What is the stabilisation wedge theory?

Physicist Professors Robert Socolow and ecologist Stephen Pacala, Co-Directors of The Carbon Mitigation Initiative at Princeton University have come up with a way to frame the challenge of global warming called ‘stabilisation wedges’. The phrase ‘stabilisation wedges’ was coined in a paper in an academic journal in 2004.

The theory claims that humanity already possesses the fundamental scientific, technical and industrial know-how to enable us to transition to a low carbon world.

In order to stabilise the world’s carbon emissions, Socolow and Pacala suggest not searching for one solution, but to harness seven categories of reduction, using current technologies that could be scaled up over the next 50 years. The wedges each play a part in lowering the angle of the line representing carbon emissions growth. Combined they would reduce carbon emissions enough to stabilise carbon concentration in the earth’s atmosphere.

A wedge represents an activity that reduces emissions to the atmosphere that starts at zero today and increases to 1 giga tonne per year of reduced carbon emissions in 50 years, a cumulative total of 25 giga tonnes of emission reduction over 50 years.

The wedges focus on:

Efficiency and conservation

• Improved fuel economy – doubling the fuel economy of the worlds cars
• Reduced reliance on cars – halving the number of miles travelled by car
• More efficient buildings – using energy efficient light bulbs in all commercial buildings
• Improved power plant efficiency – increasing current coal based electricity at twice today’s efficiency

Decarbonisation

• Substituting natural gas for coal – carbon emissions from natural gas plants are almost half that of coal plants
• Storage of carbon captured in power plants – carbon capture and storage (CCS)  technology prevents 90% of carbon emissions reaching the atmosphere. Installing CCS at 800GW of baseload coal plants in next 50 years.
• Doubling the world’s current nuclear capacity – recognised that this would require restoring public confidence in safety and waste disposal.
• Increasing wind electricity capacity by 50 – estimated to require 30m hectares of land (equivalent to 3% of the area of the United States)
• Increasing solar energy capacity by 700 – estimated to require 2m hectares of photovoltaic panels (equivalent to 3 m2 per person)
• Increasing biofuel production by 50 – estimated to require a sixth of world’s crop land. Recognised that it could affect traditional agricultural output.

Natural Sinks

• Reducing tropical deforestation and management of temperate and tropical forests – would require 2 stages
(1) doubling the current rate of forest planting
(2) eliminating tropic deforestation within 50 years
• Agricultural soil management – adopting conservation tilling in all agricultural soil, which is a way of growing crops from year to year without disturbing the soil through ploughing. reduces decomposition of organic material which would release greenhouse gases.

Wedges include solar power, wind power, more efficient appliances, green buildings, carbon capture, public transport, transport fuel efficiency and nuclear power.

ARTICLE: Stabilization Wedges: Solving the Climate Problem for the Next 50 Years with Current Technologies