Over at the Conversation, Climate Scientist Mike Hulme has a short article “Science can’t settle what should be done about climate change“. He argues the politics, not science, must take centre stage. He makes four points.

• How do we value future public goods and natural assets relative to their value today?
• Is “commodifying” nature appropriate?
• The morality of technologies for mitigation or adaptation. For instance, fracking and GM crops.
• The role of national governments against multilateral treaties or international governing bodies. Also the consequent impacts on democracy.

Christopher Wright (Professor of Organisation Studies at University of Sydney) commented

The one problem I have with the above analysis is that the focus on climate science has been a quite deliberate strategy by those seeking to deny or cast doubt on the urgency of the problem. This has meant the debate has continually stalled around issues of whether climate change is a problem or not. The science highlights that it is a very big problem indeed. However, while the science continues to be questioned, we will be unable to have the serious policy conversation about what we need to do to avoid catastrophic changes to our ecosystem.

My reply (with references) is

Science might point to a very big problem, but it cannot translate that into coherent policy terms. Nor can it weigh that against the effectiveness of policies, nor the harms policies can cause. Economics is central to asking those questions. The key figure that encapsulates the predicted harm of climate change is the social cost of carbon SCC, expressed in tonnes of CO2 equivalent. In 2006 Stern measured this as $85/tCO2¹. A year later the AR4 SPM² stated a range of -$3 to $95/tCO2 from peer reviewed studies, with an average of $12/tCO2.

The key figure for the effectiveness to policy is the marginal abatement cost. Basically this refers to the marginal cost of preventing a tonne of CO2 equivalent entering the atmosphere. For policy to be of net benefit, MAC needs to be less than SCC.

$85 is about £52, and $12 about £7.50. In the UK onshore wind turbines receive a direct subsidy equivalent to £98/tCO2³ saved, and offshore £195/tCO2. Then there are the extra costs of transmission lines, and other costs which could double those figures.

Then you need to recognize that a global problem will not be solved by unilateralist policies by a country with producing less than 2% of global emissions. So the UK is impoverished now by harmful, ineffectual, policies, and still future generations suffer >90% of the consequences of unmitigated climate change. Mike Hulme’s four points above are in addition to this, weighing further against mitigation policy.

Notes

1. The Stern review noted on pages xvi-xvii

   Preliminary calculations adopting the approach to valuation taken in this Review suggest that the social cost of carbon today, is of the order of $85 per tonne of CO2……. This number is well above marginal abatement costs in many sectors.
   

2. The UNIPCC AR4 Summary for Policymakers in 2007 stated on page 22.

   Peer-reviewed estimates of the social cost of carbon in 2005 average US$12 per tonne of CO2, but the range from 100 estimates is large (-$3 to $95/tCO2).
   

3. The renewables obligation credit (ROC) buy-out price is currently £42.02 per megawatt hour, as determined by OFGEM. The British renewable industry lobby group renewableUK, uses DECC’s carbon saving figure of 430g/kWh, as stated in an appendix to the Energy Efficiency Innovation Review in 2005. £42.02/.430 = £97.67. Onshore wind turbines get one ROC per MWh generated, offshore wind turbines 2 ROCs.

Kevin Marshall

Jo Nova discusses Mike Hulme’s four points here.