From Floods to Climate Change Policy.

An essay for the MOOC, Turn Down the Heat: Why a 4°C Warmer World Must be Avoided

Electricity generation, home heating, transport, industry and agriculture are the UK's principle sources of CO2 emissions.  A plan for carbon reduction 'Zero Carbon Britain'  has been produced by the Centre for Alternative Technology (CAT).  If made the basis of domestic mitigation it would provide an aggressive negotiating standpoint for international mitigation efforts.  The UK had an advantage in meeting the Kyoto obligations since a shift from coal to gas occurred at a convenient time.  That was a one-time shift and further carbon reduction progress has been slow, though the government remains committed reduction targets.

There are, however, senior government ministers who have given little support to climate change related policies and have down-played the importance of the issues. The floods and storms of the winter 2013/14 have put discussion of the link between climate change and recent extreme weather events onto the political agenda.

Central to this discussion is the science of climate change attribution, though few politicians acknowledge expertise in the subject. Dr Peter Stott, head of the Climate Monitoring and Attribution team at the UK Met Office, has written about connecting extreme weather events to global warming here.  The Met Office produced this report at the beginning of February, during on-going storms.  "There is an increasing body of evidence that extreme daily rainfall rates are becoming more intense, and that the rate of increase is consistent with what is expected from fundamental physics.  There is no evidence to counter the basic premise that a warmer world will lead to more intense daily and hourly heavy rain events." This is the message from Dame Julia Slingo, Chief Scientist at the Met Office.

Words from such organisations are very guarded, their employees fearful of challenge to anything that cannot be incontrovertibly supported.  Many climate scientists are not politically motivated or even care to enter into debate in the public arena but privately, take a more robust position.  I have suggested that the recent weather can be considered a 5-sigma event, one that is so unlikely that it may never have happened in thousands of years and if the data existed might fall at five standard deviations from the mean in a normal distribution.  That’s impossible to demonstrate conclusively since we do not have the data, but the more likely explanation for such an unusual event is that the climate has shifted.  What would have been a 5-sigma event under a stable climate regime has become much more common as a result of climate change.

The policy implications are profound.  It means that our spending on flood defences should not be based flood risk calculated from past experience but should be based on adaptation to forecast scenarios that are linked to the degree of mitigation we are prepared to put into place.  There is, to some extent, a trade off between mitigation and adaptation, and the greater the success of the former the less the need for the latter, but this trade-off is strictly limited.  Even if greenhouse gas and black carbon emissions were to be stopped abruptly, there is enough lag in the system before equilibrium is reached to continue global warming, and the melting of the Greenland and at least the West, if not the East, Antarctic Ice Sheets may have already reached tipping points from which there is no return, committing us to adaptation to substantial sea level rise over time.

While mitigation must proceed as quickly as possible, to reduce eventual required adaptation, adaptation needs to begin urgently.  Preventing the next costly flood is best done before the event.  Exemplar work is available.  In North Yorkshire a programme of retaining water at high levels in the catchment is underway.   Adapting to sea level rise is central to the Donna Nook coastal realignment scheme in Lincolnshire. This involves the building of more robust sea defences inland from the old sea-bank and the creation of a protective strip of salt-marsh on former agricultural land that had been reclined some two centuries ago.  Along nearby parts of the Lincolnshire coast, planning permission for new development in at risk areas is strictly restricted and a large area has been designated as a 'Coastal Country Park'  with the possibility that this land may also become subject to coastal realignment within several decades.  However, the link between the designation of land use for the park and future realignment has not been made publicly explicit since this would elicit adverse public reaction from local residents.  The lack of clear leadership from government at both central and local level and the cautious approach by the Environment Agency to public statements has done nothing to persuade the public that climate change mitigation and adaptation are necessary and urgent.