The number of heat waves and droughts has largely grown over the last 30 years with dramatic consequences for farmers. All models show that droughts will continue to happen as long as our way of life does not change. Under these conditions, what future for agriculture?
Can agriculture adapt to climate change? And even better, how can agriculture actively participate in the effort against climate change through new, more virtuous practices?
Let's start by asking ourselves : What is drought ?
It is a natural phenomenon, characterized by a deficit of water over a sufficiently long period to affect the environment.
There are different types of drought:
Meteorological drought ; which is a prolonged insufficiency of precipitation.
Agricultural drought ; related to a deficit in surface soil water sufficient to affect the proper development of vegetation.
Hydrological drought ; it happens when the levels of lakes, rivers or groundwater are abnormally low.
PART 1 : exposition of the problem
•Drought on a world level
Globally, the areas most affected by these droughts are the tropics and subtropics. Arid areas (such as Africa and Western Asia) are also affected and are particularly vulnerable. According to the report of the United Nations Convention to Combat Desertification (UNCCD), since 2000, the number and duration of droughts have increased by 29%. This phenomenon is mainly linked to a lack of water and high temperatures. For example, in case of low precipitation during winter and spring, water reserves cannot be sufficiently recharged. Together with high temperatures due to global warming, this leads to evaporation, drying and soil erosion.
Another cause is the over-consumption of water by human activity, which leads to and accelerates the aggravation of drought. Indeed, if the water reserves have already decreased due to meteorological phenomena, human activity does not decrease, leading to an overexploitation of water resources, and thus a drying up of the water tables.
In addition, atmospheric pollution is causing a progressive warming of the earth's temperature, which will accentuate meteorological phenomena such as heat waves. A heat wave is defined as a lack of precipitation and periods of high heat over a long period. This phenomenon accelerates the drying of the soil and thus droughts.
This rise in global temperatures, which is estimated to be at least +1.5°C by 2050, will have serious consequences for the environment (c.f. Fig. 1), including an increase in the frequency and intensity of fires. Each year, no less than 350 million hectares of forest are burned by fires, i.e. six times the surface area of France.
Droughts are often followed by intense showers and thunderstorms that can cause flooding. In addition, dry soil that has become impermeable absorbs rainfall less well, increasing the risk of flooding. An experiment from the University of Reading (the video here) has been particularly shared on social networks and shows in a simple way the impact that soil moisture has on water absorption. Indeed, we can see that on a wet soil, the water contained in the spilled glass is absorbed in a few seconds, while in the case of a dry soil after drought, the water is barely absorbed after 1 minute of experiment.
However, some scientists believe the experiment is biased by the thin layer of air between the glass and the soil, due to the presence of grass in Case 1.
•Drought in France
In France, the regions most affected by the drought are Provence, Pays de la Loire, Paris basin and the plains of Alsace and Limagne. Indeed, according to the SSWI (moisture index) and the SFI (hydrological index), the duration of dehydration of their soil is more important than for the rest of the French territory. But the drought does not concern only these regions of France, that is why there are 4 levels of drought vigilance. From a certain level, the prefects can take measures by decrees at the department level. This year the territory of Bourgogne Franche-Comté has been classified: Level 4 / red, "crisis", the highest alert level in France!
During the summer of 2022, a long-lasting heat wave settled in France with 3 major heat waves: from June 15 to 19, from July 12 to 25 and from July 31 to August 13. During the week of August 8, 93 French departments were subject to water restrictions, including about 60 at the "crisis" level. The month of July was exceptionally dry and sunny. This trend continued during the first part of August. In general, temperatures were above normal for most of the summer (on average 1 to 3°C above average seasonal values), making the summer of 2022 the second hottest over the period from 1900 to 2022, behind the summer of 2003. Record temperatures were also recorded: 36.2°C on June 18, 37.6°C on July 18. This has resulted in a soil drought visible on the surface of many areas with cracked soil, dried out plants and trees with autumn colors. This drought is also felt at the level of the groundwater.
