Carbon Dioxide Emissions
Concentrations of carbon dioxide in the atmosphere have been increasing since the Industrial Revolution. In 1750, there were 280 parts per million (ppm) but by 2005 the figure was 380 ppm, a rise of over one-third. As can be seen in figure 1, below, much of this staggering increase—measured at Mauna Loa, Hawaii, the meteorological station with the longest records in the world—has taken place since 1959. From 1997 to 1998, there was an increase of 2.87 ppm, the largest single yearly jump ever recorded.

Data have been obtained from measurements of air that has been trapped in ice over thousands of years. These reveal that today’s carbon dioxide concentration has not been exceeded in the past 420,000 years and probably not during the past 20 million years. As well as the level, the rate of increase over the past century is unprecedented. Compared to the relatively stable carbon dioxide concentrations—in the preceding several thousand years, there were relatively minor fluctuations around the 280 ppm figure—the increase during the industrial era, and particularly the most recent increase, is proving catastrophic.

This phenomenon is perhaps unsurprising. Fossil fuels contain the energy stored from the sun that took hundreds of thousands of years to accumulate, yet within the space of a few generations—a mere blink of the planet’s life so far—we are burning it: Figure 2 shows the dramatic and accelerating growth in carbon emissions from fossil fuel use, which is the major source of the accumulating concentrations. Half the total emissions since 1750 have occurred since the mid-1970s, with annual emissions doubling since the mid-1960s and trebling since the mid-1950s. Emissions of carbon dioxide from fossil fuel burning rose from about 10 million tons of carbon a year in 1800 to around 7 billion tons at present, which is 700 times as much. Future scenarios suggest that, unless dramatic policy changes are made, annual emissions will rise substantially and inexorably. At the extreme, they could be five times their current level by 2100, resulting in the 10°F or so of global warming referred to earlier. In fact, since our atmosphere and oceans take a long time to warm up (and cool down), the effects of these higher emissions could get even worse over time.

At the start of this century, total annual global emissions from fossil fuels amounted to more than 7,000 million metric tons of carbon (MtC). Emissions from North America (United States and Canada) made up over a quarter of the total, and those from Western Europe accounted for about one-tenth. The United States continues to have the highest fossil fuel–related emissions, reaching 1,580 million metric tons of carbon in 2003. This represents nearly a quarter of the world’s total. U.S. emissions are two-thirds higher than those of the world’s second-largest emitter, the People’s Republic of China, and almost seven times those of the whole African continent. In general, emissions from the United States have risen each year since 1900, with the exception of brief periods in the 1930s and 1980s. Since 1990, fossil fuel emissions have risen between 1 and 2 percent each year. Chapter 2 explains in detail the patterns of changing energy consumption and the underlying trends that have driven this upward and led to the increasing emissions.

Each person in the world is engaged in fossil fuel–based activity that results in the emission of, on average, 1.1 metric tons of carbon. If these emissions are compared by country, the differences are stark. Near the top of the league is the United States, at 5.5 tC per person, around five times the global average. In the fifteen Western European members of the European Union, they are 2.3 tC. The developing nations currently contribute much less, with China’s emissions at 0.7 tC per person, Indonesia’s at 0.4 tC, and India’s at 0.3 tC. Afghanistan is at the bottom of the emissions league, at 0.01 tC, just one one-hundredth of the global average and less than one five-hundredth of that of the average U.S. citizen.

Copyright © 2007 by Mayer Hillman with Tina Fawcett and Sudhir Chella Rajan. All rights reserved.