Sparks

An ocean of CO2

 By Eniday Staff

As we’ve seen previously, there are three ways to reduce the concentration of carbon dioxide in the atmosphere: produce less, collect it and capture it in the bowels of the earth, or help nature to perform processes that transform it into something else…

The third way seemingly opens up a lot of opportunities, but confusion and misunderstanding surround many of them. Let’s have a lot at what it’s all about, by referring to the proposals made on this subject in a report by the United Nations’ Intergovernmental Panel on Climate Change (IPCC). ‘Negative emission technologies’, to give them their technical name, are really about developing artificial processes (or helping natural processes) to remove carbon dioxide from the atmosphere. However we are talking about a lot – a huge amount – of carbon dioxide. In fact, to limit global warming to 1.5°C above the pre-industrial average temperature, we need to remove about 20 billion tonnes of CO2 from the atmosphere every year for the next eighty years (by way of comparison, Italy’s CO2 emissions in 2017 totalled equal to about 430 million tonnes), a task which could recall Sisyphean’s legend! However, an incredible opportunity comes to mind: our oceans. While 20 billion tonnes a year of CO2 does seem like a lot, compare that with the total volume of sea water on earth: 1,376 million cubic kilometres or, in tonnes, 1,376 followed by 18 zeros! Little wonder, then, that geological engineers have made proposals and, in some cases, test processes able to exploit oceans into places where to capture carbon dioxide.

Research analyzes some hypotheses

In 2016, the United Nations set up a research group called GESAMP to look at the ideas on the table so far. In particular, GESAMP set out to estimate the effects of the proposed solutions in terms of reducing atmospheric CO2, but also any negative environmental effects, because if you interfere with a natural process, you have to be aware that it is changed forever, maybe for the better but sometimes for the worse. GESAMP published its first report in March, covering 27 projects that range from adding reflective foams to the surface of the oceans to sinking carbon to the depths of the sea. Essentially, they were willing to look at anything, but in the opinion of the GESAMP experts, the workable hypotheses were few and far between. Examples of the proposals included fertilising sea water with iron to stimulate the growth of phytoplankton, which absorbs large amounts of CO2 and could therefore carry it in the harmless form of carbon to the depths of the sea when the micro-organisms life cycle comes to an end. Another idea was to pulverise seawater into very fine droplets to encourage the formation of clouds, which, by reflecting the sun’s rays, would reduce the surface temperature of the planet. A further proposal looked at pumping cold deep-sea water to the ocean surface, to lower the air temperature and help limit global warming.

ocean-capture-carbon-dioxide
Phytoplankton is a set of organisms capable of synthesizing organic matter from dissolved inorganic substances, using solar radiation as a source of energy

Some experiments are under consideration

Good ideas, right? Unfortunately perhaps only on the surface. The first problem with all the solutions is that in order to be effective, they would have to be applied on a huge scale, with all the practical difficulties that would entail. Secondly, there are the effects that these actions could have on the marine ecosystem, which in turn are exponentially amplified by the necessarily large scale of the interventions. As far as the water fertilisation idea goes, the experiments carried out so far (and in particular those performed off the Chilean coast) have revealed many complications. Sure, phytoplankton growth has been very intense, but this comes at the cost of micro algae being deposited on the seabed, which decompose quickly due to excessive crowding and relative scarcity of oxygen. This results in a lot of methane being released, which, if it gets into the atmosphere, makes a contribution to the greenhouse effect twenty times greater than carbon dioxide.

ocean-capture-carbon-dioxide
Microalgae can be very useful in combating CO2 emissions, but they have also proved harmful during water fertilization experiments (Algaennovation).

Experiments on forming clouds from micro-droplets of seawater became bogged down even earlier, due to the fact that seawater is full of tiny living organisms and organic material that can easily cause blockages in any pulveriser. The only experiments carried out were with demineralised sodium chloride water and, after all, we only have to think of what would happen if we put sea water in a steam iron to realise that this is not an easy process to sort out. Finally, the idea of pumping very cold water towards the surface of the Pacific immediately came up against the obvious consequence of a drastic reduction in dissolved oxygen, which would have negative consequences both on fishing and on the proliferation of phytoplankton, which gobble up carbon dioxide. Scientists at GESAMP are relatively optimistic, they reckon that some of the good ideas can be refined and implemented. They may not be possible on a very large scale, but are workable if rigorous checks are carried out on their effectiveness and possible ecological consequences. The next step is about leaving the fantasies of online dreamers behind and applying protocols agreed by the scientific community.

READ MORE: New energy devices by RP Siegel

about the author
Eniday Staff