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), water-related disasters they represent 50% of the total and have caused 1.3 million deaths between 1970 and 2019.
In recent years, the frequency and intensity of these phenomena has been especially high due to climate change. The water cycle is no longer the one we were taught at school: which areas are most affected? And how do these disasters influence access to water, hunger and health?
It affects us all, but not equally.
Droughts and floods are increasing all over the world, but their consequences are very different depending on where they occur. A recently published article in Nature shows that more than half of the population of the Netherlands and Bangladesh is at risk from flooding.
When the focus is closed, it is observed that more than 80% of the population in areas of the Republic of the Congo, Vietnam and Thailand lives exposed to floods. If these data are crossed with those related to poverty, the most affected countries are unequivocally African. In South Sudan, up to 28% of the population exposed to floods lives in conditions of extreme poverty.
The lack of resources in less developed countries multiplies the fatality of floods. A report by the NGO CARE reveals that up to 1.5 million people forced to flee their homes due to flooding in East Africa. Overall, the number of people affected in this region has quadrupled between 2016 and 2019.
The driest regions of the world
The trend in the case of droughts is similar. According to the United Nations, up to 700 million people are at risk of being displaced due to droughts by 2030. This situation is exacerbated by global warming, which causes already dry regions to become even drier. Once again, Africa is the continent most affected in this sense, with a temperature increase higher than the global average.
Droughts exacerbate water stress in less developed countries, where the demand for water is greater than its availability.
The study Progress on the level of water stress, published in 2021 by the Food and Agriculture Organization of the United Nations (FAO), shows great inequalities in these terms. Several countries in Asia and Africa were observed to withdraw 100% of their renewable water resources every year.
It must also be considered that there is some feedback between droughts and floods. Although it is a relationship that depends on several factors (type of underlying rock, climate, territorial management, etc.), droughts can cause rain to be absorbed much more slowly due to the drying out of the soil. Ultimately, this situation can favor the occurrence of flash floods.
Despite the fact that there is some distance in the prediction of floods, not so much when it comes to droughts. Having early warning systems is essential to deal with both threats. Otherwise, the interaction of these natural phenomena with society rises to a disaster 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 be concentrated in countries vulnerable to water-related climate changes, especially if they are highly dependent on agriculture.
According to FAO data, more than 34% of crop losses in less developed countries are attributable to drought. These losses are valued at $37 billion. Floods are the second most serious disaster for the sector. In this case, the economic impact is estimated at 21 billion dollars between 2008 and 2018.
The flooding of crops implies reduced light availability, oxygen depletion and chemical disturbances in the soil. All this decreases the quantity and quality of the crops. Low productivity leads to a shortage of products and an increase in their price, which favors malnutrition. In addition, we must add the material damage to infrastructure and homes, which hinder access to drinking water.
But the thing does not stop there. Floods like those that devastated Pakistan, Nigeria and Chad in 2022 latrines, sewers and open defecation sites were flooded. The resulting contaminated sludge ended up in drinking water supplies, causing disease outbreaks that severely affected the most marginalized communities.
Effects of droughts on the soil and rivers
The impacts of droughts are not far behind. First, they reduce the water content of soils, which slows down root growth, delays maturation and ultimately limits crop productivity. Added to this fact is the appearance of pests and diseases in crops, enhanced by the conditions that accompany droughts.
The lack of rain and increased evaporation also affect surface and groundwater reserves, limiting access to primary water sources. The reduced flow of rivers and streams can cause an increase in pollution due to stagnant water. This goes against the need to have safe water for cleaning and sanitation (personal or food) and thus be able to prevent diseases.
All of the above is very present in the Sustainable Development Goals 2, 6 and 13, which deal with hunger, water and weather. Future sustainability in these areas depends, among other things, on having multi-hazard alert systems to improve preparation for droughts and floods. The additional challenge is to carry out this task in conditions of scarcity of data, which is the situation of the countries most affected by these fatalities.
Daniel Jato EspinoSenior Researcher / Professor in Engineering and Environmental Management, International University of Valencia and Itzayana González-ÁvilaResearcher in Water Resources and Environmental Sanitation, Federal University of Rio Grande do Sul
This article was originally published on The Conversation. read the original.
