W. Waterways - ocean, rivers, marshes

W1. Conserving Wetlands

Wetlands – lakes, marshes and swamps – tend to be good carbon sinks. Peat bogs have been mined for their fossil fuel in the past. When we drain an existing acre of wetland, we tend to unconsciously release great amounts of the carbon that has been stored for millennia below the waterlogged wetland.

“Natural peatlands do not always have a measurable cooling effect on the climate in a short time span as the cooling effects of sequestering carbon are offset by the emission of methane, which is a strong greenhouse gas. However, given the short "lifetime" of methane (12 years), it is often said that methane emissions are unimportant within 300 years compared to carbon sequestration in wetlands. “ -- [ https://en.wikipedia.org/wiki/Mire ]

Research questions: if we were building additional wetlands to sequester carbon, do some types of mires produce less methane? Does aerating the water change the wetlands' ability to sequester carbon?

W2. Adding wetlands

Beyond not releasing great amounts of extra carbon into the atmosphere, we need to consider the other side of the coin: creating more wetlands equals more carbon sequestration. Forests aren't particularly good at the long-term sequestration of carbon, but bogs do the job.

For further reading: https://theconversation.com/trees-arent-a-climate-change-cure-all-2-new-studies-on-the-life-and-death-of-trees-in-a-warming-world-show-why-182944

A friend has recommended that beavers sequester carbon well. Beaver dams are natural bogs. Flood-carried clay accumulating in the beaver pond above carbon in the marsh lays down a rather permanent carbon sink.

Also, beaver ponds turn narrow streams into wider wetlands areas that tend to inhibit the spread of local forest fires.

For further reading: Smokey the Beaver: beaver-dammed riparian corridors stay green during wildfire throughout the western United States. https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/eap.2225 North America used to be filled with hundreds of millions of beavers.

Also see:: https://theconversation.com/beavers-offer-lessons-about-managing-water-in-a-changing-climate-whether-the-challenge-is-drought-or-floods-168545

Also see https://iopscience.iop.org/article/10.1088/1748-9326/abd34e Legacy effects of loss of beavers in the continental United States

“Compared with untilled cropland, wetlands can sequester around two times the carbon, and planted wetlands may be able to store 2-15 times more carbon than what they release. Carbon sequestration can occur in constructed wetlands, as well as natural ones.” -- ibid

Arctic beaver dams are an exception. Because of rapid Arctic warming, beavers are proliferating in river valleys which are on top of layers of permafrost. It might be that the permafrost would melt in two decades in any case, but beaver ponds on top of the permafrost are exacerbating methane production in those areas.

W3. Creating saline marshes on desert sinks

The Salton Sea used to be the Salton Sink, a dry salt flat. Southern California farmers dumped vast quantities of their selenium-laced agricultural waste water into the nearest dry stream, and that's how the Salton Sink at the bottom changed into a moderately toxic lake. It turns out that any water, even water laced with somewhat toxic minerals, will grow plankton, then fish find their way in, and then a local population of birds will expand to a size related to the size of the fish hatchery. Then a few powerboats, resorts and lakefront villages show up.

I'm willing to consider pumping seawater, agricultural runoff, local brackish groundwater or a deliberate mix of saline water and less salty water, pumped in with the intermittent energy from wind/solar, into manmade enclosed marshes or planted bogs in arid lands, for example, near the Salton Sea in California. Near the Salton Sea, seawater would be available from the nearby Gulf of California in Mexico. If the current Salton Sea can sequester carbon then artificial extensions built next to the current Salton Sea might sequester additional carbon.

W4. Rice paddies design

A relatively narrow pond with a surface elevation two feet above the Salton Sea can be established in the wide flats next to the Salton Sea with a two foot levee. A second pond can be established four feet above the Salton Sea with a second two foot levee on the back side of the first pond. This series of long, sometimes narrow ponds would be comparable to arrays of rice paddies covering hillside slopes in east Asia. Putting water into one end of each narrow pond would mean that the other end of the pond is also flooded. A series of planted mires near the Salton Sea would hopefully sequester carbon like crazy with low management needs.

In saline marsh sequestration, as with any agricultural endeavor, certain plants will thrive better and produce more permanently sequestered carbon or artificially sequesterable hydrocarbons. We might want to provide nutrients, except most agricultural wastewater is already polluted with fertilizers. Aerating the water with solar powered pumps might help move carbon dioxide into the water.

Much of the seawater will eventually become humidity in the atmosphere. From the Salton Sea area, east-blowing prevailing winds will take the extra humidity up over the West's mountains where much of the humidity will be wrung out of the air. In this way, saline marsh evaporation will eventually nourish the West's mountain forests and will in time become river water. Mangrove farms might help to put humidity into the air on dry days, and Mangroves sequester carbon fairly well.

