Caldeira Lab

Greenhouse Gases, Climate Change and the Transition From Coal to Low-Carbon Electricity

Nathan Myhrvold & Ken Caldeira

Energy transitions take time and the climate system is slow to respond to changes in greenhouse gas emissions. As a result, only rapid transitions to the lowest-emitting energy technologies can substantially reduce the amount of warming experienced this century.

Myhrvold, N. P., and K. Caldeira, 2012: Greenhouse gases, climate change and the transition from coal to low-carbon electricity. Environmental Research Letters, 7, 014019, doi:10.1088/1748-9326/7/1/014019.

Ken Caldeira - click to read the video transcript




It appears that there is no quick fix; energy system transitions are intrinsically slow. During a transition, energy is used both to create new infrastructure and to satisfy other energy demands, resulting in additional emissions. These emissions have a long legacy due to the long lifetime of CO2 in the atmosphere and the thermal inertia of the oceans. Despite the lengthy time lags involved, delaying rollouts of low-carbon-emission energy technologies risks even greater environmental harm in the second half of this century and beyond. This underscores the urgency in developing realistic plans for the rapid deployment of the lowest-GHG-emission electricity generation technologies. Technologies that offer only modest reductions in emissions, such as natural gas and—if the highest estimates from the life-cycle analyses are correct—carbon capture storage, cannot yield substantial temperature reductions this century. Achieving substantial reductions in temperatures relative to the coal-based system will take the better part of a century, and will depend on rapid and massive deployment of some mix of conservation, wind, solar, and nuclear, and possibly carbon capture and storage.


Figure: Many decades may pass before a transition from coal-based electricity to alternative generation technologies yields substantial temperature benefits. Panels above show the temperature increases predicted to occur during a 40 yr transition of 1 TWe of generating capacity. Warming resulting from continued coal use with no alternative technology sets an upper bound (solid black lines), and the temperature increase predicted to occur even if coal were replaced by idealized conservation with zero CO2 emissions (dashed lines) represents a lower bound. The colored bands represent the range of warming outcomes spanned by high and low life-cycle estimates for the energy technologies illustrated: (A) natural gas, (B) coal with carbon capture and storage, (C) hydroelectric, (D) solar thermal, (E) nuclear, (F) solar photovoltaic, and (G) wind.