“This report is a survival guide for humanity.” It is in these terms that Antonio Guterres, Secretary General of the United Nations, introduces the summary of the sixth assessment report of the Intergovernmental Panel on Climate Change (IPCC) published on Monday.
The result of eight years of work which constitutes the most complete summary possible of the current state of global knowledge on climate change. While greenhouse gas emissions have not stopped growing over the period and are expected to continue, this summary nevertheless reminds us of the options at hand that would make it possible to limit the scale of the crisis. Co-president of group I of the IPCC for a few more months, the French paleoclimatologist Valerie Masson-Delmotte answer to 20 minutes.
Now that this sixth assessment report is closed, what has changed, in seven years, on the state of scientific knowledge on the climate?
We already have a much better idea of how much each tenth of a degree of warming matters and affects the general characteristics of the climate all over the globe. It is all these new extremes (heat waves, heavy rainfall, droughts, tropical storms, etc.) that are increasing in intensity and frequency. Not only do we see them better than in 2014, but we also have a greater understanding of them.
On adaptation too, we have made a lot of progress. We have a lot more feedback on what can be done and the benefits that can be drawn from it. Above all, we have a greater awareness of the limits of adaptation. In the past, we could hear “it doesn’t matter, Man has always been able to adapt”… We now measure how fast global warming is going and the “hard limits” with which it confronts us. The melting of mountain glaciers, the rise in sea level, extreme flooding… These changes are generating and will generate irreversible losses and damage. Not just species extinctions. Our infrastructures and the organization of our human activities have rarely been designed to cope with these new conditions.
The synthesis published on Monday reiterates messages that are finally already known… What does it bring then?
It links all the facets of the climate crisis in the same relationship. Not only the physics of the climate*, but also the already real impacts of climate change and the risks to which we expose ourselves by remaining on the current trajectory. However, we know what works. It is possible to halve our greenhouse gas emissions while allowing everyone to live properly.
The Giec does not propose a roadmap, does not say what needs to be done, that is not its role. On the other hand, this synthesis presents these solutions at hand, highlighting in particular those which would allow the maximum co-benefits on health, air quality, employment, climate justice…
Whether on adaptation or mitigation, the IPCC notes each time that public climate policies are much more numerous today than seven years ago… How then can we explain that we are still very far from being at the good scale?
Several factors explain this. There is already a lack of sense of urgency, as well as difficulties in understanding the causes and consequences of climate change. No doubt also that the feedback on the actions undertaken and which work are not sufficiently shared. The report also points to cases of “maladaptation”, these “bandages” which may work in the short term but not in the long term.
There is also a very important “locking” effect. Clearly: no matter how many climate policies are multiplied, all the fossil infrastructures still built in parallel lock in greenhouse gas emissions over their entire lifespan. And we are talking about several decades.
Several scientists are calling for the goal of keeping global warming below 1.5°C to be buried, because it is already almost unattainable… What does this sixth assessment report conclude on this subject?
A first certainty: current policies do not put us on the trajectory of 1.5°C, but much more on one between 2.8 and 3.2°C by 2100. Another is that climate change will inevitably worsen in the years to come and that we will cross this limit of 1.5°C around 2030-2035. We must be aware of this, prepare for it, show solidarity with the populations who will be most affected.
But it is not because we are going to exceed it that we must bury this objective. On the contrary, the IPCC is clear on this point: by reaching our global peak in emissions as soon as possible and then initiating a frank and lasting reduction, we can succeed, in about twenty years, in limiting the damage and bring warming as close as possible to +1.5°C.
In “this practical guide”, what actions do you prioritize? The release of fossils, precisely?
Investing in fossil energy infrastructures if we cannot have solutions for capturing and storing the CO2 they will emit is inconsistent. However, these solutions are not developed on a scale today and are expensive, whereas there are competitive low-carbon energies. The report thus returns to the drop in the production costs of solar and wind power, and dwells on renewable heat, geothermal energy, nuclear power… And it is not all about energy.
An IPCC report released in the summer of 2019, but unfortunately little publicized, looked at soil degradation, an essential resource both for combating climate change and for guaranteeing our food security, storing carbon, producing biomass, preserving biodiversity…
With this synthesis concluding the sixth evaluation report, a cycle ends for the IPCC…
It started in 2015 and was very dense, with the publication of three special reports and this sixth general evaluation report. This cycle began in a very strong dynamic of action for the climate, driven in particular by the Paris Agreement. The pandemic, then the war in Ukraine, undoubtedly pushed the climate crisis down the media and political agendas, but less than the financial crisis of 2008. This can be seen as a sign of greater awareness. challenges to tackling climate change, in particular because it very often goes hand in hand with greater sovereignty, in terms of energy or food. A fashionable theme.
Personally, I will end my mandate as Group I co-chair in July. A new cycle will start in the process, and it is already recorded that the next special report of the IPCC will focus on cities facing climate change. Another key issue.
* The concentrations of greenhouse gases in the atmosphere, the average rise in temperatures, the rise in sea level, the melting of the ice cap…