Water will become even more scarce on more than 80% of cultivated land by 2050

Since the beginning of this year 2022, the accumulations of precipitation are in deficit over a major part of the country. According to forecasts of Weather report France, the situation is not going to improve. The drought will expand in the coming weeks. And some Chinese Academy of Sciences researchers announce it today. With climate change, we should expect that some 84% of land cultivated in the world are increasingly short of water by 2050. Worse, 60% of them are expected to experience shortages.

Let us recall that, for a hundred years, the world demand for water has increased twice as fast as the human population. And it is for agricultural production that we consume the most water. Water literally falling from the sky as precipitation. What scientists call green water. But also that which is drawn from rivers, lakes and groundwater which is called theblue water.

However, researchers from the Chinese Academy of Sciences have examined the water needs for theAgriculture, current and future needs. They then succeeded in predicting whether, in the context of global warming, available water levels will be sufficient to meet these needs. And their answer is generally: no!

Solutions for bringing water to agricultural land

Until now, most studies have focused only on water resources blue. This also takes into account issues related to green water. Green water is more precisely the portion of rainwater available to plants in the soil. This availability is of course dependent on rainfall. It also depends on the amount of water lost due to runoff and evaporation, agricultural practices, vegetation, soil type and slope of the land. Thus with the increase in temperatures and the expected changes in precipitation patterns, all in addition to the intensification of agricultural practices, the availability of green water will change. The researchers estimate that these changes in green water availability are expected to impact around 16% of cropland worldwide.

What the researchers especially hope is that their work will help countries better assess the threat hanging over them and develop strategies that would allow them to limit the impact of future droughts. Because such strategies exist.

Researchers point to mulching which can reduce soil evaporation. Or no-till agriculture that encourages water to infiltrate the soil. Or even adjusting the timing of sowing to better align crop growth with theevolution of precipitation. They are also considering contour farming, which consists of plowing the soil on sloping land in rows of the same elevation, to prevent runoff, but also soil erosion. All without forgetting the gain provided by the improvement of infrastructure or the efficiency of irrigation systems.

Water in agriculture, on the way to a global catastrophe?

Water is essential for life and agriculture. A study reveals the origin of the water used in the world to irrigate the fields. Result: 20% of the resources used would come from exhaustible sources. This number has tripled in forty years. Global warming would also have a say. In the event of a crisis, the entire planet will be affected…

Article by Quentin Mauguit published on 07/02/2012

A drought raged in France during 2011. Many growers found themselves helpless in the face of the phenomenon. This event reminds us how much theAgriculture is dependent on water, and therefore, in many cases, on irrigation systems. On a planetary scale, 17% of fields are equipped withwatering. They alone provide 40% of world agricultural production.

L’water used in agriculture can have several origins. Green water comes from precipitation. They are temporarily stored in the ground. Blue water is pumped from rivers, lakes or groundwater, but in a sustainable way. The third source corresponds to water extracted from reservations which renew themselves little or not at all.

Researchers from the University of Utrecht (Netherlands), led by Marc Bierkens, decided to study the origin of irrigation water used around the world. Their results, published in Water Resources Research, are worrying. The use of water resources without real sustainable management tripled between 1960 and 2000, rising from 75 to 234 km³ per year. But what will happen when the reserves run out?

Unsustainable crop irrigation management

The scientists used geographic, hydrographic and satellite to model and map water consumption in global agriculture. Their program is not limited to a country’s borders. It makes it possible to study each region of the Globe. The important results are listed below.

In 2000, nearly 20% of irrigation water came from sources that are unsustainable. India alone has extracted 68 km³ of this resource in 1 year. It is followed by Pakistan (35 km³/year), the United States (30km³/year), Iran (30 km³/year), China (20 km³/year), Mexico (10 km³/year) and finally, Saudi Arabia (10 km³/year). These waters are mainly used in semi-arid regions.

Some countries mainly use fossil waters. Unsurprisingly, these countries are: Qatar, United Arab Emirates, Saudi Arabia and Libya. They are often cited as an example to illustrate the phenomenon of the greening of deserts.

Global economic consequences

More surprisingly, some countries using mainly blue water (lakes and rivers) and green water (rain) could find themselves in water deficit because of the global warming (decrease in rainfall). Algeria, Morocco, Spain and Italy are particularly concerned.

In case of water shortages, the economic consequences would be felt on a global scale. Doesn’t France import huge quantities of fruit and vegetables from Spain and Morocco, two countries mentioned above? What would happen to food prices if they were to become scarce?

A decrease in global agricultural production could also have serious health consequences as the population continues to increase…

This study has the merit of recalling the urgency of the situation in which we find ourselves faced with the problem of the irrigation of our agricultural land.