Humanity’s grand experiment in the atmosphere continues, and a new report documents just how far it’s gone.
On Tuesday, the National Oceanic and Atmospheric Administration released its annual index of 20 key greenhouse gases. It shows that their direct influence on the climate has risen 140 percent since 1750, with 40 percent of that rise coming in just the past 26 years. That increase is almost entirely due to human activities and has caused the planet to warm 1.8°F (1°C) above pre-industrial temperatures.
The index takes greenhouse gas measurements from about 80 ships and observatories around the world—gathered in all their parts per million and parts per billion glory—and boils them down into a simple numerical index. This year’s number: 1.4.
It’s a simple number that contains multitudes. For example, carbon dioxide is responsible for 54 percent of the overall increase in climate warming seen since 1990. The four other major greenhouse gases in the index, which include nitrous oxide, methane and two types of chlorofluorocarbons, are responsible for 42 percent of the increase with 15 minor greenhouse gases accounting for the missing 4 percent.
Carbon dioxide has risen rapidly in the atmosphere, with 2016 marking the second-largest annual increase ever observed at the Mauna Loa Observatory, the world’s main measuring station.