equally prominent Swedish chemist, S. Arrhenius, independently pointed out that carbon dioxide absorbs infrared radiation from the surface of the earth that would otherwise escape to space, and then reradiates some of this infrared energy back downward. They noted that this "greenhouse effect" should raise the temperature at the surface above what it would have been in the absence of the added carbon dioxide (though the analogy to a greenhouse is far from perfect), but no data then existed to quantify the magnitude of such an effect.
For reasons that are hard to understand, this startling hypothesis attracted relatively little attention until the 1960s, when a number of scientists began to develop quantitative theories to explain the way our climate system works. In 1967 Syukuro Manabe and Richard Wetherald of Princeton published an estimate of the change of average surface temperature that would take place with a doubling of carbon dioxide from the assumed pre-1900 level. In this calculation they correctly took into account the very important fact that a warmer atmosphere would hold more water vapor, and that water vapor is another good absorber of infrared radiation.
This estimate has been checked by progressively more sophisticated and complete theoretical models of the climate system developed by Manabe and his colleagues as well as by a number of other groups. The answer remains about the same: doubling of carbon dioxide levels in the atmosphere should produce an average temperature rise of the earth's surface of approximately 3° centigrade, with an estimated uncertainty of plus or minus 1.5°C.
It must be emphasized that this estimate of a warming from increased carbon dioxide refers to the average for the globe; regional changes will undoubtedly be different. Both model results and experience with the real atmosphere indicate that the warming in the Arctic will be some three times larger than the average, and in the temperate zone of the Northern Hemisphere, where a large number of the developed countries lie, the change for a carbon dioxide doubling should be 4° to 6°C. In the Southern Hemisphere, because of its relatively larger ocean area and an Antarctic Continent that will initially be much less affected than the Arctic, the warming trend would be smaller than in the Northern Hemisphere. (Other regional differences will be discussed later, especially those concerning rainfall on a warmer Earth.)
These estimates have dealt only with the effect of carbon dioxide release. But carbon dioxide is not the only infrared-absorbing gas that we are adding to the atmosphere. Other products of fossil fuel combustion, notably hydrocarbons, carbon monoxide, and nitric oxide, react photochemically to form ozone and some methane, both of which add to the greenhouse effect. Still another very persistent and infrared-absorbing gas is used as the propellant in aerosol spray cans and as the working fluid in refrigerators-the chlorofluoromethanes (sold under the trade name "Freon"). There is also the added nitrous oxide produced from extensive use of nitrogen fertilizers. A recent estimate of the effect of all these other gases suggests that they have already contributed to the greenhouse effect and that their continued release could increase the temperature rise by half again as much as carbon dioxide alone.
Given the increased concentration of carbon dioxide and other infrared-absorbing gases in the atmosphere that has already been observed, why have we not experienced a global warming by now? Theoretically the greenhouse effect should have caused a warming of about 0.5°C in this century, and yet there was a pronounced global cooling trend between 1940 and 1965. Inevitably this question has been raised, and the apparent contradiction has been invoked by some skeptics as a refutation of the whole concept of the greenhouse effect.
Two sets of studies have now furnished apparently conclusive answers. First, data on the retreat of Antarctic sea ice have demonstrated a clear long-term trend in that area that is consistent with the expectation of a Southern Hemisphere warming. And second, analyses of other natural influences on global mean surface temperature have revealed sporadic or cyclical factors whose cooling impact apparently more than offset the greenhouse effect in the years that showed the overall cooling trend. These natural influences on climate are primarily major volcanic eruptions, which are known to place enough particles in the stratosphere to attenuate solar radiation for several years at a time, and fluctuations in the total radiation from the sun.
In short, as the fluctuation due to these natural factors (or "climatic noise") has been sorted out, a clear "signal" from increasing carbon dioxide is indeed revealed. While the data do not conclusively prove a warming effect from increased carbon dioxide, the temperature observations over the past 100 years are at least consistent with the notion of the greenhouse effect.
Let us now combine these theoretical calculations of global warming with estimates of the rate of increase of carbon dioxide that may occur over the next 20 to 100 years. Levels of carbon dioxide in the atmosphere are bound to increase under almost any circumstance; the issue of pace and timing is, however, obviously of great importance.
