The best solution to combat global warming is to succeed in the coordinated fight to reduce the emissions of the various greenhouse gases. So says Ilissa Ocko, scientific director of the Environmental Defense Foundation (EDF). The important thing, in her opinion, is balance and hitting the right measures. “Sometimes we want to move so fast against climate change that we focus on technologies without knowing all the repercussions that could result from their use. It happened to us – she says – with diesel. We were very excited and applied it to all types of vehicles. And then we found out that it's actually very problematic because of its health effects, among other things. Now it also happens to us, for example, with hydrogen”.
“Research on hydrogen as an alternative energy source –explains doctor Ocko– is advancing very fast. In fact, for a hundred years, human beings have used hydrogen as a source of energy in various applications. But, on the other hand, we have never done it on the scale that is now proposed. What many people ignore is that it is an indirect greenhouse gas. It does not trap heat by itself, like CO2, but its mere presence in the atmosphere contributes to increasing amounts of other greenhouse gases, such as methane and tropospheric ozone."
“We must therefore take into account – he adds – the climatic consequences derived from the use of hydrogen. It is the smallest molecule that exists and, therefore, leaks that reach the atmosphere can easily occur. Before we deploy hydrogen widely, and distribute it through pipelines and store it in large quantities, we need to make sure we prevent leaks, among many other things. We have to be diligent about what we do, how we do it, and be aware of the series of impacts that could occur from these new technologies that we are betting on”.
Dr. Ocko, who leads a climate science team, has a BS in Earth System Science and Engineering from the University of Michigan and a PhD in Atmospheric and Oceanic Sciences from Princeton University. Since she won a NASA scientific communication contest in 2016, she has also become a great and active disseminator of the fight against climate change. She has been the guest, a few days ago, of the new edition of the SUStainability cycle that La Vanguardia has been organizing periodically for two years. Through extensive and extensive interviews, broadcast in streaming on the newspaper's website, the deputy director of La Vanguardia, Enric Sierra, reveals the activity, studies and reflections of the main researchers and activists who work in defense of environment.
In response to Enric Sierra's questions, Dr. Ocko admits that there is no single effective solution against global warming. “Actually,” she says, “we will need a combination of different things. And hydrogen certainly has its applications in cases where we lack better alternatives, such as, for example, to reach the high temperatures at which the cement or steel sectors work. For things like that it makes a lot of sense to use hydrogen. And to maximize climate benefits, it is enough to minimize leaks. You have to make sure that when we build our hydrogen systems, we're really careful and rigorous about how we do it. For example, locating a hydrogen production plant next to the facilities destined for its final use, to avoid transporting it unnecessarily, since it increases the probability of leaks appearing”.
He also acknowledges that hydrogen will be the way forward for other applications as well. Perhaps for aviation, where it can be used to produce synthetic fuels. In his opinion, however, the general rule to produce energy should be to electrify whenever possible, because solar and wind power stand as the main strategies for carbon dioxide emissions and minimizing negative side effects. "I think we should not use hydrogen to take it to homes," he says.
Dr. Ocko, in response to questions from the deputy director of La Vanguardia, states that there is broad scientific consensus that the key to combating global warming on the planet is to reduce the amount of gases that trap heat in the atmosphere, also known as greenhouse gases, and that hundreds of such gases have been found to exist. Of all of them. however, carbon dioxide (CO2) emissions, both old and new, are responsible for nearly half of today's warming. Methane causes more than a quarter and is the second most guilty. “The two cited pollutants alone are responsible for most of the climate change,” Ocko says. However, I want to highlight the importance of the time these gases spend in the atmosphere and what this means in terms of current and future warming. Carbon dioxide and nitrous oxide are long-lived while methane is short-lived. To immediately reduce the amount of greenhouse gases, it is necessary to drastically reduce the emissions of the latter.
Dr. Ocko points out that there are currently new satellites capable of identifying where methane is emitted from and in what quantity. As a result, many emissions of this gas could be reduced. The main thing would be to prevent natural gas leaks from gas pipelines and other installations, since it is the main source of methane generation, but the use of waste for the production of heat and electricity must also be generalized, improving the treatment of wastewater, better management of rice fields and the use of additives that have been discovered to suppress the production of methane in the intestine of cows, which are the great emitters of this gas, if it is not possible to reduce the consumption of meat in the world.
In his opinion, with an adequate strategy, and without major problems, methane emissions could be reduced in the next 10 years enough to slow the rate of warming by 30%, which would be impressive. And this while the already known measures to reduce long-lived gases, such as CO2, continue to be applied, so as to limit the extent of maximum warming in the long term. “In this way – he affirms – the combination of both strategies is what will stop climate change both now and in the future”.
Dr. Ocko points out that achieving net zero long-lived gas emissions requires taking some key steps. The first is to reduce carbon dioxide emissions as much as possible and as soon as possible with the maximum possible production of renewable energy instead of fossil fuels. The second fundamental measure must be to preserve the forests. This is a key aspect because forests store a lot of carbon. She explains that it takes a hundred years for a new forest to grow, capable of storing the same amount of carbon as an existing forest. Therefore, it is key to preserve as many forests as we can. “And finally – she adds – her, everything that we cannot reduce or save, preserving carbon reserves, must be completely eliminated from the atmosphere with strategies based on nature or technology.
“Recently,” he explains, “collaborators and I have looked at the chances of preserving Arctic summer sea ice by the end of the century. We have found that, with current policies, we will not be able to preserve it. In fact, it is expected that it will disappear completely. If we reach the goal of net zero carbon dioxide emissions by mid-century, there is a 50% chance of saving it. In other words, we have the same chance of keeping it as of not doing it. But instead, if we drastically reduce methane emissions in the next ten years, with existing technologies alone, we have an 80% chance of saving the Arctic summer sea ice by the end of the century. It's worth a try".
Finally, Dr. Ocko points out that reducing methane emissions has other important benefits. For example, methane produces tropospheric ozone, which is not just another greenhouse gas, but also a toxic air pollutant. Improvements in air quality derived from the reduction of methane emissions, likewise, could also prevent 200,000 premature deaths each year, once their emissions are cut in half, as well as avoiding the loss of 25 million tons each year. . “These are – he concludes – important benefits for society that go beyond the climate damage caused by these emissions.
Finally, Dr. Ocko expressed her hope to Enric Sierra that the constant scientific advances, the awareness of society and the correct political and economic decisions, such as those that many countries are beginning to adopt, will make it possible to win the battle against climate change.
