People around the world have noticed a remarkable change in air quality as a result of Covid-19 lockdowns. With factories and heavy industry closed, and with a massive reduction in traffic on the roads, the air cleared. Skies that had long held a murky, brown hue turned blue, hazy skylines became sharp and clear, choking smog became fresh air.
The most dramatic evidence has come in the form of images from some of the world’s major cities, such as New York, London, New Delhi and Beijing. Photos from before the pandemic show the skies grey and hazy with a hint of brown; during lockdown, the skies are a perfect blue. Satellite images, for example these from China and these from the USA show a similar pattern – areas of high pollution over cities before lockdown, the pollution gone after the cities were shut down. The images are stunning, but the nagging voice of scientific scepticism is ever present – how can we be sure that this is due to the lockdowns, and not something else? It’s possible, if you turn over a few stones, to find similar before and after photos from other times. The article I have linked to here, for example, shows images of Beijing under different weather conditions in the winter of 2012. And what about the Lunar New Year, a major holiday period in China during late January and early February? Surely that would have an impact as well?
To see whether the recent images represent a real change in pollution levels, we need to take a closer look at the types of pollution represented in the images, and at the data.
New Zealand’s Ministry for the Environment describes a wide range of air pollutants, from tiny particles, to odours from mushroom and pig farms. It is mainly particles, primarily from combustion but also the by-products of chemical reactions in the atmosphere and from natural sources such as dust, which affect visibility. The particles are too small to see individually, but collectively they have major impacts – as well as affecting visibility, they can also be carried deep into the lungs, where they cause irritation. As late as the 1970s, epidemiologists disagreed about the extent to which this kind of pollution, known as particulates, was harmful. Now, particulates smaller than ten microns in diameter, which is roughly one tenth of the thickness of standard photocopier paper, are well-recognised to have a range of health impacts.
A group of scientists in Hong Kong conducted a series of detailed comparisons between cities in China which did and didn’t have lockdowns, specifically looking at the most dangerous particulates, namely those smaller than 2.5 microns. They conducted a city-by-city analysis of lockdown policies and then used air quality data from 1600 monitoring stations, from both 2019 and 2020, to see how much the pollution levels differed between the cities which were locked down and those which weren’t. Because only a third of cities in China had lockdowns, they had plenty of data for cities which weren’t locked down, allowing them to account for factors such as the Lunar New Year holiday and variations in weather.
Their analysis showed that there was a real drop in pollution which resulted from the lockdowns. Particles smaller than 2.5 microns had decreased by about a quarter, while overall air pollution, as measured by the Air Quality Index, which combines values for five major air pollutants, decreased by 22%. These figures aren’t as dramatic as the images, but they are convincing evidence that Covid-19 lockdowns are, indeed, conferring unintended environmental benefits.
The Hong Kong scientists noted that the severity of China’s air pollution meant that any changes as a result of the lockdowns would be obvious. But what about other places, and other pollutants?
Another group of scientists, based in the USA and Canada, studied changes in nitrogen dioxide in twenty North American cities. Nitrogen dioxide is a pungent, corrosive gas, brown in colour, which mainly comes from the combustion of fossil fuels. Like particulates, nitrogen dioxide irritates the lungs and increases the risk of respiratory disease. It also gives smog its brown colour. As in China, the North American cities had a significant drop in pollution, even when fluctuations in weather conditions were taken into account. The numbers are remarkably similar to those seen in China – the average drop in nitrogen dioxide was just under 22%, although there was a wide variation, with some cities experiencing reductions greater than 40%, and others less than 10%.
We might not expect to see quite the same improvements in air quality in a place like New Zealand, which doesn’t have the same level of heavy industry, and has a lot of windy weather which is very effective at blowing air pollutants out across the Pacific Ocean. However, monitoring by our National Institute of Water and Atmospheric Research, usually referred to as NIWA, has also shown a decrease in pollution. Over the four weeks of Alert Level Four, there were reductions in nitrogen oxides, including nitrogen dioxide, of greater than 50% in our three largest cities. It’s unclear to me exactly why New Zealand would have seen greater reductions than cities in the USA, Canada and China, when we have less heavy industry and are presumably less polluted. One possibility is that our windy climate has dispersed pollutants more rapidly than in other countries, leading to a more rapid decline. Another possibility is that the more thorough analyses, which aimed to correct for factors such fluctuations in local weather, had a lower degree of sensitivity. However it may simply have been that they were monitoring different pollutants – the data for particulates show reductions more like those in China and North America.
