Ethiopia, upper Ghibe valleyThe fundamental issue in the design of the new global framework – climate change and the new sustainable development goals – is whether, in 2050, developing countries will still be agrarian societies or whether three quarters of their populations will have moved to the cities and into the middle classes, as had happened in North America, Europe and Japan by 1970.

Since cities produce 75% of global greenhouse gas emissions, which are directly related to household consumption (shelter, mobility, and food), resource-use and carbon emissions will increase in these countries – a threat and an opportunity as new cities are established. Given the middle classes are expected to triple by 2050, sustainability should be seen in terms of their distribution and use, rather than the scarcity of natural resources.

I elaborate on the conclusions of the World Social Science Report 2013 that: ‘the social sciences must help to fundamentally reframe climate and global environmental change from a physical into a social problem’. The shift from environmental risk analysis to human wellbeing within ecological limits helps clarify understanding of a very complex issue: so far we have looked at the symptoms rather than the causes of the problem – levels of carbon dioxide rather than the production and consumption patterns that lead to the emissions.

Three related yet distinct global trends – urbanisation, increased energy consumption and the growing middle classes – depend on using natural resources which have a global impact. How far this causes negative environmental impact depends more on the type of resource and how we use them than on the amount used. For example, infrastructure (measured by the growth in cement and steel production) accounts for most resource-use and emissions to date.

Urbanisation is the result of a long-term, worldwide, socio-economic process –human evolution from a rural agrarian existence to an urban-industrial way of life. Land-use systems cause a quarter of total emissions, but half are generated in the storage, preparation and transport stages of agricultural production. The highest impact is from livestock farming, which uses nearly 75% of agricultural land, providing 15% of the global calorie supply and contributing 18% of global emissions.

The lifecycle emissions of meat, dairy products and eggs demanded by city dwellers are up to ten times higher than those from an equal weight of plant-derived food on which rural inhabitants depend. According to the UN Food and Agriculture Organization, emissions from agriculture would drop to below 1990 levels, even though the demand for food is expected to increase up  to three times in the next 20 years.

The use of fossil fuels for generating and producing electricity ignores consumption patterns. For example, transport emissions will soon equal the energy share of electricity, 75% of electricity use in industrialised countries is in buildings, and energy demand in China is driven by trends in basic material production; overall global levels depend on urban design, type of infrastructure and consumption patterns. The International Energy Agency believes energy efficiency has the highest potential for reducing emissions, and should be treated essentially as a fuel.

Transport volume has doubled since 1990 and makes up 25% of European Union emissions and 33% of United States emissions; transport is driven by urbanisation and wealth rather than population, and continues to increase in industrialised countries. It is estimated that emissions from transport will exceed 50% of total global emissions by 2050, half of which will be from passenger transport. Spatial organisation, population density and lifestyle choices determine natural resource use such as electricity demand, use of transport and urban goods and services.

Focusing on the consumption patterns of the middle classes could bring about change: per capita energy consumption in the transport sector is more than three times higher in the United States than in Japan and Germany; 40% of urban motorised trips in Japan are by public transport; in the United States it is 4%. Austria’s urban areas are four times denser than Australia’s but generate 60% of the amount of carbon dioxide per person Australia’s urban areas generate and greenhouse gas emissions per passenger travelling by bus, rail or trams are about one-twelfth that of the car.

As with the Montreal Protocol – the most successful global cooperation yet on the environment – the focus on consumption means that sustainability can become part of a business strategy to solve the problem. Modifying consumption amongst the middle classes will make the pie bigger; focusing on reducing carbon dioxide emissions would enable some to seize a larger slice.

Photo credit: ILRI/Stevie Mann