Around the word rainfall is decreasing. This has the effect that in coastal zone salt water percolates upward, no longer kept down by new fresh water. This is ruining land for farming across the globe, many crops can’t grow as well in salter water and production is decreasing. With modern methods of plant breeding new species of plants can be created that actually thrive on saline soil. Below a number of examples.
A nice consequence of being able to grow high caloric crops on saline soil is that it could open much more land to farming, even in remote areas where only seawater is available. With partial desalination crops can grow and store CO2 with the efficiency of 5% or 50Watt/m2 (which is the approximate solar conversion rate of plants). That is 500 kW/hectare or 50 MW/km2. The rice in the above example can be managed by robots. The yield could be used to run the equipment, so that the investment in energy sources like solar panels can be low. This could be part of an extraeconomic carbon capture operation.