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Form paddyfields of saltwater on coastal sunlit deserts, to increase earth's photosynthesis
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Problem: agriculture and other human activities have constrained the amount of sunlight captured in earth's life. Solution (Partial): since coastal marine ecosystems are very productive, expand them by pumping seawater over dikes set in sunlit seaside deserts, to create extensive shallows where plankton and sealife can grow, where little grew before. Use wind energy to pump the seawater. This might yield enough fish to pay for itself. The brine could be used to make salt at the desert end of the series of ponds. In each of the ponds, in the series of ponds of increasing salinity stretching away from the sea, different ecosystems adapted to this particular salinity could be grown, and yield different products for market. The moisture that evaporates from these ponds would, somewhere on earth, fall as rain, increasing water supply where it is (least) needed. If the entering water is fertilized, then this fertility can be used and re-used to yield more seafood from the ponds. One possible product from such ponds is the seaweed used to make agar-agar, which is used in research to thicken media, and which is relatively expensive. Others are the fish called mullet, which used to be raised in seaside Mediterrenean ponds; Canned mullet used to be sold like tuna.

If one of the first ponds in a series held fed aquaculture, like salmon or shrimp, subsequent ponds could use the fertility while thus cleaning up the water, in growing other seafood.

If cold fertile deep-ocean water was wind-pumped up into the first pond, the cold could be used for refrigeration, and the fertility could nourish phytoplankton in these ponds.

While it is disconcerting to consider such vast changes to some areas of desert ecosystems, the alternative is not doing nothing, unfortunately. The alternative is continuing to burn fossil fuels and destroy rainforests, while overfishing vast oceanic areas, with no amelioration of the resulting increase in greenhouse gases, leading to an altered climate which does not yield, under our agriculture and ocean use patterns, the food and feed we need or have come to rely on.

briancady413, Feb 23 2011

Global biomass increase estimated from NOAA/AVHRR NDVI data sets http://sciencelinks...9992399A0764761.php
It might have been this... [Wrongfellow, Feb 28 2011]

Increasing biomass in Amazonian forest plots http://www.ncbi.nlm...27/pdf/15212090.pdf
...but I think it was more likely to be this, which doesn't actually say quite the same thing. [Wrongfellow, Feb 28 2011]

Per Capita Carbon http://www.google.c...al+carbon+emissions
[MechE, Mar 02 2011]

Primary Productivity powerpoint show (See slide 34) http://www.tulane.e...nography/CHAP10.PPT
oceanic productivity to 1250 gC/m^2yr, rounded to 10^3 gC/m^2yr [briancady413, Mar 02 2011]

Chart of Global Carbon Emissions http://www.pbl.nl/e...2-emissions-in-2009
[briancady413, Mar 02 2011]

[link]






       You're going to end up with a real brine concentration problem.
MechE, Feb 23 2011
  

       The brine could be used to make salt at the desert end of the series of ponds. In each of the ponds, in the series of ponds of increasing salinity stretching away from the sea, different ecosystems adapted to this particular salinity could be grown, and yield different products for market. The moisture that evaporates from these ponds would, somewhere on earth, fall as rain, increasing water supply where it is (least) needed. If the entering water is fertilized, then this fertility can be used and re-used to yield more seafood from the ponds.
briancady413, Feb 26 2011
  

       theres a great ted talk on the use of oysters to clean pollution from new your harbours i think you might like.   

       Cant find the link though.
bob, Feb 27 2011
  

       //You're going to end up with a real brine concentration problem.//   

       Hey, cobber, brine concentration's nevah been a problem in 'strilia.
MaxwellBuchanan, Feb 27 2011
  

       //agriculture and other human activities have constrained the amount of sunlight captured in earth's life//   

       Got a reference for that? Last thing I read, if anything the total biomass is increasing as a result of human activity.
Wrongfellow, Feb 27 2011
  

       Wrongfellow, I understand that agriculture always catches less sunlight than wild ecosystems, as in agriculture there is bare soil exposed to the sun early in the season. There's a text by a Margolis on theoretical ecology which I read years ago on this - sorry but I've forgotten the title and am unsure on the author's name, too. I'll keep looking. By the way, do you have a reference on biomass increasing with human activity - I'm quite interested.
briancady413, Feb 28 2011
  

       //agriculture always catches less sunlight than wild ecosystems, as in agriculture there is bare soil exposed to the sun early in the season//   

       Hmm. Makes sense, I suppose.   

