Another study found that an estimated 42% of the global malaria burden, including a half-million deaths annually, could be eliminated through policies focused on issues like land use, deforestation, water resource management, and settlement siting. But the study didn’t cover the potential benefits of employing insecticide-treated nets as a tool for fighting malaria, ruling out a comparison of the two investments’ returns.
Worldwide, around 40% of cities’ source watersheds show high to moderate levels of degradation. Sediment from agricultural and other sources increases the cost of water treatment, while loss of natural vegetation and land degradation can change water-flow patterns. All of this can adversely affect supply, thereby increasing the need to store water in containers—such as drums, tanks, and concrete jars—that serve as mosquito larval habitats. Can we show that ecological restoration of the watershed could do more than just insecticides or mosquito nets to support efforts to reduce malaria (and dengue) in cities?
In all of these cases, finding the best option requires knowing not just the relative contribution of different interventions, but understanding their complementarity. In a world of limited resources, policymakers must prioritize their investments, including by differentiating the necessary from the desirable. To that end, finding ways to identify and maximize complementarity is vital.
Some 2.1 billion people worldwide lack access to safe, readily available water at home, and more than twice as many—a whopping 4.5 billion—lack safely managed sanitation, severely undermining health outcomes and fueling river pollution. With a growing share of the world’s population—including many of the same people—feeling the effects of environmental degradation and climate change firsthand, finding solutions that simultaneously advance environmental protection, water provision, and health could not be more important. Global health and conservation professionals must cooperate more closely to find those solutions—and convince policymakers to pursue them.