This appears to be another piece of junk science promoted by the American Association for the Advancement of Science (AAAS)!
This is more propaganda and demagoguery of the environmentalism ideology!
All these human impoundments of water represent only a minuscule amount of water compared to the oceans!
I guess, if humans continue like this, the earth will stop rotating in the not so distant future. Caution: satire.
"Human activities have been conducted at such immense scales that they literally have affected how the world turns. Valencic et al. discuss one dimension of that impact: movement of the poles due to water impoundment. Using data on how the construction of dams has altered the distribution of terrestrial surface water in reservoirs, the authors calculated the path of true north polar wander from 1835 to 2011 CE.
A dramatic change in the direction and rate of polar wander around 1950 reflects a shift from dominantly North American impoundment to greater storage in East Asia, Africa, and the rest of the world, providing a stark reminder of our growing footprint on the environment."
From the abstract, key points, and plain language:
"Artificial water impoundment contributed significantly to global mean sea level change during the 20th century and is included in recent studies of the budget of 20th century true polar wander (TPW).
We adopt a recent global database of water impoundment that accounts for 72% of an integrated global volume estimate and compute the associated TPW path from 1835 to 2011 CE. We find a highly non-monotonic pole path, with an integrated path length of 113.4 cm, a net displacement of 20.5 cm in the direction 103.4°E from 1835 to 1954 CE and 57.1 cm in the direction −117.5°E from 1954 to 2011. Across the first half of the 20th century, the mean rate of TPW was 0.30 cm/yr, while in the second half of the century it was 0.95 cm/yr.
Finally, we demonstrate that the 28% of the total global water impoundment missing in our database likely had a negligible impact on polar motion.
Key Points
- A recent study compiled a global database of artificial water impoundment (dams) from 1835 to 2011
- We adopt this database to compute the signal of the impoundment in the reorientation of the Earth's rotation axis, true polar wander (TPW)
- The calculation differs in both magnitude and orientation from previous estimates and has implications for the budget of 20th century TPW
Plain Language Summary
Any movement of mass within the Earth or on its surface changes the orientation of the rotation axis relative to the crust, a process termed true polar wander (TPW). In this study, the authors compute TPW driven by the impoundment of water in globally distributed dams from 1835 to 2011. The calculation is based on a recent, comprehensive database of water impoundment, and the resulting polar wander path and magnitude is significantly different from an earlier estimate of the signal. Constraining TPW due to impoundment and using it to correct the observed 20th century rate of TPW, will help to constrain other physical processes contributing to the signal, including melting of polar ice sheets and glaciers in our warming world."
Figure 1 Reservoir locations in the Hawley et al. (2020) database. Location of 6,862 artificial reservoirs in the database adopted in this study. Symbol size is proportional to the logarithm of the reservoir capacity.
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