It’s been a while but I took a hiatus to complete an MBA. Anyways…
In recent years, verbiage such as “carbon,” “climate change,” and “emissions” has become pretty common. Actually, it seems impossible to NOT encounter climate-related advice, recommendations, or just general info on a daily basis. It’s not a criticism, necessarily, the efforts are impressive; take a look at Skyscanner’s approach (a brand-agnostic aggregate flight/travel planning site) which highlights which option has relatively lower CO2 emissions:
Those emissions are estimated by considering the plane type, routes, distance, capacity, cruise time, and stops, compared to industry averages, as well as noting jet fuel partly produced using waste oil input materials. In another example, one major airline’s “carbon footprint” section outlines all the steps they’re taking to contribute to the cause, even including replacing substantial numbers of their fleet. Other steps include “continuous descent operation,” reducing paper waste, improving operational equipment efficiencies, introducing renewable electricity, sponsoring the planting of new trees for park spaces, contributing to R&D for more efficient engines, and increasing the volume of sustainable jet fuels used.
I can’t help but wonder, though, where do the old planes & engines go? Or are they dismantled and parts recycled? If the latter, how much energy is needed to do that? Where does it happen, and is additional fuel and energy needed to get the planes to where that happens, or to re-distribute the to-be recycles parts around the world? Then, how do the net energy or emission savings or outputs compare in each scenario? Or is it even known, and, accounted for?
Even more convoluted is the fate of periphery equipment or parts of the value chain. In one case, however, these ladder trucks used in airports do have a fate more valuable than simply deteriorating in a scrap yard.
Fortunately, we have seasoned experts advising our governments around the world on these complex technical issues, wisely removing emotion from rational decision making processes.
Unfortunately, because of the complexity, and magnitude of such numbers, and abstract nature of the topic, it’s almost meaningless to cite them. Yes, these are big numbers, but relative to what?
The grandiosity of these ideas can leave us, even the very best of us, all wondering what, exactly, does it all mean?
How much is a giga-tonne of carbon? How much is a tonne?? How much???
In all seriousness, though, I think most people and companies do genuinely want to minimize negative consequences on the planet. But these systems are so complex, and so many people with varying expertise are involved, that it’s really tricky to grasp the whole picture. So, motivations might be coming from the right place, but I think it’s important to – as some would put it – get your own house in order first… like… if you’re going to protest an oil rig, maybe ask your aboriginal counterparts for guidance rather than bobbing around in plastic neon kayaks… wearing water-resistant nylon athletic wear… flying polyester flags?
The presence of carbon in Earth’s atmosphere is not new. The gas in the four lower-most layers of the atmosphere below the Kármán line (the initial 100km of gases from Earth’s sea level upwards; Figure 1), although dynamic and influenced by temperature changes, has been historically comprised (by volume) of 78.08% nitrogen (N2) gas, 20.95% Oxygen (O2), 0.93% argon (Ar), 0.031% or 310 parts per million (ppm) carbon dioxide (CO2), and trace (<0.01%) amounts of neon (Ne), helium (He), krypton (Ke), xenon (Xe), methane (CH4), and hydrogen (H2) (National Aeronautics and Space Administration, 1977).
These GHGs naturally create the greenhouse effect, which essentially allows sunlight to pass through to the Earth’s surface, but also absorb some of the longwave infrared radiation reflected back outwards toward space and thus, creating a warming effect and enabling the atmosphere to maintain temperatures above freezing (Lindsey, 2021). Atmosphere ozone mediates much of the otherwise damaging incoming ultraviolet (UV) radiation, and is particularly beneficial from the tropopause (the interface between the troposphere and stratosphere) upwards (Meng et al., 2021). The GHGs naturally flow in cycles through various forms and rates; focusing on CO2 specifically, such systems are complex with many natural and industrial processes that, when not balanced, can influence the atmospheric release (carbon source), or the sequestration (carbon sink), of the compound (Figure 2).