Right now the edges of the Salton Sea are drying out, leaving a toxic dust that blows around. Local California agricultural wastewater is full of toxic metals such as selenium. Any attempt to create saline marshes needs to solve this post-evaporation toxic dust side issue, possibly with evaporation ponds designed to never see strong winds. We'd need to drain highly salty brine out of the far end of the pond, most likely into special evaporation pans, to avoid salt rime buildup.

If the Salton Sea, formerly the Salton Sink, is a manmade phenomenon, a dump for agricultural wastewater, is there anything ecologically wrong in artificially pumping seawater into it to keep it filled?

Another downside of saline marshes is that they can put saline water into the local groundwater. However, in many arid areas the groundwater isn't potable right now. Adding a clay or neoprene rubber bottom to the marshes would probably keep the salt water from sinking.

A lower cost alternative strategy to minimize regional groundwater contamination is to study the local underground hydrology, then install one or more wells and solar/wind pumps near the middle of the saline marshes. As salt water is pumped out, fresh water flows inward from 360 degrees around the artificial salt marsh. The shallowist well will pull in the most saline water. A deeper well is likely to pull in a somewhat brackish mixture of saline marsh water and local groundwater The marshes with water that is the least saline should be on the outside edges of the marsh complex, and the most saline bogs and evaporation pans should be near the center.

To be more fully answered: what would grow in artificial salt water or brackish water marshes?

I sense that brand new wetlands constructed on desert land will release nearly zero carbon into the air because no old carbon is available.

The same plan would work for any lowland arid region with access to salt water. Other no-outlet lakes have been drying up worldwide. The Aral Sea is for the most part a toxic, dry wasteland. The Jordan River water isn't flowing into the Dead Sea. I have read that the Great Salt Lake is shrinking. The Bonneville Salt Flats were once Lake Lahontin in geologic history. Egypt, Ethiopia, Libya, Saudi Arabia and Mauritania all have extensive arid lands abutting salt water.

We could arrange some type of climate protocols so that certain nations are honestly compensated for the gigatons of carbon that they sequester, minus their respective roles in releasing gigatons of carbon.

W5. A history of water storage and collection

Underground water tunnels with water storage go back at least to 750 B.C.E. in Iran, and the ancient technology was fairly widespread. Some centuries-old water tunnels are still functioning as originally designed. For further reading: https://india.mongabay.com/2021/12/reviving-400-year-old-mughal-era-water-structures-to-combat-climate-change-in-mps-burhanpur/?utm_campaign=The%20UnEarth%20Bulletin&utm_medium=email&utm_source=Revue%20newsletter#:~:text=A%20400-year-old%20unique,supplying%20drinking%20water%20to%20households.

W6. Pond/canal evaporation suppressors

White or mirrored floats can reduce evaporation from off-river pumped hydro reservoirs and also from canals.

One option is to use glass floats, not throwaway plastic floats, that reflect away solar rays in the infrared and ultraviolet ranges, allowing visible light through for algae growth in the water. Algae eats carbon dioxide and removes fertilizer from water, purifying it.

If the floats are blocking out wind then they may also be blocking out oxygenation of the water. Make sure that small rills upstream is properly oxygenating the water and also adding atmospheric carbon dioxide to the water, or else install a solar-powered air pump in a storage pond to add air for algae growth and for fish habitat.

One goal is to maximize the percentage of area that the reflective floats cover, in order to minimize unwanted daytime evaporation. Hexagonal floats with reasonably tall sides should jostle themselves into a closer-fitting pattern than square floats, and if a person or animal falls into the reservoir they can move the floats aside and crawl out. Floats that slightly lock or velcro themselves to their six neighbors in a correct hexagonal array would be a useful touch that further minimizes evaporation.

As a rule, generating coolness in a pond late at night, with a cooling method other than evaporation, reduces that pond's total evaporaton. A cooling tower might help.

W7. Poaching Midwest water toward the Colorado River near the Continental Divide

I expect the U.S. Southwest to stay in megadrought. What if the regional aridification builds on itself and gets exponentially worse?

Proposals have been made to pump Lake Superior water to California and also to build an undersea freshwater “garden hose” from the Columbia River's outlet down to California. I'm skeptical of the wisdom of such megaprojects, but I can suggest a simpler way to slightly increase the West's water supply.

