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Understanding climate change

Interview with Filippo Giorgi

The cover of the book by Filippo Giorgi

The cover of the book by Filippo Giorgi

More and more often, we hear about global warming, climate change and the impact of these phenomena on human rights. During the international meeting of GariwoNetwork we launched the great theme of the Righteous for the environment, women and men committed to the defence of ecosystems, indigenous populations, natural resources, who through their actions fight for the rescue of the planet.
But what is climate change? And which strategies could we adopt to counter it? We asked it to Filippo Giorgi, the person in charge of the branch of Physics of the Earth of the International Centre for Theoretical Physics (ICTP) of Trieste, who also contributed to the proceedings of the Intergovernmental Panel on Climate Change (IPCC), and author of a book, L’uomo e la farfalla; Sei domande su cui riflettere per comprendere i cambiamenti climatici (FrancoAngeli Editore) – The Man and the Butterfly, Six questions to ponder carefully in order to understand climate change-, which deals with different features tied to climate change: causes, risks, scenarios, and possible solutions.
This is what he told us.

How long have we been talking about climate change?

In the Fifties, a team run by scientist Charles Keeling started monitoring the atmosphere in the detection station of Mauna Loa, on the Island of Hawaii, and he realized that the concentration of carbon dioxide was steadily increasing. The first warning on these subject matters though was issued in the Seventies.
In the following decade, the discussion went on within the World Meteorological Organization, WTMO, until the establishment, in 1988, of the Intergovernmental Panel on Climate Change (IPCC). This panel, in charge of producing periodical assessments on global warming, would then receive the Peace Nobel Prize in 2007, together with Al Gore.

In your book L’uomo e la farfalla,  chapter after chapter you answer Six questions to ponder accurately in order to understand climate change.
But what causes such change? And how to measure it?

Now, a great deal of evidence shows that the earth climate is undergoing a process of global warming. First of all, since the beginning of the century, measurements from dozens of thousands of weather stations tell us that global temperatures have increased by little more than one degree. Other evidence then concerns the melting of glaciers, the rise in the sea level, the dissolving of arctic ice, the increase in extreme weather events. Such phenomena lead the scientific community to unanimously believe that we are now in a stage of warming. We all perceive this in our daily lives. In the mountains, glaciers are facing a stage of regression, Summer temperatures have markedly increased, the sea level is rising along the Italian coasts too (about 25 mm in the past 100 years), there are more and more frequent extreme events such as the ones that occurred in October in Northern Italy.
As far as the study of the causes is concerned, over the years there has been an increase in research and the modelling of climate has become more reliable. In the Seventies and Eighties, there was no strong scientific evidence of the causes of warming, because we were at the beginning of this trend. Now we are sure – with a probability of 95%, according to the latest IPCC report – that such a phenomenon is due to the increase in greenhouse gases deriving from the human use of fossil fuels – oil, carbon, natural gas – and the methane produced by some intensive agricultural practices.

As you remind in your book, the climate can change because of external factors, called “forcing”, which can be either natural or human-led. How can these forcing factors influence global warming? And which is thus the human impact on this phenomenon?

Ever since 1950, warming has been mostly due to the human impact, rather than the natural forcing factors – whose main one is essentially solar radiation. As proof of this, it may suffice to think that in the recent 50 years such radiation has been quite stable, alas, if anything it slightly decreased, and in some way, it counterbalanced the effect of the human forcing factors. Therefore, most of the warming is due to the increase of greenhouse gases, and on this basically the whole scientific community that studies this phenomenon agrees.

Global warming, climate change… all this causes remarkable risks. Which are the most worrisome?

