California Beat Its 2020 Emissions Target Four Years Early

California has cleaned up its air.

In 2016, California’s greenhouse gas emissions were lower than in 1990, despite a larger population and booming economy, the state’s air resources board reported. Emissions in 1990 were 431 million metric tons and they were 429.4 million metric tons in 2016.

The savings relative to the peak in 2004 are equivalent to taking 12 million cars off the road. The state only has a total of 14 million registered vehicles.

The emissions reductions come from a mixture of state-level measures that include mandating that a certain fraction of electricity come from renewable resources, regulating vehicle emissions, and a carbon pricing and trading program shared with Quebec. Electricity production was the biggest source of greenhouse gas emissions reductions, the board said, in part because of cleaner sources such as hydroelectricity from a rainy year.

While transportation emissions climbed that year, the board credits biofuels with limiting the damage.

The 2020 target is mandated by a 2006 law, but since then California has passed an even stricter law requiring emissions to be 40% below 1990 levels by the year 2030. Per capita emissions of around 10.8 metric tons per person are about half the U.S. national average.

Overall 2016 greenhouse gas emissions for the U.S. in 2016 were around 6.5 billion metric tons of carbon dioxide equivalents, and represented about 15% of global emissions in 2014.

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