COVID-19 certainly isn’t something to celebrate, but with a dramatic decline in the movement of goods and people around the globe, the residents of some cities have enjoyed unprecedented improvements in air quality in recent weeks. These improvements offer a great opportunity to think clearly about climate change and about our capacity as a species to tackle it head-on.
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Here are 5 cities that saw the biggest air quality improvements during COVID-19 lockdowns and some thoughts on how to stop global greenhouse gas emissions bouncing back to previous levels.
Los Angeles
Air quality is normally so bad in Los Angeles that the LA Times has an online mapping project showing high-pollution zones within 1,000 feet and 500 feet of the city’s freeways. An estimated 2.5 million Californians live in these areas with high air pollution. Nearly 1.25 million people live within 500 feet of a freeway, which is too close for homes, schools, and daycares, according to scientists.
Los Angeles lockdowns have offered a glimpse of clear roads and clear skies, however. In the first two weeks of March, as schools and businesses closed and more people stayed home, air pollution plummeted. Atmospheric nitrogen dioxide (largely a product of car and truck emissions) was significantly lower compared to 2019 levels, according to data from the European Space Agency’s Sentinel-5P satellite.
Those folks who did venture out may well have been shocked at how quickly they could get from A to B. Data from INRIX, a company that analyzes traffic data, found that traffic in the city moved 53% faster during the 8 am Wednesday ‘rush hour’ and a whopping 71% faster at 5 pm, where bumper to bumper traffic is an accepted fact of life on the freeways of LA. Without commuting and errands and the school run, rush hour has all but disappeared.
And LA isn’t alone in the state; Since the shelter in place order went into effect, the California Department of Transportation estimates a 40% drop in daily traffic crossing eastbound on the Bay Bridge between San Francisco and Oakland.
California NO2 emissions – 2019 March 1 to March 19 / 2020 March 1 to March 19
Source: Sentinel-5P satellite data processed by Descartes Labs
Seattle
Like LA, Seattle also had a significant decrease in traffic in March 2020. The city had one of the earliest recognized coronavirus outbreaks and stay-at-home orders went into effect quite a bit earlier than in other parts of the US.
By March 8th, morning rush hour trips into downtown Seattle had dropped by almost 40%, according to INRIX. Saturday traffic also declined as people cancelled social activities and postponed recreational forays. There was a short-lived surge in traffic to bulk stores and grocery stores early in the month as folks stocked up, but traffic dropped off precipitously, leading to lower traffic associated emissions and clearer skies for much of March.
Washington NO2 emissions – 2019 March 1 to March 19 / 2020 March 1 to March 19
Source: Sentinel-5P satellite data processed by Descartes Labs
New York
New York City is one of the hardest hit cities in the world in terms of coronavirus cases, and while NYC residents are less likely to use cars than residents of other metropolises, vehicle traffic also declined considerably in March 2020 compared to normal levels. Like in LA, this meant that the traffic that was on the roads moved faster, 36% faster according to INRIX data.
Researchers at Columbia University have also been monitoring the changes in the city in recent weeks. They noted that carbon monoxide emissions in NYC declined by more than half in the week leading up to March 13th, associated with a drop in the number of cars on the road.
New York NO2 emissions – 2019 March 1 to March 19 / 2020 March 1 to March 19
Source: Sentinel-5P satellite data processed by Descartes Labs
Venice and Milan
Alright, so I’m rolling two cities into one, but Venice and Milan are pretty close to each other and both saw significant decreases in air pollution during their lockdowns in early March. Again, the European Space Agency’s Sentinel-5P satellite tracked NO2 emissions (which can be affected by weather but are closely linked to vehicle traffic) and found a major drop in emissions across northern Italy as people stayed home.
As in LA and other big cities, Venice and Milan both suffer with smog, especially in winter when low pressure systems hold air-pollution in place. During the lockdown, researchers at the Bocconi University reported dramatic declines in NO2 emissions, likely because of big reductions in traffic. They also noted declines in particulate matter, a major human heath irritant associated with burning fossil fuels.
Milan NO2 emissions – 2019 March 1 to April 5 / 2020 March 1 to April 5
Source: Financial Times
Wuhan
Wuhan is where the novel coronavirus was first detected, so it’s not surprising that some of the first observable impacts on air quality were seen in the Chinese city. The government put strict lockdown orders in place in late January, with a dramatic impact on manufacturing activity and the generation of electricity. Nearly 35 million people were effectively immobilized and air pollution (and likely wastewater pollution from manufacturing) fell accordingly.
