Smog-filled cityscapes have become a common scene around the world, a problem that some metropolises have battled for decades. On Friday, four mayors from major cities – Paris, Mexico City, Madrid and Athens – decided to take a drastic action: They want to eliminate all diesel vehicles from their roads by 2025.
The pledge, made during the 2016 C40 Mayors Summit that was held in Mexico City the last week in November, is part of a global effort by city leaders to tackle climate change issues. The proactive approach is driven by need: Cities disproportionately suffer from alarming air pollution levels and host more than half of the world's population. In recent years, the United Nations has also held global conferences convening city leaders to discuss climate issues, declaring that the battle for sustainable development will be “won or lost in cities.”
“Mayors have already stood up to say that the climate change is one of the greatest challenges we face,” Anne Hidalgo, the mayor of Paris and chair of the C40 Cities Climate Leadership Group, said in a Friday statement. “Today, we also stand up to say we no longer tolerate air pollution and the health problems and deaths it causes – particularly for our most vulnerable citizens. Big problems like air pollution require bold action, and we call on car and bus manufacturers to join us.”
Cities are also responsible for most of the world's pollution, as the Christian Science Monitor’s Henry Gass previously reported: Urban centers cover less than 2 percent of the Earth's surface but use up nearly 80 percent of energy, and produce 60 percent of all CO2 and other greenhouse gas emissions, according to the United Nations.
Diesel-powered vehicles may be a popular regulations target because of their pollutants, linked to a variety of environmental and health impacts.
"The scientific basis for understanding that there are both cardiovascular and respiratory effects from traffic-related air pollution is stronger and consistent, and it warrants creative approaches to reduce those impacts," Joel Kaufman, interm dean and professor at University of Washington's School of Public Health tells the Monitor in a phone interview.
Diesel-powered vehicles were at first touted as a more efficient, low-carbon emission source. But subsequent research found that it also emits particulate matter (PM) and nitrogen oxides, both substances with links to various respiratory and cardiovascular problems.
The most obvious impact, however, may just be how the pollution obscures the view and makes the air difficult to breathe. Paris, for instance, has seen its famous landmark, the Eiffel Tower, shrouded in a smog in recent years. In response, Ms. Hidalgo implemented a measure to ban diesel vehicles made before 2011 from entering the city by 2020. India took similar steps in Delhi just this month, while Seoul will start to implement diesel-lowering restrictions in 2017. In the United States, regulations are in place to limit the sulfur present in diesel fuel.
Some environmental groups say the mayors' 2025 deadline is too far away, although many applaud them for leading the way, perhaps inspiring other cities to adopt similar initiatives.
Other solutions suggested by attendees of the C40 summit include a transition to electric, hydrogen, and hybrid vehicles, as well as further investment in walking and cycling infrastructure.
“It is no secret that in Mexico City, we grapple with the twin problems of air pollution and traffic,” said the mayor of Mexico City, Miguel Ángel Mancera. “By expanding alternative transportation options like our Bus Rapid Transport and subway systems, while also investing in cycling infrastructure, we are working to ease congestion in our roadways and our lungs.”