Imagine my surprise when I coincidently came across a blog post in which this surprising question was answered: Why has a drop in global CO2 emissions not caused CO2 levels in the atmosphere to stabilize? Some of their readers apparently asked why there has been no stabilization in the measured levels of carbon dioxide in the atmosphere when reported emissions of CO2 have fallen. In the post explained that it was very simple: the sinks for CO2 currently offset only about 50 percent of the emissions and additionally these sinks will slowly lose their efficiency as they start to saturate.
That is remarkable answer to a remarkable question. I wasn’t aware that global emissions dropped. The article was only written yesterday, so I was curious what new information they found. I didn’t find any new information after all, but the post linked to a IEA article which was referred to as “recent stabilization in global emissions”.
So is it a drop or a stabilization? Confusing was also the emissions graphs that were present in two places in the post. Yet at a closer look it didn’t exactly serve their case. It mentioned that there was a 2.2% increase of emissions between 1990 and 2014 and a 0.6% increase between 2013 and 2014 (which was the last year in their figure).
So what is it? A drop, a stabilization or a (modest) increase? Time to have a look at the data. Going to the source they linked to, I realized rather quickly that there is a much, much, much simpler answer than the mumbo jumbo answer about the sinks.
The link went to an IEA article dated March 16. It is titled: Decoupling of global emissions and economic growth confirmed.
The article was not about “global emissions”, but about “global energy-related emissions”. Although this may be a big chunk of global anthropogenic emissions, how much does the CO2 level in the atmosphere depend on energy-related emissions? There are also non energy-related anthropogenic emissions and even natural emissions that can possibly influence atmospheric levels.
The article explained that global energy-related emission stayed flat in the last two years, while the global economy grew 3%, therefor coming to the conclusion that emissions decoupled from economic growth for the last two years.
Apparently, IEA attributed this to improvements to the energy efficiency (which I can dig) and the growth of renewables (which I doubt have much effect). More down in the article they attributed it more specifically to the efforts of two major emitters: China (less coal use, plus share of hydro and wind) and USA (switch from coal to natural gas), but offsetted by most other Asian economy and increasing emissions in Europe (hey, don’t they also have an increasing share of renewables?). The share of wind power in China is I think much overrated: it is about 3% of the electricity production and about 1% of primary energy production, so whatever the addition of wind power capacity was in 2014 and 2015, its impact would be marginal at best.
The end of the graph seemed indeed rather flat, but there was also a possibility to download the source data which seemed to be rather interesting. These are the emission values of last years:
32.14 gigaton in 2015 is more than 32.13 in 2014 and that is more than 32.07 in 2013. That is a (small) increase in my world, one could call it a stall compared to previous years, but certainly not a “drop”. Not sure where that question from “readers” came from. It was not to be found in previous posts.
Finally, the question has a much simpler answer: the “drop” in “global emissions” has no influence on the CO2 level in the atmosphere for the simple reason that there was no drop in global emissions in the first place. If putting as much, or even a bit more, CO2 in the atmosphere than previous year(s) and assuming one thinks that anthropogenic emissions are driving the atmospheric level of CO2, then why would one expect the level in the atmosphere to stabilize?