(Russel, 2022)
Natural versus Human-Influenced GHG Cycles
Since the industrial revolution, this carbon cycle has apparently been increasingly imbalanced with a net-positive carbon release (more going into the air than is being captured by plants, oceans, etc.) in the form of CO2 with atmospheric carbon accumulating at an exponential rate and thus, increasingly contributing to that warming effect:
(Lindsey, 2021)
CO2 makes up a relatively small proportion of the GHGs, but its chemical structure results in >66% of the warming effect of GHG emissions; it is so impactful that CO2 is used as the warming-inducing benchmark and emissions are increasingly discussed in the context of carbon intensity (CI) and/or carbon-equivalent (CO2e) of a product (Lindsey, 2021; Government of Canada, 2020). The warming effects of this CO2 imbalance in such a short period of time is rapidly shifting rates or patterns of glacial melt, ice breakup, plant flowering times, sea level rise, drought onset and heat waves, rising average global temperatures, and storm intensity, and these are expected to worsen in the next few decades (NASA, 2022). At the same time, increased warming effects are causing depletion of atmospheric ozone (and its benefits) from the tropopause upwards at a rate of ~50-60m per decade, further expediting the changes (Meng et al., 2021).
The CO2 cycles are complex, not directly tangible, invisible, and span a very long time horizon; ability and/or willingness of the general public to change behaviour to address emissions changes are inconsistent. Widespread poor comprehension is reflected in a recent survey measuring respondents’ attitudes towards whether they believe climate changes will impact them (Luong et al., 2021). Interestingly, there appears to be a positive association between wealth (or, access to resources for creating or implementing solutions) and lack of concern, and yet substantial proportions of global populations are unlikely to make any behaviour changes.
Some resources offer more tangible depictions of what one tonne of CO2 can be thought of as: 500 fire extinguishers; one hot air balloon; emissions from one passenger flying from Paris to New York; 6000km driven in a diesel car; or 121.643 smartphones charged (Crown Oil Ltd, 2021).
Sometimes it’s easier to break down huge numbers into smaller or simpler units so everyone is on the same page – such as a kilogram of carbon, an ounce of steak, or a litre o’ cola:
Imagining CO2 as 1-kg or 1-tonne spheres, Visualized, it can be more easily visualized in relevant day-to-day settings (Carbon Visuals, 2022; Carbon Visuals, 2014):
A couple other visualizations in NYC (CO2 Gas visualized as 1-Tonne Spheres beside taxis; and as New York’s Daily Emissions (CarbonVisuals, 2022b)):
Although some digital renderings can be found online, they may quickly become outdated or be of low relevance to many viewers. Because of the diversity and complexity of the lifestyles, environments, low access to mitigation technologies, and static nature of existing graphic depictions, a more tailored resource may be more engaging for individuals or motivate behaviour change.
A confounding layer to this already complex issue is that the net emissions – the “cradle to grave” consideration of energy, raw materials, and GHG emissions – through the entire lifecycle of a product’s production, via a lifecycle analysis (LCA). LCAs are based on mathematical modelling that are meant to calculate the net GHG emissions or sequestration from production of a product, through its value chain, until its final consumption. This is again further convoluted as first, the comprehensive lifecycle must be defined and then, the LCA can differ as soon as any variable is changed, including any slight geographic distance over which transport of a material or final product is shipped. An example of an LCA is illustrated below (Smith et al., 2019):
Monitoring and understanding each direct and indirect input or output, as well as their contribution to GHG emissions, is often unrealistic given the tools and resources available. A recent report considered LCAs of 866 products and concluded that even for stakeholders, there is poor understanding of and much variation in reporting GHG emissions and recommended that LCAs are broken down by product (rather than averaged for product type) and such a granular approach is significantly more accurate and avoids underestimating reductions of GHGs (Meinrenken et al., 2020). There is often no consistent regulating body to validate all LCAs in the same way and therefore some discrepancy between accepted CIs can occur between jurisdictions, but governments either create an industry-accepted model or commission modelling to another party which becomes the industry standard even though they may need to be updated with time. Concerning transportation LCAs, for example, the United States uses the GREET model, while in Canada, the GHGenius model has been used although is shifting to a new model created in-house to include a wider array of LCAs and variables and rather focus on performance toward achieving the national goals (U.S. Department of Energy Office of Science, 2022; S&T Squared Consultants Inc., 2022; Environment and Climate Change Canada, 2019). These technical aspects, considered with the intricacies of the GHG cycles, create a very confusing and abstract issue.
