- Anti-farming policies in Canada, the EU and elsewhere are justified by the supposed need to control agriculture-based nitrous oxide (N2O) emissions. And governments are fond of saying the N2O is hundreds of times more powerful a greenhouse gas than CO2. But that’s not the full story. Paul Homewood (h/t Not A Lot of People Know That) points to detailed computational work done by a team of physicists from the Netherlands, US and Canada which confirms that, while a molecule of N2O has 230 times more radiative forcing strength than a molecule of CO2, it’s only because there’s so much more CO2 in the atmosphere and its effect is heavily saturated. Adjusted for relative amounts the overall effect of N2O is tiny: “But the rate of increase of CO2 molecules, about 2.5 ppm/year (ppm = part per million by mole), is about 3000 times larger than the rate of increase of N2O molecules, which has held steady at around 0.00085 ppm/year since 1985. So, the contribution of nitrous oxide to the annual increase in forcing is 230/3000 or about 1/13 that of CO2. If the main greenhouse gases, CO2, CH4 and N2O have contributed about 0.1 C/decade of the warming observed over the past few decades, this would correspond to about 0.00064 K per year or 0.064 K per century of warming from N2O.” On the basis of which, they point out that measures to restrict agricultural activity are not justified by climate effects and would risk far greater harms if they cut into food supplies.
- A Dutch court of appeals overturned a lower court decision ordering Shell to cut its emissions by 45%. Attorney Lucas Bergkamp discusses the victory here. The court rejected most of the extremist arguments of the plaintiffs but, as Bergkamp explained, also refused to pay attention to the expert witness evidence on the other side, instead declaring that it is a settled matter that the climate crisis is upon us, however the law does not prescribe the specific emission reductions a single company is responsible for. The CO2 Coalition had submitted a statement by scientists Lindzen, Happer and Koonin here.
- Kenneth Richard at NoTricksZone discusses a new paper by Greek hydrologist Demetris Koutsoyiannis that uses a widely-available model to show that the human contribution to the overall greenhouse effect is negligible. We draw your attention to it without endorsing it or not because it’s too specialized for us to follow the details. But an angle that Richard emphasizes reminds us of the topic of Outgoing Longwave Radiation or OLR, which we’ve discussed several times. In short, greenhouse theory says more OLR should be being trapped by CO2 in the atmosphere, causing warming. But satellite records show that more OLR is escaping to space, the opposite of what the theory predicts. And the increase of OLR closely tracks changes in cloud cover. One of those little discrepancies in the theory that the experts ignore until it becomes such a big discrepancy they have to stop and re-think things.
- Tony Heller of RealClimateScience.com has found a historical writeup of a ferocious storm that hit the Great Lakes in November 1835, causing the loss of 19 ships and 254 sailors. No word on whether the World Weather Attribution team at the time attributed it to horse manure.
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20 Nov 2024 | Science Notes