At this point, the uncertainties surrounding future energy demand and supply are such that any projection beyond the year 2000 can be challenged. A reasonable upper limit might be a continued (or resumed) increase in worldwide fossil fuel use at this century's historical rate of four percent per year, at least to the year 2000. Although this rate of increase would be higher than in recent years, it could conceivably take place if there were a major further increase in the use of coal (which releases slightly higher amounts of carbon dioxide per energy unit than oil or natural gas).
A reasonable lower limit might rest on some variation of Amory Lovins' "soft energy path," which assumes a progressive reduction in fossil fuel demand due to conservation and use of renewable energy sources. While it seems unreasonable to expect a sudden shift to such a soft energy path by all countries of the world, it is quite conceivable that there could be a steady decline in the rate of increase of fossil fuel use until at some time in the not-too-distant future the rate of increase would reach zero, and after that the use of fossil fuel would actually decrease with time. Accordingly, the lower limit is based on the present rate of increase dropping progressively to zero in roughly 50 years and becoming negative thereafter. (The assumptions involved in arriving at these upper and lower limits of future fossil fuel use have been discussed in an earlier paper by one of the authors.)
Figure 1, opposite, shows the range of temperature increases that might result from carbon dioxide alone-in terms of global temperatures and temperatures in the Arctic. (The centered trend line at the right of the Figure represents a "best guess" that fossil fuel use would continue to increase at roughly two percent per year in this time frame.) The message is fairly clear: possibly before the year 2000 and in any case before 2020-well short of a doubling of atmospheric carbon dioxide-the world may be on the average warmer than at any time in the past 1,000 years or more-that is, 1°C warmer than now. This "first stage" of climate change would stem from a rise from the present 340 parts per million to an atmospheric carbon dioxide fraction of about 360 to 370 parts per million. (Figure 1 also contains an estimate of the probable effect of carbon dioxide in the present century: the solid line for 1900-1980 reflects observed experience in the Northern Hemisphere, while the dashed line underneath indicates what the actual temperature might have been in the absence of the additional carbon dioxide released in this period.)
While a 1°C average change does not appear at first glance to be very significant, consider first that this change will be amplified toward the poles, and at temperate and high latitudes in the Northern Hemisphere it may be 2° to 3°C. In the temperate zone such a temperature change would correspond to roughly a four degree difference of latitude, or the present mean temperature difference between such pairs of cities as Copenhagen and Paris or Boston and Washington. As the trend continues to a doubling of the pre-1900 level of carbon dioxide-in what might be called a "second stage" of climate change-Boston would approach the same mean temperature as Miami has at present, while the southern parts of the United States and Europe would become truly tropical. The world would be returning to the climate of a period at the dawn of recorded history, the Altithermal, some 4,500 to 8,000 years ago, when the world was definitely warmer and regional climates were very different from now.
Changes in solar activity in this interval could hasten the warming, according to a theory based on solar cycles; conversely, a period of intense volcanic activity (or a major nuclear war) could reduce the effect. And recall that the addition of other infrared-absorbing gases could add another 0.5°C in the first stage of change alone.
Figure 1 does omit one factor difficult to quantify. The oceans have a large thermal capacity, and a lag of about a decade is likely as the upper layers of the world's oceans gradually warm up. This oceanic lag is expected to be somewhat shorter in the tropics than at high latitudes; and the central parts of the major continents, far removed from the moderating effect of the oceans, should be less affected by the delay than places along the coasts. In any case, this factor can only introduce a modest delay in the warming.
This, then, indicates the time scale for the first stage of the climate change that is anticipated. There is, as noted, good evidence that the change is already taking place, but has been partly disguised by natural fluctuations, so that we are not yet generally aware of it. There will be little doubt about its reality when the change becomes larger than the fluctuations, and this should be by the turn of the century, perhaps sooner.
While it is the heat balance of the atmosphere that is directly affected by increasing carbon dioxide and its greenhouse effect, temperature is of course only one feature of weather and climate. Rainfall and evaporation, together determining soil moisture, are even more crucial, especially for growing food.
