Five ways to cut your carbon footprint

As the climate crisis continues, the construction industry must take action to reduce its carbon footprint.

The COP27 Summit in Sharm El-Sheikh last November set new climate change ambitions for the world’s nations. From a fund for countries affected by climate change to World Bank reform, the implications of this year’s event will be felt for years to come. 

Autodesk was proud to be part of COP27 and sponsor the United Nations Environment Programme Building Pavillion, the event’s first buildings space for businesses and policymakers to connect and showcase climate change solutions. 

“Construction professionals have a huge role to play in tackling climate change and we know our customers support sustainability,” says Cecilie Wasberg, Account Executive, META for Autodesk.  “In fact, 92% of Autodesk’s largest customers are committed to going green, while 99% of CEOs believe sustainability is important to the success of their business.” 

Over 10 days and across 50 events at COP27, architecture, engineering and construction (AEC) professionals and policymakers discussed ways to work together towards a zero-emission, efficient and resilient buildings and construction sector, as well as actions we can take to make a difference. Here’s our roundup of the top takeaways:

1. Understand construction’s carbon footprint

Construction is a high-energy, resource-intensive industry, with significant global emissions. These are either operational or embodied. Understanding the difference is crucial when building and designing greener projects.

Operational carbon is the amount of greenhouse gas (GHG) emissions released during the operational, or in-use, phase of a building, such as lighting, heating, ventilation, air conditioning and general power usage throughout the building. Operational carbon accounts for more than a quarter of global greenhouse gas emissions.

Embodied carbon is all the CO2 emitted during the production phase. This comes from:

  • harvesting raw materials
  • transforming these materials into construction products
  • transporting them 
  • incorporating them into a building
  • maintaining, removing and replacing them. 

The structure of a building is responsible for approximately 50% of a building’s total embodied carbon, while the exterior envelope and interior account for 30% and 20% respectively

The fallout from these emissions is already huge and set to increase. Over the next 30 years, embodied carbon is predicted to account for almost 50% of all new construction-related carbon emissions.

2. Let data drive your design

Different materials and building methods can help construction professionals reduce their carbon footprint, but they need access to transparent data to make the right decisions. For example, embodied carbon can be reduced by comparing data for building products and choosing lower embodied carbon products or carbon-sequestering materials.

If AEC professionals demand more transparent data — asking manufacturers to report metrics and measurement of environmental impact, for example — they could drive change and foster industry transformation.

Construction companies can work to reduce embodied carbon emissions at all stages by enabling easy collaboration and access to common data. For example, when all stakeholders are working in the cloud and using a tool such as BIM, everyone has access to the same information. 

Data on embodied carbon associated with building materials and products can be integrated into BIM and inform the decision-making process. Stakeholders can evaluate and compare products and material selections before procurement to determine the best building practices and drive more sustainable outcomes.

There are a wealth of resources to help construction professionals build data into their designs.

  • Carbon Avoided Retrofit Estimator (CARE)

The CARE tool allows construction professionals to compare the total carbon impacts of renovating an existing building versus replacing it with a new one. 

  • Carbon Insights

Carbon Insights for Autodesk Insight, currently available as a technology preview in Revit, is an analytical tool for assessing embodied carbon. 

  • Embodied Carbon in Construction Calculator (EC3)

EC3 is a free, easy-to-use tool for benchmarking, assessing and reducing embodied carbon. The cloud-based tool includes a searchable global database of thousands of building products, pulling third-party-verified data from Environmental Product Declarations.

  • TallyLCA

TallyLCA is an Autodesk Revit plug-in that allows designers to calculate the environmental impact of their product or service choices from within an Autodesk Revit model more quickly and cost-effectively than conducting a life-cycle assessment. 

3. Prioritise retrofitting over new builds 

In 2040, about two thirds of the global building stock will be buildings that exist today. Without widespread existing building decarbonisation across the globe, these buildings will still emit CO2 emissions and won’t hit the Paris Agreement’s 1.5°C target.

Existing buildings’ embodied carbon emissions are already locked in place, so avoiding demand for more raw materials and resources for new buildings is the first step to tackling emissions. Finding ways to retrofit, repurpose and reuse existing building stock will reduce landfill waste and demand for resources, which reduces the embodied carbon associated with building new constructions.