Poaching a small stream of water from the edge of one river basin to another was practiced by the Inca empire in Peru starting around the 14th century. Building tiny mountain slope canals leading to Continental Divide passes, lined high-altitude ditches starting on the east sides of the Continental Divide and curving westward around mountain slopes to the Continental Divide and just a bit farther, will capture small amounts of normally eastward-flowing surface runoff and deliver it through the passes into west-flowing streambeds. Building perhaps 1000 tiny ditches that funnel water westward through passes between two river basins would be several orders of magnitude less expensive and equally less energy-guzzling than, say, pumping an equivalent amount of water from Lake Superior over the Rocky Mountains to the western United States.

The groundwater underneath the Continental Divide tends to flow half eastward and half westward, and the equivalent would be true at the divide between the Columbia River basin and the Colorado River basin in Western Wyoming. Much of the precipitation falling on the eastern and western slopes of the Continental Divide is going to become groundwater. Drilling wells just barely to the west of the Continental Divide and pumping groundwater into west-flowing streams with solar-powered pumps will pull much of the available groundwater through the bedrock westward to the well. That water will be pumped into west-flowing streams.

An artesian well alternative to pumping exists. Drilling roughly horizontal wells eastward, starting from the banks of streambeds on the west side of the Continental Divide, will generate conduits for a permanent active westward flow of artesian groundwater without any pumping. Each uninterrupted small stream of formerly east-flowing water will be added to the Colorado River's water inventory without the use of a pump. The gallons add up.

Drainage basin poaching will slightly lower the flow of water into east-flowing rivers that drain into the Mississippi. A similar arrangement would also slightly lower the flow of water in the Columbia River drainage basin to benefit Colorado River water users. Perhaps a financial settlement can be worked out between coalitions of states for such water exchanges.

W7a. Safety measures for dam collapse

A finger spillway can send ten times or so as much water over the spillway per foot of water rise behind the dam. This prevents overflow on an earthen dam, which cuts a channel through the dam and can cause catastrophic flooding downstream. (new invention 9-15-23)

Spillways can add oxygen to the water, which helps clean the river of pollutants such as agricultural fertilizers and which helps fish to survive in times of low dissolved oxygen, such as hot droughts.

W7b. Turning a faster-flowing stream into a wider fire prevention marsh

The two engineering issues with streams is that they can flood out with ten inches of rain, then they go nearly dry in drought periods and that allows wildfires to easily cross the stream. For droughts the problem of keeping fish ladders in use is simple enough. Simply have the fish ladder exit for incoming water be two inches lower than the rest of every spillway, and then in the worst times 100% of the remaining water will go over the fish ladder.

I'm picturing a series of Vee-shaped rice paddy dams across a stream, Vee-shaped to follow the natural contours of the stream bed, so that all the Vees fit around each other like a bunch of paper coffee cups stacked on top of each other, with extreme high water spillways on the left end and on the right end of every single rice paddy dam. Each particular Vee-shaped rice paddy dam wouldn't impound all that much volume of water, so that a vast cascading failure of these dams wouldn't produce that much excess water. Even if each vee in the stream bed impounded one foot of marsh behind its dam, that would be enough for a carbon-absorbing and wildfire-stopping wide marsh. In the event of a pretty big flood, the high water volume spillways to the left and to the right of the stream bed would dump a vast amount of water downstream, while only raising the water level behind the dam a few inches, preserving the integrity of the little Vee-shaped dam.

It's possible to put the fish ladder on the left side of one Vee-shaped dam, then the next fish ladder on the right side, then the next fish ladder back to the left, and so on, alternating from the left side to the right side. This alternation would, in times of very low water flow, create a small current all the way behind the edge of a vee from the left to the right or from the right to the left.. This flow would carry vital dissolved oxygen created at the fish ladder all the way around through the marsh in critical times of very low water flow.

W8. Sewage remediation in dead rivers and in dead ocean zones

Worldwide, farmers are dumping vast quantities of phosphates, nitrogen fertilizers, pesticides, herbicides and animal wastes into waterways. Downstream we have dead rivers and then dead zones in oceans. Of note, the entire Black Sea is a dead zone from agricultural runoffs. The entire Black Sea and the seas around Istanbul are ecologically pretty dead. People report blooms of smelly "sea snot". [https://www.smithsonianmag.com/smart-news/turkey-begins-clean-its-shores-smelly-sea-snot-180978039/] The area is awash in untreated sewage and in fertilizer runoff. The predominant animal species in the entire Black Sea, where whales once roamed, is now one species of jellyfish. Citizens might be able to withstand the local appearance, the feel of the water and smell, but we still want these waterways to at least sequester carbon, and seeing a bit of regional biodiversity will help with sequestration.

An obvious first solution would be to have governments reward farmers who do the right things and penalize the bad actors who pollute our world's rivers. Commercial phosphate and ammonia fertilizers become water pollutants when they wash off of fields. In addition, ammonia is a major source of nitrogen oxides in the atmosphere. NO2 is a serious, long-lived greenhouse gas that also causes smog microparticles, which cause asthma deaths. We need fertilizer legislation. We need a full plan to shift over to less-polluting alternatives to commercial fertilizers.

