Open Letter
Open letter to research funding bodies
Reproductive rights · Rigorous research · Better decisions
An Open Letter to the Leaders and Decision-Makers of National and International Research Funding Institutions:
The urgent need to invest in the Nexus of Demographic Dynamics, Environmental Change, and Sustainable Development for the wellbeing of people and planet
Dear Leaders and Decision-makers,
We are asking research funders to support a stronger, better-funded research agenda on demographic dynamics, environmental change, and sustainable development. At a time of accelerating biodiversity loss, climate change, and food insecurity, this work remains underfunded and too often separated from mainstream environmental research.
The scientific consensus is clear.
Population growth is recognised by the UN Intergovernmental Panel on Climate Change (IPCC) as one of the two strongest drivers of CO2 emissions from fossil fuel combustion in the last decade, alongside per capita GDP (IPCC, 2022). Both the IPCC and Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) also identify population growth as one of the principal indirect drivers of biodiversity loss and greenhouse gas emissions (IPBES, 2019; IPCC, 2023). A recent UK Government report on biodiversity loss and national security (GOV.UK, 2026) warns that continuing ecosystem degradation could put every critical ecosystem on a pathway to collapse. Population growth is identified as a principal driver, especially through rising demand for food. These ecological risks also affect food security, water availability, migration pressures, conflict, and state fragility.
Despite this evidence, research on the links between population dynamics, environmental change, and sustainable development remains scarce. A recent scoping review of more than 2,500 articles on demographic change, food security, and food production systems found that only 66 studies meaningfully addressed these intersections (just 2.6% of the literature reviewed over the past 11 years). Very few examined demand-side interventions, such as policies that address fertility transitions or dietary change as ways to ease pressure on planetary systems. This is not a trivial gap. It is a shared research opportunity with significant implications for science and policy.
Siloed ways of working harm scientific integrity and undermine the solutions needed for systems change
We recognise why this field has been approached with caution. Historical associations between population policy and coercion, racism, and violations of reproductive rights have understandably made researchers and institutions wary. Yet caution should not become avoidance or prevent collaboration across disciplines. Many of our challenges are complex and interconnected. A siloed evidence base limits our ability to understand and address them.
The evidence is unambiguous that when women have access to education, reproductive healthcare, economic opportunity and autonomy they choose to have fewer children (Bongaarts, 2025; Lutz and KC, 2011). The IPBES has affirmed that demographic transition is not automatic but flows from “conditions including women’s empowerment and their access to family planning methods” (IPBES, 2019: 55). The IPCC’s own Shared Socioeconomic Pathways (SSPs) acknowledge that whether global population peaks at 8.5 billion or 11 billion have profound implications for both climate outcomes and human welfare, with SSP1’s optimistic trajectory depending centrally on accelerating demographic transitions through educational and health investments (IPCC, 2023: 171; 313). Initiatives such as Earth4All have similarly noted the importance of equitable development for accelerating fertility decline (Callegari and Stoknes, 2023). This is not a debate about controlling people. It is a debate about investing in them.
Equipping future leaders
The implications for research funding are direct. We ask funding bodies to prioritise interdisciplinary research on demographic change, environmental sustainability, food systems, and equitable development. This should include demand-side analyses that ask, for example, how fertility transitions, migration patterns, urbanisation, and consumption choices interact with land use, food demand, emissions, and biodiversity outcomes. It should also include support for demographic literacy in the training of environmental scientists and policymakers.
Future leaders need the evidence and skills to understand these relationships. Strengthening demographic literacy would help universities, researchers, and policymakers work across the boundaries that currently separate climate, biodiversity, food security, health, and development agendas.
Act now: your leadership is vital
The wellbeing of people and planet over the coming century will be shaped in no small part by how many people inhabit it and under what conditions they live. The most effective pathways to slower and more manageable population growth (investing in girls’ education, universal access to sexual and reproductive health and rights, and the reduction of poverty) are the same pathways that deliver the greatest gains in human welfare and dignity. These are not trade-offs. They are complementary investments, and they deserve the full weight of scientific attention and public funding that their importance demands.
We urge you to act with the seriousness this moment requires together with our global partners and supporters we will be awaiting your response. For further information, or to discuss institutional support, please contact Population Matters.
