Seattle-area air quality is a bit better as the novel coronavirus shuts down economic activity and travel.

Levels of nitrous oxide (NOX), a pollutant produced by tailpipe emissions and other sources, are being detected at generally lower values in local air-monitoring devices. And a satellite that detects emissions in the atmosphere linked to cars and trucks shows declines in pollution over the Seattle area in March 2020 compared with March 2019.

But efforts to “flatten the curve” – the rate of spread of the coronavirus — have not even dented a different curve also of great importance to humanity around the world: The Keeling Curve.

The Keeling Curve is a record of global atmospheric carbon dioxide concentration maintained by the Scripps Institution of Oceanography at the University of California at San Diego. Over the past 62 years since measurements began, the curve has gone, except for seasonal variation, in only one direction: relentlessly upward. Right through the collapse of the Soviet Union in the late 1980s. Through the global economic turndown of 2008. To record levels, without stopping. And so it continues, even now as public life grinds to a near standstill.

Ralph Keeling – his late father, Charles, invented the measurement —  said even greater declines in fossil fuel use than we are presently seeing would need to be sustained for at least a year to show up clearly in global carbon dioxide levels.

Yet history has shown that emissions typically surge back to normal along with everything else after a crisis is past.


Keeling, a professor of geochemistry at UC San Diego, sees in the present rate of emissions an analogy in turning down the tap on a filling tub. The tub is still full, even though it’s filling less quickly.

“We are on a different trajectory, but if the economy recovers and fuel burning jumps back up, we will be back on the same trajectory with a little lag,” Keeling said.

“This is a cumulative problem; there is a huge pile of emissions we have added to the atmosphere. We have to cut emissions really drastically before you would see that drop. Local pollution clears up, that is a good thing. But I am talking about the global background.”

Carbon dioxide lasts many centuries in the atmosphere, where it acts as heat-trapping insulation in earth’s atmosphere. A little is a good thing: Carbon dioxide is what keeps the sun’s heat from radiating back to space, allowing life and agriculture on Earth as we know it.

But the burning of fossil fuels since the Industrial Revolution means people are adding carbon dioxide to the atmosphere far faster than earth’s natural ability to absorb it, in trees, plants and soil, and in the ocean.

The biggest contributors of greenhouse gases, including carbon dioxide, are human activities, including power generation, especially by coal burning; industrial processes, especially energy-intensive cement manufacture; and transportation. A rule adopted by the Trump administration rolling back auto fuel-efficiency standards will cause tailpipe emissions to further increase, worsening global warming.

“This rule will worsen air quality and increase greenhouse gas emissions, threatening public health and accelerating the damage caused by climate change,” Laura Watson, director of the Washington State Department of Ecology, said Tuesday in a prepared statement. The department is reviewing its legal options to fight the rule, including a lawsuit under the Clean Air Act, Watson said.

In addition to altering the climate, there is so much carbon dioxide mixed in the ocean today that it is changing the sea’s chemistry. Ocean acidification is damaging sea life.


Will the coronavirus pandemic teach people new habits, as week after week they undertake work at home and decrease travel? Could new habits reduce emissions enough to help the planet, long term?

“A lot depends on what the world is like when we come out of this, and how people behave,” Keeling said. “For changes that are positive for climate change, many of the things people are learning how to do now, they can continue to do. Do I have to go to every meeting, or is online good enough?”

Washington State Climatologist Nick Bond, like everyone else, is working remotely these days, attending conferences and conducting meetings and teaching online. “Conceivably we are being forced to do some of the things we should be doing anyway. … There may be some blessings in disguise.”

But in the short term, it’s not enough to make a difference in global warming.

“A lot of people are saying this is good for the climate problem. No, not really,” said Pieter Tans, senior scientist with the National Oceanic and Atmospheric Administration’s Global Monitoring Division. To bend the Keeling Curve, emissions from fossil-fuel burning would need to be cut by half, and then continue to decrease, Tans said. Even a 25 percent reduction would result in only a few tenths of one part per million decrease.“It would be hard to see it in the record, to pick it out of the noise of natural variability. Maybe if we have a long downturn, maybe we begin to see something above the noise.”


China, the world’s biggest greenhouse gas emitter followed by the U.S., saw at the height of its economic shutdown during the pandemic an estimated 25 percent drop in emissions, the equivalent of a 6 percent drop in global emissions, according to a report by Lauri Myllyvinta, analyst at the Center for Research on Energy and Clean Air. Economic activity in China already is beginning a return to normal, right along with emissions from steel-blast furnaces, coal burning and more, he added.

Long term, the global reality since the Industrial Revolution, Tans said, has been a steady increase both in the total amount of atmospheric levels of carbon dioxide and the rate of increase. Levels today are higher than at any time in at least 800,000 years. No human has ever breathed this atmosphere before now.

Even locally, air-pollution declines are not overall as great as might be supposed as a result of driving less and lower economic activity because of the coronavirus.

“It’s a bit of a mixed bag,” said Craig Kenworthy, executive director of the Puget Sound Clean Air Agency, which monitors air quality in the region. “Roadway pollution is down, which makes sense: There is less traffic.” But the amount of very small particular pollution is actually up,  probably because so many people are home burning fireplaces and wood stoves.

“My request to the public would be if you are not burning wood for heat, if you are doing it just because you like looking at the fireplace, please don’t,” Kenworthy said. “Viruses like irritated lungs better.

“Please think of your older neighbors and please don’t put pollution into the atmosphere.”


Very tiny particulates are dangerous to human health because they can pass directly from the lungs to the blood. Particulate pollution is linked to aggravated asthma, irregular heartbeat and even premature death.

Traffic-related air pollution such as NOX also is associated with a range of health effects including exacerbating asthma.

While any reduction in air pollution is welcome, Kenworthy sees no silver lining in the pandemic. “This is not the way I want to see pollution levels reduced.”

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