A study on sea-level rise study says that the boom in dam constructions in the 1970s have played a significant role in restricting sea-level rise.
The study wanted to measure or the increases in sea-level rise from glacial melts, thermal expansion and terrestrial water storage – water stored on or below the land surface. It says that ice-mass loss from glaciers and the Greenland Ice Sheet caused twice as much sea-level rise than thermal expansion since 1900 especially during the 1940s but because of massive constructions of dams that happened in 1970s the increase in sea-level was lower-than-average rates.
Without the construction of dams, sea-level at the time would have been 12 per cent higher.
Researchers find it challenging to determine the factors that account for sea-level rise in the last 100 years. The study says that there is a gap between measuring the increase in sea-levels and the amounts of water from sea ice loss, thermal expansion, and terrestrial water storage that goes into the oceans. But recent developments to observational data, researchers were able to come up with a new and more accurate estimation.
Researchers find that vigorous dam-building between the 1950s to 1970s has hindered water from entering the sea and thus slowed the global sea-level rise.
Does this mean that building more dams today could prevent sea-level rise?
And if so, how much more dams should we build?
Between 1900 and 2018 sea-level rose by approximately in 1.56mm per year. And glacial melts due to warming is the primary cause, especially in the 20th century. In the past 30 years, however, the speed of glacial melts has increased due to climate change resulting to 3.35mm rise in sea-level per year, making the dam’s influence preventing sea-level rise almost negligible, the BBC article says citing the study (Mc Grath, 2020).
And if dams should perform as it did in the 1970s, it will take five times as much dams to construct today than it was in the 70s, says Mc Grath (2020).
If indeed the construction of dams will be used to hold back terrestrial waters, it would need to be at a scale to be effective. Construction of dams will also require massive amounts of construction materials which will have implications on carbon emissions and building these massive projects can impact the environment as well.
Another study also examined the role of dams to protect against projected sea-level rise. The study contemplates the construction of a 637 km long Northern European Enclosure Dam (NEED) to protect northern European countries from sea-level rise.
The study says that the sheer scale of the solution of building a massive dam allows us to understand the threat climate-change induced sea-level rise.
Investigating the viability of this project, researchers find that constructing the NEED, and considering all impacts and challenges of the project proved to be more favorable than any other alternative solution to climate change which makes it a probable solution if all mitigation fails.
However, solutions like this only treats the symptoms of climate change and not the root of the problem which is to address the reduction of human-caused emissions.
To read the full studies, click the links below:
Frederikse, T., Landerer, F., Caron, L., Adhikari, S., Parkes, D., Humphrey, V. W., Dangendorf, S., Hogarth, P., Zanna, L., Cheng, L., & Wu, Y.-H. (2020). The causes of sea-level rise since 1900. Nature, 584(7821), 393–397. https://doi.org/10.1038/s41586-020-2591-3
McGrath, M. (2020, August 19). Climate change: Dams played key role in limiting sea level rise. BBC News. Retrieved from https://www.bbc.com/news/science-environment-53836018
Groeskamp, S., and J. Kjellsson, 2020: NEED: The Northern European Enclosure Dam for if Climate Change Mitigation Fails. Bull. Amer. Meteor. Soc., 101, E1174–E1189, https://doi.org/10.1175/BAMS-D-19-0145.1.