Daily Management Review

A Few Cities Contribute Over Half Of Urban Greenhouse Gas Emissions; New Study


A Few Cities Contribute Over Half Of Urban Greenhouse Gas Emissions; New Study
A latest analysis of emissions trends shows that more than half of the climate-warming gases pumped out by a total of 167 urban hubs around the world was accounted for by just 25 big cities – and almost all of them are in China.
In a study published in the open access journal Frontiers in Sustainable Cities, researchers however found that in terms per capita emissions, the cities in the richest parts of the world stull holds higher position in rankings compared to the urban regions of developing countries.
Greenhouse gas emissions as reported by 167 cities in 53 countries were compared in the report and concluded that 23 Chinese cities – including Shanghai, Beijing and Handan – as well as Moscow and Tokyo, were responsible for 52 per cent of the total global emissions of all the cities combined.
More cities from China, India, the United states and the European Union were included in the study because these regions accounted for more proportion of the global emissions and had significant relation with the climate change debate.
Study co-author Shaoqing Chen, an environmental scientist at Sun Yat-sen University in the southern Chinese city of Guangzhou, said the significant role cities play in reducing emissions was highlighted in the findings of the study.
"It is simple, logical," he said. "If you don't act, eventually you will suffer from (climate change)," he said.
Compared to the pre-industrial levels, the average global temperature has already risen by more than 1 degree Celsius, and is on track to exceed the 1.5-2 degree limit set by the Paris Agreement.
However as some of the cities in the study reported numbers from as far back as 2005, the some of the data available for use in their study was patchy, cautioned Chen and other scientists of the study.
They added that comparisons were also tricky because of a lack of consistency within cities in the manner in which they report emissions,
A much larger sample of 13,000 cities, big and small were analysed in a research published in 2018 in the Environmental Research Letters journal which found that 18 per cent of the global carbon footprint was accounted for by just 100 cities that were home to about 11 per cent of the global population.
Despite the smaller number of cities compared in this latest study, the analysis "contributes to the growing literature and our understanding of urban emissions", said Yale University Geography and Urban Science professor Karen Seto, who was also a co-author of the 2018 paper.
"It's really difficult to compare apples to apples on city greenhouse gas emissions but you have to try, and the paper makes a pretty good effort," added Dan Hoornweg, a professor at Ontario Tech University and former adviser to the World Bank on sustainable cities and climate change.
This latest study was also the first of its kind that looked into megacity emissions reduction targets and progress in curbing emissions, Chen said. Absolute emissions reduction targets had been set by 68 of the cities – mostly in developed countries. However, a reduction was seen only in 30 of the 42 cities where progress was tracked in the study.