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Carbon carbon everywhere

Carbon footprinting and the concept of 'embodied carbon' are becoming increasingly important, particularly with countries like New Zealand and the UK creating Zero Carbon Acts to limit the global average temperature increase to 1.5° Celsius above pre-industrial levels, and to allow us to adapt to the effects of climate change.

You can create a carbon footprint for a business, activity or product, but what about cities? What if you wanted to do a carbon footprint of a building? Where would you start? We talked to carbon experts Barbara Nebel and Jeff Vickers of thinkstep-anz to learn more.

In our podcast, we covered a number of concepts related to carbon emissions which benefit from some explanation, so in this blog we've shared some definitions from reliable sources.

Barbara Nebel is the CEO of thinkstep-anz. The founder and first president of Life Cycle Association New Zealand (LCANZ), Barbara initiated the Australasian EDP Programme. She chaired the New Zealand working group for the development of ISO standards for Carbon Footprinting, is on the board of the German New Zealand Chamber of Commerce, Steering Group for the Climate Leaders Coalition, serves on several Technical Advisory Groups, is a Certified LCA Practitioner and an associate editor for the International Journal of LCA. Barbara is also a judge of the Banksia Sustainability Awards.

Jeff Vickers is Technical Director at thinkstep-anz and an expert in assessing complex product life cycles ranging from buildings to agriculture, transport to electronics. He focuses on sustainability strategy, Life Cycle Assessments (LCAs) and Environmental Product Declarations (EPDs). Jeff has been embedding sustainability thinking within organisations for over a decade, and has been working across sustainability assessment, strategy and innovation. He sits on the Green Building Council of Australia’s LCA Expert Panel and holds a PhD in Civil & Environmental Engineering focused on design for sustainability.

What is Life Cycle Assessment (LCA)?

A Life Cycle Assessment is a study that looks at the environmental footprint of a product across a range of different environmental indicators. So it might include a carbon footprint and a water footprint, it might look at other environmental indicators like eutrophication, acidification and toxicity … and it looks at [these indicators] across the full life cycle of a product - Jeff Vickers, thinkstep-anz

According to Environmental Management (2017), LCA is 'a cradle-to-grave or cradle-to-cradle analysis technique to assess environmental impacts associated with all the stages of a product's life, from raw material extraction through materials processing, manufacture, distribution, and use.' Nowadays, disposal is often added as an additional stage.

There are many databases which support LCA, perhaps the best known being 'GaBi' software used by thinkstep-anz and others. There are also many open-source databases and resources, such as the European Platform on Lifecycle Assessment.

To get started, check out this Beginner's Guide to LCA by Ecochain

What is a carbon footprint?

A sub-set of LCA, carbon footprinting reportedly grew out of the concept of the ecological footprint, invented in the early 1990s by Canadian ecologist William Rees and Swiss-born regional planner Mathis Wackernagel at the University of British Columbia. Considered a sub-set of ecological footprinting, a carbon footprint is the amount of carbon dioxide or greenhouse gases, also known as 'carbon emissions' released into the atmosphere as a result of the activities of an individual, organization, community, building, product or service. It often is measured in units of CO2e or 'carbon dioxide equivalent' which is a term for describing different greenhouse gases in a common unit.

Click here to calculate your NZ household or travel carbon footprint and offset them with Toitu Envirocare.

Carbon footprinting for businesses

9 out of 10 Fortune 500 companies reporting to the Carbon Disclosure Project (CDP) use the Greenhouse Gas (GHG) Protocol to ensure they are reporting consistently. The GHG Protocol separates carbon footprints for organisations into three scopes:

  • Scope 1 covers direct emissions from owned or controlled sources.

  • Scope 2 covers indirect emissions from the generation of purchased electricity - ie. your energy bills - steam, heating and cooling consumed by the reporting company.

  • Scope 3 includes all other indirect emissions that occur in a company's value chain, including their products (see 'embodied carbon' below).

