From a site called the Institute for Environmental Analytics:
So that's a pH change of about -0.075 in 40 years, or an average of -0.019/decade (-0.19/century, if you want to unfairly extrapolate). I don't know what the projections have been--will try to post that later. Is this a significant change in ocean water, if your species has chosen to reside there?
This site looks legit, since 75% of the males who lead the Institute have beards.
Seriously though, they looked funded by real sources. Worth exploring more. The data source for this graph is from a legit journal.
The data for the other oceans (at least, Atlantic, Pacific and Indian) look very similar.
2 comments:
It seems to roughly align with the IPCC summary (below). The good news is that the worst impacts are avoidable, and we're slowly righting the titanic.
Analyses of direct measurements of ocean chemistry from time series stations and merged shipboard studies show consistent decreases in surface-ocean pH over the past few decades. Reductions range between 0.013–0.03 pH units decade-1 over records that span up to 25 years (Table SM5.3). Focusing on the individual time series locations with records longer than 15 years, there is an overall decline of 0.017–0.027 (across 99% confidence intervals). Trends calculated from repeat measurements on ocean surveys show a consistent value of around –0.02 pH units decade-1 for diverse oceanic regions (Table SM5.3), with greater subsurface than surface trends reported in the subtropical oceans (Dore et al., 2009). At larger spatial scales, surface-ocean pH trends are assessed using shipboard observations of the fugacity of CO2 and estimates of ocean alkalinity (Takahashi et al., 2014; Lauvset et al., 2015). Between 1991–2011, mean surface-ocean pH has declined by 0.018 ± 0.004 units decade–1 in 70% of ocean biomes, with the largest declines in the Indian Ocean (–0.027 units decade–1), eastern Equatorial Pacific (–0.026 units decade–1) and the South Pacific subtropical (–0.022 units decade–1) biomes (Lauvset et al., 2015). Due to the close link between carbonate ion concentrations and pH, mean trends in the stability of mineral forms of aragonite and calcite (known as the ‘saturation state’) that are important for organisms such as coccolithophorids, pteropods and corals follow those of pH, with high-latitude regions most vulnerable to under-saturation due to naturally lower mean values.
It is virtually certain that ocean pH is declining, and the very likely range of this decline is 0.017–0.027 pH units per decade for the 8 locations where individual time series observations longer than 15 years exist. This trend is lowering the chemical stability of mineral forms of calcium carbonate and can be attributed to rising atmospheric CO2 levels.
...
Overall, it is virtually certain that the future surface open ocean will experience pH drops of either 0.036–0.042 (RCP2.6) or 0.287–0.291 (RCP8.5) pH units by 2081–2100, relative to 2006–2105. These pH changes are very likely to cause 16–20% of the surface ocean, specifically the Arctic and Southern Oceans, as well as the northern Pacific and northwestern Atlantic Oceans, to experience year-round corrosive conditions for aragonite by 2081–2100. It is virtually certain these impacts will be avoided under the RCP2.6 scenario. There is medium confidence, due to the potential for parallel changes in ocean circulation, that the Arctic and north Atlantic seafloors will experience the largest pH changes over the next century.
https://www.ipcc.ch/srocc/chapter/chapter-5/ (see 5.2.2.3)
L, thanks very much for this information. Very useful.
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