Some of these models do a good job of quantifying the emissions, but it seems the challenge now is to ensure both sides of the equation are being acknowledged and regulatory decisions indeed account for the whole picture. I’d like to think the people behind such decisions can equally agree that our net impact is more valid than an absolute output, and that we should be able to all participate in both the mitigation strategies, as well as compensation mechanisms. More on this in another post.
For now, I’ve got a craving for a large cola..
References
Carbon Visuals. (2014). One metric ton of carbon dioxide gas (annotated). Retrieved May 14, 2022, from Flickr: https://www.flickr.com/photos/carbonquilt/15101137337/
CarbonVisuals. (2022). New York City’s carbon emissions. Retrieved May 14, 2022b, from CarbonVisuals: https://static1.squarespace.com/static/54c8c11ee4b0b53cb9733f51/t/558c0526e4b0f6f0dd9d0af7/1435239718006/New+York.pdf
CarbonVisuals. (2022). See the invisible. Retrieved May 14, 2022, from Carbon Visuals: https://static1.squarespace.com/static/54c8c11ee4b0b53cb9733f51/t/558bf858e4b037cdf60891f7/1435236440708/See+the+Invisible.pdf
Crown Oil Ltd. (2021). 1 Tonne of CO2: What Does it Look Like? Retrieved May 14, 2022, from Crown Oil: https://www.crownoil.co.uk/news/1-tonne-of-co2-what-does-it-look-like/
Environment and Climate Change Canada (2019) Clean Fuel Standard regulatory design. Retrieved May 15, 2022, from Canada.ca: https://www.canada.ca/en/environment-climate-change/services/managing-pollution/energy-production/fuel-regulations/clean-fuel-standard/regulatory-design.html
Government of Canada. (2020). Greenhouse Gas Pollution Pricing Act: Annual report for 2020. Retrieved May 15, 2022, from Canada.ca: https://www.canada.ca/en/environment-climate-change/services/climate-change/pricing-pollution-how-it-will-work/greenhouse-gas-annual-report-2020.html
Harrison, J. A. (2003). The Carbon Cycle | Earth Science. Visionlearning. Retrieved May 14, 2022, from https://visionlearning.com/en/library/Earth-Science/6/The-Carbon-Cycle/95
Lindsey, R. (2021). Climate Change: Atmospheric Carbon Dioxide. Retrieved May 14, 2022, from NOAA Climate.gov: https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide
Luong, K. T., Maibach, E., & Kotcher, J. (2021). Pew’s new global survey of climate change attitudes finds promising trends but deep divides. Retrieved May 14, 2022, from The Conversation: https://theconversation.com/pews-new-global-survey-of-climate-change-attitudes-finds-promising-trends-but-deep-divides-167847
Meng L., Liu J., Tarasick D.W., Randel W.J., Steiner A.K., Wilhelmsen H, Wang L., Haimberger L. (2014) Continuous rise of the tropopause in the Northern Hemisphere over 1980–2020, Science Advances. Accessed online May 14, 2022 https://www.science.org/doi/10.1126/sciadv.abi8065 DOI: 10.1126/sciadv.abi8065
NASA. (2022). Effects | Facts – Climate Change: Vital Signs of the Planet. Retrieved May 15, 2022, from NASA Climate Change: https://climate.nasa.gov/effects/
National Aeronautics and Space Administration. (1977). Untitled. Retrieved May 14, 2022, from NASA Technical Reports Server: https://ntrs.nasa.gov/api/citations/19770009539/downloads/19770009539.pdf
Russel, R. (2022). Layers of Earth’s Atmosphere | Center for Science Education. UCAR Center for Science Education. Retrieved May 14, 2022, from https://scied.ucar.edu/learning-zone/atmosphere/layers-earths-atmosphere
S&T Squared Consultants Inc. (2022). Retrieved May 15, 2022, from Home: https://www.ghgenius.ca/
Smith, L., Ibn-Mohammed, T., Koh, S., & Reaney, I. (2019). Life cycle assessment of functional materials and devices: Opportunities, challenges, and current and future trends. Retrieved May 14, 2022, from https://www.researchgate.net/publication/334686997_Life_cycle_assessment_of_functional_materials_and_devices_Opportunities_challenges_and_current_and_future_trends
U.S. Department of Energy Office of Science. (2022). Retrieved May 15, 2022, from Argonne GREET Model: https://greet.es.anl.gov/