The United States has traditionally been the world’s largest user of energy and the largest producer of CO2, accounting for 18% of energy-related CO2 emissions in 2009 (5.4 gigatons [Gt] in the US compared to 30.3 Gt worldwide) (16). Even worse is the fact that the US share of cumulative CO2 (what has been produced historically and is still mostly in the atmosphere) is 28% (17). However, this is changing rapidly, as China and India are on a pathway to the use of much more energy. China passed the United States in energy-related CO2 production in 2006 and total energy consumption in 2009. On a per capita basis, though, the United States produces three times as much CO2 as China (17.7 metric tons vs 5.8 met­ric tons) (16). Projections for the 32 countries of the Organisation for Economic Co-operation and Development (OECD)7 suggest that energy use will grow by only 0.6% per year, while in the non-OECD countries, dominated by China and India, energy use will grow by 2.3% per year over the next quarter century. According to the World Energy Outlook 2011 New Policies Scenario (18), the total energy demand in the world by 2035 will be one-third higher than in 2010, with non-OECD countries accounting for 90% of the increase. China alone is expected to account for 30% of world energy demand. Fossil fuels account for the large majority of that increase in world energy demand.

Electricity demand is expected to grow by 84% from 2008 to 2035, and coal and natural gas are likely to provide the majority of the increase, though renew­able sources of energy will also increase sharply (Figure 2.4) (19). More than half of the renewable energy component is expected to come from hydropower in non-OECD countries, while about one-quarter might come from wind power. unfortunately, the total CO2 emissions increase from 30.2 Gt in 2008 to 43.2 Gt in 2035 (19). If this actually occurs, global temperatures could rise by 6°C (20), which would be disastrous. Admittedly, projections of this sort do not have a good track record for accuracy (21), but the two main driving forces for this growth in energy use are almost certainly going to happen. One is that the world popula­tion is projected to increase from 7 billion in 2012 to 9 billion by 2050 (22). The other is that non-OECD countries, especially China and India but also Russia and Brazil (the so-called BRIC countries), are rapidly developing, and their energy use per capita will increase to be more in line with the OECD countries.