The Emissions Impact of Coronavirus Lockdowns

There’s a high chance you’re reading this while practicing social distancing, or while your corner of the world is under some type of advised or enforced lockdown.

While these are necessary measures to contain the spread of the COVID-19 pandemic, such economic interruption is unprecedented in many ways—resulting in some surprising side effects.

The Evidence is in NO₂ Emissions

Nitrogen dioxide (NO₂) emissions, a major air pollutant, are closely linked to factory output and vehicles operating on the road.

As both industry and transport come to a halt during this pandemic, NO₂ emissions can be a good indicator of global economic activity—and the changes are visible from space.

These images from the Centre for Research on Energy and Clean Air (CREA), as well as satellite footage from NASA and the European Space Agency (ESA), show a drastic decline in NO₂ emissions over recent months, particularly across Italy and China.

NO₂ Emissions Across Italy

In Italy, the number of active COVID-19 cases has surpassed China (including the death toll). Amid emergency actions to lock down the entire nation, everything from schools and shops, to restaurants and even some churches, are closed.

Italy is also an industrial hub, with the sector accounting for nearly 24% of GDP. With many Italians urged to work from home if possible, visible economic activity has dropped considerably.

This 10-day moving average animation (from January 1st—March 11th, 2020) of nitrogen dioxide emissions across Europe clearly demonstrates how the drop in Italy’s economic activity has impacted the environment.

Source: European Space Agency (ESA)

That’s not all: a drop in boat traffic also means that Venice’s canals are clear for the time being, as small fish have begun inhabiting the waterways again. Experts are cautious to note that this does not necessarily mean the water quality is better.

NO₂ Emissions Across China

The emissions changes above China are possibly even more obvious to the eye. China is the world’s most important manufacturing hub and a significant contributor to greenhouse gases globally. But in the month following Lunar New Year (a week-long festival in early February), satellite imagery painted a different picture.

Source: NASA Earth Observatory

NO₂ emissions around the Hubei province, the original epicenter of the virus, steeply dropped as factories were forced to shutter their doors for the time being.

What’s more, there were measurable effects in the decline of other emission types from the drop in coal use during the same time, compared to years prior.

Back to the Status Quo?

In recent weeks, China has been able to flatten the curve of its total COVID-19 cases. As a result, the government is beginning to ease its restrictions—and it’s clear that social and economic activities are starting to pick back up in March.

Source: European Space Agency (ESA)

With the regular chain of events beginning to resume, it remains to be seen whether NO₂ emissions will rebound right back to their pre-pandemic levels.

This bounce-back effect—which can sometimes reverse any overall drop in emissions—is [called] “revenge pollution”. And in China, it has precedent.

—Li Shuo, Senior climate policy advisor, Greenpeace East Asia

In 2010, China’s urban-dwelling population surpassed its rural population, marking a monumental demographic milestone in the country’s history.

Just three decades prior, China looked markedly different. Only 20% of Chinese citizens lived in urban areas, and many of today’s metropolises were still small villages.

Since then, huge swaths of the population have moved from farmland into cities, a shift that is still causing many urban areas to swell in size. Case in point is the growth of Guangzhou, which lays just north of Hong Kong. From 1980 to today, more than 18 million people moved into the city. A 40-year-old born in Guangzhou will have seen their small, regional city mushroom into one of the largest urban amalgamations on Earth.

Of course, this is just one example of a process that has been altering the landscape of cities from the coast of the South China Sea out to the Eurasian Steppe.

The One Million+ Club

According to Demographia’s World Urban Areas report, there are now 113 urban areas in China that surpass the one million population threshold. In comparison, North America and the EU combined have 114 urban areas that surpass one million people.

Below is a full breakdown of China’s one million+ club:

Unparalleled Urbanization

The massive scale of rural-to-urban migration isn’t just a major development within China, it has no parallel in modern history.

Since 1980, over half a billion people have moved from the countryside to an urban center. The construction of these new cities took a staggering amount of raw materials. Few data points highlight the scale of construction better than China’s cement production in recent years.

In 2018, Chinese construction used about 8x the amount of second place India, which has a similar population size.

Megacities on Megacities

Cities with over 10 million inhabitants are defined as megacities. China is already home to six megacities, with another three urban areas well on the way to achieving that status.

In fact, some megacities within close proximity have grown so large that they are merging into contiguous urban areas. The most prominent example of this phenomenon is in the Pearl River Delta region of China.

The Pearl River Delta region is not only home to the megacities of Guangzhou and Shenzhen, but also a number of other sizable cities that are quickly merging into a unified continuous entity containing up to 50 million people. Demographia still considers most of these cities to be separate labor markets ⁠— but as more connections form across the region, the Pearl River Delta could be poised to become the largest unified urban area in human history.

Westward Migration

As megacities like Shanghai and Shenzhen have grown and developed, they’ve also become more expensive places to live and do business. The economic evolution of these cities has created opportunity for smaller, less developed cities to woo both residents and businesses.

This natural reshuffling has led to impressive growth in cities further inland like Zhengzhou, which sits 350 miles (630 kms) east of the coastline where many of the country’s largest cities reside.

Using the “build it and they will come” approach, the city converted a 160 square mile (410 sq km) patch of empty land into the Zhengzhou Airport Economy Zone (ZAEZ). The project has proven wildly successful, and the city even has the nickname “Apple City” thanks to the presence of Foxconn (which produces the iPhone) and a cluster of other smartphone manufacturers.

This airport-centered zone was developed with the full political and economic backing of Beijing as part of a broader effort to increase economic activity in China’s interior cities. Zhengzhou has nearly tripled in size over the last decade, a powerful testament to the shift in economic momentum.

China’s Inland All-Stars:

Compare the numbers above to fast-growing cities in the U.S., such as Las Vegas or Phoenix, which managed 33% and 12% growth respectively over the last decade.

If this trend continues, China’s one million+ club will most likely expand once fresh census data is released in 2021.