“According to studies from the American Institute of Architects, reusing buildings saves between 50-75% of embodied carbon emissions compared to constructing new buildings,” said Ximena Rico, Autodesk LATAM’s Government Affairs Lead, at this year’s COP27. “This suggests the main focus for addressing housing needs should be retrofitting housing.” 

4. Choose carbon-storing materials

The most common building products typically have the biggest carbon footprint because of the production energy needed and their widespread use. Traditional materials like steel, concrete, aluminum, and glass account for 11% of global CO2 emissions

Instead of using carbon-intensive materials, choose carbon-storing options – like wood, cork, hemp and algae – which capture atmospheric carbon via photosynthesis. 

“Cladding and insulation are a good place to start,” says  Cecilie. “For example, use plant-based cellulose insulation instead of fiberglass or foam products, and swap metal or stucco for wood or cork cladding.” 

Concrete is one of the biggest carbon culprits, with energy-intensive, emissions-heavy manufacturing processes. In fact, if the global concrete industry was aggregated as a country, it would be responsible for more GHG emissions than all but two other countries – the US and China. 

Concrete makers across the world have pledged to cut their GHG emissions by up to a quarter this decade and reach net zero by 2050. They’re adopting new processes and using different materials to become more energy efficient, such as:

Carbon injection

Waste CO2 from industrial operations can be injected directly into concrete and transformed into a mineral,  never released back into the atmosphere as CO2. This new form is stronger than traditional concrete.

Hempcrete

Hempcrete is a non-toxic bio-composite material that’s moisture-absorbent, about an eighth the weight of concrete and captures atmospheric carbon twice as effectively as forests. 

Wood and timber

Use of wood is on the rise across the construction industry. France requires all new state-funded buildings to be at least 50% wood, while buildings for the Paris 2024 Olympics must be all-timber if they are under eight storeys high. 

“It’s a visually and acoustically pleasing material that’s lightweight, cleaner and comes with a raft of environmental benefits,” says  Cecilie. “Swapping wood for steel and concrete has the potential to greatly reduce the GHG impact of buildings, especially if the wood structure can be dismantled and reused.”

Advances in wood technology have enabled architects and engineers to make taller wood buildings. Last year, Ascent, an 86.6metre-tall, 25 storey mass-timber tower in Wisconsin was crowned the world’s tallest timber building. 

It appears wood is the gift that keeps giving to the construction professionals, with more uses coming to the fore. Glue-laminated timber (glulam) and parallel strand lumber (paralam) have been around for some time, but a new-generation engineered wood product, cross-laminated timber (CLT), is now making waves. This tough, lightweight material can be used as entire walls and floors and has been proven to stand up against earthquakes. 

5. Look beyond the building: consider landscape and infrastructure 

The grounds of buildings are another good place to sequester carbon. Minimising high-GHG materials like concrete and steel in favour of lower-intensity materials such as gravel and wood can make a huge difference.

“Plants absorb CO2 and release oxygen, which benefits the overall carbon balance of a property,” says  Cecilie. “With careful attention to material selection, maintenance procedures and plant specification, landscaped areas can become net absorbers of CO2 within a few years after initial construction.”

Green roofs are also worth considering and have significant environmental and social benefits. These sprawling sky gardens have been adopted around the world to mitigate the adverse effects of urbanisation. They reduce air pollution and GHG emissions, increase the lifespan of the roof, and help reduce the urban heat island effect – the difference in temperature between urban areas and surrounding countryside.

Sustainable infrastructure is fundamental to reducing emissions and tackling climate change. Infrastructure is responsible for nearly 80% of all GHG emissions. Better urban planning with more sustainable infrastructure, however, could relieve the planet of 3.7 gigatons of CO2 per year by 2033. 

When it comes to infrastructure, there are simple steps you can take to promote sustainable practices like: 

Use prefabrication: Make Infrastructure parts in factories and assemble on-site to reduce production and transport emissions. 

Go local: Use local materials and workforces to cut down on transport emissions. 

Consider circularity: Eliminate or reduce waste and reuse materials where possible.

Reuse materials: Repurpose materials from demolished buildings in other buildings or roads. 

The construction industry has put sustainability high on the agenda. We’ve achieved a lot, but there’s still a way to go to tackle climate change and protect future generations. With the right knowledge, tools and decisions, however, positive change is within our reach. 

Autodesk is partner at Nordic Digital Construction | BIM World Copenhagen, and this article is published in coorperation with Autodesk.

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