When COVID-19 pandemic began in the US, counties and cities across the nation imposed stay at home orders, closed schools or imposed travel restrictions. From March 2020 onward, many Americans hung up car keys and settled into their homes for work and school. Traffic patterns dramatically changed, and previously smog filled vistas became clearer.
NOAA’s Annual Greenhouse Gas Index tracks the concentrations of greenhouse gases being added to the atmosphere principally from human-caused emissions. The AGGI then calculates the heat being added to Earth's atmosphere and oceans as a result.