The groundwater represent the stored water. They allow to see the available water reserves and to have a long-term vision (c.f Fig.2). During August 2022, most of the water tables in France were placed at moderately low or low levels.
However, water reserves also relate to rainfall, which represents the amount of water that falls per precipitation. This data is unstable (see Table 1) because it is difficult to predict future rainfall.
In France, July was the driest month since 1959, with a difference of -85% to -91% depending on the region, compared to normal. Over the summer, the rainfall deficit reached 25% on average in France. This summer ranks tenth among the driest summers over the period 1959-2022 in France (c.f. Fig 3 ).
| 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 (Janvier-Février) |
Besançon | 1300 | 886,6 | 1268 | 1286,1 | 1168 | 964,1 | 1459,4 | 1034,3 | 1097,5 | 1044,9 | 940,7 | 1254 | 544,4 |
Dijon | 823,9 | 660,8 | 756,1 | 966,2 | 815,9 | 535,8 | 824,1 | 621,9 | 791,2 | 583,6 | 577,1 | 645,6 | 351,8 |
Dole | 967,5 | 698,4 | 1008,5 | 1047,4 | 913,4 | 673 | 891,2 | 757,7 | 840,2 | 739,1 | 711,2 | 887,5 | 432,4 |
Paris | 631,5 | 503,9 | 600,9 | 573,2 | 698,2 | 492,7 | 655,1 | 739,9 | 671 | 669,3 | 639,5 | 727,7 | 370,1 |
Tab. 1 : Precipitation in mm between 2010 and 2022 for the main cities of Bourgogne-Franche-Comté and Paris. In blue, the highest precipitation, in yellow, the lowest precipitation.
Source : InfoClimat.
Consequences are also visible on agriculture, which has a direct impact on prices and increases inflation.
PART 2 : Drought ans agriculture
•Impact of drought on agriculture
Agriculture is strongly affected by drought. Indeed, the absence of water in the soil has repercussions on the crops. The restrictions put in place by the prefects also concern the agricultural sector for the departments in crisis, so farmers are subject to restrictions and sometimes even bans on irrigation for their crops. Crop yields could be reduced by more than 20% in France compared to the previous year.
According to the Department of Agriculture, the drought has caused:
-An 18% decrease in grain corn production compared to August 2021
-A 21% decrease in grass production in the meadows
On a European scale, losses have tripled over the last 50 years, according to a study recently published in the journal Environmental Research Letters.
Cereal crops are the most affected by these meteorological phenomena, its cultivation covers nearly 65% of the European territory and it is mainly used for animal feed. Therefore, breeders are also affected by the drought since it leads to a lack of food resources for livestock. In some regions of France, breeders are obliged to draw on winter fodder stocks to feed their livestock.
A current example of the impact of drought on agriculture and the mustard shortage we experienced (and are still experiencing a bit) this year.
This began in 2017, when mustard seed cultivation in France was decreasing due to the cessation of certain pesticides, now banned in France, and leading to devastating insect attacks. Thus the production of mustard seeds dropped from 12,000 tons in 2017 to 4,000 tons in 2021. Canada then became the world's leading supplier of mustard seeds (supplying 80% in France, against 20% for the Burgundy production). However, in 2021, the country was confronted with a great drought, leading to a drastic decrease in its production and thus a worldwide shortage of mustard jars which particularly affected the French (and Dijon!) who are great mustard lovers. Mustard has thus become a rarer and more expensive product: a jar of mustard has been sold 13% more expensive than in 2021. Following this crisis, the Burgundy region has decided to relocate its production of mustard seeds by more than doubling its production for 2023 with 10 000 ha. Burgundy should thus become the second largest producer of seeds, behind Canada, with 15,000 tons of seeds, 40% of the needs of mustard growers. To control insect pests, studies conducted at Agrosup have resulted in mustard plants that are resistant to insects that affect production.