There are four major risks that influence human activities and a lot of social and economic factors.
The first is the melting of continental glaciers, which contain the majority of the fresh water available today (nearly 65%). The decrease in their mass means loss of water, and since now already water is scarce and its demand is increasing more and more – above all in emerging countries such as India or China, whose main water source is constituted by the glaciers of Himalaya – there can be serious problems of availability of this resource, also impacting the production of food.
The second, strictly connected to it, is the rise in the sea level: if the continental glaciers melt, the water ends up into the sea. Moreover, the sea water is heating up and this produces an expansion of water, and thus a rise in the sea level. This, of course, generates huge problems in the coastal areas. First of all, an increase in erosion and the disappearance of the coastlines, with severe damage to the infrastructures. Secondly, more and more damaging swells and sea floods. Many world areas, such as for example India and Bangladesh, every year are subject to floods due to the Monsoons; in the presence of a rise in the sea level, such floods would cause more harm. Another very serious problem is that of the intrusion of salt water into the soil, which destroys its fertility. This is happening, for example, in the delta of the Nile, but also, closer to us, in many coastal areas of Veneto and Friuli. The third risk I would like to point out is the increase in extreme weather events, in what has been defined as the intensification of the hydrologic cycle. A warmer atmosphere is more energetic and can contain more water steam. Subsequently, disposing of more energy and more steam, rains are more intense, with a worse risk of floods. For example, one of the reasons why in Italy the rains and winds of end October have been so devastating is that we had experienced very warm earlier months, with high temperatures of the Mediterranean Sea, and this has provided a lot of energy and water steam to the weather storms. We have witnessed the occurrence of a couple of “Mediterranean hurricanes” (not true hurricanes, but events with a similar structure), phenomena which generally do not occur so often in a short period of time. Furthermore, the climate models are telling us that the dry periods between different times of rainfall are becoming longer, a factor that increases the risk of drought. There is then a fourth factor, which is very important: the geographical distribution of climate change, which is not perceived the same way in all world areas. There are some so-called “hot areas”, such as the Mediterranean Sea, which is more sensitive and vulnerable to global warming. If such areas are located in poor countries, this can increase the risk of mass migrations.

The theme of climate refugees is already very topical nowadays …

People move – and have always done – for many reasons. It is difficult to uniquely associate climate and migrations. Nonetheless, in order to understand this connection, I often offer one example. In 2010, in Kashmir, there were unprecedented floods, with an impact on about 20 millions people, many of whom were evacuated. Such a broad event, in a normal climate, can occur maybe once in 50-100 years; people then go back to their cities and rebuild their homes and firms, to resume their daily lives. If, instead, such events occur every 3 or 4 years – and it is predicted that this can occur in a warmer climate – then people do not go back to those places any longer, but migrate elsewhere.
To this, we need to add that the climate distress can worsen already precarious situations, such as those that according to many observers are occurring – or will occur – in the Middle East.

In the face of this all, how does politics react?

I would like to set out a premise. The Paris accord on climate, in 2015, demanded a decrease of emissions. From this point of view, both Europe and the United States prove quite virtuous. In Europe, emissions are decreasing, thanks to a strong stimulus toward alternative, so-called “green”, technologies; this is true also in America, where, despite the recent political events, the emissions are quite steady and I believe they will soon start decreasing. The problem today is represented by the emerging countries – such as China, India, Brazil, Russia, and sooner or later also Africa. They claim their right to develop because, despite they are now the biggest emitters, it is not them who caused the problem until now. It is here, around this knot, that the political discussions run aground.

I am not confident on the fact that a governmental accord can be reached, because in this fields the schedules – 2030, or 2050 – are much more binding than the schedules of politics, that is naturally subject to continuous changes of administrations. More than such negotiations, where the role of the lobbies on the government is strong, a grass-roots stimulus, an urge from the civil society is needed, to head for a model of a green economy.

Are we in the face of something irreversible, and thus must we only adapt to these phenomena or is it still possible to act?

