Does it fix ocean acidification? Does it fix the decline in human mental performance with raising CO2 levels in the air?
If not its a distraction, not a solution.
If not its a distraction, not a solution.
The calcium carbonate dust is reflective (the aim of the engineering is to reflect sunlight away from the Earth's atmosphere in the first place). However, it doesn't contribute to acid rain or oceans like the sulfate dioxide does (the aerosol that East Asian scrubbers are removing).
The CO2 (a greenhouse gas) amount isn't increased in this engineering effort. It increases because of burning fossil fuels, though. In the East Asian countries, they are producing/using more energy (via burning fossil fuels), but only removing the reflective aerosol; they're still emitting the CO2.
If cost was no object, we'd probably need to use the calcium carbonate immediately (to prevent the sunlight from entering the atmosphere immediately), we'd scrub existing carbon from the atmosphere (CO2), and we'd convert power plants to non-emissive technologies (and also install scrubbers onto existing ones for as long as they're needed).
NASA and the US Navy have been conducting studies since the 1960s showing no loss of cognitive function up to 50000ppm or so.
Submarines and space vehicles regularly operate at CO2 levels much higher than 1000ppm. If the levels of cognitive decline were anywhere close to what some of these studies show it would be easily observable in astronauts and submariners.
Not to mention testing locations with good ventilation would show drastically higher scores over all on standardized tests, and individuals would show drastically higher scores between attempts depending on ventilation.
None of these things happen. The only logical conclusion is that there is some flaw in study methodology.
> Recent studies have shown that short-term exposure to high levels of indoor carbon dioxide (CO2) could negatively affect human cognitive performance, but the results are still controversial. In this study, a systematic review and meta-analysis of fifteen eligible studies was performed to quantify the effects of short-term CO2 exposure on cognitive task performance. The control CO2 levels used for comparison were below 1000 ppm, while the exposure concentrations were divided into three groups: 1000–1500 ppm, 1500–3000 ppm, and 3000–5000 ppm. The results indicated that CO2 exposure below 5000 ppm impacted human cognitive performance, with complex cognitive tasks being more significantly affected than simple tasks. The complex task performance declined significantly when exposed to additional CO2 concentrations of 1000–1500 ppm and 1500–3000 ppm, with pooled standardized mean differences (SMDs) (95% CI) of −2.044 (−2.620, −1.467) and −0.860 (−1.380, −0.340), respectively.
https://www.sciencedirect.com/science/article/pii/S036013232...
I don't know how large these effects are, but they are statistically significant.
Then they analyzed only complex cognitive tasks. But fewer studies included complex cognitive tasks, and they used different methods of adjusting CO2 exposure (ventilation vs adding pure CO2)
Then you’ll note that of those studies they found that:
“The effects of pure CO2 on complex cognitive task performance decreased with increased CO2 concentrations”.
Between 1000-1500, and 1500-3000ppm they found a decrease in complex cognitive tasks performance, but at a higher exposure of 3000-5000ppm they found no effect.
This makes no sense until you read
“the complex cognitive task results under pure additional CO2 concentrations of 1000–1500 ppm and 1500–3000 ppm showed publication bias.”
Handful of studies (many with sketchy methodology—reducing ventilation, which brings with it many more variables than just increased CO2), publication bias, and a negative dose dependent response.
Also that Satish et al. study (the author is the one I was referring to in my last post—they also have several other studies on the subject) shows an enormous effect IIRC, which would skew the aggregate effects in the meta study.
The effect sizes in that study were the ones I was referencing when I said that such effects would be obvious.
Since humans have been building shelter and living in caves, we have regularly been exposed to long term CO2 levels of 1000-2000ppm. The natural variations in ventilation dwarf a few hundred extra ppm in the atmosphere.
We’ve also been exposing submariners to thousands of ppm for extended periods with no observed effect, and we have many studies shows no observed effects up to 40k ppm.
We even have studies showing that small babies sleeping next to the mothers are exposed to CO2 levels of 5-10kppm.
skimming through a couple of studies, measurable impact starts around 1000 ppm. with current policy intervention, we will likely reach 550ppm by 2100
https://www.imperial.ac.uk/grantham/publications/briefing-pa...