Rob Wilby, Loughborough University, UK River basin management in a changing climate: Guiding principles to assist adaptation Rob Wilby, Loughborough University, UK

Water temperature changes since the 1970s Regional variations in water temperature increase since the 1970s. Source: Data adapted from EA (2007)

Summer rainfall anomalies since the 1770s England and Wales May-June-July rainfall anomalies 1766-2008. The thick red line shows the 30-year moving average.

Summer 2007 flash floods Source: Pitt Review (2008)

Regional rainfall projections ANN DJF JJA Changes in precipitation by the 2080s (top) and the number of models (out of 21) that project wetter conditions (lower panel). Source: IPCC AR4 (2007)

Projected changes in UK river flows Median monthly flow factors for the 2020s. Source: UKWIR (2007).

Guidance on “low regret” anticipatory measures Source: Defra (2007) Source: TCPA (2007)

Guiding principles

Summary of prototype principles mapped to WFD activities

1) Anticipate changes to water bodies that are just within their type range Source: Hickling Village

1) Suggested actions Undertake a risk assessment to determine the extent to which climate change could trigger transitions between categories and types within rivers, lakes, transitional, coastal and artificial water bodies. Maintain an inventory of the most vulnerable types in each RBD, recording information such as most significant climate threat(s), likely timescale of change, change of water body use, and next water body type. Review the monitoring programme to determine the extent to which any transitions could be detected and sites confidently assigned to new types. Establish more intensive monitoring of vulnerable water bodies to better understand the pace and mechanisms of change, and use these sites as sentinels of climate change. Revise objectives in line with transition(s) between water body type(s).

Source: Durand & Ormerod (2006) 2) Understand the extent and causes of variability and change at reference sites Source: Durand & Ormerod (2006)

2) Suggested actions Undertake long-term, concurrent meteorological, water quality and biological monitoring to improve evidence of causative links between climate variability and local ecological status. Use homogeneous climate indices (e.g., NAO, CET or EWP series) to contextualise biological samples taken under different conditions (i.e., hot- dry, cool-wet, etc). Undertake periodic reviews of conditions at reference sites to accommodate slow changes arising from ecological succession, and/or “natural” climate variability and change. Use palaeo-environmental reconstructions and other proxy evidence to represent the full range of conditions experienced at reference sites over multiple decades.

3) Assess direct and indirect influences on pressures due to climate change Source: EEA (2006)

3) Suggested actions Identify direct climate change impacts on WFD pressures and, where possible, integrate into existing approaches for the quantitative assessment of pressures. Identify pressures that could be indirectly affected by climate change mitigation or adaptation policies, using expert opinion, local knowledge, literature reviews or targeted research. Estimate the time-scale(s) over which direct and indirect climate change factors might influence pressures on water bodies. Determine the likelihood of changes in use for heavily modified and artificial water body designations as a result of climate change.

4) Identify and closely monitor climate change “hot spots” Detection time (yrs from 1990) in relation to the strength of the trend (percent change in mean) and variance of summer flows in the River Itchen, UK. Variance was estimated from reconstructed runoff records for 1961-90 (black line) and 1921-90 (red line).

4) Suggested actions Compile register of species-dependent hydro-climatic thresholds and damage functions. Overlay climate projections (of regions expected to witness most rapid warming or emergence of extremes) onto maps of pressures and water dependent conservation species to identify most vulnerable protected areas. Intensify monitoring of most vulnerable species to better understand the pace and mechanisms of change, and use indicator species to track impacts with/without adaptation. Gain management insights from those “outlier” species and habitats that appear to be more resilient to climate variability and change than expected.

5) Favour options that are robust to the uncertainty in climate projections

5) Suggested actions Apply the most appropriate climate risk information to each adaptation option (measure), drawing from a range of tools including probabilistic projections, vulnerability assessment, and sensitivity testing. Select measures that are resilient to a wide range of plausible climate conditions (i.e., low regret), rather than optimal for a single ‘central’ scenario. Implement further investigation if low regret measures cannot be identified because of low confidence in the problem(s) and in the solution(s).

6) Test for compatibility of actions with wider adaptation and mitigation objectives Concentrations exceeded 5% of the time

6) Suggested actions Assess likely effects of climate change on anthropogenic pressures (principle 3), then apply portfolio screening to determine how proposed actions may perform under the projected climate. Test all POMs for compatibility with other adaptation actions, and for likely contributions to future climate change through their impact on greenhouse gas sources and sinks. Develop processes to help arbitrate trade-offs and better align the preferred mitigation and adaptation actions of different interest groups with WFD objectives (see also principle 7).

7) Integrate cross-sectoral delivery of adaptation measures

7) Suggested actions Screen all POMs for compatibility with existing policy instruments and the adaptation actions being taken or planned by other groups. Maximise opportunities for co-delivery of WFD objectives and adaptation measures through planning liaison with other groups, stakeholder consultation, and regional spatial strategies.

8) Showcase integrated adaptation Lower Danube green corridor Source: WWF

8) Suggested actions Work with other stakeholders to develop tangible examples of adaptation in practice, perhaps through showcase schemes that are open to the public and policy-makers alike. Publish metrics that show the immediate and long-term benefits of adaptation actions.

Summary of prototype principles

Any other questions? r.l.wilby@lboro.ac.uk