The summer season is barely coming to an end, and experts are already describing it as the hottest on record. At the same time, 2023 looks like it will set new records for global CO2 emissions (already almost 37 billion tonnes last year). Extreme weather, rising sea levels, threats to populations and biodiversity - scientists are constantly warning of the consequences of global warming, encouraging our societies to take action to limit the damage. And there's no shortage of technology to do just that. "But above all, we need to act quickly," urges Nicolas Tétreault, Executive Director of CLIMACT, the UNIL/EPFL centre for climate impact and action.
go2050: 2050 is the target date for achieving ambitious climate targets. Will we get there?
Nicolas Tétreault: In order to stay on a path that is compatible with the Paris Agreements (maximum 2°C warming compared with the pre-industrial era), we already need to halve our greenhouse gas emissions by 2030. And we need to achieve at least a 90% reduction by 2050. It is estimated that we will then be able to capture and sequester around 10% of the CO2 we emit, which will limit the impact of certain emissions that will be very difficult to eliminate, notably those linked to agriculture, waste incineration and cement manufacturing. On the other hand, other emissions should fall drastically, thanks to measures to replace fossil fuels with low-carbon renewable energies, the renovation of buildings and the electrification of transport and mobility. But achieving these targets depends on strong political choices and the unwavering commitment of all players in the economy. Because unless everyone does their utmost, in a concerted manner and over the long term, it will be impossible to achieve them.
The political focus is on CO2, but what about the other greenhouse gases?
CO2 is the gas that we emit the most; the quantities are astronomical. It's also the most symbolic, because these emissions are directly linked to our extraordinary consumption of fossil fuels. We often talk in terms of CO2 equivalent, which has become the unit of measurement that everyone understands. But it's true that we need to tackle all greenhouse gases. There is a great deal of interest in reducing nitrous oxide and methane emissions, due in particular to agricultural activities.
You emphasise the role of politics and business. Will science not be enough to save the climate?
The role of science is to "set the scene" by creating scenarios and providing information. It also encourages the emergence of low-carbon technological solutions, many of which are now mature. In theory, therefore, it is entirely possible to achieve the targets set by the Paris Agreements. But in practice, society as a whole needs to make room for all this. And that's where things are slow in coming together. Take, for example, the systematic opposition to the construction of wind farms. What's more, most innovations are not competitive from day one, and economic players are still reluctant to take the risk of investing in solutions that are not immediately profitable. We also need to adapt regulatory instruments to new technologies, as the "Loi sur le climat et l'innovation" does, for example, by opening the door to CO2 capture and sequestration. In the light of climate change, we all have a responsibility to move up a gear.
While clean technologies enable us to move towards a less carbon-based society, they also give us a clear conscience, and we are therefore inclined to increase our consumption. What about this rebound effect?
It's a fair observation. Which is why it's important not to forget sobriety either, especially in our individual behaviour. For the researchers, it is important, for example, to identify what we really need to ensure our well-being with the least possible negative impact on the climate, and then to analyse how we can do without the excess, which is very subjective. Our societies must now make way for sobriety, and it is also the responsibility of all economic and political players to contribute to this. All the studies show that this is the most effective lever: we don't need to produce what we don't need to consume...
This touches on the almost taboo subject of degrowth...
I wouldn't use that word, to avoid sending out the wrong message. Sobriety is what the Confederation asked us all to do last winter, when we feared a shortage of electricity. In the end, it seems that everyone played the game without any loss of comfort. This is really what we're referring to when we talk about sobriety: living well within planetary limits, to use the title of a research paper by Julia Steinberger, our former academic co-director. Some researchers are also working on ways to increase the acceptability of sobriety. Often, all it takes to change people's minds is to present things in a positive light: cycling instead of driving means getting more exercise and being closer to nature; eating less meat means being healthier; flying less means discovering Switzerland. Let's not forget that we live in one of the most beautiful countries in the world!
The world... Aren't we underestimating the impact of developing countries on climate change?
We mustn't lose sight of the fact that rich countries are also those that pollute the most per capita. Developing countries often remind us that our societies have developed and grown richer by burning fossil fuels. Through the Paris Agreement, the global community has committed to reducing its emissions, so it's now time for us to take the first step and share our sustainable solutions with them, to show that it's possible. I would even say to the most cynical that exporting our cleantech is an advantage for us in the green economy of tomorrow.
Is there a real scientific consensus on climate change? And why are there still so many climate sceptics?
There is a very strong consensus in the scientific community today. Generally speaking, there are no longer many sceptics who doubt climate change, even though some isolated cases might still raise objections to the fact that human activity is the main driver. On the other hand, there are more and more people who, while accepting the reality of change, refute scientific scenarios about the degree of its consequences. The new climate sceptic, for example, thinks it will be just a little warmer. But it goes much further than that: we are talking about extreme climatic events, threats to populations, the collapse of biodiversity, and so on. Unfortunately, denial leads to inaction: we believe it, but we think that the consequences won't be as serious as we think and that we have time. I deplore the fact that the alarm signals sent out by the scientific community are not always heard.
Which is why your messages are more solutions-oriented?
At CLIMACT, we don't want to repeat the alarm bells, even though they are essential; we prefer to encourage everyone to move towards a more sober and sustainable society, particularly through positive messages about well-being, health, equality and inclusion. And I repeat: to move in this direction, we need a strong political commitment to adopt the solutions developed by the scientific community. The status quo is a recipe for disaster.
Is it still possible to be optimistic when you're a climate specialist?
I think so. In any case, I am! And with CLIMACT, we are taking action to help accelerate as much as possible a transformation that seems inevitable. I'm still very optimistic, because I can also see that things are moving in the right direction: renewable energies are booming, there's more and more emphasis on sobriety, on quality of life in cities, on respect for biodiversity, and so on. I can't imagine that we could take a step backwards on these issues. So that gives me a lot of hope.