In 2015, 170 countries around the world adopted the Paris Agreement. The goal is to limit the increase in average global temperature to 1.5°C. After signing, countries and cities set targets to reduce their emissions.
2% of the Earth’s surface
A new study published in the journal Frontiers in sustainable cities Presents for the first time the global balance of greenhouse gases emitted by the world’s major cities. Although these cities combined cover only 2 percent of the Earth’s total surface, they appear to be making a significant contribution to the climate crisis.
The researchers studied the emissions of 167 global cities in 53 countries and concluded that only 25 cities are responsible for 52 percent of harmful greenhouse gas emissions.
Today, more than 50 percent of the world’s population lives in cities. Cities are responsible for more than 70 percent of emissions, said Shaoking Chen of Sun Yat-sen University in China, co-author of the study, which gives them a major responsibility to decarbonize the global economy.
emission export
The cities studied were selected from countries in the Americas, Europe, Asia, Africa and Oceania. The results show that both developed and developing countries have megacities where carbon dioxide and other greenhouse gas emissions are high. Cities in Asia (such as Shanghai in China and Tokyo in Japan) appear to be major polluters, although per capita emissions data show that cities in Europe, the United States and Australia fared significantly worse than most cities in developing countries.
The researchers also consider it important to note that many developed countries are outsourcing high-carbon production chains to China, which increases export-related emissions in China.
houses and buildings
The main sources of greenhouse gas emissions were found to be the combustion of fuels and the use of electricity in homes and buildings (between 60 and 80 percent). In a third of cities, more than 30 percent of all emissions came from road transport. Total emissions from railways, waterways and aviation are 15 percent.
The results also show that thirty cities were able to achieve a significant reduction in emissions between 2012 and 2016. The top four cities with the largest drop in per capita emissions were Oslo, Houston, Seattle and Bogota. During the same period, researchers saw the largest increases in per capita in Rio de Janeiro, Curitiba, Johannesburg, and Venice.
