Each year, as conferences, expos, and festivals wrap up, we see the same story unfold: a neatly packaged carbon footprint report boasting how many tons of CO₂ were saved or offset. The intention is good. The optics? Green. But if we’re being honest, much of this is theater—based on calculations filled with estimates, assumptions, and generalizations that don’t reflect the true impact of the event.
As more organizations race to appear environmentally responsible, we need to ask a hard question:
Is obsessing over carbon footprint estimates really helping us create more sustainable events—or is it distracting us from the things that actually matter?
This post makes the case for a shift in focus: away from artificial numbers and toward real-world, human-centered sustainability metrics that prioritize infrastructure, accessibility, and behavioral nudges.
The Illusion of Precision: The Problem with Event Carbon Footprinting
Let’s begin with the basics. A carbon footprint is a measurement of the total greenhouse gas emissions caused directly or indirectly by an individual, organization, event, or product. In theory, this makes sense. But in practice—especially when applied to events—it’s a deeply flawed concept.
Here’s why:
1. You’re Working with Incomplete or Assumed Data
Did every attendee fly? Drive? Take a train? Did they carpool? What airline? Economy or business class? How long did they stay? What did they eat? What kind of waste did they generate?
Unless you’ve tracked each individual in minute detail (which you haven’t), you’re relying on rough averages and estimations that introduce major inaccuracies.
2. Generic Emissions Factors Don’t Reflect Reality
Carbon calculators often use standardized emissions values (e.g., X kg CO₂ per flight hour, Y kg CO₂ per meal). These are averages at best—and misleading at worst. Two people could take the same flight and generate vastly different emissions depending on the aircraft type, seat class, and actual load.
3. You’re Often Ignoring Contextual Factors
Calculations rarely include upstream emissions (like the energy used to manufacture event signage or lanyards) or the downstream effects (like attendees taking an extra day to vacation nearby).
4. The “Offset” Trap
Many events tout “carbon neutrality” by purchasing offsets—paying for tree planting or renewable energy credits. These can be valuable when done right, but they’re often used as a guilt-erasing shortcut rather than a commitment to reduce real emissions.
In short: the number you see in the sustainability report isn’t wrong because of bad intent—it’s wrong because it’s trying to turn a complex social and logistical system into a single digestible figure.
So, What Should We Measure Instead?
Rather than chasing numerical precision we’ll never achieve, we need to ask a better question:
What conditions need to exist for people, both event organizer AND attendees to make low-impact choices easily?
This question shifts the focus from accounting to enablement. It forces us to evaluate infrastructure, access, and design decisions—not just estimate emissions.
Here are some examples of the kind of metrics and evaluations that might serve us better:
1. Water Refill Infrastructure
Instead of estimating how many plastic bottles were “saved,” ask:
- Were there enough water refill stations?
- Were they easy to find?
- Were they promoted on signage and in the event app?
- Were bottles provided or encouraged?
Why it matters: Behavior change doesn’t happen because we “tell” people to do the right thing. It happens when the alternative is clearly more convenient and socially accepted.
2. Transportation Accessibility
Rather than estimating emissions from attendee travel based on average distances, ask:
- What percentage of attendees had access to public transportation?
- Was there on-site bike parking?
- Were shuttles or carpooling options made available?
- Was the venue chosen for its transit accessibility?
Why it matters: Transportation is often the largest contributor to event emissions. But you can’t control how everyone travels. You can only control how easy or difficult you make low-impact options.
3. Plant-Based Catering Availability
Instead of calculating emissions based on estimated meal types, ask:
- What percentage of the catering menu was vegetarian or vegan?
- Was it clearly labeled and easy to choose?
- Was it priced equally or more affordably?
Why it matters: Food-related emissions can vary drastically, and plant-based meals are often the most sustainable. But again, the goal is to design for behavior, not just report on consumption.
4. Venue Energy and Waste Infrastructure
Rather than estimating energy usage or waste diversion rates, ask:
- Does the venue use renewable energy?
- Are waste, compost, and recycling bins clearly labeled and consistently placed?
- Is there back-of-house sorting?
- Are single-use materials minimized?
Why it matters: This is about operational design, not just emissions math. A well-designed venue can do more for sustainability than a stack of compostable utensils.
5. Communication & Signaling
Don’t just ask what people did. Ask:
- What did you make it easy or desirable to do?
- Was sustainability a central theme, or a footnote?
- Were speakers and sessions modeling sustainable practices?
- Did attendees feel empowered, or guilted?
Why it matters: Cultural and social cues influence behavior just as much as logistics. Sustainability needs to be part of the experience, not just a line item in the post-event report.
A New Kind of Sustainability Report
Imagine this:
Instead of a glossy PDF saying, “We saved 40 tons of carbon,” your post-event sustainability report said:
- “83% of attendees had access to public transit within 1 km of the venue.”
- “We installed 12 hydration stations with clear signage and zero single-use bottles sold.”
- “65% of our menu was plant-based, and we ran a tasting session on sustainable catering.”
- “100% of our generators were solar powered .”
This is concrete. Verifiable. Actionable. It invites scrutiny and engagement instead of hiding behind a mysterious number.
It also allows for transparency. If something didn’t work, say so. “Only 20% of attendees used the bike valet—likely due to weather and unclear signage. We’ll improve this next year.” That’s how progress happens.
So, Should We Abandon Carbon Numbers Entirely?
Not necessarily. If done transparently, with clearly stated assumptions, carbon estimates can still offer value—as long as they don’t overshadow everything else.
Think of them like a compass, not a map. They can point in a useful direction (e.g., “travel is our biggest impact area”) but they can’t tell you exactly where you stand.
The real mistake is pretending that carbon numbers are the sustainability metric, rather than just one lens among many.
What We Gain by Shifting the Focus
When we stop obsessing over unprovable carbon numbers and start evaluating tangible, systemic enablers of low-impact behavior, a few important things happen:
- We move from reporting to redesigning. It becomes about building better systems, not just better optics.
- We empower people, not just metrics. Attendees are partners in sustainability, not just data points.
- We build momentum. Infrastructure changes (like refill stations or signage) have lasting impact beyond a single event.
And most importantly: we stop lying to ourselves. We stop pretending that we’ve “solved” environmental impact just because we generated a good-looking spreadsheet.
Final Thoughts: From Accounting to Accountability
Sustainability is not a scoreboard. It’s a practice. It’s not about proving you’re green—it’s about creating conditions where green choices are natural, easy, and expected for both the event designer/organizer, and the public.
Carbon footprinting can still be part of the conversation. But if we want to make events truly more sustainable, it’s time to get our hands dirty and measure what actually matters: infrastructure, access, behavior, and cultural signals.
Let’s stop hiding behind fake numbers and start building real systems that support real change.
Want to build a smarter sustainability strategy for your event? Start with a checklist that prioritizes accessibility, infrastructure, and behavioral nudges—and only then worry about the carbon math.
If you need help designing one, I’d be happy to collaborate.