The numbers behind offsetting emissions

This might lean ever so slightly in the politics territory, but here’s a fun calculation. Was just thinking about how big a pile of carbon would I need to offset my CO₂ contributions while on the walk.

Ideally, the CO₂ contributions should be put back underground, so the first idea would be to just cut down bury some trees (after all, once grown, trees aren’t being much of a net CO₂ scrub) – but that would be wrong. Charcoal — being pure carbon and much more stable than biomass — would be much better. Sure, you’ve got to turn wood into charcoal before you do anything with it, but the process of turning wood into charcoal doesn’t produce additional CO₂. This means: charcoal is the way to go.

Now that we know our preferred form of carbon, let’s take a look at the numbers:

  •  EU’s CO2 emissions are ~6.4 tons per year per capita. USA is 16.5. (using data for 2014).
  • Carbon represents 27.3% of CO2 by weight.
  • Density-wise, charcoal clocks between .2 and .6 tons per m3.

If you wanted to sequester the amount of carbon “you” are responsible for, the pile of carbon you’d have to manage would weigh ~1.75 metric tons (4.5 metric tons if you’re in USA). This translates to a nice 2.9 – 8.7 m³ (7.5 – 22 m³ for USA/NA in general) pile of charcoal to bury somewhere at the end of every year.

This, of course, excludes emissions related to cutting down trees, reforestation (!) and transportation; we also assume that charcoal production is using excess power from the wind farms on days when there’s too much wind. The good news, though, is this: most of the per-capita emissions is produced by companies. If you only wanted to deal with the emissions that you cause directly, the pile would probably be much smaller.

Emissions per capita stuff stolen from here.

On Google+ migration and redundancy/fragmentation of tabletop community

When Google announced that Google+ is going to shut down in about 10 or so months, most of the niche communities thriving on the platform decided to move, with MeWe being seemingly the platform of choice for most.

Of course, in some circles the migration was a bit messy. In one of the communities dedicated to tabletop and roleplaying games in particular, we’ve seen three groups pop up.

Replace ‘standards’ with ‘groups’in this xkcd and you get a good summary of what’s going on.

When the third group popped up, I asked whether having the third group up is really neccessary, given there’s already two — both of which have more members — citing concerns about fragmentations and redundancy. Got accused of promoting fragmentation (lul?) by one of the mods, upon brief explanation that asking ‘why not use the first two groups’ got mocked and subsequently banned because if there’s one thing that hasn’t changed since the invention of the first bulletin board, it’s asshole moderators.

But we’re not here to cry about asshole mods, that merely serves as an intro. Ever since that third group has popped up, I’ve started wondering:

How much fragmentation and redundancy there is there, anyway?

Spoiler alert: there’s more fragmentation than you think.

Fortunately for us, that’s really easy to determine. We’ll take a look at who is in which group, and compare how many unique people are there in each of the groups.

As a bonus, we’ll include a fourth group.

While this group doesn’t really qualify as ‘yet another fork of the tabletop gaming group’, I’m kinda curious to see how unique the group is.

Collecting group members

Manually comparing grand total of 1000+ people would probably be a very time consuming task to the point it would be a collosal waste of time. Fortunately for us, we’re on a laptop and we’re using Firefox (although most browsers other than Edge and IE would suffice for that). If we navigate to ‘members’ page of a group and press F12, we get this:

This tells us that people’s usernames are within <span> elements with class ‘user-name’. There’s no other garbage HTML. So if we do this:


We will get all users within a group. This is convenient. However, here’s where some problems pop up. Some groups don’t appear to show all members for some reason. Member counts (as reported by our javascript query) don’t agree with what MeWe reports.

Group User count (MeWe) User count (javascript)
Moe’s group 337 88
Ryan’s group 171 169
Third group 114 112
D&D group 544 543

What’s going on with Moe’s group? That’s some mighty disagreement between what MeWe claims and what I get.

Comparing the members

Before we start: I lied. document.getElementsByClassName() doesn’t quite get us what we want. It gives us array of <span> elements, and we’re after its contents. So our javascript actually looks like this:

var dnd_members = [];
for( var u of document.getElementsByClassName('user-name')) {

Repeat for every page (after changing the variable name).

We won’t bother with writing properly optimized code here for actual comparissons. We’re not working on a multi-million line dataset, so quick and dirty code will do it. We’ll also presume every person has unique name. In general, that’s a pleb mistake to make, but the dataset is small enough for chances of finding two (or more) different people sharing the same name is pretty much next to nothing, so it’ll do for our napkin statistics.

var common_moe_ryan = moe.filter(x => ryan.find(y => x == y))
console.log("overlap:", common_moe_ryan.length)

SURPRISE! Overlap between Moe’s and Ryan group boils down to 8 people (note that there’s something funny with Moe’s group’s members list). I honestly didn’t expect that much. There’s likewise next to no overlap between Moe’s group and the third group: 9 people in common (same caveat applies). Overlap between Ryan’s and third group is a whooping 20 people. There’s a grand total of 2 people who are in all three groups.

That’s honestly more fragmentation and less redundancy than I expected.

Overlapping with the D&D group

Tell you what, I’ll just make a quick matrix.

Moe Ryan Third D&D
Moe 8 9 32
Ryan 8 20 45
Third 9 20 31
D&D 32 45 31
Moe, Ryan 2 6
Moe, third 2 5
Third, Ryan 2 7
D&D, Moe 6 5
D&D, Ryan 6 7
D&D, third 5 7
All:all 1 1 1 1
Venn diagram roughly (but not 100% accurately) illustrates the overlap between the four groups.

So turns out that the D&D group does share big enough number of members with the other three groups. In fact, the overlaps between D&D group and either of the three are bigger than any overlap between any of the three groups amongst themselves.