Daily Archives: January 13, 2008
Sunday Evening. Time to be the barroom bore.
Leading scientists have proposed that we should put giant tubes in the ocean. The idea is that nutrients will rise up the tubes from the ocean depth, giving rise to algal blooms at the surface. The nutrients are moved by wave power, and the algal blooms will grow on solar energy, absorbing substantial amounts of CO2. If the plan goes ahead and is successful, it will no doubt only be a matter of time before someone proposes a method to harvest the algal bloom for biomass energy.
This plan, like any other, has a downside: algal blooms are hugely damaging to existing marine ecosystems. It could also precipitate large-scale climate events of its own if, for example, ocean currents are affected. But it appears nevertheless likely to be of net benefit on balance, just as, for example, wind, hydro, and nuclear energy are. Since there’s vastly more ocean than land (let alone land under a benign climate), it looks much better than current biomass schemes which involve similar damage to large areas of land. Another factor in its favour is that the existing ecosystem it displaces is not as dense or as productive as areas of rainforest being cleared for biomass.
So here’s another proposal. Let’s requisition some of the Earth’s poorest ecosystems for production of algal bloom and biomass. Specifically, the deserts. Where there’s very high sunlight for energy, and ample minerals to nourish the bloom. All it needs is water.
This is not about irrigating the desert. That’s a tradition that goes right back to the cradle of civilisation, for example along the Nile. Neither is it relevant that many such schemes have proved unsustainable, leaving ghost towns (or cities) where an irrigated area has deteriorated over time. In any case, freshwater sources that could be harnessed for irrigation are already under huge stress.
The only water source sufficient to pour onto the desert on any scale is the sea itself. That’s going to require a lot of energy to move vast quantities of water, maybe with something like an array of giant archimedean screws. My suggestion is that *potentially* we get back a lot more than we put in. That’s on the premise that it enables growth of rich biomass, maybe indeed huge algal blooms (though not of course existing land-based vegetation) if we create saltwater lakes. Thus the Earth’s most barren and unproductive lands become a carbon sink powered by the immensely fierce desert sun, and a biomass source.
This is of course thoroughly experimental, and I’m neither a biologist nor a civil engineer. Assuming the engineers can solve the logistics, the most obvious risk is that the areas used experience such huge buildups of salt that they become like the dead sea (or even like conventional irrigation that turns bad). To avoid that implies ongoing management of the chemical balance of the desert schemes.
Or a biological alternative. Can genetic engineering help evolution on a little by combining fast-growing algae with extremophiles that thrive in a challenging environment?
Here in Europe, we’re a major energy consuming area. We have the research capabilities and the money. And just to the south, we have the world’s biggest desert! The EU, or indeed individual countries within it, should get together with an appropriate North African country and embark on a major research programme. That needs to be managed in a politically sensitive manner, so that it’s clear that the African country (or countries) will (also) see substantial benefits if the experiment is successful.