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ClimateSeverity: Moderate

Heat, drought and Berlin's sponge city approach

Hotter, drier summers and heavy downpours are prompting Berlin to keep rainwater in the city.

Berlin · Germany

01 · The problem

What is happening

Berlin has experienced several hot and dry summers in recent years, stressing street trees, urban forests and groundwater, while intense summer storms can overwhelm sewers. The city's rainwater management rules require new developments to manage rainwater on site where possible — through green roofs, infiltration and retention — rather than sending it to the sewer, an approach often described as the 'Schwammstadt' or sponge city. Berlin's Senate Department publishes an urban climate atlas mapping heat exposure across the city.

Moderate severity. Material effects on people or ecosystems; actively managed. Severity is descriptive editorial metadata summarising documented effects. It is not a measured index or a score.

02 · Causes

Why it is happening

  1. 01

    Warming climate

    Germany's average temperature has risen, with more hot days.

  2. 02

    Sealed surfaces

    Built-up areas prevent infiltration and heat up.

  3. 03

    Combined sewer system

    In the centre, stormwater and sewage share pipes that can overflow into the Spree.

03 · Impacts

Who and what it affects

  1. 01

    Heat stress

    Hot periods affect older and vulnerable residents.

  2. 02

    Tree and forest stress

    Drought weakens urban trees and forests.

  3. 03

    Combined sewer overflows

    Heavy rain sends untreated wastewater into rivers.

04 · Solutions

Documented approaches

  1. Decentralised rainwater management

    Green roofs, swales and infiltration on development sites.

    Expected effectReduces runoff and supports cooling.

  2. Urban greening

    Protecting parks and planting climate-resilient street trees.

    Expected effectModerates heat and improves liveability.

  3. Stormwater storage

    Underground storage to reduce sewer overflows.

    Expected effectImproves river water quality.

Explore an illustrative What-If

05 · Key indicators

What can be measured

No reliable quantitative indicator is included for this issue. TerraLens shows figures only where a credible source supports them — consult the sources below for current data.

06 · Sources

Where this comes from

  1. [1]German Environment AgencyUmweltbundesamtumweltbundesamt.de(opens in a new tab)
  2. [2]Senate Department for Urban Mobility, Transport, Climate Action and the EnvironmentState of Berlinberlin.de(opens in a new tab)
  3. [3]European Environment AgencyEEAeea.europa.eu(opens in a new tab)

Links open the publishing organisation's site. Some point to the publisher's main page, where the named report or dataset can be found.

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