<b>Marcotullio<b>, P. J., L. Bruhwiler, S. Davis, J. Engel-Cox, J. Field, C. Gately, K. R. Gurney, D. M. Kammen, E. McGlynn, J. McMahon, W. R. Morrow, III, I. B. Ocko, and R. Torrie, 2018: Chapter 3: Energy systems. In Second State of the Carbon Cycle Report (SOCCR2): A Sustained Assessment Report [Cavallaro, N., G. Shrestha, R. Birdsey, M. A. Mayes, R. G. Najjar, S. C. Reed, P. Romero-Lankao, and Z. Zhu (eds.)]. U.S. Global Change Research Program, Washington, DC, USA, pp. 110-188, https://doi.org/10.7930/SOCCR2.2018.Ch3.
North America’s annual share of global CO2e emissions reached its first peak during the 1920s, when the share ranged from 50% to 58% of total emissions, which at that time were 490 to 550 Tg C (1.8 to 2.0 Pg CO2e). By 1945, global emissions levels reached 672 Tg C (2.5 Pg CO2e) per year, at which point North America accounted for about 59% of total annual emissions.11
Thereafter, North America’s annual share started a monotonic decline that, by 2008 despite reaching an absolute regional high of 1,830 Tg C (6.6 Pg CO2e), was less than 21% of the total annual global emissions. By 2013, the North American annual share of total global emissions was down to 17%. The cumulative share from North America has been steadily falling since the late 1950s, when it was about 43%, to 2013 when it stood at around 29% (see Figure 3.9). The declining annual and cumulative shares of North American energy-related CO2e emissions demonstrate the growing influence of fossil fuel combustion in emerging economies.