By a hybrid a mean more general schemes than that, a maximum/ceiling price is one sort of hybrid, a minimum/floor price is another, as are schemes with ‘allowance reserves’ such as the ’strategic reserve’ in the Waxman-Markey bill. Some good papers are below, as well as a wroking paper of mine.

Murray, B.C., Newell, R.G., Pizer, W. A., 2009, ‘Balancing Cost and Emissions Certainty: An Allowance Reserve for Cap-and-Trade, Review of Environmental Economics and Policy 3(1), 84-103.

Philibert, C, 2009, Assessing the value of price caps and floors, Climate Policy, 9, 612-633.

Peter J. Wood and Frank Jotzo, “Price Floors for Emissions Trading” (January 11, 2010). Fondazione Eni Enrico Mattei Working Papers. Working Paper 382.
http://www.bepress.com/feem/paper382

BTW I apologise for the many typos in the article – I copied across the wrong draft. I’ll fix when I return.

By hybrid do you mean an ETS with a maximum price?

As well as a carbon tax or an ETS, there is also the third possibility of a hybrid, such as proposed in the US under the Waxman-Markey and Kerry-Boxer bills, and probably under a ‘Kerry-Graham-Liberman bill’.

I am preparing some text on emission liabilities with a fellow climate change blogger and we hope to formulate a draft by the 14th. I wonder whether you would be interested in reviewing this material before we submit it to the FT for consideration.

Tim, your thoughts on this subject are also welcome. I try to keep a fairly neutral position vis a vis the subject of greenhouse gases and global warming, but it doesn’t help when people post an off-topic comment to my blog. You raise an interesting point about biotic absorption and I would appreciate details of the weblinks to your papers and the one by Knorr that you reference.

I’d just like see less money wasted and some of the long term problems fixed. Notably the education system, unless people want the next generation to become the trash of their own country with all the associated problems that brings (I’ll call it “dumb male syndrome”), including declining workplace productivity.

Other things like the roads and PT should be fixed also if we are really going to have a great population explosion, and increasing the overall population’s health (cf. spending more on hospitals) would probably be worthwhile too so we don’t end up spending all our money on keeping increasingly unhealthy people living longer via interventions that might have otherwise been avoided.

I’m sure those things are more important than all the middle-class welfare scams that exist that money gets wasted on or perhaps I’m just grumpy today!