Though it is convenient to deal with average conditions, the variability of climate is a very real factor as well. Those who grow food, livestock and forests are accustomed to gambling on the good years predominating over the bad years. It seems likely that variability of the climate will decrease as the temperate latitudes approach a more "summerlike" condition, but climate theory does not give much guidance on this point.
Let us first look at a rough picture of the present world situation in terms of water-deficient and water-surplus zones. Such a picture is presented in Figure 2, opposite, based on the balance between water supply from precipitation and the water requirements of plant life, which hydrologists refer to as "potential evaporation." Arid and semiarid regions are those where annual precipitation is less than potential evaporation.
It is clear that patterns of natural vegetation and agriculture are greatly influenced by water balance, though soil and temperature also play important roles. The map shows that many developing countries are situated in water-deficient zones, which usually means that agriculture is limited to the rainy season or may be impossible without irrigation. The tropical areas of water surplus tend to be occupied by rain forests, and here cultivation is hindered by the excess water leaching the nutrients from soil that has been cleared of trees.
As to how that picture of the present situation might change, theoretical climate system models are not yet adequate to tell us, although they do give some useful hints. We can gain some additional hints by looking at reconstructions of the Altithermal Period when the climate was generally warmer. Then the Sahara was not a desert, but a kind of savanna able to support nomadic tribes with their cattle; North Africa and the Middle East were generally more favorable for agriculture; and the present Rajasthan Desert of northwest India was a region where several large cities prospered (cities now swallowed by sand). Still another set of useful hints comes from studies of particularly warm years or seasons during this century, for which good meteorological records of temperature and rainfall have been kept. From these records we can see how those anomalously warm times differed from the long-term average.
These three sources have been used in constructing Figure 3 above. The process was somewhat subjective and also relied on some general reasoning based on concepts of how the large-scale circulation patterns would change with a global warming and a decrease in the temperature difference between the equator and the poles. (For example, it is fairly clear that the monsoon circulation that determines so much of the climate of Asia would be stronger and more regular, and that the storm tracks would on the average move poleward.) The resulting map should not be taken as a prediction of what will happen, but rather a scenario of the future climate describing what could happen.
The implications of this scenario are fascinating. It suggests that large areas of Africa, the Middle East and India, as well as a substantial portion of central China, might cease to be water-deficient areas, or at least be much less water-deficient. On the other hand, there would probably be much drier conditions in the central section of the North American continent, and drier conditions virtually throughout the central and northern areas of the Soviet Union, so that it would be harder to grow wheat, corn, barley and other major food crops in parts of what are now the "food basket" areas of North America and the Soviet Union.
In short, the climate scenario shown in Figure 3 is a useful way to illustrate some of the shifts of rainfall and soil moisture that may occur as the world gradually becomes warmer, but one must be very careful when drawing conclusions from it. After all, climate change is but one of a great many changes that will be taking place in the decades ahead. Poverty, loss of arable soil and tropical forests, condition of water supplies, distribution of natural resources, population growth, and so forth are all factors that must be considered when assessing impacts of climate change, as we shall see in the next section.
Finally, a discussion of the many aspects of a global warming would not be complete without mentioning the possibility of a future rise in sea level-which has been prominently featured by the media. Studies have suggested that the ice sheets of Greenland and the Antarctic have been shrinking slightly in the past 100 years as the Earth grew slightly warmer, contributing to a rise of five to ten centimeters in sea level. In the case of the West Antarctic ice sheet, there is a possibility that it could actually begin to partially disintegrate with the much greater prospective warming of the Polar regions and the neighboring areas.
While a straightforward melting of these enormous masses of ice would probably take many thousands of years, it has been pointed out that most of the West Antarctic ice sheet (and portions of the larger one of the East Antarctic) rests on bedrock well below sea level. Thus, warmer ocean water could work its way under the ice sheet, causing it to relinquish its frozen hold on the bedrock, and to begin sliding toward the ocean, gradually disintegrating and then melting much more rapidly through fuller exposure to the water. A rise of five to seven meters in sea level would result if the entire West Antarctic ice sheet disintegrated, since this ice sheet now rises several kilometers above sea level.
