Reports from Italy detail the grim reality of a nation in a lockdown. All businesses, except pharmacies and food stores, have closed their doors. Airlines are canceling flights and roadblocks are preventing people from leaving or entering some cities.
Other reports present how dramatically American life could change if COVID-19 spreads rapidly in the United States.
Many American cities are already encouraging "social distancing" practices. Schools and universities are temporarily closing or switching to remote learning platforms. Conferences, music festivals and other public events are being canceled or going virtual.
These types of interruptions will become more serious in the coming weeks. They could also come with an unexpected side effect: an impact on carbon emissions.
The spread of the virus has caused a drop in global greenhouse gas emissions. The reasons include a temporary hit to industrial activities in China, falling demand for oil and a decline in air travel.
In China, the world's largest carbon emitter, experts estimate that emissions over the past month have been about 25% lower than normal.
These effects are not totally unexpected. History suggests that global disasters, particularly those with major effects on the economy, tend to cause a temporary decrease in carbon emissions. The 2008 recession, for example, was accompanied by a temporary drop in global carbon emissions.
On a local scale, the climate impact of an epidemic is more complex: it is likely to depend on a wide variety of changes in the way people go about their daily lives, from how often they leave their homes to how they travel through their cities how they do their shopping.
Scientists are still working to understand how quickly the new coronavirus will spread, how it might respond to the changing climate, and why it affects some demographics more severely than others.
As a result, the virus can also teach scientists something about the complex relationships between everyday human behaviors, their response to large-scale disasters, and their carbon footprints.
"Pull a string here, and it affects everything else," said Christopher Jones, a climate policy expert at the University of California, Berkeley, and lead developer of the CoolClimate Network, a research consortium focused on tools for reducing carbon emissions.
"With the economy and carbon footprints so intertwined, you really quickly start to have all these complex interactions," he explained.
THE EFFECT OF STAYING AT HOME
Transportation is already having an impact in parts of the United States.
Schools and universities are closing campuses across the country, and many companies are encouraging their employees to work from home. In places like New York City, officials are warning residents to be careful on public transportation, where it is often impossible to avoid close contact with large crowds of people.
Some data indicates that school closings and work-from-home mandates have already reduced traffic flow around Seattle. Reports from data analysis company Inrix point to significant increases in traffic speed in the Seattle area as roads emptied.
Similar statistics have suggested that rush hour traffic has also decreased in New York City, according to Crain’s New York Business.
And reports from Bay Area Rapid Transit, which serves San Francisco, said the number of passengers on public transit has fallen precipitously in recent weeks. BART ridership fell 8% between the end of February and the first week of March. And it was 25% lower in the second week of March than in the last week of February.
In some circumstances, a decrease in the number of passengers on public transport might suggest that people are driving more. But in this case, "I would say that if the number of passengers in transit is low, all vehicle trips are also low," Jones said. "I think it's just an indicator that people are staying home more."
The transportation sector is the largest contributor to greenhouse gas emissions in the United States. As schools and businesses close their doors, reducing travel could temporarily reduce carbon emissions in communities where people spend the most time at home.
Less vehicle traffic, on its own, looks good for the weather. But there is a potential catch.
"There have been many studies done on the benefits of telecommuting, and the conclusion is generally that it 'depends,' Jones said.
If people spend more time in their homes, they could be using more energy. It largely depends on weather conditions, geography, and different family lifestyles.
"If you go back to a cold house and have to heat it up, that will more than make up for the savings of not driving your car to work, on average," Jones said. "If you come home on a beautiful day like we have in California, and there was home anyway, we're really not using much more energy than if I were at work.
There is also the possibility that people will spend more time watching television or using appliances if they are locked in their homes, said Jacqueline Klopp, co-director of the Center for Sustainable Urban Development at Columbia University. "That could end up consuming more energy," he said.
Pandemics like COVID-19 could also lead to less obvious behavior changes, which can nevertheless affect a household's carbon footprint.