A new article, predicting the likely level of sea-level rise, is an example of academic nonsense on climate change, since it fails to deal with China’s opaque COP21 “commitment” and the fallacy of predictions based on IPCC’s deliberate obscurity.
Sea-Level Rise nonsense
The article in Nature Communications includes two significant misstatements, which together give rise to my charge of “Sea-Level Rise nonsense.”
- It assumes that CO2 emissions will not peak until 2020, when actual observations indicate that CO2 emissions effectively peaked in 2013. Since the impact of CO2 emissions on CO2 atmospheric levels is incremental this is not an insignificant misstatement. What makes this mistake even more egregious is the fact that the report makes much of the importance of cutting CO2 emissions earlier rather than later.
- The article makes no indication of the climate sensitivity implied in their report. Since the IPCC includes a range of climate sensitivity estimates from 1.5C to 4.5C, this is not an insignificant omission. One suspects that the report is using the top of the range estimate. Yet the only hint that they are using the highest level of climate sensitivity estimates is given in the wording “high warming.” The use of the 4.5C estimate seems to be assumed in the prediction that sea-level rise will continue until 2300 under all scenarios. The lack of clarity in outlining the assumptions adopted is common in most “scholarly” reports on climate change, even though providing clarity on the assumptions adopted is a necessary element in all articles with the implied claim of being “scholarly.”
COP21
The Paris conference on Climate Change, tagged COP21, did not define the level of climate sensitivity implicitly adopted. Yet this was necessary at a meeting that must represent a political compromise. However, it is clear from the wording of the conference that the 192 nations that endorsed its decision implicitly accepted a climate sensitivity estimate of 2.0C, not the 4.5C at the upper end of the IPCC range, and not the lower end of 1.5C. Since the predicted sea-level rise is directly related to the assumed climate sensitivity, this is not an irrelevancy.
On the other hand, it was acknowledged that the action agreed at that time was not sufficient to cap global warming at 2.0C, and that future action would be required beyond that agreed at the significant meeting. For the authors of this article to fail to acknowledge that fact exposes their intention to write a report which is not strictly scientific, but rather is deliberately intended to be the advocacy of the particular viewpoint they are promoting. It is not even intended to spark debate of the matters at issue.
China’s Opaque COP21 “Commitment”
The only obvious difficulty with COP21 relates to China’s “promise” to keep increasing emissions until 2030. If they deliver on this promise we are all sunk, since it will result in CO2 atmospheric levels that suggest a very bad outcome for world weather, even with climate sensitivity of 2.0C.
Fortunately, China seem to be reducing CO2 emission levels, not increasing them.
However, the opacity of China’s “commitment” makes it extremely difficult to conduct a rational discussion of the action required to mitigate the impact of increasing levels of CO2 in the atmosphere on global average temperature.
We need more articles on this theme, and not obvious beat-ups, like this article in Nature Communications, which for me is another example of Sea-Level rise nonsense.