We now have the results of the study by the Copenhagen Consensus – a group of economists brought together by Bjorn Lomborg, author of The Sceptical Environmentalist – showing which options for averting dangerous climate change they judge to offer the best value for money. Five economists – Finn Kydland, Thomas C. Schelling, Vernon L. Smith, Nancy L. Stokey, and Jagdish Bhagwati (the first three are Nobel laureates) decided the rankings.
Here are they are in full:
1. Marine Cloud Whitening Research – methods for increasing the reflectivity of clouds, for instance by spraying seawater into the air. Whiter clouds would mean more of the sun’s rays reflected back into space, but some scientists fear it could cause unintended consequences such as a lack of rainfall in regions such as the Amazon.
2. Energy R&D – we need much more research into new forms of energy, the group concluded.
3. Stratospheric Aerosol Insertion Research – shooting particles such as sulphates into the highest reaches of the atmosphere. This would mimic the actions of volcanoes, which are known to cool the climate as the particles they send into the atmosphere reflect sunlight away from earth. But would it also cause acid rain? Or changes to rainfall patterns?
4. Carbon Storage Research – the science of capturing and storing carbon dioxide is still in its infancy.
5. Planning for Adaptation
6. Research into Air Capture – taking carbon dioxide out of the air once it has been emitted, such as by using artificial trees.
7. Technology Transfers
8. Expand and Protect Forests – a no-brainer? Why then has it proved so difficult?
9. Stoves in Developing Nations – more efficient cooking stoves would result in the emission of far less soot, also known as black carbon, which heats the earth because when it falls on white snow it means the snow absorbs more heat.
10. Methane Reduction Potfolio – cutting methane turns out to be quite hard, as much of it comes from animals, rotting vegetation and the natural exhalations of the soil.
11. Diesel Vehicle Emissions – this would also cut down on soot, but diesel vehicles are more efficient than ordinary engines, so there is a trade-off.
12. $20 OECD Carbon Tax
13. $0.50 Global CO2 Tax
14. $3 Global CO2 Tax
15. $68 Global CO2 Tax