The sequestration of CO2, a short-term solution?

The need for drastic and urgent solutions to reduce CO2 in the atmosphere has generated several technological-based corrective proposals, among which there is the capture and storage of carbon. But this technology is being questioned.

According to the recent special report drafted by the Intergovernmental Panel of Experts on Climate Change of the UN (IPCC), called “Global Warming of 1.5ºC”, the evidences that we already have climate change on are indisputable and alarming. Among the drastic solutions to reduce CO2 at 0.5ºC, from 2 to 1.5ºC, carbon capture and storage is considered, although it is a technology that generates serious doubts.

Because of human activities, global warming increases at a rate of 0.2ºC per decade. This increase will end, if nothing is done to stop it, placing 2ºC above the current temperature in 2050. This will cause changes in the climate that will affect large areas of the planet, which will be subject to increases in frequency, intensity and amount of rainfall in different regions. At the other extreme, there will also be more episodes of extreme heat and prolonged drought.

The increase in the level of the sea and oceans, another of the negative impacts of the greenhouse effect, would endanger large areas of the coastal population. It is also estimated that the Arctic sea ice could be lost one summer in ten or in every hundred, depending on whether the warming is 1.5 or 2ºC above the current temperature.

With these forecasts, the great coral barrier would also be affected, which in the worst scenario would entail its total extinction. For all this, the reduction of 0.5ºC is essential, and carbon capture is seen, a priori, as a quick and effective solution to stop the devastating blow of the dramatic changes that we already have.

 

What is the capture and storage of CO2?

This technique consists, first, of separating carbon dioxide (CO2) from other gases. Once captured, it is compressed to be transported through gas pipelines or liquefied gas container ships.

To store it, the most economically and environmentally sustainable is to inject it into subsurface geological formations, such as depleted oil and gas reserves, saline aquifers or unexploitable coal beds.

In the practical field, the aforementioned technique opens great questions regarding safety in the face of natural accidents, as in the case of earthquakes that affect the subsoil and cause the release of stored CO2.

The other major problem is the economic side: the investment to carry out the sequestration of this gas is detrimental to the resources that can be used to promote sustainable energies, such as wind, photovoltaic or solar thermal.

It does not stop being contradictory to invest money in mitigating the pernicious effects of the gases emitted into the atmosphere instead of promoting the generation of zero pollution energies.

 

Reforestation, a natural solution

The IPCC report refers to the fact that carbon sequestration can be a part of the solution, but the most important thing - they say - is to accelerate the transition towards a cleaner energy model.

Renewable sources, such as electricity, must provide between 70 and 80 percent of the energy. The gas would have to supplement this figure by 8 percent, while the use of coal would have to be discarded.

To act in a clear way in the capture of CO2 one must also rely on plans for forest growth, reforestation or soil restoration. In this sense, nature reclaims the principle of simplicity again, reminding us that the solution to the damage caused by man demands a return to basic ecosystem principles. And that, of course, before it's too late.

Xavier Company

Biomimetic Sciences Institute

 

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