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Droughts and floods: water up to the neck

A man carries his daughter in his arms as they leave a flooded area after heavy rains in Kathmandu, Nepal, 12 July 2019 | Fountain: EFE | Photographer: NARENDRA SHRESTA

Floods and droughts are responsible for the largest losses caused by natural disasters in the last 50 years. According to the World Meteorological Organization (WMO), between 1970 and 2019, water-related natural disasters accounted for 50% of the total and claimed the lives of 1.3 million people.

In recent years, the frequency and intensity of these phenomena are especially high due to climate change. The water cycle is no longer what we were taught in school: which areas have been affected the most? And how do these disasters affect access to water, hunger and health?

It affects all of us, but not equally.

Droughts and floods are on the rise around the world, but their effects vary greatly depending on where they occur. A recently published article in Nature shows that more than half of the population of the Netherlands and Bangladesh are at risk of flooding.

When the outbreak is closed, it is observed that more than 80% of the population in areas of the Republic of the Congo, Vietnam and Thailand live in flood conditions. When these data are compared with data on poverty, the most affected countries are clearly African. In South Sudan, up to 28% of the flood-prone population lives in extreme poverty.

The lack of resources in less developed countries multiplies the lethality of floods. A report by the NGO CARE shows that up to 1.5 million people have been displaced from their homes due to flooding in East Africa. Overall, the number of casualties in the region quadrupled between 2016 and 2019.

The driest regions of the world

A similar trend is observed in the case of drought. By 2030, up to 700 million people could be displaced due to drought, according to the UN. This situation is exacerbated by global warming, which is making already arid regions even more arid. Once again, Africa is the most affected continent in this sense, with temperatures rising above the global average.

Droughts exacerbate water scarcity in less developed countries where demand for water exceeds availability.

World map with countries colored according to their water stress.  North Africa and South Asia are the most affected regions.
World map of water stress levels (%) in 2018 by country. FAO

Studying Progress in water stress levels, published in 2021 by the Food and Agriculture Organization of the United Nations (FAO), shows a large disparity in these indicators. Several countries in Asia and Africa have been observed to withdraw 100% of their renewable water resources each year.

It should also be taken into account that there is some feedback between droughts and floods. Although this ratio depends on several factors (type of bedrock, climate, territorial government, etc.), droughts can cause rain to be absorbed much more slowly due to the drying of the soil. Ultimately, this situation can contribute to the occurrence of flash floods.

While there is some distance in flood prediction, there is not much in terms of droughts. Early warning systems are essential to combat both threats. Otherwise, the interaction of these natural phenomena with society reaches a catastrophic level, causing strong impacts.

Water, hunger and health

According to the United Nations, between 720 and 811 million people suffered from hunger in the world in 2020. A year in which more than 30% of the world’s population did not have regular access to safe food. These figures tend to refer to countries that are vulnerable to water-related climate change, especially if they are heavily dependent on agriculture.

According to the FAO, more than 34% of crop losses in less developed countries are due to drought. These losses are estimated at $37 billion. Floods are the second most significant natural disaster for the sector. At the same time, the economic effect is estimated at 21 billion dollars in the period from 2008 to 2018.

Flooding crops means less light available, oxygen depletion, and chemical changes in the soil. All this reduces the quantity and quality of the crop. Low productivity leads to food shortages and higher prices, which favors malnutrition. Added to this is the material damage to infrastructure and homes that hinder access to drinking water.

But the matter does not stop there. Floods like those that hit Pakistan, Nigeria and Chad in 2022 flooded latrines, sewers and open defecation sites. The resulting contaminated sludge entered the drinking water supply, causing disease outbreaks that severely affected the most marginalized communities.

Effects of drought on soil and rivers

The effects of the drought are not far behind. First, they reduce the water content of the soil, which slows down root growth, delays maturation, and ultimately limits crop yields. Added to this fact is the emergence of pests and diseases of agricultural crops, exacerbated by the conditions that accompany droughts.

Lack of rainfall and increased evaporation also affect surface and groundwater supplies, limiting access to primary water sources. Reducing the flow of rivers and streams can cause an increase in their pollution due to stagnant water. This conflicts with the need to have safe water for washing and sanitation (personal or food) and thus be able to prevent disease.

All of the above are present in Sustainable Development Goals 2, 6 and 13, which deal with hunger, water and climate. Future resilience in these areas depends, among other things, on the availability of multi-hazard warning systems to improve drought and flood preparedness. An additional challenge is to carry out this task in the face of the lack of data that characterizes the countries most affected by these deaths.Talk

Daniel Jato Espino, Senior Fellow/Professor in Engineering and Environmental Management, International University of Valencia and Itzayana González-Avila, Water and Environmental Sanitation Researcher, Federal University of Rio Grande do Sul

This article was originally published on The Conversation. Read the original.

Source: RPP

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