A little-known index is key to understanding how the Earth's climate continues to build up heat in the air and oceans, resulting in sweeping changes across the globe.
Why it matters: Known as the Annual Greenhouse Gas Index, or AGGI, which NOAA produces, it clearly shows that despite numerous agreements and goals for cutting greenhouse gas emissions, the ability of the atmosphere to trap extra heat keeps growing.
Details: This year the AGGI rose to a value of 1.43, meaning that the increase in the atmosphere’s heat-trapping capacity attributable to human activity has risen 43% since 1990. James Butler, who directs NOAA's air monitoring program, tells Axios the growth in the AGGI is accelerating.
- "It’s a measure of what we’ve already committed towards causing climate to change,” Butler says. "Since 1990, we’ve added 43% more long-lived greenhouse gases than in the previous 240 years.”