1. Environmental and Natural Resource Economics 3rd ed. Jonathan M
Environmental and Natural Resource Economics 3rd ed. Jonathan M. Harris and Brian Roach Chapter 18 – Global Climate Change
Copyright © 2013 Jonathan M. Harris

2. Figure 18.1: Carbon Emissions from Fossil Fuel Consumption, 1860-2008
Carbon emissions from fossil fuels have risen steadily since the Industrial Revolution, with a much more rapid rate of increase after The rate of increase has accelerated further since 2000, with an especially notable growth in emissions from coal, largely due to increased emissions from China and other rapidly developing countries.
Source: Carbon Dioxide Information Analysis Center (CDIAC), accessed August 2012.
Note: Emissions in million tons (MMt) of carbon. To convert to MMt of CO2, multiply by 3.67.

3. Figure 18.2: Projected Carbon Dioxide Emissions, 1990-2035, by Region (Million Metric Tons of CO2)
Current projections by the Department of Energy show global carbon emissions increasing through 2035, mainly based on growing emissions from the developing world. The DOE projections show OECD (developed) economies’ emissions remaining about constant, while emissions from developing economies increase steadily. Note that these are “business as usual” projections that do not take into account the possibility of policies to reduce carbon emissions in developed nations, and to encourage low-carbon development paths for lower-income nations.
Source: U.S. Department of Energy, The vertical axis in Figure 18.2 measures million metric tons of carbon dioxide (the vertical
axis in Figure 18.1 shows million metric tons of carbon; the weight of a given amount of emissions measured in tons of carbon dioxide is about 3.67 times the total weight in carbon). Note: OECD = Organization for Economic Cooperation and Development.

4. Figure 18.3: Per-Capita Emissions of Carbon by Country
Current per capita carbon emissions show a huge disparity across nations. U.S. per capita emissions are about twice those of Europe and Japan, while developing nations have much lower emissions per person. Some developing nations, such as China and Mexico, have reached per capita emissions levels similar to those of developed nations such as France. Considering the large populations of developing nations such as India, the potential for increased total emissions from these nations is very great.
Source: U.S. Department of Energy, International Energy Annual 2008.

5. Figure 18.4: Global Annual Temperature Anomalies (°C), 1850-2010
Global temperatures have risen by about 1 degree Centigrade since the Industrial Revolution. The upward trend is especially marked since about According to the Intergovernmental Panel on Climate Change (IPCC), human-caused impacts on the atmosphere, primarily carbon emissions, have contributed substantially to the observed warming over the last 50 years.
Source: CDIAC, accessed 2011,
Note: The zero baseline represents the average global temperature from 1961 to 1990.

6. Figure 18.5: Sea Level Rise, 1880-2000
100 50
Sea level (mm)
-50
-100
Ocean temperatures have increased along with atmospheric temperatures. This leads to expansion of ocean water volume and, together with melting icecaps, causes sea-level rise. At the higher ranges of projected temperature increases, sea-level rise could be several meters, swamping major coastal cities and low-lying regions such as Bangladesh and much of Florida.
-150
-200
Source: IPCC, 2007a.
Note: Solid line shows average of different studies; shaded area shows 90 percent confidence intervals.

7. Figure 18.5: Global Temperature Trends, 1990-2100
Degrees Fahrenheit -2 2 4 6 8
1900 to 2008 observations
1900 to 2008 simulation
Lower emissions scenario
Higher emissions scenario
Even higher emissions scenario
Projections of future temperature trends vary across a wide range, but all show temperatures continuing to rise. The lower range projections show an increase of about 2 degrees Centigrade (3.6 degrees Fahrenheit) above pre-industrial levels by 2100, but high range projections show an increase of as much as 8 degrees Fahrenheit. These are global averages, and temperature changes in the higher range would imply massive impacts especially in hotter, drier, and coastal areas.
Source: U.S. Global Change Research Program,
Note: CO2e = CO2 equivalent ; ppm = parts per million;

