The technologies for achieving climate neutrality of energy use in the built environment are already available. While reducing demand for heat, power and light and materials reuse and recycling will certainly have a part to play, the greatest contribution will have to come from renewably generated heat and electricity. Although these technologies exist, they are more expensive than today’s fossil fuels, for two reasons: not all the external (pollution) costs of fossil fuel use are passed on to consumers, and renewable sources are still in the process of development.
Technically speaking, it is no problem to cut CO2 emissions to zero, but it involves costs and inconvenience, which means it will not happen of its own accord. Substantial cuts in carbon emissions in the built environment will not therefore materialise on their own, let alone 100% climate-neutrality.