Flooded towns, cows swept away by currents, cut roads and railway lines which have still not been completely restored… Storm Leslie left its mark on France with record amounts of precipitation. If the precise assessment of the damage has not yet been established, certain consequences will persist over time, such as those on agriculture. 20 Minutes takes stock.
The direct consequences
With quantities equivalent to months of rain in a few hours, Storm Leslie was “unprecedented in its scale”, assured the Minister of Ecological Transition Agnès Pannier-Runacher on Friday. Consequences ? “Agricultural soils are oversaturated with water,” explains doctor of agrometeorology Serge Zaka, founder of Agroclimat 2050.
“In the event of a flood, the flooded fields very often find themselves inaccessible,” he explains. If some manage to access it, the harvest will be much too wet. If it has to be stored, mold can grow. This is particularly the case for sunflowers and corn. In fact, the harvests are postponed. » But waiting also means taking the risk of a loss of returns. “There may be ears of corn that lie down, sunflower seeds that fall, others that germinate on the plant and which are then not edible,” specifies the specialist.
The other important period in agriculture is sowing. In the same way as for the harvest, heavy precipitation disrupts this phase. “If the soil is flooded, the seed is suffocated and the seedling does not take off,” indicates Dr. Serge Zaka. So here, too, we have to push back. » And when the harvest period is postponed, it is only the following year that the losses are felt.
Long-term impacts
“In agriculture, dates are perfectly calibrated in relation to the varieties of our regions,” underlines the specialist. If we shift them, we shift the entire crop cycle. » And the problem is that Leslie is added to other phenomena. Sowing has already been postponed at the start of the year due to heavy rains.
“We are currently experiencing the rainiest period since measurements began, with, over a rolling year, cumulative precipitation reaching 1,279 mm. Normally, at this time of year, we have about 60% of the corn fields harvested. Today, we are at around 10%, or six times less,” indicates Dr Serge Zaka. He adds: “The situation is starting to weigh on farmers’ finances but also on their morale. On wheat yields, we are at -40% because in autumn 2023, there was excess water during the sowing period, but this was also the case during the harvest period, at the start of the summer 2024. The consequences of episodes like storm Leslie are therefore not minimal, on the contrary. We are going to question our agricultural sovereignty. »
An accumulation of “bad years” in agriculture
For four years, farmers have been experiencing weather episodes “constantly”. “In 2021, we had -30% economic yields on vines due to frost, in 2022, up to -50% for corn due to drought. Historically, we have already experienced severe floods or droughts, but we experienced a distance from these exceptional events which meant that, economically speaking, agricultural businesses could get by. From now on, it is not even just a single climatic episode but it is a multi-event,” says Serge Zaka.
Thus, “agriculture is the first victim of this excess water”, declares the doctor in agrometeorology. As French activity is established in a temperate climate in central Europe, the alternation of seasons is essential to “produce in a peaceful manner”. “However, with climate change, we observe that these alternations of weather are less and less valid. Climate change is accentuating periods of intense drought, followed by almost monsoon rains, all in excess temperatures that favor diseases. Agriculture finds itself confronted with all these problems,” points out the specialist.
And the fact that the water tables are already almost full is not “positive for the future”, he insists. “The only reassuring point is that, if we are faced with a drought in 2025, our aquifers will be able to take over. But hoping for floods when we experience droughts, and vice versa, is not the principle of agriculture. »
Solutions to deal with this observation
According to Serge Zaka, there are other solutions to adapt to this situation than genetics or irrigation. To “manage” and mitigate the impacts of water deficits and excesses, he proposes “soil conservation agriculture”, that is to say, having “more vibrant soils”, “less plowing”, “more legumes”, “less artificialized”.
Landscape management can also intervene on water. “Simplification, notably the consolidation or retracing of our waterways, has accelerated the flow of water on the continent unlike regenerative hydrology, which means a complex landscape where water is slowed down,” explains- he.
Our file on global warming
Before concluding: “in France, we try to focus on the cultures that have been present for generations, in each region. But given that climatic zones are changing, it is necessary to better manage our crop distribution area and make it evolve, too, with crops adapted to this changing climate. »
