In 2016, a full four years before a legislatively mandated deadline, California achieved an important milestone – it had reduced its greenhouse gas (GHG) emissions below the state’s 1990 levels. Under AB 32, CARB was required to establish a target for the state’s 2020 GHG emission rate, mandated to match or be lower than the state state’s 1990 GHG emissions level. CARB set the ambitious AB 32 goal at 431 MMTCO2e. In 2016, the state’s GHG emissions dropped to 429.4 MMTCO2e. Achieving these reductions earlier than expected is all the more impressive as it has been achieved during a period of substantial economic and population growth in the nation’s most affluent state.

Almost all of the emission reductions came from the electricity generation sector; where increased use of renewables, a productive hydro-electric season, and the replacement of coal-fired power with electricity generated by natural gas led the carbon-reduction effort. Thus, GHG emissions could increase should lower levels of rainfall dry up hydro electricity’s contribution to the power supply and increase the use of natural gas peaker plants to compensate for the loss of renewable power during hot summer days.

The transportation sector’s carbon emissions have actually increased year-over-year since 2013, in spite of the fact that today’s vehicles are more energy efficient and emit drastically less pollutants than their predecessors from the 1990s. Although transportation emissions are lower today than in the base year of 2000, between 2013 and 2016 GHG emissions from the transportation sector rose at an average annual rate of 2.8 million metric tonnes of carbon dioxide equivalent (MMTCO2e) per year. This upward trend is blamed on a variety of different factors: low gas prices, a growing economy, higher employment, consumers’ preference for roomier, less efficient vehicles and a slower-than-anticipated transition to electric models.

Transportation is the largest single source of GHG emissions in California, spewing 39.5% of the state’s total GHG emissions into the atmosphere. Not only is the mass of transportation emissions increasing, its portion of the inventory is growing as well. Thus, to both maintain the accomplishment of reaching the AB 32 goal, as well as meeting the much more stringent SB 32 requirement – which is a 40% reduction below 1990 levels by 2030 – the state will need to achieve substantial reductions from the growing mobile source of GHG emissions in the near term. Unfortunately, the Administration of Governor Jerry Brown is taking steps that makes meeting this goal all but impossible.

To understand this, it is important to note that CARB cites one of the reasons that the transportation sector’s GHG emission are increasing is because of “slower than anticipated transition to electric” vehicles. This could have been predicted, given how long it has taken California to achieve long sought zero emission vehicle (ZEV) sales targets.

By way of reminder, it was 28 years ago that CARB first adopted requirements for automobile manufacturers to build and sell ZEVs in California. The mandate, established in 1990, that stated seven percent of the vehicles sold by major auto makers be ZEVs by 1997, still has not been met (in 2017 5.31% of total auto sales were battery electric or fuel cell vehicles). Although the original seven percent goal was long ago modified by CARB, 2018 might be the year where California meets the 1997 ZEV sales targets as projections show that 9.5% of total automobile sales could be ZEVs by the end of the year. Nevertheless, it is instructive and notable that California needed 28 years to achieve this rather modest ZEV sales objective.

The historical pace of ZEV adoption is critical to forecasting the future, helps us understand why GHG emissions in the transportation are increasing and informs the challenges facing the state as we shift our attention to achievement of the SB 32 GHG emission targets. Part of the problem with Governor Brown’s strategy to reduce GHG emissions in the transportation sector, and meet a 40% reduction goal for 2030, is that it is both overly dependent on one technology – battery electric vehicles – and that it is overly dependent on back-loaded emission reductions.

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