We Flipped the Lens on Global Emissions - and Built Something New

Hot off the heels of our “How Emissions Show Up in Our Lives – and What We Can Do About Them” Research & Insights report, I wanted to reflect on why the work was so much fun, what we learned, and why this kind of analysis is essential if we want to help people make high-impact choices without overwhelm.

Why Do This Report?

As you know, one of Possible by Design’s goals is to meet busy people where they are with ideas that maximize their impact with the least effort – minimizing the cost and ideally saving them money in the process.  That inherently implies that we have a solid footing for both:

1. where our greenhouse gas emissions come from, and

2. if we nudged something through a personal choice, how much impact it would have.

   
   

And that’s where things get tricky – because most global emissions data is not organized in a way that helps real people understand their own impact.  While there are lots of greenhouse gas datasets out there, the world normally tracks and reports production emissions, and it’s hard to see where emissions show up in our daily lives.  And without that visibility, it’s nearly impossible for people to know which choices actually matter.

Starting Point

I’m a big fan of global efforts to help us see complex things on a single page, such as from Our World In Data (OWID) and the Visual Capitalist.  I sometimes include a slide with this image from Dr. Hannah Ritchie’s OWID 2020 report:

Even though the production emissions data in the OWID pie chart are for 2016, I like seeing the data this way and the emissions are still representative of today’s emissions for the different sectors.  There’s so much to see and understand here – I can still get lost for minutes re-absorbing the sources and magnitude of each of the slices in the pie chart.

The challenge is that I always walk away from this chart wondering what it means for me; production-based charts don’t tell us how emissions show up in our daily lives.  Yes, fly less if I can.  Eat less livestock.  Turn down the heat in the winter.  Drive an EV.  Use transit.  But what else?  “Use less cement” doesn’t really help me.  I’m not involved in landfill emissions nor the management of fugitive emissions from energy production.  And if I make any nudges, how much does it help?  I know we need more.

So I started looking for work that tried to flip the lens – not “how the world emits” but “how emissions show up in our lives”.  There are many good resources that try to look at emissions through a consumption-based lens rather than a production-based lens.  For instance, in March of 2018, the C40 Cities published a report called Consumption-Based GHG Emissions of C40 Cities.  In the report, they explain that “Consumption-based GHG accounting is an alternative to the sector-based approach to measuring city GHG emissions. This focuses on the consumption of goods and services (such as food, clothing, electronic equipment, etc.) by residents of a city, and GHG emissions are reported by consumption category rather than GHG emission source category.”  The total consumption-based emissions were 3.5 GtCO₂e for the 79 C40 Cities included in the study.  This was great!  Sound methodologies and interesting insights, but what about mapping the whole world’s production emissions to consumption categories?

There were other good reports trying to look at single categories like food.  Still aggregating production-side emissions, but trying to bundle them in a way that would let us see representative numbers for important components of global consumption.  OWID wrote about food emissions in 2021 in a report entitled “How much of global greenhouse gas emissions come from food?”.  They referenced and reconciled two other reports that estimated that food emissions were one quarter to one third of total global emissions.  But as they were production-side aggregates, they still included consumer-side emissions that we might bundle elsewhere (e.g., cooking, refrigeration) and the report that estimated “one third” included non-food agricultural products (e.g., cotton, wool, leather, rubber, biofuels).  These reports were incredibly helpful, but they were only available for a subset of global emissions. 

This was starting to feel like a Sankey diagram, because a global emissions Sankey diagram would force us to map every tonne of emissions from its source to its final use – exactly what we needed.  So exciting!  Had anyone made one?  There must be one out there, right?  The answer was no – not that I could find.  Consumption-side analyses exist for individual categories and specific cities - the C40 work and OWID's food reports are excellent examples, and we leaned on them heavily. But a map of all global emissions - the full ~51 Gt - sorted by how they show up in daily life, in a single diagram? We couldn't find one. So we built it.

I had never made a Sankey diagram.  Could I easily make one in Powerpoint or Excel?  No, but the good folks at Sankeymatic had made a free online tool that was easy to use.

Here We Go

We used Rhodium’s 2022 emissions data set and seven production categories.  We settled on seven consumption categories:  Food and Diet, Products and Services, Home Energy and Buildings, Passenger Transport and Travel, Shared Infrastructure and Public Services, Land Use and Ecosystems, and Waste and Leakage.  We leaned on the best expert frameworks out there - from C40 Cities to OWID - and made a few small tweaks so the categories feel intuitive and reflect how emissions actually show up in our daily lives, not just how industries report them.  With some reasonable assumptions about how to allocate emissions amongst the categories, out came the first Sankey diagram:

Whoa!!!  Seeing the whole system re-sorted through a consumption lens was genuinely eye-opening:

1. “Food and Diet” definitely needs to be a focus for our personal choices.  (We already knew this from OWID’s “one-quarter-to-one-third” discussion of food sector emissions, but somehow this 11.83 Gt (~23%) number jumps out anew.)

2. At 11.31 Gt, “Products and Services” is ~22% of our emissions when we look through a consumption lens.  I knew that simply de-materializing would help with emissions, but this shines a spotlight on it.

3. Do most of our “Transport” emissions really map to Passenger Transport and Travel?  I would have imagined more going to Food and Diet and Products and Services.  (Nope – that’s right.  Emissions from internal combustion engines and hybrids moving people are over 5 Gt/yr.  Most goods move by ship and rail, which have a very small footprint once amortized across shipments.)  Ouch.  We really need to look at how we move ourselves.

4. Huh.  I guess we do all need to take responsibility for “Shared Infrastructure and Public Services” too – I appreciate the asphalt roads around me and the emergency services that keep us safe.  Not sure how much we can do about those emissions, but good to have them on the map so we don’t forget.

5. “Land Use and Ecosystems” (e.g., deforestation for non-food agriculture, land-use change for timber, pulp, and forestry products) and “Waste and Leakage” (e.g., methane from landfills, composting emissions, packaging waste, sewage and wastewater treatment) are small but incredibly important too – they contain some of the most stubborn emissions in the system.  Let’s park them for now and circle back later to see if we can do anything to help there.    

The next thing that jumped out was that we could meaningfully group the seven consumption categories into three and lean into finding high-impact, easy-to-do ideas in our “Personal Life” grouping:

This is exciting!  Over 40 Gt of the 51.2 Gt of emissions in 2022 now seen through the lens of categories to which we can relate.  For the first time, we can see the whole global emissions picture organized around the choices people actually make.  It also gives us a way to help people focus on the handful of choices that drive the majority of their footprint - and ignore the noise.     

Next Steps

I’m such a nerd - I feel giddy with excitement about where this will lead.  I love that we can trace all the way back to the production categories that get updated every year.  And we already have a next-level breakdown of the seven consumption categories to keep teasing apart the problem and see the best answers.

I know that if we want to bend the curve in 2026, we need to make the best recommendations we can and have a rock-solid footing for people to see why they should consider them.  And now that we have a clear, intuitive map of where emissions show up in our lives, we can help people and policymakers focus on the smaller set of choices that matter most. 

I know that there’s a lot of work still ahead but this is a solvable problem - we can get there.  And that’s the heart of Possible by Design – making climate and sustainability action feel clear, doable, and worth it.

The full report - including the Sankey diagram and the methodology behind it - is on our Research & Insights page. The analysis leads somewhere surprising - into the economics of what it would actually cost to clean all of this up. That's coming in a future post. Spoiler: the numbers are smaller than you think.