There is an unsettled debate about what level of human population is environmentally and agriculturally sustainable at current, or increased, levels of consumption.  Twelve years ago, Joel E. Cohen, wrote a provocative book, entitled, “How Many People Can the Earth Support?” that ratcheted up the debate. More recently, the World Wildlife Fund released the Living Planet Report 2008, which gives an overview of how human activities might be impacting the planet’s natural resource base.

The WWF report asserts that:

1. We are facing an “ecological credit crunch.” At current rates of consumption, we will require two planets by the mid-2030s.

2. While this challenge is enormous, we can reverse current trends through an integrated approach by governments, private sector players, and civil society. Technology transfers, incentives for local innovation, sustainable urban planning, empowerment of women, and access to voluntary family planning can all contribute to achieving long-term sustainability.

From a demographic perspective, this report provides some important insights on the possible relationships between population and sustainability.  According to the Living Planet Index, in just 35 years, the Earth’s wildlife populations have experienced a 33% decline in numbers, largely impacting tropical, terrestrial, dryland and freshwater plant and animal species. This loss is due to a number of factors including habitat loss from agricultural development, exploitation of species, pollution, the rapid growth of invasive species, and climate change. If human demands for natural resource use and infrastructure development increase, more wildlife populations will be at risk of endangerment or extinction, affecting food, water, health, energy security, and frequency and vulnerability to natural disaster.

Population and consumption trends are highlighted in this report. Globally, population and per person consumption is on the rise. While high-income countries contain 15% of the global population, they are responsible for 36% of the global ecological footprint due to consumer demand for natural resources. In middle-income countries, populations are variable; some countries are experiencing slower population growth while the region overall has doubled in population since 1961. Concurrently, per person footprints have also increased by 21%.

The accelerated rate of consumption and production in emerging economies contributes to increasing individual footprints.  In China, rapid increases in population and per person footprints yielded an overall quadrupling of the country’s total ecological footprint.

Overall, middle-income countries are responsible for the largest demand on the Earth’s resources; their consumption patterns account for 39% of humanity’s total footprint. Low-income countries show the most rapid population growth, decreasing biocapacity per person, and the lowest per person ecological footprints in the world.  These trends are shown in the graphs released in the Living Planet Report 2008:

 40WorldIncome.pdf

While many nations consume resources produced within their national boundaries, international trade of natural resources accounts for over 40% of the total global ecological footprint.

The Living Planet Report 2008 raises some compelling questions about our ecological future.  By incorporating demographic data with trends in consumption, trade, and biodiversity, this report recognizes the complexity of the issue and the corresponding need for an integrated approach to the problem.