Industrial ecology, monitoring and remediation
In March 1958, Charles David Keeling recorded 313 ppm of CO₂ at Mauna Loa. By 2025, the annual mean reaches 427 ppm (May 2025 peak: 430.2 ppm; May 2026 peak: 432.00 ppm) — a 36% increase over 67 years, amounting to 114 ppm of uninterrupted measured rise.
In May 1985, Farman, Gardiner, and Shanklin published in Nature a 40% drop in stratospheric ozone over Antarctica — from 300 Dobson Units to 180 DU. A single chlorine atom from CFCs can destroy 100,000 O₃ molecules via a catalytic cycle. The Montreal Protocol (1987), ratified by 198 countries, reduced CFC production by 99%. Full recovery is estimated around 2066.