Humans have always followed the course of water. From the banks of the Nile to the shores of the Ganges, from the Tigris to the Rhine, civilizations have flourished wherever there were rivers to drink from, irrigate with, or navigate on. Water enabled life, defined trade routes, the borders of power, and the rhythms of history, thus establishing a foundational link that remains relevant in the 21st century.

However, while international attention focuses on strategic resources such as lithium, gas, or rare earth elements, water often remains an underestimated commodity in geopolitical debates. Nevertheless, it is the only truly irreplaceable resource; there is no energy, technology, or substitute that can replace water for human survival, food production, or ecosystem sustenance.

In a world affected by climate change, population growth, and accelerated urbanization, water sources have become vectors of power, vulnerability, and conflict. More than three billion people depend on transboundary river basins. And in many of them, there are no multilateral legal mechanisms to ensure equitable use. This is where the concept of water security comes into play, understood not only as access to water but as the ability to sustain livelihoods, protect ecosystems, and prevent emergencies, such as droughts, floods, or pollution, in complex socioeconomic scenarios.¹

Water threats are thus multidimensional, not only due to scarcity or excess, but also due to lack of governance, poor quality, and inequalities. Therefore, water security becomes a strategic parameter, where control of the resource, infrastructure, and information are as determining as the physical availability of water.²

Can this resource be the catalyst for the next wave of global instability? Or will it, conversely, become a driver of cooperation and diplomacy?

Although 70% of the Earth's surface is covered by water, only 2.5% is fresh water, and less than 1% is directly available for human consumption.³ Now, what makes water a critical resource is not just its physical scarcity, but also its uneven distribution. In equatorial countries like Papua New Guinea, rainfall exceeds 3,000 mm per year, while in regions like Egypt or Saudi Arabia, it barely reaches 100 mm.⁴ This is why more than 1.9 billion people today live under water stress or absolute scarcity.⁵

This inequality has also been exacerbated by climate change. In the Sahel, temperatures are rising 50 % faster than the global average. Longer droughts, coupled with increasingly frequent floods, are degrading the soil, displacing communities, and triggering food crises.⁶ Similarly, in the Lake Chad basin, the 90% decline in its surface area has left millions of people in a situation of extreme insecurity due to the destruction of ecosystems and, with it, of ways of life and social ties.⁷

But water inequality is not just climatic or natural, it is also political. As Zeitoun and Warner explain, states with greater control over river headwaters or with more technical capacity impose forms of hydro-hegemony that they use as tools of power.⁸

In this context, access to water no longer depends solely on rainfall or aquifers; human decisions, infrastructure, and power relations also shape water geopolitics.

In many regions of the world, water has shifted from a shared resource to a source of friction. Transboundary river basins today encapsulate a significant portion of the structural tensions between development, sovereignty, and water security. Examples such as the Nile, the Tigris-Euphrates, the Mekong, or the Syrian case thus foreshadow scenarios of systemic and geographical imbalances that are reconfiguring water access as an expression of power.

More than 90% of Egypt’s water supply comes from the Nile, whose main tributary, the Blue Nile, originates in Ethiopia and accounts for more than 80% of the total flow.⁹ Historically, Egypt has maintained a privileged position regarding water sharing thanks to the 1929 and 1959 treaties, signed without Ethiopian participation, which granted it veto rights and a fixed share of the flow.¹⁰ However, the construction of the Grand Ethiopian Renaissance Dam (GERD), which began in 2011, upset that balance. While Ethiopia views it as essential for its energy development, Egypt, on the contrary, fears that the filling will reduce flow during drought years, consequently calling it an existential threat.¹¹ In this regard, various negotiations promoted by the African Union failed in 2021, partly due to Ethiopia's refusal to accept a legally binding agreement on the filling and management of the reservoir.¹²

