We face sea level rise due to the climate crisis and fisheries collapse due to overfishing. Can we can address both at once by diking around coastal deserts, flooding them with the excess seawater and growing mangroves, etc. in the resulting shallow waters?
Perhaps there is an opportunity to reduce atmospheric CO2 while doing something with a lot of seawater that would otherwise flood our coastal regions, in a way that increases coastal fisheries, all while using existing technology.
Coastal deserts could be surrounded by dikes and flooded with excess seawater, like a salt water rice paddy. This would increase photosynthesis, as the shallow oceans created absorb more sunlight photosynthetically than the desert they would partly replace. It would also remove seawater from the sea, and, on a massive scale, could lessen coastal flooding from sea level rise. It could also increase fish catches sustainably, as shallow waters are typically very productive fisheries, and the increased area of shallow water created by this could be fished, and might foster intensive sustainable aquaculture, like mullet and milkfish ponds.
If windmills powered both dike creation and seawater pumping, then perhaps setting this up could be nearly carbon-neutral - once operating, the increased photosynthesis allowed would make this carbon- negative, to the extent that fixed carbon is stored, instead of re-released.
About 70% of earth's surface is ocean: http://www.noaa.gov/ocean.html About 14% of the earth's land surface is 'desert'
6 comments:
The volume of seawater used to flood deserts is too insignificant to prevent the effects of rise in sea level. For example, just consider that the Pacific Ocean has an area of 166,241,700 square km according to NASA. (http://pumas.gsfc.nasa.gov/files/02_10_97_1.pdf)
Kuhan, Thanks for your comment,
While I concede that flooding deserts couldn't cope with many meters of sea level rise, I still think that we might cope with an early stage of sea level rise, say tens of centimeters, by flooding deserts with several meters. Deserts cover about a third of earth's land area, or about a tenth of all earth.
Hence we could avoid a small 10 cm. rise worldwide by flooding half the deserts to 2 meters deep. This could both allow us to continue to live in our seaside cities and fields, and allow fertile oceans to cover what was barren desert, which would increase carbon dioxide capture by life.
Brian
You mentioned that growing fish may not help.
Are you aware of the decline in fish stock in oceans and in the phytoplankton annual production.
Increasing phytoplankton and fish growth can capture most of the anthropogenic carbon emissions.
Nualgi, Thanks for your comment,
I agree that increasing marine phytoplankton could capture most anthropogenic carbon releases, I'm unsure of the ultimate fate of that carbon. If that carbon re-enters the atmosphere quickly, little is accomplished, unless that carbon's in the form of methane, in which case extreme damage could be done.
I'm really excited by the possibilities of iron fertilization of oceanic areas limited by iron, although I think more research needs to be done to see if this will truly help.
There's a recent article addressing this: http://russgeorge.net/2015/03/29/ocean-organic-carbon-persists-for-millenia/
Brian
Growing any phytoplankton will not help, you have to specifically grow Diatom Algae.
This is the key.
Diatoms are the natural food for Zooplankton, Krill and Fish. So fish biomass will increase.
This is live storage of carbon.
Fish too help in sending carbon to ocean depths via feces, gut balls and their bones.
Fish in oceans may have declined by as much as 14 Billion tons or at least 6 Billion tons.
The fish stock in the oceans is estimated to be 8 to 15 Billion tons, 200 years ago and is not 0.8 to 2 Billion tons.
How much diatom is required to feed 6 to 14 Billion tons of fish ?
A small percentage of this sinks to ocean bed in each Nitrogen / Carbon cycle, this add up to a significant amount over many cycles.
Impact of Iron Fertilization on fish has not been studied, since none of the Iron Fertilization experiments were long term experiments.
We have a patented product to grow Diatoms - Nualgi [ Nutrition for Algae ], we use this in aquariums, ponds and lakes to keep them clean, well oxygenated and free from Cyano blooms.
Sorry this sentence is to be corrected -
The fish stock in the oceans is estimated to be 8 to 15 Billion tons, 200 years ago and is now 0.8 to 2 Billion tons. This is a decline to 75% to 95%.
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