A number of factors at play in the world are acting together to create multiple challenges. These include:

A growing population: From about 1 billion people on the Earthin 1800, the planet’s population expanded to about 6 billion in 2000 and to more than 7 billion now. It is predicted to grow to at least 9 billion by 2050 and around 11 billion by 2100. This rapidly growing population brings with it increasing demands for resources of every kind, from water and food to energy and materials for clothing, shelter, transport, work and leisure.

Growing urbanization: In 1950, about 30% of the world’s population lived in urban areas. This proportion has now increased to over 50% and it is predicted that by 2050 two thirds of the world’s population will be urban. Currently around one in eight people live in the world’s 28 mega-cities with more than 10 million inhabitants; but by 2030, the world is projected to have 41 of these mega-cities. As the world continues to urbanize, sustainable development challenges will be increasingly concentrated in cities, particularly in the lower-middle-income countries where the pace of urbanization is fastest. Integrated policies to improve thelives of both urban and rural dwellers are needed1- and systems thinking about how chemistry and other sciences can ensure that these environments are healthy and sustainable.

Shortages of materials: The planet’s resources are increasingly under strain and many critical resources are already either in short supply or will become so in the coming decades. Examples include:

Water: The Earth is a water rich planet, and annual human and animal consumption is much less than 1% of the world’s total water supply. But clean,affordable water that is fit for human beings to drink is in short supply on our planet. Population growth and economic development are driving a steadily increasing demand for new water supplies, and global demand for water has more than tripled over the past half century. Globally, the largest user of fresh water is agriculture, accounting for roughly three quarters of total use. In Africa this fraction approaches 90%. In the USA, agriculture accounts for 39% of fresh water use, the same as the fraction used for cooling thermal power plants. Future prospects are not encouraging. Global water withdrawal in 2000 was estimated to be 1,000 cubic miles (4,000 km 3), about 30% of the world’s total accessible fresh water supply. By 2025 that fraction may reach 70%. Over-pumping of ground water by the world’s farmers already exceeds natural replenishment by more than 160 km3, 4% of total withdrawals. WHO estimates that, globally, 1.1 billion people lack access to clean water supplies and that 2.4 billion lack access to basic sanitation. 1,000 m3 is the per capita annual amount of water deemed necessary to satisfy basic human needs. In 1995 166 million people in 18 countries lived below that level. By 2050 potable water availability is projected to fall below that level for 1.7 billion people in 39 countries. Water shortages now plague almost every country in North Africa and the Middle East.2

Energy: Overall, there is no present shortage of energy in the world, since there are massive reserves of fossil fuels like coal, oil and natural gas in the ground. But continuing to extract and burn these reserves as the main means of generating energy is not sustainable. Sooner or later, these reserves would be exhausted; and meanwhile their combustion would continue to contribute massive amounts of greenhouse gases to the atmosphere, with severely damaging consequences for climate change. So, there is a shortage of clean, sustainable energy generation worldwide.

Endangered elements: Of the 118 elements that make up everything on the planet,44 will face supply limitations in the coming years. These critical elements include rare earth elements, precious metals, and even life-essential elements like phosphorus. Research into more abundant alternatives, more efficient uses, recycling and recovery will help mitigate risks and move industry towards sustainable supply chains.3

Food: In the 20th century, agricultural production was able to more than keep pace with the rapidly expanding global population – although the highly uneven access to food in different places meant that many people still starved. The combined pressures of population growth, climate change and water shortages mean that it will be increasingly difficult for agricultural output to continue growing at a sufficient pace to avoid malnutrition and starvation in many parts of the world.

Environmental pressures: Our physical environment (the air, land and water on the surface of the planet) and our biological environment (including all the flora and fauna that live in the physical environment) form a complex, interactive ecosystem that is increasingly subjected to pressures of many kinds, including:

Increasing pollution: Pollutants from human activities – industry, agriculture, sewage and waste water disposal, energy production, transport, etc.

Deforestation: Destruction of forests in order to make way for agriculture, mining and human settlements is continuously eroding this vital natural resource, which is a repository of valuable natural products as well as a major factor in the capture of carbon dioxide from the atmosphere.

Contamination with pharmaceuticals: Pharmacy products for both human and veterinary use find their way into the environment and get taken up by diverse species of organisms, damaging them and in some cases entering the food chain that ends with consumption by people.