Of course, we are still in time to act. We must though not forget that the more temperatures rise, the worse impact these phenomena will bear. The issue anyway is about containing the problem within limits in which adaptation policies manage to counterbalance the effects of climate changes. For example, if a rise in the sea level is expected, it will be necessary to build higher stems or dams, like in Holland.
Global warming will, in facts, continue. The point is, and will be, to contain it within limits we deem acceptable – and do so through sustainable adaptation measures. Let me resume the talk about the Paris Conference. Here the discussion revolved around the threshold of 2 degrees of warming in comparison to the pre-industrial values. Actually, in Paris, the 1.5 degrees were also mentioned, but as we have already reached the threshold of 1.1 degrees, I don’t think it will be possible to remain under 1.5 in a short time. The objective of 2 degrees (actually about one degree more than the current values) is instead absolutely within our reach through an urgent and forceful action on the reduction of the use of fossil fuels. The problem, though, was not only the threshold digits. I think the main and more dangerous issue is the so-called business as usual scenario, the most extreme one, in which the concentration of carbon dioxide keeps increasing in the absence of adequate countering measures. Unless we act, the global climate can warm up by 4-5 degrees in a century. And it has never occurred, at least in the last dozens of thousands of years, that in a century the global temperature ever rose to such high levels. It may suffice to think that the last glacial era, whose peak was 18,000 years ago, had a completely different climate, with a sea level that was by 120 meters lower, and a climate which was colder by 5 or 6 degrees. Thus, by reaching in the near future 4-5 degrees of increase, we would be in the face of a storm comparable to the difference between a glacial era and an interglacial time, but over just 100 years, not over thousands of years. In the era of the dinosaurs, dozens of millions of years ago, temperatures were much higher than now – up to 6-8 degrees higher -, the concentration of carbon dioxide was much higher and on the earth, there were no glaciers. However, today such a situation would be devastating: a great deal of Italy, for example, would not be there anymore due to the rise in the sea level.
If the climate changes, nature adapts itself. The problem is the impact on human society, which could become something completely different in its structures and balances. It may suffice to think that the migrants could be us, forced to move to faraway areas because the Mediterranean Sea is a warm area running the risk of desertification. Thus, safeguarding the climate also means safeguarding our society and particularly the future of our children and grandchildren. The “butterfly” that gives the title to my book, refers to the “butterfly effect” by Lorenz, the inventor of the theory of chaos, and does not describe anything but the complexity of the climate system, its great variability: we cannot know with certainty how the climate system, so complex and interconnected, will be able to respond to such extreme, huge and rapid events, even with our current most advanced models.

Do you think we will be regarded as the generation that has seen climate change and has done nothing to avert them, or will we rediscover our gender solidarity – whereas by gender we mean the human gender – in the face of a global threat?

I don’t think the catastrophe will be really averted by solidarity (which unfortunately is currently not very up-to-date in our societies), but rather by survival. The human species has had numerous times in which it could destroy itself, such as the nuclear crisis, but at the end that did not happen, every mad threat has been stopped. I thus think that, as a species, we have great resilience, and thus I believe with some more awareness we will head for a solution – which is completely within our reach. Moreover, it is important to underline that such a solution does not demand historic changes, but it is only about better and more equal use of the resources we have. It is necessary to reduce waste – it may suffice to think that we waste 60% of the energy we produce – and aim at renewable energies, which still today could provide the whole world energy demand, without even needing to develop new, revolutionary technologies. The problem of renewable energy is not really the availability and production of energy, but rather its distribution. In my opinion, it is thus not really about facing radical societal changes.
Of course, many sectors based on fossil fuels would be hit by similar measures, but I believe the era of oil is over, and also countries like Saudi Arabia are realizing it: Ryadh itself in facts, is building a solar plant that, once finished, will be the most powerful on earth. The urge toward green economy is thus a rationality choice, which in my opinion is unstoppable. Anyway, it is important to bring about environmental culture. In Italy it is totally absent, perceived as something “political”. Paradoxically, in Italy, the environment is often seen as an enemy that hinders development, but this is nonsense: having a better environment means improving everybody’s life.

Martina Landi, Chief of Gariwo Editorial Staff

19 December 2018

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