Beyond mustard, inflation in the food sector could amount to
5.3% for the year 2022 (c.f. Fig 4), study by INSEE (data from March 2022). Indeed, the prices of some foods are exploding such as fish, meat, wheat products and fruits and vegetables, with increases of 6% to more than 20%, we note that in 2021 pasta has increased by 10.8% (c.f Fig.4).
Agriculture also affects its own future, as the long-term consequences of soil degradation or excessive water withdrawal will harm future crops.
•Impact of agriculture on drought
Agriculture has a significant impact on the environment, more than two thirds of water consumption by humans is for agriculture, it also harms the quality of water, at fault? The runoff of fertilizers, the use of pesticides and the effluents of breeding.
Currently, 5 billion m3 of water are withdrawn each year in France only for the agricultural sector, 60% of the water withdrawn is devoted to irrigation, to compensate for the lack of rainwater for watering their crops. This is an artificial technique that provides the necessary amount of water. This consumption varies from year to year, depending on weather conditions and the type of crops.
Fig.5 : (left) Diagram of water consumption and withdrawal in France according to sector of activity.
Source: Translation of figure from Agences de l’eau. (right) Diagram of the distribution of irrigated areas. Source : Translation of figure from Agreste-Enquête Structure 2016
Irrigation accounts for 9% of the water removed from the groundwater, but 48% is consumed. As shown in the diagram, the water used for irrigation is not returned to the aquifers, unlike the energy sector, which withdraws 64% of water but consumes only 22%. (c.f. Fig 5 - left)
Corn is one of the most cultivated crops in France, (c.f. Fig 5 - right) it is a very water intensive crop. 45% of the irrigation in France is used to grow corn, but it is produced mainly to feed livestock. It is estimated that 13,000 liters of water are needed to produce 1 kg of beef.
Air pollution is also a consequence of agriculture, according to the graph, at the scale of France, 45% of greenhouse gas emissions are methane, mainly emitted by livestock via enteric fermentation and animal waste management. (c.f. Fig 6). The increase in the greenhouse effect is one of the consequences of global warming, this gas is naturally present in the atmosphere, it retains part of the heat received from the sun's rays, its increase allows it to retain more radiation which results in meteorological changes such as heat waves. According to projections, by 2030 ammonia and methane emissions from the livestock sector could exceed their current level by at least 60%.
PART 3 : What to do ?
•As an individual, what can you do to save water everyday ?
House
Take a shower than bath: it is about 150 to 200 L of water for a bathtub, for a shower it is about 40 to 65 L of water for 5 min.
Start the dishwasher and washing machine in economy mode and only when they are full.
Choose a double flush toilet which can save up to 50% of water. Even better, if your land allows it, you can install dry toilets, designed to be increasingly easy to use.
Put a water saver on the faucet. It can save 30 to 70% of water. This system reduces the water flow, but the pressure remains the same.
Recycle water for daily use: the water flows for a few seconds before reaching an adequate temperature, you just have to store this water in a basin and then reuse it for watering or as water for washing your food: vegetables / fruits.
Paper production requires a lot of water consumption. Using 100% recycled unbleached paper can save up to 90% of water.
Garden
Use watering in the evening or early morning: this prevents water from evaporating.
Irrigate at the foot of the plant and not the leaves.
Choose long but infrequent watering sessions rather than many short ones. Indeed, when you water in a short way, you only water the top layer of the garden, which will be absorbed by plants with small roots, while trees and shrubs have much deeper roots. In addition, surface watering will evaporate more easily than deep watering. Finally, deep watering allows plants to be more resistant to drought.
As useful for the garden as for the house: the recovery of rainwater thanks to adapted containers. This rainwater can be used in the toilet water of the house but also to water the plants of the garden.
Food
Prefer tap water. To make a plastic bottle that holds 1 L of water, it takes 100 mL of oil, 80 g of coal, 42 L of gas and 2 L of water! Drinking tap water not only reduces plastic pollution, it also saves water.
