We will approach the question with some conservative order of magnitude estimations. Let us start by considering the average CO2 equivalents (CO2eq) per person per year which is ~7 tonnes. Just to put this in perspective, it is roughly 2 return flights from London to Hong Kong in economy class. Those ~7 tonnes CO2 eq/person/year is roughly 0.02 tonnes CO2 eq/person/day. Attending a one-week (5 days) conference about sustainability, therefore, is about 0.1 tonnes CO2 eq/person. Thus, a conference of 500 people would generate 50 tonnes CO2 eq. Continuing our analogy, it would be 14 return flights from London to Hong Kong in economy.

Now comes the tricky point. How many weeklong conferences on sustainability are in a year of about 500 people each? For that, the website proves helpful. In 2023, a rough counting gives ~600 conferences/year under the tag “sustainability”. Not counting the ones under other tags such as “environment” or “environmental”.

One may argue though, that not all of them would host 500 people neither last 5 days. However, since we are considering only one tag, let us assume each of those conferences as qualifying for our estimations. Again, very conservatively. That gives a total of 30,000 tonnes of CO2 eq. Let us change our analogy at this point. A typical passenger vehicle emits about 5 tons CO2 eq per year. Thus, the conferences will generate the equivalent of 6,000 vehicles in a year.

One question is of relevance. How conservative are these estimations? Take your pick and do the math! Also, a reflection point would be: Of course, we must discuss sustainability…just let us try to be sure that conferences lead to actions.