       I added a couple of links for you - if I remember right, the theory was that by increasing the concentration of CO2 in the atmosphere, we've increased the rate at which photosynthetic organisms are able to synthesise sugars, making the total biomass of the planet grow more quickly than it would have done otherwise.
Wrongfellow, Feb 28 2011
  

       [edited for orders of magnitude issues] If only 10% of estimated typical shallow ocean productivity of about 10^3 grams of atmospheric carbon bound per square meter per year(gC/m^2 yr) could be sequestered from being re-emitted into the atmosphere, then current human carbon emissions totalling about 10^16 gC/yr could be balanced with a flooded desert area of 10^14 m2, or about ten times the Sahara Desert, which covers about 10^7 km^2, or about 10^13 m^2. So covering the Sahara with seawater, and then sequestering 100% of the resulting productivity, could balance the carbon budget of earth. Hmm. Seems impossible.
briancady413, Mar 01 2011
  

       //covering just 0.1% of the Sahara with seawater, and then sequestering just 1% of the resulting productivity, could balance the carbon budget of earth.//   

       Is that right? I mean, I am amazed, but your numbers seem plausible. Wow - seriously wow.   

       Looking at it the other way around - all human CO2 production is equivalent to wiping out a coastal marine area equivalent to 0.1% of the Sahara. Given the grand scale of things, doesn't this seem so utterly trivial as to be unlikely to matter? I mean, this is saying that an increase by 0.1% in the size of the Sahara would screw up the climate of the entire planet. Bollocks, say I.
MaxwellBuchanan, Mar 01 2011
  

       I make global gC/yr to be closer to 8.4x10^15, which means if we sequestered 10%, we'd have to cover more like 8% of the Sahara just to cover production, a much more daunting task.   

       (See link, corrected for Carbon instead of C02 and using a world population of 6700 million). Please provide references for shallow ocean productivity as well.
MechE, Mar 02 2011
  

       //Looking at it the other way around - all human CO2 production is equivalent to wiping out a coastal marine area equivalent to 0.1% of the Sahara.// Yes. // ... I mean, this is saying that an increase by 0.1% in the size of the Sahara would screw up the climate of the entire planet.//   

       No, it's not, because the coastal marine zones are not like typical Sahara desert areas in terms of productivity.
briancady413, Mar 02 2011
  

       //I make global gC/yr to be closer to 8.4x10^15, which means if we sequestered 10%, we'd have to cover more like 8% of the Sahara just to cover production, a much more daunting task.//   

       From your link, ~5 x10^3 gC/person year x 10^10 persons per planet (rounding up from 6.7 billion)= ~5 x 10^13 gC/year, right?   

       On the other hand, if you are right, is 80% of the Sahara too much to ask for us to be able to have agriculture that works, and weather we can stand?
briancady413, Mar 02 2011
  

       The Sahara is pretty large - it is also increasing in size at a reasonable pace. In getting an idea of the scale of the task, I wonder how much of Nevada, in percentage terms has been transformed into lush, green carbon sequestering countryside, what with the assistance of a dirty great hydroelectric damn providing a steady flow of cheep/free energy, and a constant income stream of billions of gambling dollars a year?   

       Compare to the Sahara, which doesn't have any of these transformative advantages, and is much, much bigger (I guess).
zen_tom, Mar 02 2011
  

       ~5x10^6 gCO2/person*year, or 1.36x10^6 gC/person*Year, the link is in tonnes not kg.   

       80% of the sahara (or even 8%) is a non-trivial engineering challenge. The pumps alone are going to be a significant energy suck, to say nothing of the resources neccesary to maintain everything. Add in the rate of evaporation and most of your surface area is going to have a torrential current, not suitable to sustaining life.   

       I'm not saying its a bad idea, but it's not a one step fix to the greenhouse gas problem.
MechE, Mar 02 2011
  

       Oops, thanks for catching that three orders of magnitude error. So, 30E9 tons Carbon = 3.0 *10^16 gC/yr emitted by humans per year (from the dutch link) divided by 100 gC /m^2*yr(if we could sequester 10% of primary productivity); we'd have to flood about 3.0E14 m^2 of desert to balance human's CO2 flux, which is about the size of ten Saharan deserts. Hmm. [Goes back to drawing board]
briancady413, Mar 02 2011
  

       //if only...// that parasentence has way too many superfluous numbers in it to be anything except bullshit. Let's look....   

       //typical shallow ocean productivity of about 10^3 grams of atmospheric carbon bound per square meter per year//   

       so a kilogram per year per m2 ? really ? that's 3 grams per day. Seems high...   

       //human carbon emissions totalling about 10^13gC/yr//   

       Each of the 6.775x10^9 humans on the Earth produces about 1.5kg of bound C per *year* ?   

       Umm... according to many cites, respiration produces about 1kg of CO2 /day/person: about 250g of bound C ...per day.   

       So your figure is off by a couple orders of magnitude just for breathing, not including cars, trucks, boats, planes, industrial processes, deforestation, etc. etc. etc.   

       Why not do it the easy way ? Instead of calculating CO2 emissions from humans and mankind's processes, why not take a figure from before there was widespread industrialization and go from there ?   

       (I've already done it on another idea, but I don't recall which one)
FlyingToaster, Mar 02 2011
  

       //that's 3 grams per day. Seems high...// See that primary productivity powerpoint link. I'm actually rounding down.
briancady413, Mar 02 2011
  

       [FT] See mine above about an 3 order of magnitude issue.
MechE, Mar 02 2011
  
      
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