Just 25 mega cities, 23 in China, produce world's greenhouse gas emissions, study finds

THE world's most greenhouse gas emissions come from just 25 big cities - 23 of which are located in China, a study has found.

The mega cities that emit the most greenhouse gases are Handan, Suzhou, Dalian, Beijing and Tianjin in China - including Tokyo and Moscow.

As part of his commitment to the Paris Agreement, China's president Xi Jinping has pledged to cap carbon emissions by 2030 and achieve carbon neutrality by 2060.

On the other hand, the United Kingdom has pledged to reduce its emissions by 68 per cent by 2030 and reach a carbon-neutral footing by 2050.

The researchers of the study from the Sun Yat-sen University have for the first time recorded greenhouse emission levels of 167 cities across the world. The team says though the cities cover two per cent of the Earth's surface but they are responsible for the climate crisis.

Currently, China is running a massive 1,058 coal-fired power plants — equal to more than half of the world's entire capacity.

The researchers conducted sector-level greenhouse gas emissions inventories of 167 cities from 53 different countries.

"Nowadays, more than 50 per cent of the global population resides in cities," paper's author and urban environmental management researcher Shaoqing Chen of the Sun Yat-sen University in Guangzhou, was quoted as saying.

"Cities are reported to be responsible for more than 70 per cent of GHG emissions, and they share a big responsibility for the decarbonization of the global economy.

"Current inventory methods used by cities vary globally, making it hard to assess and compare the progress of emission mitigation over time and space," he added.

The study also found that high level of emissions were found in both developed and developing countries, but said megacities like Shanghai and Tokyo were significant emitters.

It also added that cities in Europe, the US and Australia put out more emissions than the majority of urban cities in developing countries.

Of the 42 cities with available longitudinal data, the team found that emissions decreased for 30 locations between 2012 and 2016, with the largest per capita reductions seen in Oslo, Houston, Seattle, and Bogotá.

In contrast, the largest increases in per capita emissions over the study period were seen in Rio de Janeiro, Curitiba, Johannesburg, and Venice.

According to the team, 113 of the 167 cities studied set targets for reducing their levels of greenhouse emissions, with 40 having carbon neutrality goals, but the findings show that they are long way off meeting Paris Agreement targets.