Climate change risk management for land projects - new CIRIA guidance

Rising Geo-Climate Risks

Extreme weather events are inflicting tangible damage on UK land projects. Severe wet weather in 2023/24 caused widespread flooding, prompting £60 million in government recovery payments to thousands of farm businesses, while heat and drought have intensified subsidence and ground movement issues.

Updated Environment Agency flood risk mapping in 2025 integrates long-term climate projections, expanding risk zones and requiring higher allowances for rainfall, river flows, and coastal change in assessments. This dovetails with National Planning Policy Framework revisions that mandate proactive adaptation, alongside sustainable drainage standards and biodiversity requirements that scrutinise site ground conditions more rigorously.

CIRIA's new C824 guidance addresses previously underserved climate-driven geotechnical and geoenvironmental hazards—slope instability, soil desiccation, altered groundwater, and contaminant release on brownfield land. Its development, involving partners like RSK Geosciences, responds to industry concerns over escalating delays, costs, and liabilities absent standardised approaches.

A key trade-off lies in balancing accelerated housing and infrastructure delivery against resilience imperatives: added measures may increase initial expenses and complicate approvals in high-risk zones, yet inaction risks greater future claims, disrupted programmes, and uninsurable assets as weather patterns shift further.