What tools do we have at our disposal to combat the global warming and climate change generated by an increasing level of greenhouse gas emissions from human (anthropogenic) activity? These tools can be grouped into three broad categories (see infographic), three options that are not alternatives to each other, but could be used together.
The first option is climate change mitigation, which helps to prevent a rise in temperature by stabilizing the concentration of greenhouse gases in the atmosphere, gradually reducing emissions to zero. This option provides for two types of interventions. The first gathers tools with the aim of preventing the production of greenhouse gases. Efficiency and energy savings fall into this category, as does the replacement of fossil fuels of energy with other ‘carbon-free’ fuels (i.e. those that do not emit greenhouse gases – in particular carbon dioxide, CO2, the most significant of the greenhouse gases – in the production and use phases, such as renewables) and the replacement of high-intensity fuels that emit greenhouse gases (such as coal) with lower-intensity fuels (such as natural gas).
Work on energy mix
These interventions allow the production of greenhouse gases to be gradually reduced while maintaining the same energy consumption. The only thing that would change would be the energy mix used by a given country. In addition, the first category also includes interventions aimed at preventing the production of greenhouse gases by another sector that contributes significantly to anthropogenic emissions: the sector that includes agriculture, forest management and land use, identified in scientific texts with the acronym AFOLU, i.e. Agriculture, Forestry and Other Land Use.
The second category of mitigation interventions, on the other hand, includes those used to capture carbon dioxide after it has been produced (e.g. by the burning of fossil fuels), but before it is dispersed into the atmosphere and contributes to a increase in concentrations. The best-known technologies are carbon capture and storage (CCS) and carbon capture and utilization (CCU). They are often identified jointly using the acronym CCUS (Carbon Capture Utilization or Storage). The next option – number 2 in Figure 1 – consists of the interventions that can be put in place once greenhouse gases have been produced and dispersed into the air. This type of action is known as ‘climate intervention’, better known by the futuristic name of ‘geo-engineering’. In essence, this means methods that counter-balance the increased capacity of the Earth's atmosphere to retain energy and heat due to the increasing concentrations of greenhouse gases.
In the picture Eni research, the organic solar panels, Eni “Waste to Fuel” in Gela and “culla dell’energia” plant installed off the coast of Ravenna
The easiest way to intervene is to remove from the atmosphere the carbon dioxide previously emitted into it. Plants naturally implement this technique, by capturing carbon dioxide from the air, breaking it down into carbon and oxygen, then using the carbon to produce the organic material of which they are made up (roots, stem, branches and leaves). The tools of reforestation and soil afforestation also fall within this second option. And because nature, as is often the case, is a source of inspiration for humans, methods are being studied to artificially simulate these mechanisms that take place in plants. However, techniques of removing carbon dioxide from the atmosphere must be kept separate from other geo-engineering interventions related to the management of solar radiation.
In the latter case, proposals have been made of much more futuristic and, most of all, controversial techniques, which do not act on the ability of the atmosphere to retain the energy received from the Sun (the greenhouse effect), but are aimed at acting directly on the amount of energy that comes to the Earth from the sun, thus reducing it. Their use raises considerable doubts and misgivings on the part of climate experts. The third and final option is to respond to climate change by preparing for it and implementing all those measures that can – to the greatest extent possible – reduce its negative impact on humans and the environment. This type of intervention is known as ‘climate adaptation’.
The author: Giuseppe Sammarco
Energy Sector Integrated Technical Studies Eni, Development, Operations & Technology.
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