8. Figure 18.7: The Relationship Between the Level of Greenhouse Gas Stabilization and Eventual Temperature Change
0°C
1°C
2°C
3°C
4°C
5°C
Eventual Temperature change (relative to pre-industrial)
400 ppm CO2 e
450 ppm CO2 e
550 ppm CO2 e
650 ppm CO2 e
750 ppm CO2 e
Stabilization of atmospheric carbon at ppm CO2 would imply a temperature increase of around 2-3 degrees Centigrade (median estimate, with a wide margin of error as shown). “Business as Usual”, with no sustained effort to control carbon emissions, implies an atmospheric concentration of ppm by the end of the century, leading to an average temperature rise of about 4 degrees Centigrade (7 degrees Fahrenheit), with a margin of error extending up to 6 degrees Centigrade (10 degrees Fahrenheit) or more.
Source: Stern, 2007.

9. Eventual Temperature Rise Relative to Pre-Industrial Temperatures
Table 18.1: Possible Effects of Climate Change
Type of Impact
Eventual Temperature Rise Relative to Pre-Industrial Temperatures
1°C
2°C
3°C
4°C
5°C
Freshwater Supplies
Small glaciers in the Andes disappear, threatening water supplies for 50 million people
Potential water supply decrease of 20–30% in some regions (Southern Africa and Mediterranean)
Serious droughts in Southern Europe every 10 years
1–4 billion more people suffer water shortages
Potential water supply decrease of 30–50% in Southern Africa and Mediterranean
Large glaciers in Himalayas possibly disappear, affecting ¼ of China’s population
Food and Agriculture
Modest increase in yields in temperature regions
Declines in crop yields in tropical regions (5–10% in Africa)
150–550 million more people at risk of hunger
Yields likely to peak at higher latitudes
Yields decline by 15–35% in Africa
Some entire regions out of agricultural production
Increase in ocean acidity possibly reduces fish stocks
Human Health
At least 300,000 die each year from climate–related diseases
Reduction in winter mortality in high latitudes
40–60 million more exposed to malaria in Africa
1–3 million more potentially people die annually from malnutrition
Up to 80 million more people exposed to malaria in Africa
Further disease increase and substantial burdens on health care services
Coastal Areas
Increased damage from coastal flooding
Up to 10 million more people exposed to coastal flooding
Up to 170 million more people exposed to coastal flooding
Up to 300 million more people exposed to coastal flooding
Sea level rise threatens major cities such as New York, Tokyo, and London
Ecosystems
At least 10% of land species facing extinction
Increased wildfire risk
15–40% of species potentially face extinction
20–50% of species potentially face extinction
Possible onset of collapse of Amazon forest
Loss of half of Arctic tundra
Widespread loss of coral reefs
Significant extinctions across the globe
Impacts of climate change on water supplies, food and agriculture, health, and ecosystems become more extreme at the higher temperature projection scenarios. Some beneficial effects in the lower range projections, such as increased crop yields in temperate regions, are outweighed by negative effects such as major declines in crop yields in tropical areas as temperatures continue to rise.
Sources: IPCC, 2007b; Stern, 2007.

10. Table 18. 2: Estimates of Annual Damages to the U. S
Table 18.2: Estimates of Annual Damages to the U.S. Economy from Global Climate Change (Billions of 1990 dollars)
Cline (2.5°C)
Fankhauser (2.5°C)
Nordhaus (3°C)
Titus (4°C)
Tol (2.5°C)
Agriculture
17.5
3.4
1.1
1.2 10
Forest loss
3.3
0.7 X
43.6
Species loss 4
1.4 5
Sea level rise 7 9
12.2
5.7
8.5
Electricity
11.2
7.9
5.6
Nonelectric heating
–1.3
Mobile air conditioning
2.5
Human amenity 12
Human mortality and morbidity
5.8
11.4
9.4
37.4
Migration
0.5
0.6 1
Hurricanes
0.8
0.2
0.3
Leisure activities
1.7
0.75% GDP
Water supply availability
15.6
Water supply pollution
32.6
Urban infrastructure
0.1
Air pollution
3.5
7.3
27.2
Total in billions
61.1
69.5
55.5
139.2
74.2
Total as percent of GDP
1.3
1.5
Estimates of damages from global climate change vary by study, but in general are in the range of 1-3% of GDP in standard economic analyses.
Source: Nordhaus and Boyer, 2000, p. 70.
Note: “X” denotes items that are not assessed or quantified. GDP = gross domestic product.

