After September 11, 2001, airplanes did not fly over the US for three days.  Given the opportunity to do a large scale experiment on the cheap, environmental and climate scientists jumped at the chance to measure the difference in air pollution with no planes in the sky.  There was an immediate effect, a reduction in air pollution and the cleanest skies in decades.

Empty skies after 9/11 set the stage for an unlikely climate change experiment

On the morning of September 11, 2001, officials at the U.S. national air control centre couldn’t make out what was happening, at first. [. . .] Officials at the U.S. Federal Aviation Administration did the only thing they could think of to try to control the situation: ordering every aircraft in U.S. airspace, about 4,000 of them, to land somewhere, anywhere, immediately.

[. . .]

“I remember walking to and from my office (in the days after the attacks) and thinking how incredibly clear the skies were,” Andrew Carleton, a geographer at Pennsylvania State University, later wrote.

About a year after the attacks, Carleton, David Travis, a geographer at the University of Wisconsin, and another colleague argued in a paper that thin clouds created by contrails reduce the range of temperatures. By contributing to cloud cover during the day, they reflect solar energy that would otherwise have reached the earth’s surface. At night, they trap warmth that would otherwise have escaped.

The effect during the three days that flights were grounded was strongest in populated regions where air traffic was normally densest. The increase in range came to about two degrees Celsius.

A change of two degrees celsius in just three days.  Imagine what the effect will be when roughly 90% of all air traffic worldwide stops, when more than two thirds of private car use ceases for months or even a year.  In barely one month of quarantine over most of the world, there has already been a noticeable environmental impact.  More below the fold.

The World Economic Forum talks only about NO2 emissions in this article:

Here’s how lockdowns have improved air quality around the world

The COVID-19 pandemic has caused industrial activity to shut down and cancelled flights and other journeys, slashing greenhouse gas emissions and air pollution around the world. If there is something positive to take from this terrible crisis, it could be that it’s offered a taste of the air we might breathe in a low-carbon future.

Measurements from the European Space Agency’s Sentinel-5P satellite show that during late January and early February 2020, levels of nitrogen dioxide (NO₂) over cities and industrial areas in Asia and Europe were lower than in the same period in 2019, by as much as 40%.

Reading that oil is now worth $0 (yes, zero dollars) per barrel is hilarious.  Especially when people aren’t allowed to drive.  From a BBC writer in India:

India coronavirus: Can the Covid-19 lockdown spark a clean air movement?

“This was an unprecedented opportunity for us to take a close look at how air pollution levels have responded to an extraordinary development,” Sarath Guttikunda, who heads Urban Emissions, an independent research group that provides air quality forecasts, told me.

Federal pollution control authorities quickly reported a marked improvement in air quality levels in 85 cities.

Dr Guttikunda and his team of researchers looked at the data spewed out by the 100-odd air quality monitoring stations all over India. They decided to concentrate on the capital Delhi and its suburbs – a massive sprawl called the National Capital region, where more than 20 million people live. Last winter, air pollution here had reached more than 20 times the World Health Organization’s safe limit.

[. . .]

“The current crisis has shown us that clear skies and breathable air can be achieved very fast if concrete action is taken to reduce burning of fossil fuels,” says Sunil Dahiya, of the Centre for Research on Energy and Clean Air, which has also been tracking air pollution levels during the lockdown.

But will this prompt change? After all, urban Indians’ and the media’s panic and outrage during the deadly winter pollution every year soon gets lost in the fog of summer heat and concerns over monsoon rains and droughts.

“We don’t yet have a democratic demand for clean air,” Arunabha Ghosh, Chief Executive Officer of the Council on Energy, Environment and Water, a leading climate think tank, told me. Orders to clean up the air have almost always come from the courts, responding to pleas by NGOs.

Multiple news sources such as The Guardian, NBC, Financial Times, Wired, and many others are writing about it. Imagine the reports from scientists in a year or two.

The item from Reuters makes the biggest point: If the enviromental impact of COVID-19 to have any lasting effect, we can’t go back to how we were living.  We have to keep fossil fuel and resource consumption where it is now.  Are people willing to be unselfish enough to accept this, to kill capitalism and choose survival?  Are we willing not to “kickstart economic recovery” and have a planet worth living in?

Coronavirus could trigger biggest fall in carbon emissions since World War Two

LONDON/WASHINGTON (Reuters) – Carbon dioxide emissions could fall by the largest amount since World War Two this year as the coronavirus outbreak brings economies to a virtual standstill, according to the chair of a network of scientists providing benchmark emissions data.

[. . .]

Experts warn that without structural change, the emissions declines caused by coronavirus could be short-lived and have little impact on the concentrations of carbon dioxide that have accumulated in the atmosphere over decades.

“This drop is not due to structural changes so as soon as confinement ends, I expect the emissions will go back close to where they were,” said Corinne Le Quéré, a climate scientist at the University of East Anglia in eastern England.

After world greenhouse gas emissions dipped in the aftermath of the 2007-2008 global financial crisis, they shot back up a whopping 5.1% in the recovery, according to Jackson.

Its inarguable that shutting down “the economy” has had and will continue to have a massive effect on the environment, potentially even slowing down things like shrinking Arctic and Antarctic ice.  The real question is: Are we going to learn this time as we should have learnt in 2001?  Or are we going to selfishly worry about short term and temporary stuff again?

We seem to never miss an opportunity to miss an opportunity.