Talks on reducing construction emissions begin

The construction and upkeep (heating and lighting) of buildings contributes around 40% of global greenhouse gas emissions according to the World Green Building Council. By comparison, the Air Transport Action Group says that aviation is responsible for around 2% of emissions.

Yet, even with more people living in cities than the countryside for the first time in human history, emissions from buildings are rarely discussed at international meetings. With existing commitments to fighting the climate crisis slipping, finally getting to grips with construction industry emissions could be one way to help nations meet their climate obligations and improve air quality at the same time.

Nearly 150 events linked to construction and maintenance are slated for the two weeks of COP27. Following on from the inaugural Built Environment Day at COP26 in Glasgow last year, discussions taking place will include creating net zero targets for cities in Africa. Two of the largest, the Egyptian capital Cairo, and Nigeria’s main city, Lagos, both suffer from inadequate buildings and infrastructure, leading to poor air quality.

The four biggest cities in South Africa – Johannesburg, Cape Town, Tshwane (greater Pretoria), and eThekwini (greater Durban) – are the first on the continent to commit to its new buildings being carbon neutral by 2030. But that still leaves a stock of buildings with lifespans of 50 – 100 years which aren’t carbon neutral in these cities alone.

In a year when we’ve seen buildings swept away by the flooding in Pakistan and cities from New Delhi to London enduring record-breaking heatwaves, even the industry itself – one often slow to change – has realised the necessity to alter their ‘business as usual’ mentally. Nothing demonstrates this better than the fact the financial clout of venture capitalists is shifting to green building practices.

Matt Kennedy, director for climate and sustainability at Arup Group, the British architectural and design firm with a revenue of £1.8 bn in 2020, is positive. ‘My expectations are high’ he has said. ‘We all need to build greater resilience wherever we live.’

This is never truer than 2021. In addition to natural disasters, the strain on Europe’s gas supplies created by the Russian invasion of Ukraine has forced everyone from individual homeowners to councils and private businesses to seek out alternatives to fossil fuels for lighting and heating. Many are also considering the energy efficiency of their buildings as costs rise.

However, Michael Doust of the WRI Ross Center for Sustainable Cities has said that the retrofitting of buildings is at less than 20% of what it needs to be to reach global decarbonisation targets set for 2030 by the UN-backed Marrakesh Partnership. This set the year 2030 as the date for all new buildings to be carbon neutral and for existing buildings to have reduced their carbon emissions by 40%.

An important way to reduce construction emissions is going to be the use of ‘green’ (i.e. greener) steel and concrete. Concrete is the most used building material in the world. Green concrete is a form of the material which requires less heat to produce and absorbs carbon dioxide as it sets, capturing the carbon for the lifespan of the building.

Others are looking to generate electricity from concrete by changing its physical make-up. ‘Engineering the nanostructure of concrete … will allow the material to capture thermal energy from the surroundings and convert it into usable electrical energy’ says Maria Konsta-Gdoutos, Professor of Civil Engineering at the University of Texas at Arlington. She has obtained a grant worth $1.5 m from the US National Science Foundation to conduct further research as part of a multinational group of scientists in the US and Europe.

Meanwhile, the world’s largest emitter of greenhouse gases – China – has set 2030 as the date for emissions from construction materials to peak. This is a rollback of five years from the original date of 2025, ensuring there’s still much to be discussed as COP27 continues. 

Photo by Ben Allan