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Climate Change – Just add water

There is a broad agreement that something needs to be done to reduce atmospheric CO2 at scale – yet there is debate about what that something is.  There is also a growing consensus that mother nature does it best – through photosynthesis.  Carbon dioxide and water, converted by sunlight into carbohydrates, is stored in plant biomass and through their roots, sequestered in soils.

What if CO2 were not the poison of our era, but the feedstock of a carbon-sequestering, agricultural economy that can feed our growing populations? –  Just add water.

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Water
To fix the carbon cycle at scale using plants, we need more water.  Luckily, we have an abundance of it.  If the earth were shaved flat by a giant scraper, we would all be underwater – a mile deep.  We are not short of water, it’s just that 97% of it is too salty.

Desalination
Desalination is bad for the environment?  Well yes and no.  Most desalination plants are powered by fossil fuels, but they don’t need to be.  As we and others have demonstrated, it is perfectly practical to use solar and wind power instead. 

Where?
Greening arid regions, especially those that were formerly more vegetated than they are today. The red areas on the map, indicating very high vulnerability to desertification look like a good place to start, especially in places where water insecurity leads to food insecurity, migration and conflict.

If all the world’s degraded land were somehow combined into one country – The Federated States of Degradia, it would occupy an area the size of Russia and would be inhabited by 3 billion of the world’s poorest and most vulnerable people.  Would the re-establishment of vegetation with forest gardens over such an area drawdown sufficient CO2, while feeding the world?  It might just.

Sea level rise
If we extract that much seawater, what will be the impact on sea level rise?  There is a finite amount of water on earth that is constantly cycled through evaporation, condensation, and precipitation.  More water on land, in plants, in the air and in the soil must mean less water in the sea.

Salt
“Salt is born of the purest parents: the sun and the sea.” ― Pythagoras
If we desalinate that much seawater, without putting the concentrated brine back in the sea, what do we do with all that sodium chloride salt? Right now, we don’t know, but Salt batteries are a promising new development as is forward osmosis. Sodium chloride is also the feedstock to over 1,400 industries and processes, including most plastics, acids and alkali. 

Minerals derived from seawater
Once sodium chloride is precipitated out of seawater, the remaining minerals are much more concentrated.  We are collaborating with others to find frugal techniques for separating them out.  Top of the list is magnesium, followed by lithium and cobalt.  Seawater also contains an abundance of minerals that plants need as macro nutrients: Nitrogen, Phosphorus and Potassium.  The micro-nutrients are there too: boron, copper, iron, calcium, manganese, molybdenum, zinc

Portland cement or seashells?  Which is stronger?
Seashells are among the toughest natural materials, and their primary component is calcium carbonate.  Surprisingly, calcium is the first element to precipitate out of sea water as it evaporates, and it does so in the form of calcium carbonate.  Can we grow bricks and blocks out of seawater?  It seems so and without any chemical treatment or process heat.  Portland cement by contrast is an energy intensive material to manufacture and for every ton of it, a ton of CO2 is emitted.

Light, heat and plant growth
Sunlight is comprised of 45% visible light and 50% invisible, infrared heat.  More light equates to more growth, but more heat equates to less growth, and most plants, like most people are happiest at around 20ºC, where they also grow fastest and with optimum water use efficiency.  As temperature increases, plants transpire more water, causing their stomata (like sweat pores on the leaf) to close.  This is to preserve water and prevent desiccation, but it also restricts their uptake of CO2 and hence growth.

Rainfall enhancement
What comes down must (first) go up.  The source of all rainfall originates from evaporation and transpiration from plants, through the water cycle.  It works by using the energy of the sun to evaporate water from the earth to the atmosphere and back again in a continuous cycle – from liquid to vapour and back to liquid.

Desertification is land degradation in drylands in which biological productivity is lost to natural processes or degraded by human activities, causing fertile areas to become increasingly arid. It is the spread of arid areas caused by a variety of factors, such as climate change and overexploitation of soil by humans and grazing animals.  When deserts emerge due to unchecked depletion of nutrients in soil, then a virtual "soil death" occurs, vegetation dies, and the water cycle is broken. 

Cost - Could it be negative? 
Our premise is that if we fix the water cycle, nature will fix the carbon cycle. Photosynthesis converts water and carbon dioxide into carbohydrates – the food and energy for all life. Wet the ground anywhere and something will grow – moss, grass, a carrot or a tree.  Part of this premise is that the overall cost to humanity of reversing desertification is negative.  For example:

·      What is the value of making the Horn of Africa, Yemen and other dryland regions food secure?  The World Food Program has an annual budget of $8 billion, so there is a start. 

·      What is the value of providing the populations of drylands, especially women and refugees, with interesting and profitable employment?

·      What is the value of making arid parts of Africa, Arabia and Australia food secure, a few degrees cooler, less dusty and a lot greener? 

·      What is the value of not increasing salt toxicity in the sea but realising the value of all the minerals contained in seawater?  Especially those on the critical list?  They are all to be found in seawater and interestingly, magnesium which is near the top, is the second most abundant after NaCl salt.

·      Many of the current and past world conflicts have lack of water at their core.  This map Illustrates 466 of them that have occurred in the last 10 years, and unsurprisingly, they cluster around arid regions.

How much do they cost?