Future Estuary Tim Reeder Climate Change Advisor

1m 0m 4m 3m 2m New barrier, retain Thames Barrier, raise defences Raise Defences New barrier, raise defences Existing system Improve Thames Barrier and raise d/s defences Over-rotate Thames Barrier and restore interim defences Flood storage, improve Thames Barrier, raise u/s & d/s defences Flood storage, over rotate Thames Barrier, raise u/s & d/s defences Flood storage, restore interim defences Note: Each box represents one or more portfolios of responses Maximum water level rise: Defra 2100 High Improve defences Maximise storage New Barrier New barrage TE2100 developed options

Water Shortage in London?

Summer Precipitation 2020s 50% probability level: central estimate 2050s 50% probability level: central estimate 2080s 50% probability level: central estimate

Climate Change Adaptation Sub Committee

Low Emission Medium EmissionHigh Emission Change in Summer Mean Temperatures 2080s London

Potential environmental changes affecting the Thames estuary London Higher ambient air temperature Salinity gradient shifts further upriver Less rainfall during the summer Higher ambient air temperature Salinity gradient shifts further upriver Raised sea water temperature Reduced freshwater flow, warmer river temperature Bigger population - increased polluting load from sewage treatment works?; increased heat load from heating networks?; increased abstraction in the freshwater Thames? Result: An estuary with less dissolved oxygen

Warmer drier environment - a changed ecosystem? “New ecology” resulting from southern species expanding their range, and new invasive species thriving New species have different requirements – current water quality objectives may no longer be relevant Very young Seabass are sensitive to cold winters; a warmer estuary might be a better nursery for this species In the Medway estuary, a marginal rise in temperatures (from power stations) produced Golden Grey and Thin Lipped Grey Mullet populations