Every food has a "water footprint" calculated by the Water Footprint Network. This footprint calculates the amount of direct and indirect water needed to manufacture different products. Among the most water-intensive foods are: chocolate (17,000 L of water/kg), coffee (16,000 L of water/kg), beef (15,000 L of water/kg), dried fruits (cashews, pistachios, almonds, hazelnuts; between 5,000 and 14,000 L of water/kg) and pork (5,000 L of water/kg). On the contrary, the foods that consume the least water are fruits and vegetables (237 L of water/kg for lettuce, 287 L of water/kg for potato).
Laundry
The fashion industry uses 4% of the world's available drinking water to create new clothes (the production of a pair of jeans represents 11,000 L of water and that of a t-shirt 2,500 L of water). To save water, it is therefore advisable to favor eco-responsible brands (for this, trust the textile labels: (take a look here) or better yet buy second hand.
Another way to save water is to reduce the number of times we wash our clothes. Indeed, if some clothes need to be washed after 1 use (underwear, sportswear), others can largely be worn several times before ending up in the washing machine (a sweater can be worn 5-6 times before being dirty, a pair of jeans until there are stains or it smells bad, etc.). Beyond saving water (and energy), it also allows you to keep your clothes longer.
Little extra
Wash your car in specialized car washes: car washes are equipped with water evacuation systems that save up to 200L of water.
We challenge you to pick 5 water-saving actions from the list !
•What about agriculture ?
In the face of intensive agriculture, sustainable agriculture is now developing. Sustainable agriculture is based on 3 pillars of sustainable development: ecological, social and economic. Many farmers have implemented actions to reduce their water consumption:
Irrigation is done at night to reduce water stress and avoid more evapotranspiration than during the day.
Increased monitoring of water systems to avoid leakage.
The implementation of irrigation systems that water only the roots of the plants.
Recovery of rainwater.
Installation of windbreaks to limit water evaporation during irrigation and to distribute water evenly over the plot.
The Groupement d'intérêt économique et environnemental (GIEE), which brings together a group of farmers, more than 12,000 farms, is a label designating groups composed mainly of farmers who, through the agroecological transition, are committed to improving the economic, environmental and social performance of their production.
Agroecological practices are characterized by a lower impact on the environment and
focus on :
soils adequately fertilized (as much as possible with organic fertilizers) and protected against wind and water erosion. The fertility of the soil is characterized by its nutrient index after soil analysis, the application of fertilizers is intended to increase the biological fertility of the soil.
the use of water in a reasoned way and recycled in the same way as other forms of energy (biogas, solar, wind, ...)
the respect of the biodiversity with a rotation of the cultures is practiced, as well as the agroforestry, the agroforestry designates the association of trees with cultures and/or animals
92% of farmers have implemented at least one agro-ecological approach, including input reduction (73%) or soil conservation (71%) and finally water conservation comes in third place (62%).
(see Fig 7 ).
•And to go further ...
Agriculture is a very connected practice, and in recent years there has been increasing talk of AgTech and thus the development of automated and connected tools adapted to the needs of farmers. These new technologies that are emerging to make agriculture more sustainable are: sensors, applications, drones and agricultural robotics.
Farm3 has developed 12-square-meter crop chambers, called FarmCubes. These are technological tools adapted to the needs of farmers. In a 12m2 FarmCube, up to 5,000 plants can be grown without pesticides, with reduced use of nutrients (up to 70% less than traditional agriculture) and saving up to 99% of water compared to traditional agriculture using its closed circuit aeroponic system.
The FarmCube can be used as a complement to traditional agriculture in order to ensure a constant production independent of climatic hazards which are increasingly frequent as we have seen or as a tool to grow ultraplants more resistant to climatic hazards that can then be planted in the ground (discover our FarmCube)
Conclusion :
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