Drought has become one of the most serious environmental problems of our time, both globally and in particularly vulnerable countries like Spain. We're not just talking about less rain for a few months: the combination of climate change, poor water management, population pressure, and intensive land use is pushing rivers, reservoirs, aquifers, and entire ecosystems to their limits. All of this translates into very real impacts on the economy, health, and daily lives of millions of people.
Understanding the causes of drought, its different types, its consequences, and possible solutions is key to knowing what we can do.From government agencies to ordinary citizens, this article will explore, calmly but clearly, why droughts occur, how they affect ecosystems and society, which areas are most affected worldwide and in Spain, and what tools we have to reduce their effects and adapt to an increasingly complex water reality.
What is drought and why is it more than just “lack of rain”?
Drought is a prolonged climatic anomaly in which water availability falls below normal levels in a particular region.It is not just that one year it rains less, but that for a longer or shorter period the balance between what enters the system (precipitation, snow, aquifer recharge) and what leaves (evapotranspiration, human consumption, agricultural, industrial, ecological flows, etc.) is broken.
Spain is a good example of a territory where drought is part of the historical climateEspecially in the Mediterranean region and the southern half of the Iberian Peninsula, characterized by dry and semi-arid environments. However, what were once relatively predictable cycles of wet and dry years are becoming more extreme and irregular, with several very dry years followed by episodes of torrential rain that do not always help to replenish water resources.
Recent figures reflect this worrying trendThe 2021-2022 hydrological year was among the driest on record, with rainfall well below average, and 2022-2023 followed the same trend, accumulating deficits exceeding 10%. Meanwhile, temperatures are breaking record after record, and the CO₂ concentration in the atmosphere has increased, which accelerates the evaporation of available water.
This anomaly is very clearly visible in reservoirs and aquifers.These reservoirs, which serve as the water "storehouse" for many regions, have fallen below 50% of their capacity by mid-summer, significantly below the average of the last decade. In areas of southern and eastern Spain, water restrictions are no longer exceptional, but rather an increasingly common scenario. In many cases, the problems affecting reservoirs and aquifers They are directly linked to decisions regarding land management and use.
Types of drought and how they affect ecosystems and society
There is not just one type of drought, but several categories that are linked together.Understanding them helps to see how a "simple" rainfall deficit ends up becoming a major agricultural, economic, social and environmental problem.
Meteorological drought
La meteorological drought It is the earliest phase and refers to a prolonged period with below-normal rainfall. in relation to the historical values of an area. It is measured by comparing the rainfall with the average of many years and, when the deficit persists, it is considered that we are facing a situation of meteorological drought.
In the Mediterranean context, these periods of low rainfall are relatively common.But when they last for several years or are combined with very intense heat waves, they become the trigger for much more serious problems: less aquifer recharge, drier soils, water stress for vegetation and, ultimately, less water available for everything.
Agricultural or agrarian drought
Agricultural drought occurs when soil moisture is insufficient for crops to develop normally.This may be due to a lack of rain, very high temperatures that increase evaporation, or agricultural planning that is not well adapted to the conditions of the land and climate.
Its effects are quickly noticeable in food production: decreased crop yield, crop lossesA reduction in pastureland for livestock leads to lower incomes for farmers and higher prices for certain products in the markets. In rural regions heavily dependent on agriculture, a prolonged agricultural drought can result in poverty, debt, and even farm abandonment.
Hydrological drought
Hydrological drought occurs when a lack of precipitation results in abnormally low flows in rivers, lakes, reservoirs, and aquifers.This is the most visible aspect for most of the population: reservoirs at record lows, rivers reduced to trickles of water, and wells that are beginning to dry up.
At this stage, the guarantee of supply becomes seriously complicated. for urban, agricultural, industrial, and environmental uses. The authorities are forced to activate special drought plansto restrict consumption, prioritize certain uses over others and, in extreme cases, to establish temporary cuts in drinking water or irrigation.
socioeconomic drought
Socioeconomic drought occurs when a lack of water begins to profoundly disrupt economic activity and social life.Not only are there a lack of water resources, but key sectors such as agriculture, livestock, energy, tourism and industry are suffering, generating unemployment, territorial tensions and, in some cases, population displacements.
