Building Sustainable Cities for the Future Together Globally

Introduction

Cities cover two per cent of the planet's surface and account for more than seventy per cent of its energy-related emissions. That concentration is usually described as a problem. It is also the single biggest opportunity we have: change how a city works and you change the emissions of everyone in it at once.

Density is the quiet win

A household in a dense, well-served neighbourhood uses roughly half the energy of one in low-density sprawl, before anybody installs a single panel. Shorter journeys, shared walls, viable transit and district heating do most of the work. The cheapest carbon reduction available to most cities is permission to build homes near the jobs and services people already travel to.

Retrofit is the harder half

Around eighty per cent of the buildings that will stand in 2050 are standing today, so new-build standards alone cannot get a city where it needs to go. Fabric-first retrofit — insulation, airtightness, ventilation, then heat pumps — cuts demand before it has to be met, which is what keeps the grid investment affordable.

Measure the city you have

Most municipal climate plans fail on data rather than on ambition. Without building-level energy records, a city cannot tell which interventions paid off, and every budget cycle reopens the same argument. Metering first, targets second, is slower to start and much faster to finish.

What comes next

The cities making real progress share one habit: they treat climate policy as infrastructure policy, funded and maintained on infrastructure timescales, rather than as a campaign that ends with an announcement.