Well, I’ve been proven right again. Arctic News picked up on the same issues I had found with the IPCC Sixth Assessment Report.
Downplaying the temperature rise from pre-industrial
One of the first issues that comes up is the baseline. The IPCC uses 1850–1900 as a baseline, like it did before (in SR1.5). This is one out of many instances where the IPCC creates a perception that it would take many years before the 1.5°C threshold would be crossed. This 1850–1900 isn’t pre-industrial. The Paris Agreement calls for pre-industrial as a base.The IPCC image on the right shows a 1.09°C rise from 1850–1900. This isn’t the rise to the year 2020, but it is the rise to the period from 2011 to 2020.
Instead, when taking the 2020 temperature rise and going back one century, NASA data show a 1.29°C rise from 1920, and this is a conservative figure, as 0.1°C can be added to translate NASA’s sea surface temperatures into ocean air temperatures and another 0.1°C can be added for higher polar anomalies, which brings the temperature rise up to almost 1.5°C and this isn’t the full rise from pre-industrial by a long shot.Furthermore, the IPCC uses seasonally-biased data to “reconstruct” the temperature rise before its baseline, making it look as if there was no rise before its baseline.
Instead, the rise from pre-industrial to 1920 could be as much as 0.3°C (1750 to 1920) + 0.2°C (1520 to 1750) + 0.29°C (3480 BC to 1520).
Adding up the rises for all these elements gives a total rise from pre-industrial to 2020 that could be as high as 1.29°C + 0.1°C + 0.1°C + 0.3°C + 0.2°C + 0.29°C = 2.28°C, as highlighted by above images and as further discussed at the pre-industrial page. Ignoring peak peril by averaging over long periods
The map shows that the average global temperature was 1.70°C higher in February 2016 than around 1900 (i.e. 1885-1914). The map also shows local anomalies as high as 15.1°C and even higher peaks were reached on specific days.
In February 2016, the temperature
was 1.70°C higher than in 1900
(i.e. 1885-1914, the 30-year period
centered around the start of 1900)This raises questions as to how the thresholds set at the Paris Agreement should be measured, i.e. is a threshold deemed to be crossed when the anomaly from pre-industrial crosses the threshold for a month, or for a year, or for a decade? Wouldn’t a long period effectively grant polluters a long grace period to keep polluting? When in doubt, wouldn’t downplaying the danger violate the precautionary principle?
When building a bridge, an engineer will calculate how much load it can handle by first looking at how many heavy trucks will be using the bridge at times of PEAK traffic, rather than to average the weight of all vehicles on the bridge over a 30-year period. Caption and image by Sam Carana from earlier post.
Downplaying the near-term temperature rise
The Paris Agreement calls for politicians to limit the temperature rise to well below 2°C from pre-industrial, while calling upon the IPCC to describe pathways to achieve this.
Instead, the IPCC comes up with five scenarios. The only two scenarios for which the rise remains well below 2°C are SSP1-1.9 and SSP1-2.6 (images right).
The position of methane is of vital importance in these scenarios. As a requirement for both the SSP1-1.9 and SSP1-2.6 scenarios, methane emissions would need to have fallen since the year 2015. Even for SSP2-4.5, for which 2°C does get crossed, methane emissions would need to fall.So, have methane levels fallen since 2015?According to NOAA, the methane level in the atmosphere was:
in 2015: 1834 ppb
in 2016: 1843 ppb
in 2017: 1850 ppb
in 2018: 1857 ppb
in 2019: 1866 ppb (the level given by the IPCC)
in 2020: 1879 ppbNote also that above NOAA data are for marine surface data. At higher altitudes, even higher levels show up. The image on the right shows that the MetOp-1 satellite recorded a mean global methane level of 1954 ppb at 293 mb on August 24, 2021, pm.
Mind you, the IPCC report does include some frightening images, such as one with CO₂ levels as high as 1200 ppm by 2100, corresponding with a temperature rise of up to 8°C (Figure 4.3) and one with a temperature rise of as much as 17.5°C by 2300 (Figure 4.40). What the IPCC doesn’t mention is that at 1200 ppm CO₂e the clouds tipping point would get crossed that results in an additional 8°C temperature rise. With a high rise in methane levels and the GWP for methane calculated over a short horizon, such a huge temperature rise could eventuate within a few years time. The IPCC downplays the methane threat by simply excluding the potential for a high rise in methane levels, while using a 100-year GWP for methane and while also waving away the potential for strong methane releases from oceans to the atmosphere.
[ from earlier post ]
For a really high methane emissions scenario, the image on the right shows a trend that is based on NOAA 2006-2020 annual global mean marine surface methane data and that points at a mean of 3893 ppb getting crossed by the end of 2026, a level less than twice as high as the recent 1954 ppb mean methane level.
Such a high mean methane level by 2026 cannot be ruled out, given the rapid recent growth in mean annual methane levels and with double-digit growth sustained beyond 2020 to date. It is deceptive to assume that methane levels have fallen and will continue to fall, the more so since the IPCC doesn’t point at the most effective policies to achieve this.By how much would such a doubling of the methane level raise the total carbon dioxide equivalent (CO₂e) level for greenhouse gases? A methane level of 3893 ppb would translate into 583.95 ppm CO₂e (at a GWP for methane of 150 for a 9-year horizon) or 778.6 ppm CO₂e (at a GWP for methane of 200 for a 5-year horizon).The image below right shows trends based on IPCC AR6 GWP values pointing at a GWP for methane of 150 for a 9-year horizon and points at an even higher GWP for a shorter horizon.
A short horizon is quite appropriate given that the above trend points at the possibility of such a high level for methane getting reached by 2026.
But even with less methane, when using a short horizon for the GWP of methane and adding the impact by 2026 of further greenhouse gases (carbon dioxide, nitrous oxide, water vapor, etc.), that would cause the 1200 ppm CO₂e clouds tipping point to get crossed that results in an additional 8°C temperature rise.
Given that humans will likely go extinct with a 3°C rise, and a 5°C rise will likely end most life on Earth, the IPCC could have given a little more warning that a huge temperature rise may happen over the next few years.
This IPCC report should be returned to be rewritten, to instead focus on the best policies to facilitate the necessary changes. The scientific evidence in favor of what needs to be done is overwhelming, from all kinds of perspectives, while it’s also simply the right thing to do.
So the Sixth Report is exactly what I said it was – garbage. But it will make a lot of politicians and some scientists happy. Some of these people are not actually interested in solving deadly climate change (despite their useless and misleading lip service). Misinformation permeates the Sixth Report and using the wrong pre-industrial baseline will “buy” polluters enormous amounts of time to totally wreck the world.
Don’t wait on these clowns to “save” you or anyone else. That’s not going to happen. It’s going to be up to you to do what you can to save yourself and your children / grandchildren. We can at least make them more comfortable (delay their suffering) if we act now.