Iterative Risk Management

Published: 21st May 2013 17:30Last Updated: 3rd December 2013 17:31
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Background to the method

Iterative risk management (IRM) – also known as adaptive management - is an established approach that uses a monitoring, research, evaluation and learning process (cycle) to improve future management strategies.

The approach is very flexible, and can be applied to projects or sector analysis. It is most relevant for medium-long-term where potential to learn and react.

Ideal problem types

The approach is very flexible, and can be applied to projects or sector analysis. It is most relevant for medium-long-term where potential to learn and react.

Where has this tool been applied?

The Thames Estuary 2100 project (TE2100). This developed a tidal flood risk management plan for London, assessing a short-, medium- and long-term programme to address sea level rise (SLR), with the aim of leaving major irreversible decisions as far as possible into the future to make best use of available information (EA, 2009, 2011). Four future SLR scenarios were considered, including an extreme scenario (>2m by 2100). A series of defence options were appraised using CBA, complemented by Multi-Criteria Analysis that captured indirect and ancillary impacts. The plan recommends the maintenance of the existing flood defence system initially, followed by a programme of renewal and improvement, with a decision made on the ‘end of century’ option by around 2050 (to be in place by 2070) of either a new downstream Thames Barrier or a major rebuild of the current barrier, noting this decision will depend on conditions at that time. The project included a monitoring and evaluation strategy, with established decision points. If monitoring reveals that SLR is happening more quickly (or slowly) than projected, options can be brought forward (put back).

Strengths and weaknesses of this approach

The key advantage of IRM is that rather than taking an irreversible decision now– which may or may not be needed depending on how climate change evolves - it encourages decision makers to ask “what if” and develop a flexible approach, where decisions are adjusted over time with evidence (Reeder and Ranger, 2011). This helps ensure the right decisions are taken at the right time. Benefits can be expressed in physical terms, therefore does not require monetary valuation of benefits. Increases applicability to non-market sectors. It can be applied where uncertainty is high, e.g. where probabilistic information is low or missing

However, the disadvantages of the approach are in the identification of suitable risk thresholds, in cases where there are multiple risks acting together, under different scenarios and threshold assumptions.

Process of applying this tool/method.

Its principal improvements include (Reeder and Ranger, 2011):

  • Understanding of the economic costs of current climate variability and any existing adaptation deficit. 
  • Identification of major risks of concern resulting from current climate variability and climate change.
  • Construction of future major risk scenarios.
  • Investigation and identification of vulnerability/impact thresholds that trigger risks when coping capacity is exceeded, and with effective indicators.
  • Identification of possible adaptation options or option portfolios that could be adopted to raise different threshold levels.
  • Develop adaptation pathways/route maps of options. 
  • Assess options against economic and other criteria.
  • Recommend an initial preferred route or pathway, with key monitoring variables.
  • Implement, monitor and change the strategy with learning.

Why is this method useful for the field of climate adaptation?

Its potential application to adaptation has been recognised (Tompkins and Adger, 2004) and aligns with the IPCC Act-Learn-Then act again approach (Klein et al. 2007) and the concept of ‘adaptation pathways’ (Downing, 2012). While the broad concepts are established, the inclusion of economic appraisal within IRM is less common, and less methodologically developed.

Useful resources

Reeder, T. and Ranger, N. (2011). How do you adapt in an uncertain world? Lessons from the Thames Estuary 2100 project. World Resources Report, Washington DC. 

EA (2009a). Investing for the Future Flood and Coastal Risk Management in England A Long-term Investment Strategy. Published by: Environment Agency, 2010.

EA (2009b). Thames Estuary 2100. Managing flood risk through London and the Thames estuary. TE2100 Plan Consultation Document April 2009

EA (2011). TE2100 Strategic Outline Programme. Published by: Environment Agency.

EA (2012) Thames Estuary 2100 Final Plan: Managing flood risk through London and the Thames estuary.