Commercial U.S. animal feedlots allow animal feces and urine to mix and to sit together. That produces NO2. Even simple grooves or pinholes in the concrete slab under a typical feedlot might allow the urine to run off and the feces to dry out better so that it produces less methane.

Feeding kelp, among other feed additives, to cows might cut bovine methane emissions and produce more meat per pound of feed.

I note the existence of various other complaints about large-scale meat production, particularly animal cruelty complaints and the use of large amounts of land for very little food. Brazil is being cleared of its rain forest primarily for meat and soy production.

For further reading: https://theconversation.com/a-few-heavy-storms-cause-a-big-chunk-of-nitrogen-pollution-from-midwest-farms-146980

For further reading: https://theconversation.com/to-reduce-harmful-algal-blooms-and-dead-zones-the-us-needs-a-national-strategy-for-regulating-farm-pollution-186286

For further reading: Florida’s Red Tides Are Getting Worse and May Be Hard to Control Because of Climate Change https://insideclimatenews.org/news/19012022/florida-red-tide-climate-change-desantis/

W9. River oxygenation for phosphate pollution

Without farm or sewage legislation, one way to remediate dead rivers and dead oceans is to bubble air through the water. Adding oxygen gives the local fish a fighting chance, especially in overheated rivers that can't hold as much oxygen. Recovering a dead aquatic zone toward biodiversity can create a local food source and it also helps with carbon sequestration. In streams and rills that flow over rocks, oxygenation happens naturally. Building micro-sized dams and water splash points into sluggish streams can help create this oxygenation.

Many river deltas and dead marine environments have no natural splash points. For these zones I will recommend trying solar-powered air pumps to bubble air through the water. Perhaps they can be hidden under bridges or docks. Solar powered air pumps will aerate the water in especially hot periods when water flow is low, so that natural aeration is low, and when warmer water holds less oxygen. This would give the local algae more of a chance to gobble up excess free nitrates in the water, and they might give local fish a chance to survive and eat the algae.

As an example, this remedy should apply to the Mississippi River and to chronic dead zones in the Gulf of Mexico near the mouth of the Mississippi. River. Bridges might be good places to hide bubblers from public view.

W10. Cooling small refuges of ocean

Many tropical coral reefs are bleaching out. We probably want to establish local shelters of relative ocean coolness to which a fraction of sea life can retreat in emergency conditions. By establishing a cool local refuge, some corals and other slow-moving flora/fauna can stay alive through a heat wave and can later repopulate the local reefs.

Mirrors on the surface or above the surface of the ocean are going to take quite a bit of abuse from winds and waves. Better is to put reflecting mirrors far enough below the surface of the ocean so that storm waves don't destroy them. Sunlight penetrates into the ocean, hits the mirrors and penetrates back out of the ocean into space. The goal is to get a relatively cool refuge spot in a local region of ocean where local sea life including corals can survive extreme temperatures. In the event of a killing ocean heat event, survivors in the marine refuge should be able to recolonize the rest of the local ocean

Bubbling air through a refuge might also help, as unnaturally hot seawater contains less oxygen for sea life to use.

Environmental conditions can occasionally get violent on the ocean's surface and in the air above the ocean's surface, but 20 meters or so below the surface the wave action isn't all that bad. One solution for a local deepwater (100 meters) cooling refuge areawould be a thin, reflective sunlight shield placed 20 meters down, with many holes to reduce occasional water overpressures on one side of the shield and to let a bit of sunlight through to the local ocean bottom. A combination of anchors fixing the deepwater sunlight shield in place and floats pulling the shield up should hold the sunlight shield in place against soft currents.

In practice, most of the sunlight penetrating 20 meters down will be reflected back up to the surface by the shield, and then back up into the atmosphere and off into space. This cools the local ocean water and bottom a bit.

The main problem will be creating a surface slippery enough that local flora/fauna doesn't start attaching itself to the reflector. Also we don't want larger animal life getting stuck in any of our reflector's holes. That's why tiny holes or enormous gaps might work better than moderate sized holes.

Alternatively we can place long-lasting glass mirrors on a flat sea bed in shallow waters. This solves the problem of holes. We want the mirrors to act as rocks that don't sink significantly into the local sand or mud, so that they keep reflecting. If the mirrors are wide enough and smooth at the edges, coral and kelp can't use the mirrors as a base for growing.

At reasonably high latitudes, tilt the mirrors a bit so that reflected sunlight is sent straight upward in summer.