11. Table 18.3: Damage to the U.S. Economy from Climate Change
In Billions of 2006 Dollars
As a Percentage of GDP
2025
2050
2075
2100
Hurricane damages 10 43
142
422
0.05%
0.12%
0.24%
0.41%
Real estate losses 34 80
173
360
0.17%
0.23%
0.29%
0.35%
Energy sector costs 28 47 82
141
0.14%
Water costs
200
336
565
950
1.00%
0.98%
0.95%
0.93%
Total costs
271
506
961
1873
1.36%
1.47%
1.62%
1.84%
Damages typically increase over time.
Source: Ackerman and Stanton, 2008.

12. Figure 18.8: Increasing Damages from Rising Global Temperatures
At higher ranges of projected temperature increase, damages can rise a high as 10% of global GDP, according to economic studies using integrated-assessment dynamic models based on scientific and economic analysis.
Source: Nordhaus, 2000, p. 95.
Note: National damages are weighted by population to derive global output damage.

13. Figure 18.9: Long-Term Costs and Benefits of Abating Global Climate Change, 1990-2270 2 4 6 8 10 12 14 16
Percent of GDP
Benefits, high damage case
Benefits, central case
Costs
Cost-benefit analysis of policies to respond to climate change typically show costs being higher in the short-term, while benefits of action are larger in the long-term. This poses a dilemma of how to balance costs and benefits. The choice of a discount rate is a key factor here, since higher discount rates will make longer-term costs seem relatively insignificant. In the Stern Review on the Economics of Climate Change (2007), the choice of a low discount rate leads to a high weighting for long-term benefits, and a recommendation for strong action to avert climate change.
Source: Adapted from Cline, 1992.

14. Increase in average annual number of coastal flood victims
Table 18.4: Regional-Scale Impacts of Climate Change by 2080 (millions of people)
Region
Population living in watersheds with an increase in water- resources stress
Increase in average annual number of coastal flood victims
Additional population at risk of hunger (figures in parentheses assume maximum CO2 enrichment effect)
Europe
382–493
0.3
Asia
892–1197
14.7
266 (–21)
North America
110–145
0.1
South America
430–469
0.4
85 (–4)
Africa
691–909
12.8
200 (–2)
The impacts of climate change will tend to fall more heavily on poorer areas of the world. Developing nations face increased costs of flooding, damage to agriculture, and water stress.
Source: Adapted from IPCC, 2007b.
Note: These estimates are based on a business-as-usual scenario (IPCC A2 scenario). The CO2 enrichment effect is increased plant productivity, which at maximum estimates could actually decrease the number at risk of hunger.

15. Figure 18.10: Carbon Stabilization Scenarios (450 and 550 ppm CO2), 1980-2120
Since damage from a stock pollutant such as atmospheric carbon is related to the level of accumulation, not emissions, control of the problem requires stabilization of atmospheric carbon levels. The Intergovernmental panel on Climate Change (IPCC) has called for stabilization at levels no greater than 450 – 550 parts per million (current levels are 380 ppm). To achieve these targets, global emissions would have to decline sharply starting around 2020, as shown above.
Source: Adapted from IPCC, Climate Change 2001: The Scientific Basis,
Note: ppm = parts per million.