Replacement cycles should inform climate change mitigation policy

It’s curious there is so much public discussion about electric vehicles and why and how we should ‘flip the fleet’ … and so little about buildings. Yes, we need to move people and goods in far less polluting, carbon-intensive ways. But decarbonising buildings is even more urgent and the graph below shows why, in a compelling and easy-to-grasp way.

IEA, Estimated time required to replace 90% of the existing stock under normal replacement rates, IEA, Paris. Licence: CC BY 4.0

Replacement cycles are a very useful concept that should guide policy making about the relative urgency of different climate change mitigations. Buildings generally remain in use for extended periods: the graph below shows replacement cycles of 65 to 107 years. On the other hand, cars have comparatively much shorter lifespan of 13 to 26 years; we could ‘flip the fleet’ to lower-carbon alternatives much more quickly.

This is why it is so urgent to address energy efficiency in the building sector. With buildings enduring for around a century, the decisions made today regarding construction standards and efficiency will have a long lasting impact on energy consumption. Currently we are running up a huge carbon debt future generations will be forced to pay. We need to address operational energy consumption and embodied carbon in the structures and maintenance immediately. Better we’d gotten serious about it 30 years ago, but now is the only option we have. There is no reason to wait to make these improvements—we know how to make them now.