Living with Global Warming
Table of Contents
Should we try to prevent global warming? Or should we use our resources to adapt to the consequences of warming? An argument for the former is that climate change will exacerbate existing problems — specifically, malaria, hunger, water shortage, coastal flooding and threats to biodiversity. This is a particular concern for developing countries, many of which are beset by these problems but lack the economic and human resources needed to obtain and implement technologies that would finesse or cope with them. This paper analyzes costs and benefits of two different approaches. One approach — mitigation — would limit carbon dioxide (CO2) in the atmosphere largely by reducing emissions due to human activities. The Kyoto Protocol is an example of this approach. The second approach — adaptation — would reduce society’s vulnerability to, or help cope with, the consequences of global climate change due to higher CO2 emissions.
The projections underlying this study are from researchers who are sympathetic to mitigation. However, their conclusions show that adaptation is preferable. Cost estimates are based on reports from various United Nations-affiliated organizations. The findings:
- By 2085, the contribution of (unmitigated) warming to the above listed problems is generally smaller than other factors unrelated to climate change.
- More important, these risks would be lowered much more effectively and economically by reducing current and future vulnerability to climate change rather than through its mitigation.
- Finally, adaptation would help developing countries cope with major problems now, and through 2085 and beyond, whereas generations would pass before anything less than draconian mitigation would have a discernible effect.
The Kyoto Protocol will cost participating countries about $165 billion annually. Kyoto, however, will not stabilize, much less reduce, atmospheric concentrations of CO2. Stabilizing atmospheric levels of CO2 at 550 parts per million (much higher than today’s levels) would cost several trillion dollars. Halting climate change, if that were possible, would cost many more trillions of dollars. Focused adaptive measures to reduce or eliminate the risks posed by malaria, hunger, water shortage, coastal flooding and threats to biodiversity, by contrast, would cost less than $10 billion a year. Moreover, these measures can be implemented now:
Malaria. Today, some 4.4 billion people worldwide are at risk from malaria spread by disease-carrying mosquitoes. This will grow to 8.8 billion people in 2085, even in the absence of climate change, due to increased population in developing countries where the disease is epidemic. Global warming is projected to increase the population at risk by 3 percent (256 to 323 million additional people) in 2085. This is due to an increase in the range of mosquitoes, for example, to higher altitudes. However:
- Meeting the Kyoto Protocol’s emission reduction targets would reduce the population at risk from malaria by only 0.2 percent
- Stabilizing CO2 emissions at 550 ppm would reduce the population at risk from malaria by 0.4 percent
- By contrast, investing an additional $1.5 billion annually on malaria prevention and treatment today would cut the current annual world death toll of malaria in half — from one million to 500,000 a year.
Hunger. Today, at least 521 million people worldwide are at risk of hunger. The good news is that their numbers are expected to fall to 300 million in 2085, despite an increase in global population, due to continuing increases in agricultural productivity. However, global warming is projected to partly offset that decline, exposing an additional 69 million to 91 million people to food shortages by 2085. This would occur due to a slight fall in the rate of agricultural productivity growth, as changing weather patterns increase drought and spread deserts. Thus:
- Meeting the Kyoto Protocol’s emission reduction targets would reduce the population at risk of hunger by approximately 1.5 to 2 percent in 2085.
- Stabilizing CO2 emissions at 550 ppm would reduce the population at risk of hunger by approximately 9.7 percent in 2085.
- By contrast, investing an additional $5 billion to solve agricultural problems that developing countries face today would reduce the population at risk of hunger by 50 percent — beginning today, and in 2085, and in the intervening years.
Water Shortages. Today, 1.75 billion people face shortages of drinking water. This is expected to increase to 6.5 billion people by 2085, due to the increasing population of poorer countries. Global warming may increase the number at risk by nearly 13 percent (862 million) in 2085 — or it may have a positive effect, cutting the population at risk by more than a third (37 percent), or 2.4 billion people. The actual affect depends on changes in weather patterns that occur with global warming, which climate models are currently unable to project accurately on a regional basis. As a result:
- Meeting the Kyoto Protocol’s emission reduction targets would, at best, reduce the population facing water shortages by 1 percent in 2085 — and could, in fact, exacerbate the problem.
- Stabilizing CO2 emissions at 550 ppm would, at best, reduce the population facing water shortages in 2085 by 860 million, but could increase the population at risk by 2.4 billion.
- Institutional reforms such as allowing water pricing and transferable water rights would help stretch water supplies. The water available for nonagricultural uses could be doubled by reducing agricultural water use 18 percent.
Coastal Flooding. Today, 10 million people are at risk of coastal flooding, and this number is projected to increase by 3 million by 2085 as coastal populations increase. Global warming is expected to raise sea levels by about 0.5 meters by the end of this century — due to such factors as melting ice sheets, storm surges and thermal expansion — putting an additional 81 million people at risk. However:
- Meeting the Kyoto Protocol’s emission reduction targets would reduce the total population at risk from coastal flooding in 2085 by 18 percent.
- Stabilizing CO2 emissions at 550 ppm would reduce the total population at risk from coastal flooding by approximately 80 percent in 2085.
- By contrast, investing an additional $1 billion annually in preventive measures — like building sea walls and other hardened structures and an orderly relocation of coastal populations — would address this problem just as well, if not more effectively.
Risks to Biodiversity. Due to development and agriculture, the forested area of the world is expected to fall 25 percent to 30 percent by 2050 and the area of coastal wetlands are expected to decline 40 percent by 2085. The major risk to biodiversity is the loss of natural habitat to development. Increased levels of atmospheric CO2 favor plant growth; however, the effects of global warming on sea levels and weather patterns could reduce wetland area.
- Between now and 2085, global warming could increase forested areas by 5 percent; but it could reduce the area of coastal wetlands another 13 percent.
- Mitigation could cost several trillion dollars, but would have little effect before 2085.
- At a cost of less than $10 billion annually, the adaptive measures mentioned previously (such as those to reduce hunger, water shortages and costal flooding) could slow, halt or even reverse habitat loss by increasing the efficiency of land and water use.
Developing countries are most vulnerable to warming because they lack adaptive capacity. That capacity can be increased by enhancing economic development, human capital and the propensity for technological innovation, which are precisely the goals of sustainable development. Moreover, enhancing adaptive capacity would also increase their ability to mitigate greenhouse gas emissions.
Such an integrated strategy — simultaneously pursuing sustainable development while advancing the capacity to adapt to and/or mitigate climate change — could be accomplished by meeting the United Nations' Millennium Development Goals. In any event, achieving those goals would cost no more than the Kyoto Protocol while delivering substantially greater benefits.
Accordingly, over the next few decades the focus of climate policy should be to: (a) broadly advance sustainable development, (b) reduce vulnerabilities to climate-sensitive problems that are urgent today and might be exacerbated by future climate change, and (c) implement “no-regret” policies, such as eliminating subsidies for energy consumption, land conversion and agricultural overproduction in developed countries, while (d) striving to expand the universe of such measures through research and development of cleaner and more affordable technologies. Such a policy would help solve urgent problems facing humanity today while preparing it to face future problems that might be caused or heightened by climate change.