W10a. Undersea Mirrors

There's an extreme cost to allowing 1.7 teratons of greenhouse gases locked in the earth's permafrost to be released into the atmosphere through thawing. That's why we need to develop a strong portfolio of ways to cool the entire earth, region by region.

A sea mirror is a flexible floating mirror. Each sea mirror starts with three buoys, a small deadweight in the middle and an anchor rope which is attached to the sea bottom on a continental shelf. In sunny day mode the mirrors ride just below the ocean's surface with three buoys protruding out of the water, and at night the mirror compresses the air in the buoys and drops to 100 meters below the ocean's surface.

On a typical day the mirror deploys at the surface of the ocean at 9:00 a.m. local solar time and drops back down at 3:00 p.m. Given a storm, fog or rough waves, the sea mirror stays deep all day. Periodically the sea mirror can stay deep and sunless for a week in order to rid itself of various sun-hungry plant hitchhikers. At deep water times, purse seine fishing boats can trawl the surface waters without fear of running afoul of any gear within 100 meters of the surface.

The mirror strips are held streaming backwards in place by the prevailing sea current. The mirror design uses a series of long strips in order to let air-breathing sea creatures breach and breathe between the strips. They're designed to not wrap around whales and sea turtles.

The ultimate goal is years of one square meter of solar reflection back into space for the price of one squate meter of low cost, thin reflector. We don't even need a great reflector, just an adequate reflector.

W11. Oceans as active carbon sinks

Certain researchers want to add nutrients to the ocean, in order to encourage algae growth. This process is intended to sequester carbon on the ocean's bottom. The question is, what will a certain degree of hyperfertilizing the open ocean do to the ocean's ecology? How much fertilization, how much ecology change will be too much? Will fertilization tend to make certain ocean species extinct locally or globally?

Other researchers are somewhat evading these artificial fertilization objections by installing pumps to artificially upwell nutrient-rich deeper water to kelp farms. Growing kelp on ropes in floating kelp farms is becoming a big business in Asia. If scientists want to observe the effects of a series of live experiments on fertilizing the ocean, that might tell us more about future ocean fertilization proposals.

For further reading: Floating offshore farms should increase production of seaweed. https://www.economist.com/science-and-technology/floating-offshore-farms-may-increase-production-of-seaweed/21805108

The global oceanic conveyer belt of currents naturally raises plant nutrients from the deep ocean to near-surface waters. As such, the oceanic conveyer belt is responsible for much of the ocean's current ability to photosynthesize carbon dioxide dissolved in the water column. Scientists are now worried that because of climate change, this conveyer belt is slowing down or is possibly shutting down. I can see some argument for the artificial upwelling of deep oceanic water for the purpose of restoring natural nutrient levels in the ocean to pre-anthropocene levels. Such a project would hopefully restore the local upper ocean's current ecology while maintaining the ocean's current ability to transform carbon dioxide into hydrocarbons, where most of the hydrocarbons should sink into the deep ocean and stay there for thousands of years. We might even want to force a tiny increase over pre-anthropocene upwelling levels in order to sequester even more carbon while affecting the upper ocean's ecology only minimally. It's possible that a minimal change in upper ocean ecology might be more than offset by a larger long-term net reduction in ecological harm over the rest of the planet.

For more information on the recent slowing down of Antarctic ocean currents, see: https://www.bbc.com/news/world-australia-65120327

Researchers hope that kelp farmers will someday drop their kelp stalks into the deep ocean, where they would sink to the bottom of the deep ocean and sequester their carbon. This act of carbon sequestration isn't actually happening right now and it might not ever happen because farmers don't want to spend the extra marine fuel and their work time hauling kelp stalks out to sea, but it's a theoretical possibility.

I see a possibility for constructing automated kelp farms that move around quite slowly in the deep ocean. Each farm would have a few large hurricane-surviving floats sticking well out of the water on posts and a framework perhaps 10 meters below the waves, holding the floats together and supporting cables which support the kelp. PV panels on the floats would intermittently power the kelp farm's propellors. Occasionally the farm gives a haircut to its forest of kelp stalks and the cut off parts of the stalks drop to the bottom of the ocean. Probably rough sandpaper wires would do the cutting of the stalks. They would naturally saw back and forth against kelp stalks with wave action or with propulsion of the entire farm. These farms would travel out from a port and eventually return in a loop to that certain port for their regular maintenance. [draw sketch diagrams]

Whales generally sink to the bottom of the ocean when they die. This effectively sequesters carbon into the depths of the ocean. The deep ocean may have its own ecosystem but the sunken carbon apparently stays down there. [https://www.climateforesight.eu/oceans/whales-carbon-sequestration/] Unfortunately the world only has perhaps 3,000 blue whales left, also whales have a 50 year lifespan and they don't reproduce that quickly. For this timing reason I consider sinking whales to not be a short-term climate solution.

