Tom Evslin: It’s the subsidence (not the rising seas)

This commentary is by Tom Evslin of Stowe, an entrepreneur, author and former Douglas administration official. It is republished from the Fractals of Change blog.

Recently-flooded Pakistan is the poster child for “reparations” to be paid to third world countries by the developed world for the damages caused by climate change. However, the scale of the disaster is largely due to poor governance in Pakistan and local practices that won’t be cured by shoveling cash to the same kleptocrats who have swallowed up past foreign aid without improving the lives of their citizens. Almost all press accounts of the disaster fail to mention that so much water has been pumped out from under the areas which flooded, that the land is sinking — a process called subsidence — much faster than seas are rising.

Tom Evslin

The monsoon rains were the worst in 40 years and may have been exacerbated by global warming (responsible scientists don’t attribute individual weather events to climate trends). There is more glacial runoff into the rivers of Pakistan than there used to be, certainly a function of higher temperatures. The seas are slowly rising. However, the disaster was preordained by the flood of people moving into the affected areas recently and deep drilling for water both to support expanded agriculture on the alluvial soil and water-hungry manufacturing in cities like Karachi, parts of which are sinking five times faster than the surrounding sea is rising. As the aquifers are depleted, the sandy soil compresses and the land above sinks. Earthquakes hasten the settling process as does the weight of new structures.

Until recently it has been almost impossible to distinguish rising ocean levels from subsiding land since the sea reaches further in both cases. However, satellite-based measurements now give us an extremely accurate measurement of both sea and land level. An article published by Voice of America in 2019 titled “Cities Sinking in Pakistan’s Baluchistan Provincediscussed the sinking problem but without explicitly predicting the flooding:

“Local and American experts warn unchecked groundwater extraction in major urban centers in Pakistan’s Baluchistan province has triggered the sinking of the land at a rate of 10 centimeters a year, causing cracks in buildings, roads, and agricultural fields.

“The land subsidence is occurring in numerous locations in northern parts of Baluchistan, including districts of Qilla Abdullah, Pishin, Mastung and the provincial capital of Quetta, the largest population center in the province [nb. an area very hard hit by flooding.]

“The area is arid and groundwater is the only source of water for domestic and agricultural use, said Professor Din Muhammad Kakar of the University of Baluchistan.

“’We have drawn a lot of water from the subsurface and the over-exploration of the groundwater has triggered the phenomenon of land subsidence since 2010,’ said Kakar, who is dean and chairman of the department of seismology.”

The alluvial plain is just above sea level and historically floods frequently; that’s why the soil is rich and doesn’t become depleted of nutrients. People build just above the most recent flood level (and sometimes below it). When the land sinks, the next flood of the same magnitude will reach more land than the one before it. When there is a 40-year flood through land which has sunk and become many times more populated since the last major flood, there is predictably a disaster. That’s what happened in Pakistan.

Subsidence is a major threat in many places beyond Pakistan. A recent study measured subsidence worldwide:

“Satellite data indicate that land is subsiding faster than sea level is rising in many coastal cities throughout the world. If subsidence continues at recent rates, these cities will be challenged by flooding much sooner than projected by sea level rise models. We measured subsidence rates in 99 coastal cities around the world between 2015 and 2020 using satellite data. Subsidence rates are highly variable within cities and from city to city. The most rapid subsidence is occurring in South, Southeast, and East Asia. However, rapid subsidence is also happening in North America, Europe, Africa, and Australia. Human activity — primarily groundwater extraction — is likely the main cause of this subsidence. Expanded monitoring and policy interventions are required to reduce subsidence rates and minimize their consequences.”

An article in The Washington Post about the barriers built to mitigate flooding in Venice goes on and on about whether the wall will be effective as the sea rises. Buried at the end of the article is the main reason for recent flooding in Venice: the land the city is built on is sinking, largely because of water extraction.

It’s politically popular to attribute all disasters to climate change. Ignoring other natural and man-made causes of catastrophe — like subsidence — makes it impossible to take effective avoidance and mitigation measures. No matter how many Teslas we drive or how many dollars we pay in reparations, Pakistan and many other countries will suffer increasingly severe floods so long as water is being pumped out from under collapsible sandy soil.

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4 thoughts on “Tom Evslin: It’s the subsidence (not the rising seas)

  1. The attitude that the climate of an entire planet that is roughly 8000 miles in diameter can be controlled by meager human efforts is pure arrogance. Earth’s climate has been changing for thousands of years and the issue is a lot bigger than any bureaucratic or scientific manipulation can alter. That is not to say that we earthlings have been the best stewards of the environment, but our poor stewardship amounts to very little in contributing to the current climate status. Likewise, any effort to actually control the climate of the entire planet would be akin to doing “you-know-what” in the ocean. Instead of declaring that “the sky is falling”, the focus should be on how we can adapt to the natural phenomena (e.g. climate change) that are far beyond human efforts to control and practicing better stewardship of this planet that we call home.

  2. Clearly, there are many reasons for sea-level change. Subsidence, erosion, tectonic plate shifts, to name some. And clearly, the climate models are inaccurate. CO2 may be part of the cause. But so is the shift in the earth’s magnetic poles, the Milankovitch Cycles, and solar phases.

    A far more dangerous problem is dealing with the ‘kleptocrats’ profiteering from these changes as they claim to have a remedy… that amounts to so much snake oil. Not only are these corrupt politicians and corporate hustlers wrong for the most part, they’re diverting precious resources away from what we should be doing – namely, moving to higher ground if you find yourselves in an affected area.

    After all, to think that humans can change their behavior and stop climate change, let alone convince everyone specifically what they should be doing in every instance, is the height of hubris.

    • Our attitude to anthropogenic climate change smacks of the aboriginal Americans’ attitude toward real estate ownership: “These men who come from the Big Water say they want to own Manhattan Island. How can anyone own a piece of land?”

      • “How can anyone own a piece of land?”

        It depends upon what you mean by ‘own’ (ownership). By agreeing to live under a market based free enterprise system, in some cases anyone can own land, or in others everyone can own it.

        Of course, what that has to do with the causes of climate change is anyone’s guess.

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