Cities that don't consume the earth

Tommy WiedmannAssociate Professor Tommy Wiedmann is a passionate defender of this finite planet and his research revolves around the question - how do we achieve concurrent human and planetary well-being? One of the world’s most widely cited academics, Tommy has recently been contributing to the international report ‘Consumption-based Green House Gas Emissions of C40 Cities’. The C40 Alliance functions as a global facilitator of conversations, as a research hub and a generator of bespoke climate change solutions for modern cities.

Cities emit 70% of the world’s carbon dioxide. Or so we thought. In actuality, it could be much higher than this. Carbon footprint accounting has traditionally been focused on sector-based production. The innovation of this report, and part of Tommy Wiedmann’s core research mission, is the inclusion of consumption-based emissions in its account and analysis of individual cities. His team at UNSW has partnered with the University of Leeds, UK, to develop the model and calculations for the C40 report.

Interestingly, the report revealed that much of a city’s footprint lies outside its boundaries. “We have done this consumption- based analysis for 79 cities around the world, including for the cities of Sydney and Melbourne. We found that about half of Sydney’s and Melbourne’s carbon footprint comes from outside of the city boundary.”

The broadened equation of consumption based analysis: consumption = production + imports - exports, creates a truer and more alarming picture but it does allow city planners to develop inventories and strategies that can target the real problem. And seeing the true picture is vital.

We need to make equal efforts to reduce emissions in building materials and from food production and we need to address emissions from consumption

A/Prof Tommy Wiedmann

“We’re still going in the wrong direction on climate change,” said Mark Watts, executive director of C40 Cities. Global carbon emissions have increased 60 percent since the international 1997 Kyoto agreement to reduce emissions. Using more renewable energy and mass transit won’t be enough to reverse this. We have to reduce our consumption.”

Tommy Wiedmann adds “All the efforts to reduce emissions from buildings and traffic are good, but they are, by far, not the only emissions we need to look at. We need to make equal efforts to reduce emissions in building materials and from food production and we need to address emissions from consumption.”

Wealthy, service-based ‘consumer’ cities like Sydney and Melbourne are in fact outsourcers of pollution. Many cities in developing nations, who are producing obvious GHGs, are often doing so in the process of producing our consumer goods. When the emissions associated with our consumption of goods and services are included, our cities’ emissions have grown substantially and, according to the C40 Report are among the highest in the world on a per person basis.

Much of the responsibility and the power, then, falls to us, the citizens. And we can act now, as communities and as individuals. Shopping consciously with ethical, environmental and sustainable local and global production in mind, and in daily practice. As Wiedmann says, “Smart and sustainable cities of the future will have to be zero carbon ‘inside’ and low carbon ‘outside’. They will have to be regenerative, absorbing CO2 emissions from the atmosphere through green infrastructure, and making the most of reusing, repurposing and recycling goods, materials and waste.”