Sustainable Construction: Facts & Figures

It’s always important to know your stuff and be able to back it up with solid data. That’s why we’ve collated all the essential facts and figures on sustainable construction that you CityChangers might need. These will be sure to get your adversaries thinking and your advocates firmly on board.

The Built Environment

• In 2016, an estimated 54% of the world’s population were living in cities. This number is expected to rise to 70% by 2050.
• It is estimated that over the next 40 years the world will build 230 billion square metres – roughly the area of Paris – in new construction every single week.
• Buildings emit more energy-related carbon than the entire transport sector globally.
• The amount of man-made mass has reached over 1 trillion tonnes, exceeding the biomass of the entire natural world.
• Roughly 80% of buildings standing today will still be around in 2050.
• In Europe, buildings account for 36% of CO₂ emissions, including operational impact and embodied carbon – i.e. the emissions generated during construction as well as manufacturing and transporting materials.
• Embodied carbon in construction is responsible for 15% of world greenhouse gas emissions.
• Between 2017 and 2018, emissions from the global construction sector rose by 2% to reach a record high.
• The importance of buildings can be seen by the amount of time we spend in them; it is thought that the average person spends 90% of their lifetime indoors.
• The construction sector in the EU accounted for 5-6% of GDP between 2010 and 2019.
• Construction is also the no.1 industrial employer in Europe, accounting for 7% of total employment and almost 1/3 of industrial employment in Europe.
• Yearly, the UK’s Environmental Agency has to respond to around 350 serious pollution-related incidents caused by construction.

Materials

• Buildings and the construction industry are responsible for using up 50% of raw materials.
• Construction alone uses half of all non-renewable resources consumed.
• Concrete is the second most consumed substance on the planet, after water.
• 8% of worldwide human-caused greenhouse gas emissions come from the production of cement.
• Construction represents 50% of the global steel demand.
• 11% of the carbon emissions is the embodied carbon in the materials.
• Roughly 15% of the materials delivered to a construction site are not actually used. This could be due to damage caused by transportation or the weather as well as building mistakes, overbuying, and vandalism.
• Paradoxically, buildings could well be a vital part of the solution to climate change. By using the right materials, for instance:
  • Every cubic metre of wood used in construction can retain 1 tonne of CO₂.
  • 1kg of straw can sequester up to 1.35 kg of CO₂.
  • Raw earth has 1/40 the carbon footprint of concrete.
  • Hemp can absorb 13 tonnes of CO₂ per hectare.
  • A cork oak forest can absorb up to 14.7 tonnes of CO₂ per hectare annually.
  • Bamboo can sequester up to 12 tonnes of CO₂ per hectare per year.
• If we compare conventional construction materials to natural materials in terms of emissions, there is an indisputable winner:
  • 1 tonne of steel generates 4 tonnes of CO₂, equivalent to 1544.45 litres of gas
  • 1 tonne of concrete generates 1.15 tonnes of CO₂, equivalent to 442.89 litres of gas
  • 1 tonne of timber generates 0.57 tons of CO₂, equivalent to 220.31 litres of gas.
• Alternatives using plastic and recyclables as well as sustainable concrete (a controversial topic) have all been proven to reduce CO₂ emissions by up to 50%.

Waste

Waste is not just a household issue, but also presents a significant conundrum in construction. It’s about reducing waste as well as how we handle any waste produced.

• Buildings and the construction industry account for 33% of waste and water use.
• It is expected that waste will rise from 2.01 billion metric tonnes (2016) to 3.40 billion metric tonnes by 2050. 1/3 of this is still poorly managed and is sent to open dumpsites or burned.
• In general, construction waste makes up a quarter of total UK waste.
• 32% of UK landfill waste comes from construction and demolition of buildings.
• A report states that construction, demolition, and excavation currently produces more than 60% of UK waste (2018).
• It is thought that proper waste management could reduce greenhouse gas emissions by 15-20%.
• Open burning of waste is a major source of black carbon which is thought to have a global warming potential 5,000 times higher than CO₂.
• 2.5 billion bricks arise as demolition waste each year, with only 5% claimed for reuse.
• Considering all waste management options:
  • only 19% is recovered through recycling or composting
  • 8% of waste is sent to sanitary landfills (with gas collection)
  • 31% represents open dumping
  • 11% is incinerated
  • just under 4% is sent to controlled landfill, while ¼ is disposed of at landfills of unspecified types.
  • This means almost 70% is still being dumped or sent to landfill.

• In the US, 44,000 buildings and 270,000 homes are demolished annually.
  • Even though 90% of the debris could be recycled, only a third is actually sent to recycling.
• Building debris is a significant issue in China. In 2015, 80 people were killed and 33 buildings were destroyed by the collapse of a vast construction and demolition waste dump.
• The divide between wealthy and poor nations is clear: on average, lower-income nations rely more on open dumping, which represents 93% of waste disposed. In high-income countries only 2% of waste is dumped.

Transport

• It has been estimated that 2/3 of freight transport within cities is to and from construction sites.
• Emissions from transport account for 23% of all emissions in the buildings and construction industry.
• CO₂ emissions from the transportation of materials accounts for 2.4% of total construction CO₂ emissions while 4.2% of total emissions is generated by on-site construction.
• We should also mention transport emissions on a city-wide scale here. By making urban development more sustainable and attempting to create Krapfen cities rather than doughnuts, emissions from commuter transport can be reduced. In 2017, transport represented 27% of total greenhouse gas emissions in the EU, with road transport accounting for over 70% of this.

Energy

• The UN reported that 30-40% of energy consumed worldwide is used in buildings.
• Buildings represented 55% of electricity used in the EU in 2012.
• In order to achieve net-zero carbon building by 2050, experts estimate that indirect building sector emissions will have to see a 60% decrease in emissions from power generation by 2030.
• Between 2010 and 2018, use of renewable energy sources for buildings grew by 21%. Meanwhile, coal use decreased by 10% in the same period.
• Using the latest sustainable technologies in construction could save €410 billion annually on worldwide energy spending.

Sustainable Buildings for the Win

• The payback period for green investments in new green buildings was 8 years in 2012 and lowered to 7 years in 2018.
• The expected operating cost decreases for new green buildings over 12 months and over 5 years.
  • More than 15% of respondents to a World Green Building Trends survey (2018) said there was an operating cost decrease of 23-21% over the first 12 months and a 43-49% decrease within five years of operation.
• Most architects and contractors agree that building sustainably gives buildings a higher asset value. 27% of them believe it adds more than 10% to the value.
• The average larger-scale architecture, engineering, and construction company is planning to spend €3.5 million on better sustainability efforts over the coming years.
• Three-quarters of construction firms in the UK, Ireland, Nordic and Benelux countries reported that sustainability initiatives led to better use of resources.
• It seems that switching to sustainable methods also helps to attract and keep the best employees as over three out of four workers would rather work for an ethical company with a good reputation than receive a higher salary.
• And consumers are interested too; over 90% reported that they are likely to opt for another company if it associates itself with a good cause.

In a Nutshell

As a result of the world we have created and constructed up to this point, the World Health Organization estimates that 7 million premature deaths per year can be linked to air pollution. And as we have seen, clearly our buildings play a significant role in the generation of these emissions; yet buildings could be used to mitigate the environmental impact too.

Buildings are part of the ecosystem of the city. Therefore, while it’s true that every little helps and one sustainably built building is better than none, there needs to be a city-wide strategy to make a real difference. Sustainable urban development and city planning, alongside mobility and transport considerations, should all be brought into the bigger picture with our buildings and construction sectors to create truly sustainable, durable, and future-proof solutions.