While air pollution has decreased as a result of the Covid-19 pandemic, the situation is less rosy for plastic pollution. With mask-wearing required by many health authorities, and encouraged by many more, disposable surgical masks are being found in increasing numbers in the ocean. Other Covid-related waste includes gloves and bottles which once contained hand sanitiser.
Although, at first glance, recent reports of increased deforestation in the Brazilian areas of the Amazon would not appear to be linked to Covid-19, they do warrant a closer look.
In mid-January, Tasso Azevedo, the coordinator of a Brazilian group monitoring forest destruction, warned that deforestation in 2020 could exceed that of 2019, itself a record year, “unless something really big happens in the next two or three months to avoid the high season of deforestation that starts in May”. It’s hard to know what he was thinking of when he said “something really big”, but there’s now no doubt that something really big did actually happen – the Covid-19 pandemic. So what impact, if any, has this had on deforestation?
An optimist might have hoped that measures to control Covid-19 might restrict human activity, and therefore slow the deliberate destruction of the Amazonian forest, but there is no evidence that this has happened. In April, there were already reports that deforestation was increasing rather than decreasing. By June, Brazil’s national space agency, which monitors satellite data, was reporting a 34% increase in deforestation for January to May, as well as 2,248 fires during the month of June, compared to 1,880 in the previous June. Fires most commonly occur in recently logged areas, to clear them for farming. In July, Brazil’s space agency released data for June, showing yet another increase. Three days later, the head of the group responsible for reporting this data was sacked, with no explanation.
Deforestation in the Amazon was increasing before Brazil’s current president, Jair Bolsonaro, came to power at the start of 2019. However there was a surge in deforestation in 2019 which is directly attributed to his anti-environmental rhetoric and his dismantling of agencies supposed to protect the forest and a lack of effective enforcement. This has continued in 2020, although Bolsonaro himself has claimed he is being unfairly blamed and that Brazil has an exemplary environmental record.
Attributing any of this rainforest loss to Covid-19 is difficult, given that it seems to be simply a continuation of what happened in 2019. It would be reasonable to conclude that the Covid-19 pandemic, and any moves to try to control it, have made no difference to deforestation. However there is one piece of evidence which suggests something rather more sinister is going on.
In May, Brazil’s Supreme Court released a remarkable recording of a cabinet meeting in April where, among other things, Bolsonaro insulted the governors of Rio de Janeiro and Sao Paolo for trying to control Covid-19, and threatened to sack the head of the police force, or even the justice minister, because members of his family were being investigated for corruption. The justice minister, Sergio Moro, resigned two days after the meeting.
From that same cabinet meeting, there is a video clip from the environment minister, Ricardo Salles, which is relevant to our discussion here. Salles appears to be the kind of environment minister we would expect from Bolsonaro – a man who will attempt to discredit science which doesn’t support his agenda. According to official information from the Brazilian government, Salles was a popular choice for environment minister among those with a vested interest in continued deforestation and fewer environmental regulations in the Amazon – “construction and real estate companies, industry, trade, agriculture and livestock organizations”. There is no mention of him being supported by any environmental groups.
In the video, Salles can be seen saying, “We need to make an effort while we are in this calm moment in terms of press coverage, because they are only talking about COVID, and push through and change all the rules and simplify norms". By that time, Brazil had reported more than 43,000 cases of Covid-19, and more than 2,700 deaths.
When I began this article, it was the accelerating deforestation that I meant when referring to Brazil’s other disaster. But since then, a report has been released by UNICEF and the World Health Organisation warning of another disaster in the making while we are distracted by Covid-19. Childhood vaccination rates, already in decline, have fallen to an alarming degree. Brazil is one of ten countries which account for more than 60% of unvaccinated children, and it’s one of four that had seen declines of more than 20% in vaccination rates since 2015. One of the other four is Samoa – and I’m pretty sure that most of us haven’t forgotten about the measles outbreak there last year. More than eighty people died, the majority of them children under the age of five.
Brazil’s president has been outspoken about the need to keep the economy functioning in the face of the Covid-19 pandemic, but it’s yet to be seen whether he will show a similar commitment to maintaining childhood vaccinations. While, at this stage, the World Health Organisation is reporting only that Brazil’s vaccination campaigns may be postponed, with more than two million reported Covid-19 cases and nearly 80,000 deaths, it is hard to imagine that other health services will continue as normal.
It’s a timely reminder that, while Covid-19 is undoubtedly a serious disease, and absolutely warrants the global effort and attention it has received, we cannot forget the other problems we face. The survival of our children, and of a crucial part of our planet’s life support system, is under threat. We can’t afford to let ourselves be distracted.
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