6.2 Environmental risks

Transboundary pollution (TBP) refers to environmental contamination or hazard that originates within one country's territory but travels—through the atmosphere, ocean currents, rivers, or other physical systems—to affect the environment, health, or economy of one or more other countries. Because the pollutant crosses a political border, the country that suffers the impact typically has no direct control over the source, and the country that produces the pollution often has little economic incentive to address a cost imposed elsewhere. This creates a distinctive global risk: environmental harm is generated locally but experienced internationally, so managing it requires cooperation between states rather than unilateral national action.

TBP differs from ordinary local pollution in one crucial respect: the geographic separation between cause and consequence. A factory polluting a river that stays within one country's borders is a domestic environmental issue. The same pollutant reaching a river shared with a neighbouring state, or radioactive particles drifting across a continent, becomes a transboundary issue—raising questions of legal responsibility, compensation, and diplomatic negotiation that purely domestic pollution does not.

Global flows are the continuous movement of goods, capital, people, and information between places, driven by international trade, transport networks, and tourism. While these flows connect economies across the world, the physical infrastructure that carries them—cargo ships, shipping lanes, ports, and airports—produces environmental damage that is highly localized. A shipping lane crossing an ocean is a global connection, but an oil spill or ballast water discharge along that route causes concentrated harm to a specific stretch of coastline or marine ecosystem.

This creates a spatial mismatch: the environmental cost of global trade and tourism is not spread evenly across the countries that generate or benefit from the flow. Instead, damage clusters around transit points, coastal waters near major shipping lanes, ports, and refuelling or docking locations. Coastal communities near busy maritime routes may experience oil pollution, noise disturbance to marine life, and contaminated ballast water discharge, despite having little direct control over the international shipping traffic passing through their waters.

Food miles and tourism-related travel add further examples of this pattern. Transporting food long distances to satisfy global consumer demand generates carbon emissions concentrated in shipping and aviation corridors, while tourist flows can create local pressures such as coastal erosion, waste generation, and water contamination at destination points, even though the demand driving these flows originates from distant source countries.

Industrial agriculture -- large-scale, mechanized farming run by agribusiness corporations to supply global food markets -- relies heavily on irrigation to maximize yields of thirsty commercial crops such as soy, cotton, rice, and almonds. As agricultural production has globalized, with farming increasingly concentrated in regions offering cheap land, favourable climates, and weak environmental regulation, the pressure on local water resources has intensified far beyond what small-scale subsistence farming would require.

Much of this irrigation draws on groundwater aquifers, which are often 'fossil' water sources that recharge extremely slowly, if at all. When extraction rates from agribusiness operations exceed natural recharge, water tables fall year on year -- a process called groundwater depletion. This can dry up wells, reduce river baseflow, cause land subsidence, and in extreme cases lead to the shrinking of entire water bodies as inflowing rivers are diverted for irrigation. Depletion is therefore a slow-onset environmental risk: unlike a flood or spill, its damage accumulates invisibly over decades until a threshold (a collapsed aquifer, a dried river) is crossed.

Because agribusiness operates within globalized supply chains, the water used to grow a crop is frequently consumed in one country while the resulting food is exported and eaten in another. This embedded water is known as virtual water. A country that imports water-intensive crops effectively imports virtual water and avoids depleting its own resources, while the exporting country absorbs the environmental cost of falling water tables, degraded soils, and reduced river flow to sustain export agriculture. This creates a spatial mismatch between who benefits from cheap, abundant food and who bears the ecological cost of producing it -- linking directly to the broader pattern of the global shift of agriculture into regions with lower production costs and weaker environmental oversight.

Responses to agribusiness-driven water depletion include regulating groundwater extraction licences, pricing water to reflect scarcity, promoting water-efficient irrigation technologies (such as drip irrigation) over wasteful flood irrigation, and shifting cropping patterns away from the thirstiest export crops in water-stressed regions. However, because export agribusiness generates significant income and employment, governments -- particularly in LICs seeking foreign exchange earnings -- often face a trade-off between short-term economic gain and long-term water security, making effective regulation politically difficult.