"Urban transport systems based on a combination of rail lines, bus lines, bicycle pathways, and pedestrian walkways offer the best of all possible worlds in providing mobility, low-cost transportation, and a healthy urban environment." –Lester R. Brown, Plan B 4.0: Mobilizing to Save Civilization.
Part 1. Facing the Climate Challenge: Introduction
The earth is getting warmer. The 15 warmest years since global recordkeeping began in 1867 have all come since 1980. Hardly a week goes by without new reports of ice melting, record temperature highs, or more destructive storms. 1
The temperature series maintained by the Goddard Institute for Space Studies of the National Aeronautics and Space Administration (NASA) shows that the 10 months preceding June 2002 (August 2001 through May 2002) were uncommonly warm, setting several records. Temperatures for September and November were the highest ever recorded for those months in the last 134 years. Those for August, December, January, March, April, and May were the second highest on record for those months. If these record or near-record temperatures continue, then 2002 will likely set a new annual record, moving above 1998, the previous high. 2
With emissions of carbon dioxide (CO2), the principal greenhouse gas, continuing to rise, further increases in temperature are almost inevitable. The latest report by the Intergovernmental Panel on Climate Change (IPCC) projects that global average temperature will rise by 1.4–5.8 degrees Celsius (2.5–10.4 degrees Fahrenheit) by the end of this century. This will undoubtedly alter every ecosystem on the earth and every facet of human activity. 3
Perhaps the most pervasive evidence of warming to date is seen in ice melting. In Alaska, where wintertime temperatures now average up to 7 degrees Fahrenheit above the norm, glaciers are retreating at an accelerating rate. A similar situation exists in the Andes. And recent data on the Himalayas indicates that glaciers there too are melting at an alarming pace. 4
One of the concerns of scientists is that climate change will not always be a linear process. For example, if the ice in the Arctic Sea continues to melt, leaving the sea ice-free during the summers, as projected for sometime within the next several decades, the heat balance of the region could change dramatically. With the Arctic Sea largely covered with ice and snow, roughly 80 percent of the incoming sunlight is bounced back into space, while 20 percent is absorbed as heat. But an ice-free Arctic Sea during the summer would mean that 20 percent of the incoming sunlight will bounce back into space and 80 percent will be absorbed as heat. While the melting of the Arctic Sea ice does not affect sea level, a dramatic warming of the Arctic could lead to rapid melting of the Greenland ice sheet. 5
An article in Science reports that if the Greenland ice sheet were to melt entirely, and this could only happen over a long period of time, it would raise sea level by 23 feet. At some point, feedback loops, such as the one just described for the Arctic, could begin to reinforce existing trends. Once certain thresholds are crossed, change can come rapidly and unpredictably—leaving a bewildered and perhaps frightened world in its wake. At issue is whether our political institutions, which could not prevent these mega-scale changes, will be able to deal with them when they occur. 6
1. National Aeronautics and Space Administration, Goddard Institute for Space Studies, “Global Temperature Anomalies in .01 C,” at <www.giss.nasa.gov/data/update/gistemp/GLB. Ts.txt>, viewed 20 June 2002.
3. Intergovernmental Panel on Climate Change, Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change (New York: Cambridge University Press, 2001), p. 13.
4. Timothy Egan, “Alaska, No Longer So Frigid, Starts to Crack, Burn and Sag,” New York Times, 16 June 2002; Andes from Andrew Revkin, “A Message in Eroding Glacial Ice: Humans Are Turning Up the Heat,” New York Times, 19 February 2001; Himalayas from Robert Marquand, “Glaciers in the Himalayas Melting at a Rapid Rate,” Christian Science Monitor, 5 November 1999.
5. Richard Kerr, “Will the Arctic Ocean Lose All Its Ice?” Science, 3 December 1999, p. 1828.
6. Dorthe Dahl-Jensen, “The Greenland Ice Sheet Reacts,” Science, 21 July 2000, pp. 404–05.
Copyright © 2002 Earth Policy Institute