Internationally, episodes of food insecurity, inflation, poverty, and conflict associated with severe droughts have already been documented.Organizations such as the WHO and NOAA emphasize that in many developing countries, drought exacerbates the vulnerability of the population, increasing the risk of disease, malnutrition, and mortality, and forcing internal or cross-border migrations. In this context, the food insecurity It is one of the most serious and sustained effects.
Main causes of drought: between climate and human activity
Drought has an undeniable natural component, but today it cannot be explained without taking into account the human impact on the climate and the territory.Below we break down the most relevant factors that cause or intensify it.
Scarcity and irregularity of rainfall
The most obvious cause is the absence or scarcity of rain during the periods of the year when it should be more abundant.In the typical Mediterranean climate, a significant portion of the rainfall is concentrated in autumn and spring; when these seasons are "dry," the annual water balance is severely affected.
Furthermore, rainfall tends to become increasingly irregular and concentrated in intense episodes.with downpours that, in just a few hours, release large quantities of water. Paradoxically, these episodes do not always alleviate the drought: because the rainfall is so intense, much of the water runs off quickly, causing floods and washing away fertile soil, but replenishing aquifers and reservoirs less effectively than a gentler, more prolonged rain would.
The role of climate change and global warming
Climate change is one of the key drivers of the increased frequency and intensity of droughts.The general increase in temperatures favors faster evaporation of water in soils, reservoirs, rivers and vegetation, while atmospheric circulation patterns are being altered, modifying the trajectories of storms and the distribution of rainfall.
In Spain, records show a clear increase in warm days and nights and heat wavesas well as a trend towards more variable rainfall. This picture coincides with the forecasts of the scientific community: more dry periods, more heat, greater evaporation, and therefore a higher probability of prolonged droughts, especially in the Mediterranean basin and in already vulnerable semi-arid areas.
Overexploitation of aquifers and surface waters
Excessive extraction of groundwater for irrigation, industry, and urban supply depletes aquifers that take years, or even decades, to recharge.When pumping exceeds the natural renewal capacity, a sustained drop in the water table occurs, springs and wetlands dry up, and future water availability is compromised.
This overuse is not limited to the subsoilIn many river systems, the sum of diversions for irrigation, water transfers, and other uses reduces flows so much that rivers can barely maintain their ecological function. During droughts, this extra pressure makes the impacts much more severe and long-lasting.
Intensive agriculture and poor irrigation planning
The expansion of intensive agriculture, especially in dry climates, has driven up the demand for waterHigh water consumption crops in semi-arid areas, large irrigated areas and inefficient or poorly managed irrigation systems mean that a very significant portion of available resources is allocated to agricultural use.
When these practices are not adapted to the local hydrological reality, dependence on irrigation becomes a risk factor.During periods of drought, farmers face restrictions that directly affect their livelihood, while intensive water use accelerates the decline of reserves in reservoirs and aquifers.
Deforestation, erosion, and loss of soil retention capacity
The removal of forests and natural vegetation, along with the overexploitation of agricultural soils, impairs the land's capacity to absorb and store water.Degraded soils erode easily, lose organic matter and become less porous, so water runs off more quickly into waterways, instead of infiltrating and recharging aquifers.
Over time, these dynamics lead to desertification processes in which the landscape loses fertility and productivity.The use of nitrogen fertilizers and other chemicals also contributes to groundwater pollution, increasing the fragility of the water system as a whole. In this regard, the removal of forests and natural vegetation It is a determining factor in the loss of soil retention capacity.
Physical factors: Mediterranean location and orography
In the case of Spain, the geographical position and the complex orography add their own elements to the problem of droughtAlthough it is located in temperate latitudes, the Mediterranean character of the climate means that much of the country is warmer and drier than one would expect given its location.
The main storms arriving from the Atlantic easily unleash their fury on Galicia and the western coast of the Iberian Peninsula.However, they encounter mountain barriers such as the Pyrenees, the Cantabrian Mountains, and the Betic System. These mountain ranges give rise to phenomena such as the Foehn effect: humid air is forced to rise, cools, and precipitates on the windward slope, so that the air descending on the other side arrives much drier and warmer.
The result is a very marked contrast between a humid north and northwest and a much drier center, south and eastThis uneven distribution of rainfall explains why some basins, such as the Mediterranean ones, experience severe water crises while other areas maintain values closer to the average.
Environmental impacts of drought
Prolonged droughts have a profound impact on the functioning of ecosystems and biodiversity.Vegetation is one of the first elements to show signs of stress: reduced growth, yellowing leaves, premature leaf drop, and, in extreme situations, mass mortality of trees and shrubs.
