California's industrial emissions of greenhouse gases dropped for the third straight year in 2011, according to figures released this month by the California Air Resources Board (CARB). The decline adds to a so-far unbroken trend since CARB started tracking the emissions in 2008.
The figures include emissions from power plants, oil and gas production and refining, cement manufacture and a few other industrial processes. They do not include CO2 emissions from motorized transportation or from sources such as households and commercial businesses, which altogether account for about half the state's emissions.
According to CARB, the state's reported industrial greenhouse gas emissions totaled 111,044,931 metric tons of CO2 or its equivalent -- down from 117,624,594 tons in 2010. The reduction, 6.58 million tons of CO2, is equivalent to taking 1.37 million cars off the road. Furthermore, 2011's emissions represent a drop in annual emissions of more than 22 million tons from 2008's levels. That's about a third of what humans worldwide emit each day.
If anything, the drop is likely somewhat higher than reported: The 2011 data includes more stringent reporting than in previous years, and some of the emissions counted in 2011's figures were likely left out of those for 2008-2010.
The main factor behind the drop in emissions was a 10 million-ton decrease in emissions from electricity generation, which more than made up for increased emissions from the oil, gas, and cement industries. According to CARB, that decrease in electrical generating emissions reflects both an increase in non-carbon power generation such as wind, solar, and hydro, and a decrease in consumption.
Mandatory reporting of greenhouse gas emissions in California was enacted when the California Global Warming Solutions Act (AB 32) was passed in 2006. Under the law, all facilities that emit more than 25,000 tons of greenhouse gases per year must track and report those emissions every six months. The "floor" for reportable emissions drops to 10,000 tons this year.
The same law requires the state to reduce greenhouse gas emission levels to 1990 levels by 2020 -- that's 433 million metric tons in total, from all industrial and other sources -- and establishes the nation's leading carbon "cap and trade" law, which is expected to help Californian industry contribute about a fifth of the needed reduction in emissions.