Energy supply: Over a quarter of all greenhouse gases emitted in 2004 came from energy production. That is the largest share of all seven sectors presented by the IPCC authors. In the 35 years after 1970, emissions grew by more than 1.5 times their 1970 levels. Current developments are not changing, warns the IPCC. If the current trend persists, by 2030, 50 percent more greenhouse gases were blown into the atmosphere.