When forests and scrublands weaken, they lose their ability to perform photosynthesis and absorb carbon dioxide.This reduces their role as carbon sinks. This lower CO₂ sequestration adds to the effects of climate change itself, creating a vicious cycle: less healthy vegetation, less carbon captured, and even greater warming.
In ecosystems well adapted to dry periods, biodiversity acts as a bufferSome species are more resilient than others, with seed banks capable of surviving for years in the soil and life cycles synchronized with water availability. However, in areas heavily altered by human activity (deforestation, land-use changes, unplanned urbanization), this resilience diminishes, and drought can trigger almost irreversible degradation processes.
Continental water resources are also suffering on multiple frontsThe reduction of flows in rivers and wetlands deteriorates water quality. increases the concentration of pollutantsThis promotes the proliferation of algae and microorganisms and endangers fish, amphibians, and waterfowl that depend on these habitats. Ultimately, many ecosystem services are compromised: food production, natural water filtration, pest control, pollination, and the maintenance of fertile soils.
Social and economic consequences of droughts
Beyond its impact on nature, drought has a strong social, economic, and health component.Sectors such as agriculture, livestock, energy and tourism depend directly on water and are the first to suffer the restrictions.
In the countryside, decreased yields and crop losses translate into lower incomes and, sometimes, the disappearance of small farms.This drags down associated industries (food processing, transport, commerce) and can cause price increases for certain products, also affecting the urban population.
The energy sector is not left out eitherThe reduction in reservoir levels limits hydroelectric production and affects the operation of thermal power plants that require large volumes of water for cooling. In a context of energy transition and overall increased consumption, this added pressure complicates the management of the electricity system and can lead to higher electricity bills.
Tourism, especially in coastal and inland areas with a high concentration of visitors, is another of the major victims.In scenarios of severe drought, the use of swimming pools, beach showers, golf course irrigation, and other facilities is restricted, which reduces the perceived quality of the destination and creates tensions between economic activity and the basic needs of the resident population.
From a health perspective, the scarcity of drinking water and limitations in hygiene increase the risk of disease.From gastrointestinal infections to dermatological problems, the WHO has documented that between 1970 and 2019 droughts caused more than 650.000 deaths worldwide, mostly concentrated in developing countries where access to safe water and robust health systems is limited.
In extreme situations, drought can become a factor of social and political instability.Competition for access to water exacerbates existing conflicts, fuels migration, and perpetuates poverty and exclusion. The combination of reduced food availability, rising prices, increased unemployment, and loss of livelihoods creates fertile ground for tensions and humanitarian crises.
Areas of the world and of Spain most affected by drought
In recent years, some drought episodes have made headlines due to their severity and durationRegions of Chile and Argentina, countries in the Horn of Africa such as Somalia, and territories of Madagascar have experienced critical situations with dramatic impacts on food security and the health of the population.
In the western Mediterranean region, various areas of Spain, France, Italy, Morocco, and Algeria have been identified as particularly hard hit.In these territories, high temperatures, irregular rainfall, and heavy pressure on water resources mean that each dry cycle leaves a greater mark than the previous one.
In Spain, the drought has hit the south and the eastern coast of the peninsula particularly hard.While the north and northwest have, in some years, recorded rainfall levels close to or even above the average. This duality is evident when comparing, for example, the Atlantic basins (wetter) with the Mediterranean basins (more vulnerable), where the expression "it doesn't rain here" has become more than just a daily complaint.
River basins are the most realistic unit for understanding this disparity.Systems like the Ebro, Júcar, and Segura rivers exhibit recurring tensions between agricultural, urban, and environmental users, while efforts are made to maintain minimum ecological flows to guarantee the survival of river ecosystems. Hydrological planning and inter-territorial coordination are crucial here. Understanding the dynamics of watersheds It is key to managing conflicts and prioritizing uses.
Solutions and strategies to deal with drought
Drought is not a phenomenon that can be eliminated, but its impacts can be reduced and our capacity to adapt can be increased.The measures range from large infrastructure projects to changes in management and daily habits.
Storage and regulation: reservoirs and other infrastructure
One of the classic strategies for dealing with rainfall variability has been the construction of reservoirs and dams.These systems allow water to be stored during wet years or seasons for use during dry periods. In a country with such an irregular climate as Spain, this infrastructure network has been key to guaranteeing water supply for human consumption, irrigation, and hydroelectric power generation.
