Polski
The agricultural sector is the world’s largest user of water, consuming about 60% of the total amount abstracted, and in some areas as much as 80%. Water is an essential element for the efficiency of agricultural crops, but, with climate change, the availability of water is becoming increasingly unstable and uncertain. Water scarcity in agriculture is already affecting food production, and its impact on the environment and economy in the future could be downright catastrophic. This is the first time scientists have calculated an integrated agricultural indicator of water scarcity on a global scale.
How is climate change affecting agricultural water scarcity?
Water scarcity in agriculture is a situation in which the amount of available resources is insufficient to meet the needs of crops. Water scarcity can result from a number of causes, such as groundwater and surface water pollution, intensive cultivation, soil erosion, socioeconomic development, and increasing demand for water as the population grows.
However, one of the main causes of water scarcity is climate change, including droughts and extreme weather events. Reduced precipitation and increasing temperatures are reducing the availability of water in the soil, making it harder for plants to grow. Many regions around the world are already experiencing water shortages, leading to reduced agricultural production and rising food prices. Its insufficient quantity can also affect the quality and quantity of food, which can have dire consequences for our health.
Projections show that agricultural water shortages will worsen with climate change. Already today, some 815 million people on Earth are suffering from hunger. According to a 2021 UN report, by 2050 the world will need 50% more food than it does now, which means agricultural production must also increase. However, water scarcity may have a limiting effect, especially in low-income countries.
Agricultural water scarcity forecasts – new study
Until now, the traditional assessment of water scarcity has focused exclusively on so-called “water scarcity. Blue water, that is, water from rivers, lakes and groundwater, or green water – rainwater. However, they may not reflect actual crop water stress conditions. In a new study, published in the journal AGU Earth’s Future, scientists have developed a new index to measure and predict water scarcity from these two major sources combined. This is the first such study that uses a comprehensive indicator and predicts a global shortage of blue and green water as a result of climate change.
To study the impact of climate change, the integrated agricultural water scarcity index (WSI ag) was developed, which includes blue and green water components and calculates WSI ag for both historical, present and future periods. The analysis shows that about 40% of the world’s farmland has experienced water shortages in the past, and the situation is getting worse every year. WSI ag predicts that water shortages will be higher in the future, and could reach as much as 83 – 84% of the world’s arable land by 2050. The increase in ag WSI is mainly due to lower water availability and higher crop water demand.
“Agricultural production, as the largest user of both blue and green water resources, faces unprecedented challenges” – Xingcai Liu, associate professor at the Institute of Geographical Sciences and Natural Resources Research of the Chinese Academy of Sciences and lead author of the study. “This indicator provides a consistent assessment of water scarcity in agriculture, both in rain-fed and irrigated fields“.
Green water, which is in part rainwater, has sometimes been overlooked in studies because it is invisible in the soil and cannot be used for other purposes. Its amount depends on the amount of rainfall, the type of soil and vegetation, the amount of water lost through runoff or evaporation.
The study highlights the important role of green water in agricultural resource management and provides useful information on how agriculture can adapt to future climate change. The new index, which takes into account blue and green water requirements, has great potential to help assess risk and look for causes of water shortages in agriculture and develop strategies to reduce the impact of future droughts.
