cc: , , , date: Wed, 25 Feb 2004 13:02:05 +1100 from: subject: RE: Climate stabilisation targets to: Dear Tim, Thanks for your inquiry, especially as it provided me with some useful links to thinking on targets. I am not able to add to your list, as I think the CAN includes Greenpeace and WWF which have similar targets. To my knowledge Australia has no defined target although the Minister for the Environment has spoken of a 60% reduction in emissions as desirable post-Kyoto. My own thinking, which I am trying to distill into a 'popular' book on EGH which I am writing, is that the 2dC above pre-industrial is a fairly credible target, but of course there is no one target that will avoid dangerous effects for someone somewhere from increased extreme events etc., and I worry about the unquantifiable increase in risk of some global catastrophic change. All we can really say from a scientific viewpoint is that risk increases with target warming, and the lower it is the better. But, if we go with 2dC as a warming limit we are still faced with the huge uncertainty range re what stabilised CO2 concentration this requires. With the official IPCC range of climate sensitivity having a factor of three uncertainty, and the possibility that the uncertainty range is even larger, especially with biospheric and other feedbacks in the C cycle, we run a small by finite risk of exceeding 2dC warming even at 450 ppm CO2. For both targets (temperature and CO2 concentrations)we are faced with a political choice of levels of risk, even though those levels are poorly established. I guess my thinking is veering towards setting up strong/urgent carrots and sticks to reduce emissions, without firm top-down targets, and see where it leads us with time. Stress that it is urgent, keep monitoring progress on reductions, and monitor scientific advances that might firm up the levels of risk. My hope would be that with strong enough incentives such as subsidies and quotas for renewables or C-sequestration etc., we might make progress on reductions faster than expected, with market forces eventually taking over as low-C technology becomes competitive and even more profitable through advanced technology. Targets for emission-reductions may be most realistic and practical. Maybe that is naive, but I see strong opposition to top-down targets, although some industry pressure for level playing fields which may favour some government-imposed standards, incentives or even targets. I hope you can keep me informed of your progress, and any reactions to my thoughts would be most welcome. Best regards, Barrie Pittock. Dr. A. Barrie Pittock Post-Retirement Fellow, Climate Impact Group CSIRO Atmospheric Research, PMB 1, Aspendale 3195, Australia Tel: +613 9239 4527, Fax: +61 3 9239 4688, email: WWW: http://www.dar.csiro.au/res/cm/impact.htm Climate Change: An Australian Guide to the Science and Potential Impacts, ed. Barrie Pittock, 2003 (1.4Mb): http://greenhouse.gov.au/science/guide/pubs/science-guide.pdf Note: The old is no longer supported. Currently I am working on a couple of books and other writing re science issues. Please refer any matters re the Climate Impact Group to Dr. Penny Whetton, Group Leader, at , tel.: +61 3 9239 4535. Normally I am in the lab Tuesdays and Thursdays. "Far better an approximate answer to the right question which is often vague, than an exact answer to the wrong question which can always be made precise." J. W. Tukey -----Original Message----- From: Tim Mitchell [mailto:t.mitchell@uea.ac.uk] Sent: Friday, 20 February 2004 1:03 AM To: Pittock, Barrie (AR, Aspendale) Cc: Mike Hulme; Nick Brooks Subject: Climate stabilisation targets Dear Barrie, I am working with Mike Hulme on the stabilisation of climate. I am writing to ask whether you know of any institutions that have made position statements regarding the stabilisation of climate. Statements may refer to the stabilisation of: * carbon intensity * greenhouse gas emissions * atmospheric concentrations of greenhouse gases * global warming We are trying to document the levels at which different organisations recommend stabilisation. The attachment gives some examples. We would be most grateful for any assistance you might be able to offer. Please reply to both myself and my colleague, Nick Brooks. Many thanks Tim _____________________________________ Dr. Tim Mitchell Tyndall Centre for Climate Change Research email: t.mitchell@uea.ac.uk web: http://www.cru.uea.ac.uk/~timm/ phone: +44 (0)1603 59 1378 fax: +44 (0)1603 59 3901 post: Tyndall, ENV, UEA, Norwich, NR4 7TJ, UK _____________________________________