7.8 Sustainable Development

The idea took shape in the UN's 1987 report Our Common Future, often called the Brundtland Report. Its definition asks that development meet the needs of people today in a way that doesn't use up the resources future generations will need.

Sustainable development is often described as balancing three goals: economic growth, social fairness and environmental protection. A factory that creates jobs but poisons a river fails the test; so does a nature reserve that pushes local people into poverty.

• Resource depletion: using resources faster than they can be replaced, like overfishing, draining aquifers or cutting forests.
• Pollution: industrial growth often pollutes air and water before countries adopt stricter rules, as happened in Britain in the 1800s and in China's industrial cities in recent decades.
• Climate change: burning fossil fuels for industry, transport and power raises greenhouse gas levels. Under the Paris Agreement (2015), countries set their own targets to cut emissions.
• Mass consumption: more people buying more goods raises waste and resource use, which is a critique of Rostow's final stage (7.5).

In 2015 all UN member states adopted the 2030 Agenda, with 17 Sustainable Development Goals (SDGs) and 169 targets. They include ending poverty and hunger, good health, quality education, gender equality, clean water and sanitation, affordable clean energy, decent work, reduced inequality, sustainable cities, climate action, and protecting life on land and in the sea.

Progress has been uneven. The UN's 2025 progress report found that only about 35% of the targets with data were on track or making moderate progress, nearly half were moving too slowly, and 18% had gone backward since 2015. Extreme poverty and child mortality have fallen, while hunger, conflict and climate goals have lagged. Local projects, such as small-scale finance for farmers and new public transportation in growing cities, count toward specific SDG targets, so the goals help measure what each project achieves.

Ecotourism is tourism to natural areas that aims to protect the environment and benefit local people. Costa Rica is the classic example. After heavy deforestation in the mid-1900s, it protected about a quarter of its land in parks and reserves and began paying landowners to keep forests. Forest cover has since recovered to more than half the country, and nature tourism is a major source of income.

Ecotourism has limits. Too many visitors can damage the places they come to see; the Galápagos Islands, for example, charge high entry fees to manage crowds. Profits may go to foreign tour companies rather than local communities, and flying tourists long distances adds carbon emissions. Done well, ecotourism gives communities a reason to protect nature; done poorly, it's mass tourism with a green label.