Record levels of greenhouse gases continue to trap heat in the atmosphere, according to NOAA’s annual analysis.
The Annual Greenhouse Gas Index tracks greenhouse gases being added to the atmosphere then calculates the heat being added to Earth’s atmosphere and oceans.
NOAA reports that the warming influence of the gases combined trapped the same amount of heat as an atmosphere instead containing CO2 at 500ppm.
The index is based on hundreds of air samples collected from sites in NOAA’s Global Greenhouse Gas Reference Network.
Each sample is analyzed at NOAA’s Global Monitoring Laboratory in Boulder, Colorado. It uses 1750 as a base level, and 1990 as 1.0 to measure how greenhouse gases have increased since the Kyoto Protocol to reduce pollution.
In 2019, the index rose to 1.45, meaning heat trapped in the atmosphere primarily attributed to human activity is 45% higher than in 1990.
Five greenhouse gases account for 96% of the increase, with CO2. having the largest influence.
Methane also rose significantly and is much more effective at trapping heat in the atmosphere than CO2.
Ozone depleting gases such as CFCs continue to decline due to controls adopted by the Montreal Protocol.