Researchers at NASA observed significantly lower NO2 emissions over this region of China during January and February. There’s usually a week-long drop in pollution at the end of January or in early February associated with the Lunar New Year celebration, but this time the drop persisted for many weeks. Some residents will have seen skies clearer than ever before in their lifetimes.
Source: Financial Times
What does it all mean?
Just looking at the handful of cities above shows that human activity has a significant effect on air quality and global greenhouse gas emissions. There’s no hiding from satellite data and as cities, states, and countries open back up, emissions have also bounced back.
For some government officials and climate activists, those few weeks of lockdown offered a real opportunity to highlight the benefits of greener living. Fewer cars on the road, a switch to renewable energy, people-powered transport and electric vehicles, more stringent regulations around factory emissions, and just a slower pace of life in general can lead to stark improvements in air quality. And as the world is threatened by a major respiratory disease, making changes to support improved air quality seems particularly timely.
Interestingly, the lockdowns have led both directly and indirectly to decreases in fossil fuel consumption. Reductions in manufacturing, transport, and electricity to power offices mean less fossil fuel is being burned and renewable energy sources such as wind turbines and solar arrays cost little to keep running, meaning they’re still operating at close to full bore while coal power plants are operating at a greatly reduced rate. In early April, worldwide daily fossil fuel emissions were around 17% lower than at the same time in 2019, according to one study.
The result is a world on track to reduce global greenhouse gas emissions by nearly 8% in 2020, according to the International Energy Agency. Of course, the good news for climate change comes at the expense of nearly half a million deaths from COVID-19 at the time of writing and massive economic upset. With luck, hard work, good policy, and a populace coming together, we can hopefully curtail more deaths and lessen economic trauma. To sustainably reduce emissions, though, climate change itself needs to be recognized as a global disaster for the economy and health.
Will air quality improvements stoke enthusiasm for a green recovery?
Short-term improvements in air quality in US cities and elsewhere in the world are likely to have some immediate health benefits. Any such benefits may be offset by the coronavirus itself, however, as well as by the impact of lockdowns and economic trauma on access to healthcare and the general physical and mental wellbeing of people worldwide.
Without determination to make reductions in road, air, and ocean traffic emissions permanent, air pollution will rebound quickly. Indeed, it already has in many places. And the health impacts of air pollution tend to be seen over the longer-term anyway, so any excitement over this brief blip of clearer air needs to be put in perspective.
Global emissions need to fall nearly 8% every year between now and 2030 to keep global warming under 3.6 degrees Fahrenheit, the figure seen as the tipping point for catastrophic climate change. This means taking steps now to restart economies in a greener, more sustainable way. But, by the middle of June, with lockdowns and stay-at-home orders lifting, emissions increased to just 5% below 2019 averages. Emissions in China have already returned to normal, and China accounts for around 25% of global carbon pollution.
Big structural change is needed to divest from the gas-powered cars, power plants, planes, and industry if there’s any hope of reaching that 8% annual drop in emissions. Unfortunately, fears over public transport may actually lead to higher traffic volumes as people return to work and normal daily activities. And even folks in the US who continue working at home are likely to use more electricity in the coming months as air-conditioners become necessary during a summer predicted to be even hotter than average.
In Europe, policymakers released a plan in May to transition the continent away from fossil fuels. The $826 billion stimulus package includes measures such as expanding wind and solar power, investing in hydrogen as a fuel source, and retrofitting old buildings to improve energy efficiency. Paris and Milan have added many miles of new bike lanes (great for electric bikes!), as has my nearest city, Vancouver, in Canada.
However, in China, electric vehicle incentives have been rolled out, but new coal plants have also been given the go ahead. And in the US, the current administration has rolled back 100 environmental regulations, including those focused on emissions from power plants and vehicles.
If more governments pushed for a ‘green’ recovery, researchers suggest there could be a reduction in atmospheric CO2 of up to 19 parts per million by 2050, compared to a fossil fuel-focused recovery. In the meantime, if you’ve been able to breathe a little easier these last few months you may want to consider the impact of your own return to ‘normal’ activity. Reduce, reuse, recycle gets us only so far. Another part of the equation is considering the environmental impact of household goods across their lifecycle, from manufacture to end of life. As you venture back out into stores, then, check in with LeafScore.com to see if you can find a more eco-friendly version of what’s on your shopping list. And if we haven’t yet covered it, give us a shout!