This could make the migrations of the historic past seem almost insignificant by comparison. However, it must be emphasized that glaciologists do not agree on the timescale for such an event. Whether the West Antarctic ice sheet would disintegrate in a matter of centuries or millennia following a major warming is still being debated, but in any case few, if any, experts now claim that the time involved could be less than about 200 years.
It is very likely that Arctic and Antarctic floating sea ice will become less extensive as the warming progresses, a trend that is already evident in the Southern Hemisphere. The Arctic Ocean is now mostly covered the entire year by floating ice, but early in the next century this ocean may become ice-free in summer. However, in contrast to the massive ice sheets that rest on land, a melting of sea ice would have no influence at all on sea level. It is nevertheless significant that, so far as can be determined from studies of Arctic Ocean bottom sediments, that ocean has never been completely free of its ice pack for some three million years-the change that we are talking about may thus be larger than any previous one in that entire period.
Clearly, the strategies or policies that we may adopt to deal with the carbon dioxide problem depend in large part on the way we perceive it as well as on the adequacy of the national and international decision-making processes to address it. Even if the future could be predicted and precise estimates of future carbon dioxide-induced damage could be made, efforts to control fossil fuel use and carbon dioxide emissions on a worldwide basis would face extremely tough political opposition. Both consumers and powerful vested interests in the fossil fuel production and use industry would oppose any moves to curtail the availability of this conventional and convenient source of energy. Given the great uncertainties in our scientific predictions of future temperature and precipitation changes, any concerted worldwide agreement to limit fossil fuel use seems out of the question for some time to come.
And the same negative conclusion almost certainly applies to any early attempt to act on a number of proposals that have been advanced for removing carbon dioxide from the stack gases of fossil fuel-fired power plants and sequestering these billions of tons in the deep ocean or depleted oil and gas fields. While there is no doubt that this is feasible from a purely technical standpoint, the most efficient means presently available for scrubbing the carbon dioxide out of stack gases requires nearly 50 percent of the combustion energy of the fuel, and that is only the first step. Even a regional project of this sort-a dumping facility off the coast of Spain has been suggested, drawing on power plants of Western Europe-would be a mammoth undertaking, and the economic hurdles and political obstacles seem virtually insurmountable, at least under present conditions.
Thus, the action focus in the short and medium term should be on strategies for arriving at a clearer picture of the future, and for mitigating or delaying the adverse effects of prospective climate changes and taking advantage of their favorable aspects. Such strategies should aim to be effective over a wide range of eventualities, since the problem areas often cannot be pinpointed as yet. Moreover, we must be realistic about which courses will be acceptable and feasible.
What, then, ought we to do? Three types of strategies seem to make clear sense:
- Strategies that lead to improved choices: examples are the organization of environmental monitoring and warning systems designed for early detection and attribution of carbon dioxide-induced climate change, provision of improved climate data and the knowledge of their application (especially to developing countries).
- Strategies that help to slow the increase of carbon dioxide: examples are energy conservation, adoption of renewable (non-fossil fuel) energy sources, increased use of nuclear energy, and reforestation (which protects soil and also takes carbon dioxide out of the atmosphere, but probably could not remove enough to counteract the current production rate).
- Strategies that increase resilience to climate change: examples of such measures are the application of agricultural technology, protection of arable soil, improvement of water management, and maintenance of adequate global food reserves.
It should come as no surprise that these measures seem like "conventional wisdom"-they are good ideas, all of which have already been acted on to a greater or lesser degree. They will help us to cope with the inevitable short-term vagaries of the climate as well as a longer-term climate change, and will make our food and energy systems more reliable. Hence, these measures should be adopted in any case. The issue of carbon dioxide-induced climate change may serve as a stimulus to employ them sooner.
The drafters of the World Climate Programme, adopted by the World Meteorological Organization in 1979, recognized the need for such actions, and the component programs for World Data and Applications are designed to meet the needs of developing countries in the first area above. Others must probably be adopted at national or regional levels, such as application of agricultural technology, reforestation and protection of arable soils, and improved water management.