However, reservoirs are not exempt from impacts and limitationsIts construction involves flooding entire valleys, displacing populations, and altering river ecosystems, as well as disrupting the natural transport of sediment. Over time, the reservoir itself siltes up, reducing its usable capacity and necessitating costly maintenance operations.
Aquifer exploitation and its risks
Groundwater has traditionally been another “reserve” against droughtsaccessible through wells and boreholes. Aquifers function as natural underground reservoirs, where water is stored in a way that is more protected from evaporation.
However, overexploitation has proven to be a dangerous trap.Extracting more water than is replenished causes sharp drops in the water table, land subsidence, and saltwater intrusion into coastal aquifers. Furthermore, diffuse pollution from fertilizers and manure has deteriorated the quality of many groundwater bodies, further complicating their safe use.
Desalination and new water sources
Technological development has strongly promoted desalination as a tool to combat the scarcity of fresh waterDesalination plants separate salt from seawater to obtain water suitable for human consumption, urban uses and even irrigation in certain cases.
In islands and coastal regions with few of their own water resources, desalination has become a basic part of the supplyA clear example is Formentera, where virtually all the mains water comes from a desalination plant. In peninsular areas affected by prolonged droughts, these infrastructures are also being used to reinforce water security, although their energy costs and the management of the generated brine pose environmental and economic challenges.
Water reuse and efficiency
Another key approach is to make better use of every drop, reducing losses and promoting reuse.Modernizing distribution networks to prevent leaks, implementing precision irrigation systems, reusing treated wastewater for urban, industrial or agricultural uses, and implementing water-saving technologies in homes and businesses are key elements.
In the agricultural sector, which accounts for around 80% of water consumption in Spain, improving efficiency is especially relevant.Systems such as drip irrigation, the use of soil moisture sensors, irrigation scheduling based on climate data, and the selection of crops better adapted to the local climate can significantly reduce water demand without compromising productivity.
Technological innovation and alternative solutions
In addition to conventional infrastructure, innovative technological solutions are emerging to diversify access to waterAmong them are atmospheric generators, which capture moisture from the air and transform it into drinking water, useful in contexts where traditional networks do not reach or are insufficient.
Sensor and remote control systems are also being developed to intelligently manage water supply and irrigation networks.Detecting leaks, optimizing pressures, and adjusting supply to demand in real time. Projects focused on energy efficiency, carbon footprint monitoring, and reforestation contribute to reducing the impact of climate change and, consequently, mitigating some of the structural causes of drought.
Public policies and integrated resource management
Drought management cannot be left solely to technology; it requires robust regulatory frameworks and long-term planning.Water policies should promote responsible use, prevent overexploitation of aquifers, encourage reuse, protect aquatic ecosystems, and ensure equitable access to the resource.
The participation of users, irrigation communities, administrations and citizens is essential for the measures to be effective and socially accepted.Savings and awareness programs, incentives for efficiency, penalties for abusive uses and transparency in information on the state of resources are essential elements in modern and sustainable water management.
What can we do individually in the face of drought?
Although most water consumption is concentrated in agriculture and industry, everyday decisions also contribute.Reducing our household consumption, opting for efficient technologies, and supporting responsible policies helps to lessen the global pressure on resources.
Simple actions like turning off the tap while brushing our teeth, showering instead of bathing, or quickly repairing leaks and drips They may seem insignificant on an individual scale, but on a collective level they represent thousands of cubic meters of water saved per year.
Equip homes with dual-flush toilets, tap aerators, low-consumption appliances, and greywater harvesting systems (For example, for garden irrigation) is another direct way to contribute. In businesses and public buildings, the implementation of sensors, automatic shut-off devices, and consumption management systems is equally important.
Beyond direct savings, informing and raising awareness among our community about the importance of water and the reality of drought is a powerful toolSupporting reforestation projects, watershed conservation, sustainable agriculture, and renewable energy helps reduce the impact of climate change and, therefore, one of the major drivers of the current water crisis.
Drought is not just a matter of "whether it rains or not," but a symptom of a water and climate system under enormous pressure.Understanding its causes, types and impacts, and assuming that every decision, from hydrological planning to the use of the tap at home, is part of the solution, is the first step so that future generations do not remember these years only as the time when we started running out of water.
