Whether it's a creaky old house or a brand new, state of the art office block, the buildings we live and work in have a big impact on the environment.
The challenge to reduce this footprint is sizable. According to a recent report from the Global Alliance for Buildings and Construction, International Energy Agency and the UN Environment Programme, building construction and operations were, globally, responsible for 36% of final energy use in 2018.
Published in December 2019, the Global Status Report for Buildings and Construction also stated that, worldwide, the sector accounted for 39% of energy-related carbon dioxide emissions in 2018.
It's within this context that architects, designers and lawmakers are undertaking efforts to try to boost the sustainability of the built environment.
These efforts to "green" buildings can take many forms, from using sustainable construction materials to deploying energy efficient technologies such as automatic lighting and LED bulbs.
And while new buildings can be designed with sustainability and efficiency in mind, the reality is that a lot of the planet's building stock is old.
The U.K., for example, is home to many in-use buildings that are over 100 years old. While these structures can be aesthetically striking, they can often be troubled by a raft of issues, from poor insulation and sub-standard ventilation to high maintenance costs.
Take the U.K.'s Houses of Parliament, in central London: One section of the estate, Westminster Hall, dates back to 1099. Plans are being developed to restore this sprawling, aged, complex, with lawmakers set to temporarily move out when works eventually begin.
Such a situation begs the question: Is it better to knock things down and start from scratch or take a more rounded view and retrofit and renovate older buildings so that they're cheaper to maintain and better for the environment?
"Definitely, retrofit is the way forward," Cristina Gamboa, CEO of the World Green Building Council, told CNBC's "Sustainable Energy."
"There has to be a sensibility and a consciousness of the limited resources we have in the world," she added.
To date, 28 major cities — including London, Tokyo, Sydney, New York and Johannesburg — have signed up to the World Green Building Council's Net Zero Carbon Buildings Commitment.
Gamboa hailed the "leadership" of these cities, stating that they were "enacting net zero carbon buildings policies but also putting out incentives for industry to transform faster."
While retrofitting and ambitious pledges may be a useful way of boosting the performance of buildings, will we ever be able to build large-scale developments without energy intensive materials such as cement?
"So, I think the answer is no," Gamboa said. "We cannot build without it, right. There has to be solutions that … address climate, people and different geographies around the world."