There are dozens of locations worldwide where atmospheric greenhouse gas (GHG) levels are recorded and tracked. One of our favorites for CO2 is the NOAA's Mauna Loa location in Hawaii. The series of CO2 reasons over the past few decades has steadily increased.
September data, which is usually the seasonal trough for the annual cycle, is now in hand and shown in the data below. The vertical lines in the chart below indicate May readings, the typical seasonal peak. The NOAA website also contains information on atmospheric methane, nitrous oxide, and sulfur hexafluoride GHG levels. This Insight updates an earlier Mauna Loa Insight published in June 2022.
Coupled with multiple sets of research done on evidencing ancient greenhouse gas levels, the NOAA has stitched together how the more recent trend connects to the very long history of atmospheric greenhouse gas levels. Yes, it has cycled over time, but clearly, the graph’s extension during the past few decades is extra-cyclical relative to history. Major variables thought to have driven the increase in atmospheric CO2 revolve around the industrial age but have included meaningful population growth and the vast expansion in transportation and power use of fossil fuels.
The oft-quoted desired limit of global temperature increase of 1.5 degrees Centigrade (~3 degrees F) is directly linked to a PPM (part per million) level of greenhouse gases in the atmosphere. There are different estimates of that critical PPM level but many use 450 PPM as the estimate linked to 1.5 degrees Centigrade. PPM rises above that level would cause even greater warming.
Tracking how fast we approach key levels is critical for knowing how soon we’ll reach 450 PPM or higher levels. To calculate this, we have taken the number of PPMs between the September reading of 415.6 and 450 (approx. 34) and divided that number by the recent year-over-year monthly PPM increase of 2.65. The resulting 15.5 tells us how many more years at the current rate of PPM increase before we get to 450 PPM and the estimated 1.5 degrees Centigrade (~3 degrees F) global warming.
The charts below show A) the trend in year-over-year amounts of PPM increase and B) a history of how many remaining years have been implied by the past rates of increase in PPMs.
Source: NOAA Global Monitoring Laboratory
Source: NOAA Global Monitoring Laboratory
On the lower graph showing years remaining, we see that in early 2012 the then level and rate of increase implied 40 years or to the year 2052 before reaching 450 PPM. Today’s reading of 15.5 years at the recent rate of increase gives us to 2037. To extend the 15.5 years left before 450 PPM is reached, the rate of increase in PPM has to decrease and ultimately reach no growth—or net zero—in order to plateau at that level.
The Covid-induced economic slowdown may have impacted the slow deceleration in the 2020 and 2021 rate of PPM increase. The return to higher rates of PPM increase in 2022 probably stems from the economic recovery from Covid with some tempering from recent Chinese policy on covid.
Future rates of increase could be slowed by recession yet also accelerated by energy mix changes (i.e., more coal burning) as a result of the war in Ukraine. CO2 reduction efforts could also improve the outlook, though those efforts to date don't add to be significant enough to change the trajectory over the next few years. It remains to be seen. If we are to experience a global recession as some predict, it might give more time for C02 reduction and elimination efforts to have more of an impact.
Motivations to slow the rate of carbon accumulation in the atmosphere seem to be building. However, putting aside climate deniers, it is difficult for many individuals to connect to the emissions issue. On measurement, it seems easier and more direct for people to think about how many tons of CO2 emissions an individual could save than an amorphous if not perhaps seemingly insignificant increase of 1.5 degrees C.
If we also need to see gigatons of reductions–that’s billions of tons of reduction–an individual’s saving of five tons of emissions (the annual average of a typical passenger vehicle) can lead to a “why bother?” Particularly if the community in general is not making a similar reduction effort. It is also true that having a distant 15- or 30-year goal in mind doesn’t connect with our typical thinking about maybe the next three years.
Despite the difficulty in comprehending the issue in all its nuances, more industries and governments are leaning into the complexities of the emissions count. Given that there is no magic bullet of one- or two- solutions to rising CO2 levels, however, we will continue to hope that the 1,000’s of smaller efforts will begin to add up to a significant PPM impact. We’ll check in again when the May 2023 seasonal peak levels are in hand.
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