What are greenhouse gases?

A good definition by Ecometrica (2012) is: a greenhouse gas (GHG) is any gas in the atmosphere which absorbs and re‐emits heat, and thereby keeps the planet’s atmosphere warmer than it otherwise would be.  

The main GHGs in the Earth’s atmosphere are water vapour, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and ozone. GHGs occur naturally in the Earth’s atmosphere, but human activities, such as the burning of fossil fuels, are increasing the levels of GHG’s in the atmosphere, causing global warming and climate change. The Kyoto Protocol is an international treaty for controlling the release of GHGs from human activities. Different greenhouse gases last in the atmosphere for different lengths of time, and they also absorb different amounts of heat. The 'global warming potential' of a GHG indicates the amount of warming a gas causes over a given period of time (normally 100 years).

Source: Ecometrica Greenhouse Gases, CO2, CO2e, and Carbon:

What Do All These Terms Mean?

Greenhouse gases let visible light from the sun in which heats the Earth, but trap some of the infrared light as it radiates away into space. This trapping of heat is a bit like a greenhouse, hence the name, although actual greenhouses trap heat by preventing convection, or hot air rising away, which is quite a different effect. - NZ National Institute of Water and Atmospheric Research (NIWA)

Learn more from NIWA here

What is embodied carbon?

Embodied carbon is the carbon footprint of a material, or the is the total greenhouse gas (GHG) emissions generated to produce a product. It includes how many greenhouse gases (GHGs) are released throughout the supply chain and is often measured from cradle to (factory) gate, or cradle to site (of use), cradle to grave (end of life) or cradle to cradle (if it is remanufactured or recycled). Embodied carbon includes emissions caused by extraction, manufacture/processing, transportation, end-of-life processes and assembly of every product and element in the asset.

Embodied carbon Carbon emissions associated with materials and construction processes throughout the whole lifecycle of a building or infrastructure. Embodied carbon therefore includes: material extraction, transport to manufacturer, manufacturing, transport to site, construction, use phase (eg concrete carbonation but excluding operational carbon), maintenance, repair, replacement, refurbishment, deconstruction, transport to end of life facilities, processing, disposal. - World Green Building Council (WGBC)

Learn more from WCGC report 'Bringing embodied carbon upfront' here

Opportunity to decarbonise: embodied carbon in buildings

thinkstep-anz have written a report 'Under construction' identifying opportunities to decarbonise New Zealand’s building and construction sector by 40% with a focus on embodied emissions from now until 2050, the year by which New Zealand aims to be 'net zero carbon'.

The strategies set out in this report could save approximately 1,200 kt CO2e per year: equivalent to taking 460,000 passenger cars off the road permanently and 15% of New Zealand’s total light vehicle fleet.

thinkstep-anz identified that the key materials contributing to embodied GHG emissions in New Zealand were found to be steel and concrete, which together contribute more than 50% of the carbon footprint of both residential and non-residential construction (excluding fit-out and building services). Aluminium was also very significant for non-residential construction. For residential construction, timber framing was the next biggest contributor, followed by paint, aluminium and plasterboard.

Decarbonising the built environment to achieve or exceed the 40% decarbonisation potential identified in this report will require the following:

  • Collaboration among all players in the building sector

  • Communication of good information and data

  • Innovation in the manufacturing sector

  • Policy development encouraging the use of materials with low embodied carbon.

Have your say

The NZ Ministry of Business, Innovation and Employment (MBIE) seeks your views on proposals to increase the operational efficiency of buildings, and to reduce the embodied carbon across the lifecycle of buildings as part of the Building for Climate Change programme. This is the first public consultation under the new Building for Climate Change programme – the building and construction sector’s contribution to New Zealand’s goal of net zero carbon emissions by 2050.

How to make a submission

To learn more and get key insights from the thinkstep-anz 'Under Construction' report, check out our podcast: