The international group of climate experts is not mandated to issue recommendations. It is content to evaluate the possible solutions to fight against global warming, remind its members. For “mega-basins”, his observation seems mixed.
Were “mega-basins” recommended by the IPCC, the intergovernmental group of experts on climate change, to mitigate the deleterious effects of global warming? While several thousand people gathered at Sainte Solinein Deux-Sèvres, Saturday March 25 and Sunday March 26, to protest against the construction of one of these artificial water reserves, the debate also raged on social networks.
“Obviously, we will not hear the obscurantists of the Nupes-EELV tell us that the IPCC, in its summary note for decision-makers, recommends the creation of ‘mega-basins’“struck on Twitter, on March 25, Guillaume Kiefer, former Les Républicains candidate for the 2022 legislative elections in Morbihan. And he is not the only one to affirm it on the blue bird social network.
“It’s FALSE, FALSE and FALSE. The Giec does not recommend ANYTHING”gets carried away the blogger good mate on the same platform, adding: “Fed up with always seeing the same Twitter accounts making misinformation.” So what exactly is the position of the IPCC vis-à-vis “mega-basins”? To determine it, franceinfo spoke with three authors of the sixth report of the group of experts on the climate.
The IPCC makes no recommendations
To support his point, Guillaume Kiefer shares on his Twitter account a screenshotactually taken from a section of the summary report of the sixth IPCC report (PDF, page 8). In this passage, “water management and storage on farms, (…) irrigation” are presented with a “high degree of trust” as “effective examples of adaptation options” to reduce climate risks. What the ex-candidate LR interprets as a recommendation of “mega-basins” by the IPCC.
“The Giec is not prescriptive and does not recommend anything”immediately retorts Christophe Cassou, climatologist and co-author of the report. “Its mission is only to provide the most up-to-date state of knowledge and to provide objective decision support on all possible solutions. [contre le changement climatique]. It is then up to the decision-makers to choose”recalls the climatologist. “When politicians say that the IPCC recommends something, it is so as not to assume a decision which is theirs and to find a blank check for the solution they choose”, laments the scientist.
The IPCC experts interviewed by franceinfo are categorical: the extract from the report cited by Guillaume Kiefer does not refer specifically to “mega-basins”, but to water storage in general. “The term ‘basin’ is not even mentioned in the excerpt”points out Yamina Saheb, co-editor of the report.
“Adverse effects” outweigh the benefits
The solution of water reservoirs, on the other hand, is addressed in other sections of the report and the assessment made of it is mixed. “Reservoirs are expensive, have negative environmental impacts and will not be sufficient everywhere beyond certain levels of global warming”underlines the IPCC report in its chapter devoted to water management (PDF, page 1833).
Irrigation can however”reduce drought risk and benefit livelihoodsrecognizes Christophe Cassou. The basins thus worked in certain areas.” But these positive effects are offset by “several potential adverse effects”, points out the climate expert. Of the “effects” against which a “proper management” is necessary, note the report in another section (PDF, page 556).
Artificial water reserves are thus criticized by the IPCC for their possible deleterious effect on groundwater. The very operation of “mega-basins” “consists of pumping water from aquifers – groundwater – to store it on the surface”, recalls Gerhard Krinner, research director at the CNRS and one of the coordinators of the IPCC summary report. However, the IPCC report (PDF, page 563) warns that the “overuse of groundwater for irrigation” can lead to a “depletion of reserves”highlights Yamina Saheb. Bedpans can also lead “to tensions, if deep water is only made available to the few farmers connected to the reservoirs”, adds Gerhard Krinner. Another disadvantage pointed out by the researcher, the quantity of water lost by “evaporation” basins due to the outdoor storage of collected water.
The ‘mega-basins’, an example of “maladaptation”?
For Gerhard Krinner, “mega-basins” could rather be an example of “maladaptation”, a phenomenon also described in the IPCC report (PDF, page 20) : “Instead of thinking about reducing consumption, infrastructures such as ‘basins’ could confine users to an unsustainable path.” “After a while, this adaptation measure may lose its effectiveness.predicts the climate specialist.
“This is what happened in Spain, where the tank policy is at the end of its tetherillustrates Christophe Cassou. This policy could be adapted 30 years ago, but today the country is experiencing a chronic crisis to fill its reservoirs.” For all these reasons, “the IPCC summary report absolutely does not speak of ‘mega-basins’ as an example to follow”concludes Gerhard Krinner.