Chapter 5 (IPCC A6 WG II Report) entitled Demand, Services and Social Aspects of Mitigation makes this finding:

Demand-side mitigation and new ways of providing services can help avoid, shift, and improve final service demand. Rapid and deep changes in demand make it easier for every sector to reduce greenhouse gas (GHG) emissions in the short and medium term (high confidence).

The indicative potential of demand-side strategies to reduce emissions of direct and indirect CO2 and non-CO2 GHG emissions in three end-use sectors (buildings, land transport, and food) is 40–70% globally by 2050 (high confidence)

Here they are referring to actions taken by individuals, households, communities, and organizations to change how energy and resources are used. This is in contrast to supply-side strategies (e.g., building wind farms, solar plants, or carbon capture), demand-side is all about how we live, travel, eat, and consume.

They use the Avoid-Shift-Improve framework when evaluating mitigation strategies. In this context they find:

The greatest ‘Avoid’ potential comes from reducing long-haul aviation and providing short-distance low-carbon urban infrastructures.

The greatest ‘Shift’ potential would come from switching to plant-based diets.

The greatest ‘Improve’ potential comes from within the building sector, and in particular increased use of energy-efficient end-use technologies and passive housing. 

It’s clear from the above that if we, at scale, reshape how we live, move, and eat, we could cut emissions from buildings, transport and food by 40–70% worldwide by 2050!

This is a BIG deal!

We have the solutions and know-how to radically cut emissions we just need to use them!