Xie Gaodi from the Institute of Geographic Sciences and Natural Resources Research (IGSNRR) at the Chinese Academy of Sciences is the lead author of a recent research paper published in the journal Sustainability. He recently talked with Global Footprint Network about the unsustainability of giant cities.
Between 2008 and 2012, the population of Beijing climbed from 23 million to more than 30 million—a whopping 30 percent in just four years. One direct impact of this rapid demographic surge, which includes permanent residents and "floating" population such as tourists, was the drastic increase in Beijing's reliance on food produced in areas located outside of, and increasingly further out from, the city's boundaries, stresses a new article in the journal Sustainability authored by several researchers in China. The challenge caused by Beijing's insufficient agricultural resources was compounded by high land prices, the researchers pointed out.
Over those five years, Beijing's dependence on non-local food supplies grew from 48 percent to 64 percent of total food consumption in the metropolitan area, according to the article, "The Outward Extension of an Ecological Footprint in City Expansion: The Case of Beijing."
The authors introduce the notion of Ecological Footprint distance (abbreviated as Def) to reveal the average distance that natural resources required to support a population's Ecological Footprint travel to reach that population.
Researchers stressed that food accounts for the significantly biggest part of Beijing's consumed biocapacity in terms of weight.
Because of challenges collecting data, the researchers chose to focus on food resources (vegetables, fruit, meat, eggs, fish, grain and oil) produced within China. And they exclusively used geographic data from Beijing's giant food wholesale market Xinfadi, which makes up more than two-thirds of Beijing's overall food market—hence deemed representative by the researchers.
That partial lens led them to conclude that Beijing's Def grew from 567 kilometers in 2008 to 677 kilometers in 2012, with an average annual increase of about 25 kilometers. Beijing’s Ecological Footprint distance in winter and spring was much higher than in summer and fall. This was to due to the seasonal variations that increased food production capacity in the warmer months of the year in areas closer to the capital.
Lead author Xie Gaodi, from the Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, kindly agreed to an interview about the recent article. He answered our questions via email.
How did you start working with the Ecological Footprint?
Xie Gaodi: In 1997 I began focusing my research on natural resources and sustainable development in China. We started looking for indicators which could effectively show us the actual sustainability status of local development. Several papers written by Mathis Wackernagel and William Rees et al. came to our attention, such as "Our Ecological Footprint: Reducing Human Impact on the Earth" (1996) and "Perceptual and structural barriers to investing in natural capital: Economics from an Ecological Footprint perspective" (1997).
These papers spurred my interest in the Ecological Footprint. I made up my mind early on that the EF is a good tool to analyze sustainability. Every other year or so, my team, together with Global Footprint Network and WWF, compile China's Ecological Footprint Report. The Ecological Footprint is now a well-known tool not only in Chinese academia but also throughout China.
Your research paper seeks to evaluate the geographic reach that is required for Beijing to access the biocapacity it needs to feed its population. What was your ultimate goal?
XG: In the last 30 years, China has been pushing through a fast urbanization process. In just the most recent years, several mega-cities have sprouted as more and more people have been moving away from rural areas to find work. Some cities such as Beijing and Shanghai, with over 20 million residents, are getting so huge that I worry about their sustainability. Their Ecological Footprint clearly extends way beyond their own biocapacity.
My goal with this research has been to show how far a big city’s EF or biocapacity extends, starting with Beijing. The conclusion from our findings is clear: China ought to favor the development of small or medium-sized cities because they are more sustainable.
What does Def actually indicate/infer with regard to sustainability?
XG: The further Def climbs up and away from biocapacity, the less safe it is. Food safety is compromised when food travels from far away, becoming vulnerable to such factors as weather events. Long travel distances also affect the quality of food, including its nutritional value. Besides, a food ecosystem that depends on so much transportation is the source of a whole set of environmental issues — including carbon emissions.
Typically Global Footprint Network refers to "imports" as resources from other countries. Your paper defines them as coming from outside the boundaries of Beijing but from Chinese sources of production. What about true foreign imports from outside China?
XG: Beijing's "imported" biocapacity should include both food imports from China and from abroad. The challenge we're facing is the difficulty to get enough reliable data about foreign food imports in such a huge city as Beijing. My guess is that they make up between 10 and 20 percent of the biocapacity consumed in Beijing — but that's just a guess at this stage.
So we just calculated the Def of "imported" biocapacity within China, but we will calculate the Def of imported biocapacity from foreign sources as soon as we are able to.
Based on your research, what does "sustainable development in metropolitan areas" look like to you? What policies do you suggest would pave the way in that direction?
XG: In my view, "sustainable development in metropolitan areas" is attained when the population can access the necessary resources to support its Ecological Footprint and need for ecosystem services, thanks to biocapacity that originates close enough so as to spare residents undue environmental pollution and worry about their food safety.
This can be achieved through such policies as:
1. Careful land use that rationally plans population density and natural assets' availability across that land.
2. Ensuring the closest possible proximity of available biocapacity.
3. Reducing the transportation of resources.
The governments of some big cities such as Beijing and Shanghai have truly realized that their city has grown too large. They have even begun to take some measures to limit or control urban growth. But at the national level, debates are still ongoing as to whether urban planning should favor small- and medium-sized cities.