I've also seen a report that krill - small crustaceans in the ocean - can in time consolidate radioactive isotopes dumped by malfunctioning nuclear power plants and then move them down to the bottom of the ocean when they die. Each mid-ocean crustacean's heavy shell takes it downward after death. This doesn't justify dumping radioactivity into an ocean but it's nice to know that the oceans might be able to clean themselves somewhat.

W12. Sea level rise

The ocean is rising. Sunny day ocean flooding is a problem, but it's the storm surges that cause the big trouble. 90% climate-enhanced storm surges and 10% sea level rise can ruin the subway systems of coastal cities.

Salt water intrusion, whether by hurricanes or by king tides, can rot out the iron reinforcing bars within skyscraper foundations on beachfront property.

Honestly, there's not that much individual cities can do about sea level rise, other than having the entire world get greenhouse gas levels back to around 280 ppm and try to control the secondary effects of climate change. We might dream of building new fresh-water glaciers, but removing even onr inch off of the top of the world's 40 million square miles of ocean is an enormous undertaking. Under the name of “resilience” we can build levees around coastal cities, but if we allow the ocean to keep rising and if we allow exponentially stronger hurricanes, any height of levee will in time be topped regularly.

U.S. federal flood insurance subsidizes wealthy coastal and riverfront houses that are repetitively rebuilt where they shouldn't be rebuilt. With the advent of climate change, federal flood insurance is costing those of us who can't afford beachfront property a small fortune.

In the same vein, river and ocean dikes often protect wealthy people's property, and dikes are being touted as a climate resiliency solution. We need to ask, resilient for who?

W13. Barrier island lifesaving typhoon shelters

The world's oceans are getting steadily hotter each year, just as surely as atmospheric carbon dioxide levels are rising every year. Current atmospheric greenhouse gas levels pretty much lock in ocean temperature rise, with perhaps a 30 year lag between higher CO2 levels and higher ocean temperatures. Higher ocean surface temperatures are linked to rapid hurricane intensification, which seems to lead to exponentially more powerful hurricanes and higher storm surges, possibly arriving with shorter weather prediction windows.

Low barrier islands can be quickly cut off from mainlands by storm surges, stranding people on these islands. Also, tsunami waves have been known to hit certain beaches and barrier islands with almost no warning. For these reasons I recommend the construction of public high water shelters on such islands.

Each long-lasting shelter needs to stand in public parkland on strong posts. It needs stairways supported by these strong posts so that in case of a tsunami, massive numbers of people can all climb and reach shelter quickly, including relatively slow climbers. The stairways and a wheelchair ramp are designed to present a minimal cross section profile to any oncoming tsunami waves so that the stairways aren't washed away. The shelter on top needs a sturdy roof and a prow to turn notably high hurricane waves. Life rings, poles and ropes will be useful. A locked safe room containing an emergency supply of clean water, survival food and a citizens band radio is recommended, with instructions on how to open the safe.

W14. Building river deltas

Parts of Louisiana are disappearing. The Army Corps of Engineers has straightened and dredged the Mississippi River so that vast amounts of silt flow into the Gulf of Mexico each spring.

Silt from annual Mississippi River flooding should be building up wetlands along the Louisiana coast. Allowing flood water to build up even a few inches in the wetlands slows down the flood water and allows silt to fall to the bottom of the wetlands.

The rest of the world needs to also experiment with river delta restoration.

W15. Helping fresh water lenses underneath low-lying islands

Low-lying islands normally have a lens of fresh water just under their soil and above the deep salt water. When climate-enhanced storms flood their islands with salt water, the salt water sinks and contaminates their fresh water lens so that the island has no more usable fresh water supply for months.

One medium-term solution would be to construct a wave-inhibiting wall of moderate height around the perimeter of a low-lying island. For moderate typhoons this would keep the island's lens of fresh water intact. This partial solution might not help with the storm surge levels that strong typhoons bring.

It would be nice if interlocking sections of this wall could be grown from wire frames carrying an electric current in the water just off the island.

W16. Cloud brightening with pure water (or with airborne sea salt particles added)

Others have proposed throwing microscopic sea salt crystals into the atmosphere. Under certain atmospheric conditions, fog droplets at cloud levels will form around such microscopic particles, and then the extra clouds created will reflect an extra amount of sunlight back into space.

In my own opinion, the main issues with a sodium chloride proposal are as follows:

1. Can microscopic sea salt particles thrown into the atmosphere drift over land masses, land on plant leaves and burn microscopic holes into leaves? Can these microscopic holes in leaves possibly become entry routes for fast-spreading fungal diseases? How can this agricultural side issue be best well-controlled?

