Thanks all for discussing this!

I also think the AR6 policymaker summary is an easy read and says what we have to do and how we can do it. This is the report from the IPCC.

https://www.ipcc.ch/report/ar6/syr/summary-for-policymakers/

Sometimes inventories get hidden in really long documents, talking about how great the leadership of GiantCorp is, or complaining about how Province A is having to do all this work, when the other provinces aren't pulling their weight. But you can usually flip past to the tables and find the real info.

Every country that's a part of the Paris Agreement produces a yearly report. Most states and provinces in the developed world do, too. Cities are spottier -- only about 5-10% have produced any inventories at all, and most only have done 1 or 2.

@modulux It's really hard to ground truth these kinds of numbers -- it's not like we can directly measure carbon emissions from a city over a year. But there are ways to check.

Typically, climate data folks will try different estimation techniques and hope they match up. They measure per-capita values to see if they're within expected ranges.

And they do roll ups -- the emissions for all the provinces in Canada should roughly match the emissions for for Canada as a whole.

If you work for a company of medium size, they may also produce an inventory.

Hey, thanks everyone for your responses. I'm a yes; this used to be my job.

I think everyone who lives on this planet should have an idea of what's causing the emissions in their city, state or province, country, and on the planet. That's the only way we can tell good policies (reduce a lot of emissions) from bad ones (don't reduce emissions).

@PhoenixSerenity I didn't know that! Wow.

@BathysphereHat that's really interesting!

@log they aren't going to be great.

@themediumkahuna does the university integrate the results into a climate action plan? And actually execute on that plan? That's pretty awesome.

@Django "The industry wants Ottawa to rely on Alberta’s measurement of methane emissions rather than the federal government’s own measurements when it calculates reductions in methane in its deal over a new pipeline and other support for the industry."

So, it's about generally tracking fugitive emissions. I stand corrected!

@Django ah, I might have misread the story! I thought it was about emissions reductions from adding a new pipeline.

@Django if you're asking about the story you're sharing: that's not actually about a greenhouse gas inventory.

@Django especially for industrial emissions, climate data specialists have to collect data from industry (how much steel manufactured, how many cattle raised). For energy use, it's usually numbers reported by the energy companies. So, yes, corporate reporting plays a big part.

@Django

For local, provincial, and national inventories, it depends. A typical inventory uses some sort of activity data and multiplies it by an emissions factor. So, total number of vehicle kilometers traveled, times a factor representing emissions per kilometer, gives total emissions for transportation.

@Django you took a lot of leaps ahead of me. I'm not sure what you're asking.

If you're asking whether self-reporting matters for corporate GHG inventories, the answer is yes. They're almost entirely self-reported afaik. They are also investor relevant information, so it's a big deal if you fake your reporting.

@grob also, consumption-based inventories are uncommon.

@tarix29 agricultural emissions are tricky, too!

@grob that seems pretty legit! You can get a lot of information from a top-line scan or an executive summary.