Significant non-economic factors include an educated public and its leaders, together with long-term planners. An important aspect of this is the ability and willingness of planners to recognize the signals of coming change and to interpret those signals for the institutes they serve as well as the general populace. If the scope of such anticipatory actions is to be remotely adequate to the likely extent of climate change, the burden could be substantial. While many of the actions can best be undertaken at the national level, regional cooperation could make an enormous difference, and the development of the technology and forecasting systems clearly calls for the widest possible forms of international cooperation, making use of existing U.N. organizations in particular.
But if concerted worldwide action programs can only be limited for the immediate future, it is not too early to speculate on some of the implications of the climate changes now foreseen, for the relations among nations and possibly for the development of relevant principles of international law and shared responsibility.
Here a crucial element of the problem is that a small number of industrialized countries are likely to remain the principal sources of the additional carbon dioxide, which in turn is the major agent of climate change. Between 1950 and 1976 the United States, the Soviet Union, China, the United Kingdom, West Germany and Japan were the largest carbon dioxide-producing countries. These and similar nations are likely to continue for many decades to be the major cumulative contributors of carbon dioxide to the atmosphere, and this fact alone suggests that developed nations will bear much of the responsibility for the new climatic regimes, should they occur.
One aspect of this is that the carbon dioxide/climate problem could become a significant source of controversy, both between one developed nation or region and another, and between the developed nations as a group and any developing nations which find that the changes have adversely affected them. The current controversy between Canada and the United States over measures to control "acid rain" suggests what might be in store on a much wider scale. As yet there is no international mechanism to consider a given country's responsibility for the climate change, let alone to set carbon dioxide standards, establish control measures, and enforce what some would assert as a legal claim for having affected a nation's climate adversely. Liability claims, sanctions, and indemnity awards are probably unworkable ways to resolve carbon dioxide-related problems such as disruptions in trade, environmental damage, and population relocations. By the time such claims are brought to court, settled, and (if possible) enforced within a future international legal framework, the damage will probably have already occurred. Hence we should not expect much of international law when it comes to resolving cases that deal with adverse climatic impacts suffered by regions or nations and attributed to increased atmospheric carbon dioxide.
But legal remedies are only a corner of the problem. As climate change unfolds, and is perceived to be the result predominantly of the energy practices of the major industrialized countries, there could be strains and controversies highly disruptive to present patterns of close relationship and alliance, as well as to the overall structure of global international cooperation. Will the major nations responsible for most carbon dioxide release show awareness of the problem and make moves to mitigate it? Will they wish to avoid potentially serious damage to their international standing and influence?
Finally, the time is almost bound to come-if not in the next decade, then surely by the turn of the century-when it will be both possible and necessary to take a much harder look at potential national and international measures to reduce fossil fuel consumption.
We must view the prospect of a carbon dioxide-induced climate change against a backdrop of other equally important environmental and societal problems facing the people of the world. In the first half of the next century, as the environmental changes will probably become increasingly more apparent, the world could well contain twice as many people, consume three times as much food, and burn four times as much energy. Our future problems will be serious even without a shifting climate.
It now appears that the possible global climate change may be very disruptive to some societies, though not generally disastrous. It may trigger shifts in agricultural patterns, balances of trade, and habitual ways of life for many people-and eventually, a few centuries from now, may even force abandonment of low-lying lands due to a rise of sea level. Ideally, we may hope that the countries of the world would unite to control and limit the use of fossil fuels, thereby averting or at least delaying this disruption.
The political motivation to do this is apparently lacking, however, nor is it likely to develop in the foreseeable future. There are powerful transnational as well as local interests that would surely oppose such measures, and there is no international machinery that could make such a drastic decision, much less enforce it.
The alternative, then, is to prepare for the climate change in store for us. We can hope that the necessary measures to do this are adopted at all levels of society. The outline in this article indicates a number of measures that make sense right now, even if there were no impending long-term changes. In addition, the scientific community must continue to probe the many factors involved, factors concerning the physical system that determines climate and also the factors governing the impacts of climate change on human activities. [Full Article]