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What-If

Explore what could change.

Choose a place, a documented issue and one of its documented interventions, then set how far it goes.

ILLUSTRATIVE SCENARIO — NOT A SCIENTIFIC PREDICTION. Built from documented causes, impacts and solutions plus general qualitative patterns. It contains no modelled numbers.

3 · Intervention
PilotScaledTransformative

Adopted across much of the area, with dedicated budgets and enforcement.

Illustrative scenario

What if London took a scaled approach to “Thames Barrier”?

Starting point · documented

WaterSeverity: Moderate
Tidal flood risk on the Thames

London is protected from North Sea surges by the Thames Barrier and a long-term adaptation plan.

The intervention · documented

Thames Barrier

A movable barrier that closes during high surge tides.

Protects central London from tidal flooding.

Schematic direction of change

Supply and demand measures can act within years, while groundwater, rivers and wetlands often take much longer to recover.

Schematic, unitless illustration: relative pressure over time without the intervention compared with the intervention in place. Not based on measured data.NowLonger term →Relative pressure (unitless)
Without the intervention With the interventionSchematic shape only — no data, units or dates.

Causes this could address

  • Sea level riseRising seas increase the frequency of barrier closures.

Impacts that could ease

  • Risk to people and propertyLarge numbers of homes and critical infrastructure lie in the tidal floodplain.
  • Rising maintenance and upgrade costsDefences must be raised over time.

Wider reach at higher intensity is an assumption of this illustration.

How change might unfold

  1. Near term

    Operational gains such as reduced losses or new storage begin to show.

  2. Medium term

    Supply becomes more reliable in ordinary years if measures are sustained.

  3. Long term

    Aquifers and ecosystems recover slowly, if extraction and pollution stay below recharge and assimilation.

Faded stages are less likely to be reached at scaled intensity.

What this would not change

Rainfall variability and drought remain; interventions change how well the system copes, not the weather.

What it depends on

  • Sustained funding and institutional capacity
  • Consistent enforcement and monitoring
  • Local stakeholder support
  • Participation of affected communities

ILLUSTRATIVE SCENARIO — NOT A SCIENTIFIC PREDICTION. Built from documented causes, impacts and solutions plus general qualitative patterns. It contains no modelled numbers.

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