We have evidence that road salt creates algal blooms in freshwater lakes and releases toxic metals from the soil into runoff water. For further reading: https://ensia.com/articles/road-salt-lakes-aquatic-ecosystems-harmful-algal-bloom/ How much can extra salt inhibit agriculture?

2. The salt particle proposal as written requires perhaps 1000 ships that chase waves of high humidity across the ocean. All of these ships have up-front carbon costs because they're constructed of steel, and then all of these ships burn some kind of fuel. Is the short-term solar heat reduction benefit worth the long-term increase in carbon dioxide emissions? CO2 will remain in the atmosphere for perhaps 2000 years if we leave the atmosphere alone. How can the CO2 side issue be best well-controlled?

My alternative device, in its simplest form, uses solar energy to release a distilled water cumulus contrail downwind from an island peak with zero other chemicals other than water added to the contrail, possibly 1/2 kilometer in length and 40 kilometers downwind, into the sky, with the contrail cloud starting perhaps 1 km downwind from any particular island's volcanic peak. The cloud reflects sunlight back into space. We might find as many as 100 suitable island or coastline sites. As with the ships proposal, reflecting sunlight back into space with a water cloud doesn't do anything directly about greenhouse gas levels but it does cool the local ocean a bit. Compared to ships that burn fuel, my proposal runs on 100% solar-source energy. Lifetime operation costs per square meter of extra cloud per sunny hour should be lower, for the fundamental reason that ships must not fail catastrophically with all hands lost, while objects on land can often be repaired after they blow down in hurricane-force winds.

I leave open the possibility of developing both island-based and ship-based marine brightening devices. Great areas of open ocean will have no useful nearby islands at all.

I have formed no strong opinion yes or no on island-based sea salt particle seeding right now. I estimate that the side issues involved with putting sea salt crystals in the air can probably in the end be carefully managed, but these side issues still need more study.

Sea salt seeding puts micro-droplets of seawater into hot air. The particles dry out and form microscopic sea salt crystals. Given island-based cloud seeding, a mountain slope chimney would take a mixture of dry particles and hot, humid air up to the mountain's summit and then the humid air mixture would continue to rise in columns above the summit, being carried away from the island by trade winds. Because air pressure drops with altitude the mixture will cool, also with altitude some mixing with cooler air may occur, and then the supersaturated and cooled air will start condensing into fog droplets around sea salt microparticles.

The followup toxicity questions would be, are there effective ways to limit sea salt particle fallout? What if 99% or 99.99% of all sea salt particles fall back into the ocean and never reach land, because we evaporate larger seawater droplets in order to create slightly more massive sea salt crystals? Can the production size of the sea salt crystals sometimes be increased so that we expect the heavier crystals to fall into the ocean as needed? The size of the salt water droplets created, and the amount of salt in each droplet, dictates the size of the airborne sea salt crystal. Given a rare powerful wind blowing toward land, can sea salt crystal launchings be suspended?

On August 9, 1976, Hurricane Belle had top winds at 120 mph. Wind shear then tore the entire cloud shield off of the top of the hurricane before final landfall, leaving a still-powerful low level wind swirl. Belle came ashore around Bridgeport, CT on August 10 with a top wind gust of 77 mph and with almost zero rainfall. However, strong onshore winds put an enormous amount of salt spray into the wind. A mixture of salt spray and dried sea salt particles blew five to ten miles inland and stuck onto tree leaves, denuding the trees. In one month the forests re-leaved. Wikipedia mentions that airborne salt buildup took out a power line in Rhode Island. I mention this incident because we want to fully study a side issue with marine brightening - potential salt particle damage to agriculture. Being forearmed with answers to engineering issues strengthens a project's overall argument.

I observe that in New England, sea salt particles will eventually dissolve in rain water. Dissolved sea salt gets into the ground water, into the rivers and back into the ocean. As we saw with Hurricane Belle, a massive influx of sea salt particles can have an immediate effect on agriculture but will rarely have a long-term effect. We might look into salt particle intrusion issues in agricultural areas near the Sahara Desert, but I suspect that the existing natural salt in their remaining water already overwhelms local agriculture. Coastline plant species are most likely better adapted to blowing salt spray.

One tool to reduce the dropping of sea salt particles and saline fog droplets on agriculture is to pay attention to weather forecasts. Salt particles will have a limited half-life in the atmosphere. Also, we can avoid dumping any salt particles at all into the sky on the worst 10% of days when prevailing winds will take many of the particles over a nearby continent.

