Few things are as institutionalized in the US economy as the way we use energy. Decisions made decades, even centuries ago, impact our daily lives – the way we fuel our cars, how we warm our homes and cool our offices are largely legacies from prior generations.

As the world meets in Lima, Peru to hack out the beginnings of a new climate agreement, a new report released last month tackles the question, is it technically feasible for the US to cut carbon emissions by 80% by 2050 (based on 1990 levels), enough to help avert more than a 2 degree rise in global temperatures that scientists say will be catastrophic. (The US study was done in conjunction with 14 other countries. Results discussed here are for the US only, but the greater target of avoiding 2 degree temperature change relies on more than just the US cutting emissions). In other words, the study lays out a pathway for deep decarbonization of the US economy.

Source: Deep Decarbonization Pathways report

The report is important for two main reasons. First, instead of choosing a policy and analyzing it moving forward, the study uses a scientifically agreed upon goal and works backwards to discover what choices will impact any progress. Second, by analyzing targets and the technical feasibility, it leaves room for readers to interpret what policies will get us there.

The target is not only feasible, but the results could largely feel gradual, say the reports authors, which included energy consulting firm Energy Environment Economics (E3) and national laboratories Lawrence Berkeley and the Pacific Northwest. The report and its implications should be a challenge to any energy investment decision made today at national and local levels.

Decarbonization: Four Choices

The report broadly outlines four scenarios for deep decarbonization, to reach a target of lowering GHG emissions by 80% of 1990 levels by 2050. It’s a starlingly ambitious number that relies on shifting any and all energy demand to electricity, which is decarbonized wherever possible. For example, each scenario moves the US from relying primarily on gasoline for our cars to electricity. The four scenarios include:

• High renewable: relying heavily on renewable energy for generation capacity
• High nuclear: a higher share of electricity comes from nuclear power, with hydrogen and biofuels playing a larger role in the transportation sector
• High carbon capture and sequestration (CCS): preserving fossil fuels’ dominance in the electricity sector, this approach uses CCS to capture CO2 emissions
• Mixed cases: a mix of the above three approaches

Source: Deep Decarbonization Pathways report

In all of the cases, the authors emphasize three major transitions. First, everything from our buildings to our cars needs to be more efficient (shifting to an economy run almost entirely on electricity means that even with efficiency gains, electricity capacity will have to double by 2050). Second, the energy supply is decarbonized (how it’s decarbonized is described in the four scenarios above – see chart for an example on residential demand) and third, wherever possible, fuels are supplanted with electricity.

 Source: Deep Decarbonization Pathways report

Knock Knock, Washington

The report shies away from spelling out policy recommendations, but it’s not hard to infer what should – and must – be done to reach the goals. Take, for instance, the second chart the authors present (second only to the graph showing falling CO2 emissions, the whole point of the project), and the theme of inertia is front and center. Decisions made today have carbon implications, not only for tomorrow, but decades and perhaps a century down the line.

Source: Deep Decarbonization Pathways report

Fixing problems with a short-term view, without considering the impact those decisions will have thirty years out could derail progress. The report states that:

“From the perspective of this study, there are different ways that the U.S. can achieve the 2025 target, some of which would lay the necessary groundwork for deeper reductions to follow, and others that might meet the target but tend to produce flat, rather than declining, emissions in the long term. This indicates the importance of evaluating near-term approaches in the light of deep decarbonization analysis.”

In other words, projects that may seem like low-carbon choices right now, such as building a new natural gas-fired power plant, might be off-target in any scenario but High CCS. Another example is tighter fuel emission standards that help short-term air quality goals but do nothing to move autos off gasoline.

The report could serve as a rallying cry to the divestment movement; decisions made today that are not in line with the 2050 vision are at risk to become a stranded asset. “There is still sufficient time for the U.S. to achieve 80% GHG reductions by 2050 relying on natural infrastructure turnover. However, to achieve emissions goals and avoid the costs of early retirement, it is critical to account for economic and operating lifetimes in investment decisions,” the report reads. 

Technical and political feasibility aren’t the same. Still, “In terms of technical feasibility and cost, this study finds no evidence to suggest that relaxing the 80% by 2050 emissions target or abandoning the 2°C limit is justified.” Perhaps the inertia, and the legacy from this report, can be an understanding of how to start.