“A dire warning.” These are the words chosen by the president of the Intergovernmental Panel on Climate Change (IPCC) to describe the new part of the sixth report of these scientists, responsible for taking stock of the state of knowledge on climate change. . Devoted to the effects of global warming and how to adapt to it, this second part is accompanied by detailed sheets, region of the world by region of the world.
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If the IPCC does not analyze by country, these sheets allow us to know a little more about what awaits us if we do not reduce our greenhouse gas emissions. Franceinfo looks at the situation in France, which straddles several regions.
In mainland France
At the current level of warming (+1.09°C), Europe is already affected by heat waves and droughts. In the future, four risks, which will worsen if warming continues beyond 1.5°C, have been identified. At present, the promises of the States (which are not yet kept) lead us towards a warming of 2.7°C in 2100.
The heat. The first risk identified is that of mortality linked to heat waves. The death toll goes “double or triple for a warming of 3°C”, scientists warn. They specify that beyond this threshold, it will be difficult, if not impossible, to adapt. The south of France is particularly threatened, with up to 20 to 30 days of temperature above 35°C per year with a warming of 3°C.
The warming will reduce animal and plant habitats and modify so “irreversible ecosystems”from 2°C warming. “Forest fire risk areas will expand in Europe, threatening biodiversity and carbon sinks”those ecosystems that capture part of the greenhouse gas emissions, write the scientists.
Agricultural losses related to drought and heat. According to the authors of the report, “substantial agricultural production losses are projected for most European regions during the 21st century and these will not be offset by production gains in Northern Europe”. Irrigation, which can be an effective solution, will be increasingly limited by reduced water availability, particularly if warming exceeds 3°C.
The lack of water. This risk primarily concerns Southern Europe, in which there are many French regions, from Aquitaine to the Southern Alps. In this zone, more than a third of the population is at risk of running out of water from a temperature increase of 2°C. From 3°C, this risk doubles and “significant economic losses in water and energy dependent sectors may occur”. Central Europe, where the rest of our country is located, will be affected from this threshold.
Floods and rising waters. At the current rate of our greenhouse gas emissions and the implementation of our adaptation strategies, the damage caused by coastal flooding will be “multiplied by 10 at the end of the 21st century”. As for the rise in sea level, it represents a “existential threat” for coastal cities, especially after 2100.
The Mediterranean is particularly “brittle” face to this rising water, points out Wolfgang Cramer, CNRS research director at the Mediterranean Institute of Biodiversity and Marine and Continental Ecology (IMBE) and one of the authors of the report. “Historically, the level of this sea has changed little [la Méditerranée a une faible amplitude de marée et connaît moins de tempêtes que l’Atlantique]so you have a lot of cities, heritage and wetland natural areas very close to the coast”he explains.
One of the authors of the chapter devoted to Europe, Gonéri Le Cozannet, specifies that this selection “does not mean that these are the only risks” for the region. “There are cascading risks”continues the researcher at Bureau of Geological and Mining Research (BRGM). He quotes for example the risks of cavity opening after a flood – water widens an underground cavity, causing a hole on the surface – or the cracking of houses by the shrinkage-swelling of clay after a drought.
In the overseas island departments
Particularly threatened by climate change, the small islands are the subject of a detailed file. Many French territories, such as Guadeloupe, Martinique, Réunion or Mayotte, are concerned.
Already very strong impacts. In these territories, global warming is a very present reality. The report cites in particular heat waves, more intense tropical cyclones, changes in precipitation, rising sea levels, coral bleaching, invasive species…
Threatened ecosystems. These islands are sometimes home to one of the ecosystems most threatened by global warming: coral reefs. From 2°C, 99% of corals will die, victims of bleaching. It’s not much better for the rest of the ecosystem of these islands: endemic species will disappear if warming reaches 3°C, according to the IPCC.
Habitability on borrowed time. Finally, it is quite simply the possibility of living on these islands that is threatened by global warming. “The vulnerability of these communities, especially those that depend on coral reefs for life, may exceed the limits of adaptation well before 2100, even with a low greenhouse gas emission scenario”, scientists warn. Beyond the rise in sea level, which is eating into their territories, these islands risk running out of fresh water and food.
In Guyana
With Guyana, the French territory is also exposed to the risks that threaten the Amazonian forest. This forest, “one of the greatest reservoirs of biodiversity and carbon”East “very vulnerable to drought”. It has already caused damage in 1998, 2005, 2010, 2015 and 2016. This is reflected in an increase in tree mortality and a reduction in forest productivity. Climate change is also favoring the spread in the region of dengue fever, chikungunya and the Zika virus, transmitted through mosquito bites.