There are multiple facets of sustainability as encompassed in the Intergovernmental Panel on Climate Change (IPCC)’s definition, covering everything from protecting biodiversity to zero-waste strategies. In the built environment, most dialogues involving sustainability center carbon - net-zero carbon, carbon offsets, embodied carbon, and more. With all the carbon vocabulary, it can be challenging for anyone who is not a sustainability expert and well- researched advocate to involve themselves in this area of sustainability. Understanding why there is a strong focus on carbon and the associated carbon vocabulary is vital to both industries and individuals to engage in climate-friendly behaviors.
The key to understanding carbon is to first understand climate change. Climate change refers to the rapid changes in global climatic conditions which are resulting in the disruption of the Earth’s natural systems. Climate change is anthropogenic, meaning that climate change is human-induced, and can be traced back to the Industrial Revolution when the burning of fossil fuels began and the release of greenhouse gases, gases that trap heat in the atmosphere, started at a pace unseen throughout human history. There are different gaseous compounds that are categorized as greenhouse gases, including methane and nitrous oxide, but the one most focused on in climate change mitigation is carbon dioxide - commonly referred to as carbon. This is because, of all the greenhouse gases, carbon dioxide has the greatest global warming potential making its concentration contribute heavily to climate change.
There are different types of carbon emissions that are tracked and reported in the context of the built environment. The most prevalent is operational carbon emissions. Operation carbon emissions refer to the carbon dioxide emissions released during the operation of a building. The energy used to heat, cool, ventilate, and light a building contributes to its operational carbon output. For many decades this type of carbon emission has been the focus of the sustainable buildings movement; however, there has been a recent shift to include another type of carbon emission - embodied carbon. Embodied carbon refers to the carbon emissions associated with each stage of building construction, from extraction and transportation of raw materials to demolition at the building’s end-of-life. Taking account of both operational and embodied carbon gives a holistic view of the entire carbon life cycle of a building, resulting in more effective carbon reduction strategies.
There are countless carbon reduction strategies that can be utilized by companies, industries, and individuals. The selected strategies depend entirely on the end goal: carbon neutral or net-zero carbon. Carbon neutrality focuses on offsetting any carbon emissions, often purchasing carbon offsets or carbon credits to account for emissions and company or individual is unable to eliminate. Net-zero carbon focuses on carbon elimination as a net-zero carbon building has zero carbon output, so there is nothing to offset. Ideally, every carbon reduction goal should be net-zero carbon as this will have the greatest direct impact on climate change.
Regardless of whether a carbon-neutral goal or net-zero carbon goal is targeted, any effort to reduce carbon emissions is beneficial. This can be as easy as implementing more efficient building processes. For example, installing energy-efficient lighting and water- conserving flush and flow fixtures, and solar photovoltaic panels are simple ways to reduce operational carbon emissions. Reusing building materials or using low-carbon building materials are great ways to reduce embodied carbon within the built environment. On the individual scale, turning off lights when not in use, participating in a municipal recycling program, and limiting the amount of airtime travel are all viable methods to reduce carbon emissions. When deciding on a strategy, it is important to assess the current carbon footprint of a building, site, or individual to find the greatest opportunity for carbon reduction. After all, a good carbon reduction strategy is one that reduces carbon emissions, and together with both industry and individual effort, the rate of climate change can slow, ensuring the longevity of the planet and humankind.