Currently concentrations are at 430 ppm CO2e, and rising at 2 ppm per year. Stabilization at 550 ppm CO2e would require global greenhouse gas emissions to peak in the next 10 to 20 years, and by 2050 they would need to be around 25% lower than in 2000. Given population growth and economic growth, the reductions in emissions per capita and per unit of global GDP would be larger - on generally accepted projections for population and GDP growth, the global average for per capita emissions would need to fall to half of current levels and global CO2e emissions per $ of global GDP would need to be one-quarter of current levels.