Earth’s complex natural systems sustain all life. Biodiverse terrestrial, freshwater, and marine ecosystems also enhance human livelihoods and well-being.
When human numbers were small, our impact on the environment was localized and minimal (for a visual representation of how human population numbers have grown throughout history, check out Population Education’s famous “dot” video!). However, as the global population has grown and technologies have evolved, human pressure on nature has increased. Human activities drive large scale changes through land and sea use, the hunting and harvesting of animals and plants, pollution, and invasive species introductions. The sustained overuse of natural resources over the last century has caused unprecedented levels of environmental destruction, including the loss of ecosystems and decreased biodiversity.
One overarching result of this environmental overreach is climate change.
Making the population and climate change connection
Greenhouse gases emitted from land use changes and escalating fossil fuel use are elevating Earth’s temperature faster than at any point since the dawn of civilization. This warming is altering the planet’s capacity to supply food and fresh water and to sustain human health and well-being. Climate impacts—such as weather extremes and increasingly dangerous wildfires—are hitting harder and sooner than scientists anticipated even 10 years ago.
Humanity’s global population is projected to continue growing at least through the end of the century. If our patterns of energy use, transportation, agriculture, and deforestation do not change, ecosystem degradation and climate change will threaten the welfare of everyone on our planet. Limiting the impacts of climate change requires a global shift toward renewable energy sources, sustainable land use practices, and responsible consumption patterns. Underlying these shifts in how we treat our planet is the need to stabilize the human population—by ensuring that family planning information and services are available to all who desire them. It is only through reducing consumption and ending the increase in the number of consumers that we will be able to chart a sustainable course for future generations.
The environmental implications of slowing population growth through measures like voluntary family planning and education are compelling. Project Drawdown argues that meeting the global unmet need for contraceptives, together with increasing access to education for women and girls, could result in emissions reductions of up to 85 gigatons of CO2 equivalent by 2050. This is comparable to permanently closing over 22,000 coal-fired power plants.
Addressing unmet need for contraceptives as a rights-based solution
Voluntary reductions in fertility are amplified across generations. For example, if the whole world today adopted the fertility rate of Germany, Japan, Spain, Portugal, or Italy, the population would shrink to just above 4 billion by 2100, as opposed to the 10.9 billion currently projected by the United Nations Population Division medium-fertility variant. Reducing fertility rates through rights-based development strategies such as voluntary family planning services and girls’ education has the potential to yield a myriad of social and environmental benefits—among them increased climate resilience and adaptive capacity for the world’s most vulnerable populations, and the empowerment of a whole generation of women and girls.
Understanding the links between population and the environment is critical to combating climate change. Human impacts on the environment are compounded by population growth and growing affluence. A growing global population puts strain on the availability and equitable allocation of natural resources. More humans means increased demand for food and increased use of energy, which generally results in higher overall emissions.
Opportunity lies in the adoption of more efficient practices and in the prevalence of family planning information and services for all who desire them. The future trajectory of production practices and consumption patterns will determine the scope and severity of climate change, the effects of which will be most devastating for the world’s most marginalized people.
Ultimately, curbing human impacts on the environment and averting further climate change involves shifting the global economy in favor of renewable energy sources, reshaping food production and consumption patterns, ending deforestation, and investing in ecosystem protection and rehabilitation. Slowing population growth is an important tool in tackling these challenges.