Is mass urbanisation in China improving the country’s climate balance?

While the expansion of cities is considered harmful to the environment, a new study suggests administrative decisions can make a huge difference. 

Over the past three decades, 290million people left rural China for life in the city. It has been assumed this mass emigration, and the deforestation it causes, has contributed to the country’s climate emergency, but now researchers at the University of Copenhagen have published jarring evidence pointing to the opposite. 

Employing remote sensing technology using satellite observations to map natural resources, the team revealed that biomass and carbon stocks have increased in China over the last 20 years. This is true both in rural areas and recently developed cities. Effectively, the results contradict previous understandings of urbanisation’s impact.

Between 2002 and 2010, carbon loss from aboveground biomass in China’s urban areas equated to 20m tonnes. However, from 2002 to 2019, there was a gain of 30m tonnes of carbon in built up zones, while in the same period the aboveground carbon stocks increased by 290m tonnes. 

‘Even though urban growth is to blame for a loss of carbon during the first half of the period, green policy initiatives compensated for the loss and lead to an overall balancing effect. Indeed, a slight surplus in the climate account has been achieved,’ said lead study author, PhD student Xiaoxin Zhang, of the University of Copenhagen’s Department of Geosciences and Nature Management.

Projects considered to have worked include an afforestation strategy – with billions of new trees planted in recent decades – and an ecological civilisation policy dictating specific percentages of urban parks, green roofs, trees, and vertical gardens are required in city developments. 

Elsewhere, building upwards, rather than outwards, has also had an impact. Just 6% of China’s city growth has been at the expense of its forests, while agricultural land only fell by 3.8% in the study period. However, with a target for climate neutrality by 2060, scientists have made it clear planting trees and parkland will not suffice. 

‘There is a limit as to how much and for how long trees can suck up CO2. At some point, a mature forest will completely stop capturing carbon. Thus, if China wants to be climate neutral, planting more trees won’t be enough. For this reason, it is crucial for them to drastically reduce emissions from fossil fuels. Nevertheless, in this study we observed what could be called a kickstart of their green transition,’ said Professor Fensholt, an expert in remote sensing and Earth observation ecology studies of terrestrial ecosystems at the University of Copenhagen. 

In related news, India, China, and the US were found to be the most sceptical countries when it comes to climate change. 

Image credit:  Iewek Gnos