# What are the technical solutions to measure $\ce{CO2}$ emissions?

I'm currently at COP24 (United Nations Climate Change Conference) in Katowice, Poland.

(some editing since I took a screenshot of my laptop)

I've asked some guys about $$\ce{CO2}$$ emissions but very few have sufficient technical knowledge.

My assumption is that they assume the data is right.

https://ourworldindata.org/co2-and-other-greenhouse-gas-emissions#how-do-we-measure-or-estimate-co2-emissions

More recent energy statistics are sourced from the UN Statistical Office, which compiles data from official national statistical publications and annual questionnaires.

https://www.thenakedscientists.com/articles/questions/how-do-you-measure-carbon-dioxide-emissions

The Intergovernmental Panel on Climate Change has published a five-volume set of guidelines that all the countries now use, as part of the UN Framework Convention on climate change, for estimating emissions on all greenhouse gases and it does produce uniformity across countries.

Although there are some large power plants in which they actually put measurement devices in the smoke stack and can measure the amount of CO2 that comes out, that is unusual.

About measuring $$\ce{CO2}$$ in the atmosphere, we have a satellite for that: https://climate.nasa.gov/climate_resources/99/graphic-measuring-carbon-dioxide-from-space/

About air quality index - https://en.wikipedia.org/wiki/Air_quality_index - we have a number of standards for that (shame there are multiple standards)

### About new $$\ce{CO2}$$ emissions - what are the scientific ways to measure that?

• Hello, and welcome to Earth Science. It isn't clear what your question is. Are you asking how to measure CO2 emissions? How to detect CO2 cheaters? Something else? (The screen shot of text doesn't help; please include your entire question as text, unless there's a truly helpful image you want to include.) – Daniel Griscom Dec 15 '18 at 22:44
• The goal of including the image - proof that I was there. I'm seeking scientific way to measure CO2 emissions - something that cannot be easily tweaked by governments who have history of harvesting organs and breaching human rights: bmj.com/content/363/bmj.k5250 – Mars Robertson Dec 16 '18 at 17:34
• Hi Mars, we will answer your question also without any proof that you were there. Many people just ask stuff like that out of sheer curiosity, they get answers as well. As it stands now, your question has a bit strange formatting and it would help readers if you could de-spaghettify it. – AtmosphericPrisonEscape Dec 17 '18 at 15:25

In addition to satellite measurements of carbon dioxide, there are numerous ground based stations that also measure carbon dioxide: Italy, Hawaii, Australia, just to name a few.

If you want to catch carbon dioxide emitting cheaters, a dense network of such ground based stations would be needed around the world. The measurements would need to combined with meteorological data, particularly wind directions and strength. I imagine this would also require significant computer modelling to analyze all this data in a timely manner. This would need to be operated by a totally independent organization with lots of money. This will be difficult to achieve.

Alternatively, and probably more costly would be to have a constellation of satellites in geostationary orbit around the Earth constantly measuring atmospheric concentrations of carbon dioxide. As with the ground based stations, the data would need to be combined with meteorological data and processed via a computer model.

Monitoring compliance will not be cheap or easy.

There is an EU programme having exactly this aim. See this press release. Monitoring anthropogenic CO2 emissions needs the combination of in-situ measurements, satellite observations and modelling of both the atmosphere and biosphere.

So as Fred already said, ground stations measure the ground concentrations of $$CO_2$$. For satellite observations one measures the intensity of infrared radiation $$I(z)$$ in a absorption band that is unique to the chemical of interest, i.e. $$CO_2$$, that has a laboratory-known opacity $$\kappa$$. Opacity is just a measure for the intransparency of a gaseous medium, also giving rise to the word 'opaque'. The background intensity $$I_0$$ can be determined in a non-absorbing band, or 'atmospheric window' by the same measurment.
We then know from the radiative transfer equation the following relation: $$I(z) = I_0 \, \exp\left(-\int dz \, \rho(z) \, \kappa \right)$$ which contains the unknown density profile $$\rho(z)$$ in $$[\rho]=\frac{kg}{m^3}$$, and the integral over it over the atmospheric profile $$dz$$. To solve this one, requires modeling of the profile, but there's an approximation to this, which can give us the column density $$\Sigma$$ of a chemical, with $$[\Sigma] = \frac{kg}{m^2}$$, and the approximation is $$I(z) = I_0 \, \exp\left(-\Sigma \kappa \right),$$
which is straightforward to invert and determine $$\Sigma$$. Then one simply plots $$\Sigma$$ distributed over the globe, and in this way one can find the emission regions of any chemical, or other interesting things like the Ozone hole.