This is an optimistic book, but it starts from a challenging place.

In 2020 the global population was approximately 8 billion. By 2050 it will likely hit 10 billion. The additional 2 billion people will all have something in common: they will need somewhere to live. The majority of these 2 billion people will be in the Global South, in urban areas, and will be housed in high-density, high-rise buildings. They will need to cool their homes, mainly flats, not heat them. So next time someone tells you we need to build less, not more, ask them where they expect the 2 billion to live. Population growth may be flatlining in many European countries, raising for them the valid question: Do we really need to build more homes? But in the countries of the Global South, and in countries like the UK, USA and Canada, the population continues to rise – and we all need somewhere to live. It is this increasing demand for housing that puts humanity in such a challenging place. This population growth will create further massive demand for new buildings and the production of cement, steel and other building materials associated with this wave of construction will become a major source of greenhouse gas emissions (GHG).

To meet this construction demand the world will need to add 190 billion m2 of new buildings every decade for the next 40 years, which is equivalent to adding a London-sized city to the planet every 70 days. The challenge, as defined by carbon finance company Aureus Earth, is that, “Without intervention, business-as-usual construction would alone consume 60% of the remaining global carbon budget (500GtCO2e) if humanity is to limit global temperature rise to 1.5°C”.

How we build, renovate, heat and cool our built environment has become the biggest cause of climate breakdown and is the central problem addressed in this book.