I'm temporarily enamored with Ascension Island in the tropical Atlantic ocean for several reasons. First, the island is a geological curiosity. Two centuries ago the island was an 859 meter tall volcanic cinder with no tree growth or topsoil at all. Starting in the year 1830 a British botanist brought 40 species of trees to Ascension Island in order to stabilize the island's production of drinking water. The project worked in part. Ascension Island is now permanently covered to its peak with cloud forest, although modern satellite maps still show a rather sparse covering of trees on its steeper slopes. Call it 19th century geoengineering if you will.

Second, Ascension Island is 1,600 km from the coast of Africa and 2,300 km from the coast of South America. Ascension Island has a minimal population and almost no local farming on its steep volcanic slopes. Placing a marine brightening station on Ascension Island might be less expensive than maintaining a brightening station far at sea, and the island's remote location minimizes any salt microparticle intrusion issues on either faraway continent's agriculture.

Ascension Island is a few degrees south of a major hurricane formation zone. I can see an argument that a marine brightening station on Ascension Island can inhibit future hurricane formation. Hurricane Ian may have exploded in ferocity in the Carribean Sea and in the Gulf of Mexico, but the tiny atmospheric swirl that later became Hurricane Ian can be traced back across the Atlantic to the African coast. If a $100 billion future hurricane similar to Hurricane Ian in 2022 can be inhibited down to a $50 billion hurricane, the insurance industry might donate $5 billion for the project while they pocket the other $45 billion in savings for themselves. Now, would the insurance industry consider an utterly strange geoengineering project if it put $45 billion into their pockets? We won't know for sure, not until their accountants find enough time to count that much dough.

I'd recommend running a mountain slope solar updraft chimney up the slope of Ascension Island to its 859 meter peak, then imparting a vortex swirl within the chimney's air at the volcanic peak in order to maintain a steady vortex in the still-rising air current, in order to put air supersaturated with water vapor into the air at perhaps a 1500 meter altitude. This cloud launching system would minimize the total mass of sea salt particles dropping straight back down onto Ascension Island and the starting elevation would also increase the staying power of salt particles in the atmsophere.

The right engineering idea can work wonders. Building a vertical 859 meter tall solar chimney is almost past the current engineering capability of human civilization, but I could build a mountain slope solar chimney of similar function all by myself using tent poles, tarps and tent stakes, and I'm 69 years old. On second thought, please get some other crew of workers to perform this particular job, if you don't mind.

At the bottom of the mountain slope updraft chimney, heliostats, also known as solar tracking mirrors, would power the heating of salt water and the heating of air for the chimney. Microscopic droplets of heated salt water would be pushed into the rising column of hot air, creating salt microparticles in the air, always with limited total moisture that could later cause precipitation as the column of air rises and cools. This hot air and microparticle mixture would rise up the mountain slope, out the top of the updraft chimney and beyond, mixing and becoming cloud far up into the atmosphere where air pressure is perhaps 20% lower.

At the top of the chimney I would recommend a sort of spray nozzle device for the air exhaust. Spraying one stream of hot and humid air straight up, one stream angled up but toward the south and one stream angled toward the north, with these parallel streams pulled away from the island by steady winds, should create a wide strip of cloud stretching downwind from the island. The contrail strips will merge well downwind.

Jet contrails look unnatural across the sky. It's possible to somewhat break up the long thin line of contrail cloud by somewhat randomly opening and shutting doors on the exit nozzle parts, as much as 20% of the time. Areas below the contrail cloud need a minimum amount of sunlight.

Once a month or as needed, if we run hot air supersaturated with distilled water at above 100% humidity up the chimney then the precipitating water will dissolve any stray sea salt crystals and wash them out of the inside of the chimney.

Noted in passing

For completeness I'll mention another sky seeding scheme here. Seeding the stratosphere with sulfur dioxide has been suggested by others as a way to shade more sunlight. Unfortunately, sulfur dioxide is a component of smog, smog is related to asthma and asthma kills many people in the USA and in Asia. Perhaps 100,000 people per year die of asthma in the U.S. now. Sulfur that reaches the stratosphere can blow thousands of miles from its release point. Because I can't picture any clear way to decouple extra sulfur emissions from extra asthma deaths, I can't recommend deliberately putting sulfur into the atmosphere.

Next, we might suspect from tree deaths in New York's Adirondack Mountains that seeding the stratosphere with sulfur might exacerbate known acid rain issues. In particular, tree deaths from acid rain can increase the severity of future temperature/humidity events. Acid rain issues from sulfuric acid can also affect the ecology of nearby lakes.

The oceans are getting full of plastic microparticles and plastic trash. So far, this type of pollution has been no more than peripherally related to climate change, although it might be affecting one of humanity's prime food sources.