While economics and social science dominate in thinking about international development, the subjects of environment and health are more rooted in the natural sciences.  Each of the chapters in this section tackles a concept associated with the natural world, understanding and describing a biophysical reality independent of human agency or the values of society.  At first glance, these are technical fields of knowledge and the domains of agronomists, water engineers, and medical practitioners.  Some degree of familiarity with the tools of natural science inquiry is useful, including a comfort with quantitative measures, a critical perspective willing to subject theories to empirical testing, and a willingness to revisit or discard cherished explanations when they are proven false.

Ancient maps used the phrase ‘here be dragons’ to denote unfamiliar territory; yet no one should be discouraged from entering these topics. Although these topics are rooted in the natural world, each has implications for real-life decisions over food, water, land and health which are intimately tied to the institutions society uses to govern itself.  This speaks to international development as the interplay of natural and social science, the porous membrane between an impartial “world without us” and the influence of the human condition.

Natural science is part of the substance, the material “freedom from want”, at the heart of development.

In the post-war period, natural sciences and engineering were expected to provide the “freedom from want” described by Roosevelt in 1941.  Looking back at the key wins for development, one experiences what historian David Edgerton (2009) describes as the “shock of the old.”  Vaccines, bed nets, and water treatment trace their roots to nineteenth-century efforts in public health, while the hybrid crops of the Green revolution relied more on centuries-old plant breeding than modern genomics.  Science raised the production function to derive more benefit from the limited bounty of a finite world. Sixty years after Roosevelt’s address, half of the Millennium Development Goals focused on food, health and physical surroundings.

In practice, the way science evolves is often longer term, and less predictable, than anticipated.  Billions of dollars in development finance were, and continue to be, invested in intentional efforts to create vaccines or improve crops. Meanwhile some fields of science evolve in tandem with application.  The first aircraft flew before aeronautics could fully explain how they did so.  It was once thought that the basic human needs of food, water, and health would be met long before the luxuries of television or the Internet reached all corners of the world.  Yet today more people have access to a mobile phone than to a toilet.  Science provides tools, yet its influence depends on whose hands it empowers: whether by governments designing smarter health systems, or poor farmers growing more nutritious food.  In sum, natural science contributes much of the substance of what is considered as development.

Natural science explanations are shaping how development is understood.

Thinking on development has taken a positivist turn, with natural science has subtly reshaped the intellectual rules that guide thinking on development.  Early development thinkers were steeped in classical literature and the writing of philosophers.  A generation ago, the test for accepting a development theory was whether it helped understand the world: Did it interpret historical events or predict what might happen next?  Stages of economic growth and demographic transition were concepts valued for their ability to diagnosis the problems facing society and for prescribing action.  Today the rules of natural science exercise an increasing influence on the imagination.  Thinking on development has become much more data-driven.  The apparent success of mathematical models in economics, or randomized-controlled trials in clinical medicine, inspired the application of these methods more broadly.  The search for development shifted from a quest for explanation, to a search for “what works,” narrowly defined links of cause-and-effect between interventions and outcomes.

Development theories must now be falsifiable, and development practice to be based on empirical evidence.  Grand narratives still shape global agendas, but in everyday life the practitioner is more likely to speak of policy experiments, measurable targets, and development indicators.  Yet the reality of development is messy, full of wicked problems with multiple variables and causal mechanisms, most of which cannot be controlled.  Today people are adapting to change in the world’s glacier-fed rivers and semi-arid lands often without relying on the computer models of greenhouse gases.


Edgerton, D. (2009). Shock of the old: technology and global history since 1900. Oxford, UK: Oxford University Press.


— Study Guide Theme
Environment and Health
— Study Guide Chapter