The energy and climate landscape has significantly evolved in the past years, especially after the December 2015 historic agreement on climate change in Paris. This shift has happened also thanks to a significant technological evolution which, however, has increased the uncertainty and the capacity of planning by both private and public players. In addition, this transformation is far from complete, and it could be still lacking some technological components, such as the full development of energy storage or CO2 removal, which can prevent the achievement of the energy transition in the timescale proposed by the Paris Agreement. We discussed these issues with Carlo Carraro, a global leading expert in environmental and climate change economics, Vice-Chair of the Working Group III and Member of the Bureau of the Nobel Laureate Intergovernmental Panel on Climate Change (IPCC) since 2008.

The IPCC is the international body whose aim is to assess climate change science and provide a scientific basis for governments to develop climate related policies. Its work also prepares for the negotiations at the United Nations Framework Convention on Climate Change (UNFCCC) conferences, such as the COP21 in Paris.

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In your opinion, what is the world like after the Paris Agreement, the landmark agreement to limit global warming adopted by 196 parties at the 21th UN Conference of the Parties (COP21) in December last year?
Well, it is not very different than from it was before, since COP21 took decisions which per se have quite a limited impact in the short term. However, let’s try to see this in perspective. During the past forty years, greenhouse gas emissions (GHG) have constantly increased, and have been increasing at an increasing rate. So, despite 40 years of negotiations on climate change, GHG emissions have reached the highest levels ever recorded in human history. It is clear that all the decisions which have been made, from Rio to Kyoto and all the other intermediate steps, did not produce any effective measure against climate change, as emissions have continued to increase anyway more than ever.

In this sense, the Paris agreement, if it is effectively implemented, will determine a radical change of course. If the agreement is implemented, 2030 emissions will remain the same or increase just slightly compared to those in 2015. Emissions would stabilize for the first time ever. True, there is skepticism about the actual implementation of the Paris Agreement, or the fact that some countries, e.g the U.S., have ratified it but will not able to put into practice the measures which are implicit in the agreement. However, I personally believe that we already have the economic resources and the technology to implement the Paris Agreement at a relatively low cost. This is why I think we will achieve the stabilization of GHG emissions by 2030. The following steps, however, are more challenging. We need to achieve an 80% reduction of GHG emissions, compared to 1990 levels, by 2050 (as already agreed by G20 countries), zero emissions by 2070-2080 and a negative value in the post 2070-2080 period. By “negative emissions” I mean a reduction of the stock of greenhouse gases already in the atmosphere, in addition to zeroing the annual flow.

This is the real challenge. Emissions could be stabilized in 2030 even with an energy mix which is not significantly different from what we have now, with fossil fuels still playing a significant role. Reaching 2050 with an 80% decrease, or 2070-2080 with no emissions at all, would instead require a complete transition to a zero-carbon world.

Yet, this process is still missing significant technological components. The first is CO2 removal, a crucial technology to reduce the stock of emissions in the atmosphere, which is largely inadequate at the moment. The BECCS [Bio-energy with Carbon Capture and Storage], for instance, is an unsustainable solution: these large plantations absorb CO2 and when they are burned the GHGs emissions are captured, but the amounts of land required for them to be effective is excessive and in competition with the agricultural production we require to feed a growing global population.

What we need therefore is a new technology. Research is going on in several fields and we can reasonably expect that in twenty or thirty years we will be able to extract CO2 from the atmosphere and then reuse it for example to produce ethanol (and finding an economically efficient way to reuse CO2 will be another great challenge).

If this technology develops rapidly enough, it will not be simply a way to remove the current stock of emissions, but also to keep fossil fuels in use. If we can take the CO2 out of the atmosphere, we can then continue using the sources that produce it, as we will be able to compensate the effects of this usage. Thus, to understand how this energy transition will be shaped, it is fundamental to find out how rapidly CO2 removal will develop; if we are able to use it only after 2050, then the transition will inevitably have to consist of a drastic reduction in fossil fuel use and its substitution by renewables. If the technology is developed earlier, then the transition will be more smooth.

There is another technological element we need to consider. Due to the intermittency of renewables, if a large scale storage technology is not developed soon we won’t be able to reach a higher share of renewables than 30 or 40% of total electricity consumption,. And this is still far from being achieved, even if research and development is ongoing. For instance, water can play a key role using pumped-storage hydroelectricity, despite the process being an old one: in Germany, water is pumped up to massive basins using wind or solar energy, and is then released through turbines to generate electricity when there is no wind or sun. In Switzerland, researchers are working on compressed air, by constricting it into caves via solar, hydro or wind energy, and then venting it out to activate a turbine once one of these forces is missing.

Yet, this is still largely insufficient. We therefore need to develop a new storage technology, or the elimination of fossil fuels between 2050 and 2070 is unlikely to take place. In order to prepare the energy transition we need to work on an international investment plan for research and development, with resources from both for the public and the private sector, in order to generate the required technological advancements to achieve a zero-carbon world.