A similar logic is repeated for the Tigris and Euphrates rivers. Both originate in Turkey and are vital for Syria and Iraq. Since the 1980s, Ankara has been promoting the ambitious Southeastern Anatolia Project (GAP), which includes the construction of 30 large dams.¹³ The most significant ones—Atatürk on the Euphrates and Ilisu on the Tigris—have reduced the flow of water reaching Syria and Iraq by more than 50%. Turkey justifies its position as an extension of its national sovereignty. In the words of former Turkish President Suleyman Demirel: “Water belongs to the Turks just as oil belongs to the Arabs.”.¹⁴ Iran, for its part, has diverted tributaries of the Tigris, such as the Alwand or the Zab, without agreements with Iraq.¹⁵ Among the numerous consequences are the retreat of marshes, agricultural crises, and local conflicts over water, in addition to the Iraqi Ministry of Water Resources' forecast of a deficit of 10.8 billion m³ by 2035.¹⁶

In Asia, the Mekong represents one of the most complex and asymmetrical scenarios. The river flows through six countries – China, Myanmar, Laos, Thailand, Cambodia, and Vietnam – and supports more than 60 million people through fishing, agriculture, and hydroelectric power generation.¹⁷ In the last two decades, China has built 11 large dams on the upper Mekong River (known as the Lancang in China) without consulting downstream countries. Beijing claims its infrastructure helps regulate water flow during droughts, but independent studies and complaints from riparian governments suggest it has worsened seasonal shortages, altering ecological cycles and displacing sediment essential for agricultural fertility.¹⁸

Simultaneously, Laos has adopted a central role in the transformation of the river. With the support of Chinese and Thai companies, the country promotes an aggressive hydroelectric development policy to become the “battery of Southeast Asia.”.¹⁹ Projects like Xayaburi, Don Sahong, and Pak Beng have led to the displacement of thousands of people, the loss of rural livelihoods, and a drastic decline in river fishing.²⁰ In Cambodia, the ecological collapse of Tonlé Sap Lake has led to migrations and growing food insecurity.²¹ Faced with this, the Mekong River Commission lacks binding authority, and China only participates as an observer. This situation has been further worsened by Beijing's creation of the Lancang-Mekong Cooperation, which has consolidated a parallel governance model. The United States has attempted to counter this hegemony by supporting countries like Vietnam, but its influence remains limited against China's political and economic weight.²²

Another example of the strategic importance of water is observed in the case of Syria. Between 2006 and 2010, a historic drought (the worst in 900 years according to NASA) devastated agricultural production in the northeast of the country, wiping out wheat crops, reducing livestock, and pushing more than a million and a half people into extreme poverty.²³ Around 40,000 families moved to already collapsed cities, fueling social tensions that would later lead to the 2011 revolts. Thus, this collapse had its structural origin in decades of intensive and poorly planned water policy, gradually aggravated by climate change. The promotion of water-intensive crops, diesel subsidies, and the proliferation of illegal wells accelerated the depletion of aquifers.²⁴ Regionally, Syria also suffered from the reduced flow of the Euphrates due to Turkish dams, which did not have effective water-sharing agreements. In this regard, subsequent studies have confirmed that the drought, aggravated by climate change, was one of the factors that catalyzed the outbreak of an armed conflict that still endures.²⁵

Water is an essential asset for human life, but it also constitutes a profoundly geopolitical and strategic resource involved in the power configurations of the 21st century. Thus, in contexts where river basins are shared, but no binding cooperation frameworks exist, control over flow, dams, or sediment becomes a silent tool of pressure.

Phenomena like hydro-hegemony allow states with greater technical capacity or a privileged geographical position to impose their interests, often at the expense of the water security of others. Water flows between territories, but it also carries political decisions, historical asymmetries, and climate vulnerabilities.

In this scenario, climate change acts as a threat multiplier. Rainfall is more erratic, droughts are more severe, and extreme events are more frequent. In many regions, uncertainty has set in: it's no longer a question of if another crisis will occur, but when.

Faced with this, it is urgent to move towards shared management mechanisms that recognize both the interdependence between countries and the ecological limits of each basin. If water is increasingly a field of dispute, it can also be a meeting point.