Intended for healthcare professionals

Analysis And Comment Contraction and convergence

Healthy response to climate change

BMJ 2006; 332 doi: (Published 08 June 2006) Cite this as: BMJ 2006;332:1385

Contraction and convergence; myth and reality

Congratulations on such a comprehensive review of climate change
issues (BMJ Volume 332, 10 June 2006)

On grounds of morality the principles of contraction and convergence
is unassailable. In the real world it is a pipe dream. It would only work
by being enforcible which implies an international policing authority with
real teeth. Can we seriously believe that the US, China or Russia would
submit to such an authority? Sadly there is no mileage in morality when
affluent lifestyles are threatened.

However, what will drive nations towards a low carbon future will be
the economics of energy. Already uncertainty about security of supplies of
oil and gas is having economic consequences. As the world crosses the
summit of ‘peak oil’, expected within the next five years, price
volatility will really hit home.

It is right to plead for changes in individual behaviour, but only
the de-carbonising of energy at source will make a predictable and
sustained impact on CO2 emissions. The only long term route to this goal
will be through the adoption of renewable energy technologies on two

First, small-scale to micro-generation systems are rapidly
approaching market viability. Within five to ten years millions of homes
could become cost-effective mini-power stations linked to a local mini-
grid under the umbrella of distributed generation. The Energy Saving Trust
estimates that this sector could meet 40% of UK electricity demand.

Second, base load electricity could be provided by gigawatt scale
technologies mostly drawing energy from wind, rivers and seas. Tidal
stream, tidal estuary, tidal impoundment, wave power and offshore wind
could more than match the output of today’s nuclear power. In the short
term, ‘balancing power’ to compensate for intermittency would be provided
by combined cycle gas power plants. In the longer term surplus
electricity, which is an intrinsic problem with renewables, will be
directed to producing hydrogen for grid connected gigawatt scale fuel
cells in a symbiotic coupling with high energy density renewables
installations. All this will, of course, depend on massive government
investment, but so would nuclear!

On the demand side, buildings are the biggest carbon culprits. The
only effective answer, embracing both new and existing buildings, is the
concept of the carbon budget, enforcible by law. This could also be
adapted for transport. These have complex implications, perhaps for
another time.

Competing interests:
None declared

Competing interests: No competing interests

10 June 2006
Peter F Smith
Special Professor in Sustainable Energy
University of Nottingham NG72RD