To the Editor

The News Feature 'We are seven billion' in the October 2011 issue of Nature Climate Change1 touches on the important role of family planning programmes in influencing population growth, but neglects to consider the vast unmet need for family planning that exists in developing countries. Addressing this unmet need by increased investment in voluntary family planning programmes that respect and protect rights offers a cost-effective strategy for supporting climate change adaptation2,3.

According to the United Nations medium variant projection, the world population will have increased from today's seven billion to over nine billion by 2050, surpassing ten billion by the end of the century4. The majority of this growth is projected to take place in developing countries: the countries that have contributed the least to climate change, but are the most vulnerable to its impacts. While struggling to adapt to climate change they face the additional burden of feeding and providing for their growing populations. In Africa, one of the continents most vulnerable to climate change5, the population is expected to more than triple between now and 2100 (ref. 4).

An analysis of the national adaptation programmes of action — in which the 40 least-developed countries set out their most pressing climate adaptation issues and priorities — found that 93% of the countries identify rapid population growth as a factor that either exacerbates the impacts of climate change or impedes their ability to adapt6. Climatic impacts identified as being exacerbated by population growth include soil degradation, freshwater scarcity, migration, deforestation and loss of biodiversity6.

In developing countries, an estimated 215 million women have an unmet need for contraception — that is, they say they do not want to have a child in the next two years, but are not using a modern method of contraception, often because they do not have access to the necessary services7. This offers considerable scope to reduce population growth and increase climate resilience, simply by preventing unplanned pregnancies through ensuring that women have access to the family planning services that they want and need. To advance this 'win–win' strategy, rights-based sexual and reproductive health programmes, including family planning services, should be recognized as legitimate components of national climate change adaptation programmes and climate change funding mechanisms.