Year kt of CO2 equivalent 1970 17.8173 1971 18.463 1972 19.202 1973 17.2912 1974 17.8602 1975 18.1127 1976 18.4659 1977 17.9988 1978 18.8802 1979 19.3656 1980 20.0199 1981 20.8512 1982 21.2497 1983 21.3873 1984 21.4782 1985 21.7777 1986 22.1029 1987 22.4624 1988 22.8303 1989 23.2502 1990 23.6707 1991 24.077 1992 24.5482 1993 24.9097 1994 25.2433 1995 25.5508 1996 25.8362 1997 26.1022 1998 26.3359 1999 26.55 2000 26.5386 2001 26.716 2002 26.6675 2003 26.9025 2004 27.0288 2005 27.2057 2006 27.3832 2007 27.5719 2008 27.7546 2009 27.9375 2010 28.1205 2011 28.401705 2012 28.68291