Earth Day’s Legacy: 20 Million Marchers, 2,253 Defenders Lost, and South Korea’s Climate Ruling

TL;DR: In 1970, 20 million people marched for the first Earth Day; since 2012, at least 2,253 environmental defenders have been killed or disappeared, about three per week; in 2024 South Korea’s Constitutional Court ruled the nation’s climate targets unconstitutional and mandated binding emissions cuts through 2049.

On April 22, 1970, an estimated twenty million Americans took to streets, parks and campuses to demand cleaner air, water and land. The demonstrations followed a massive oil spill off Santa Barbara the previous year that had galvanized public concern about pollution. Organizers tallied participation using police estimates, media reports and volunteer counts, arriving at the twenty‑million figure that is still cited today.

Global Witness documented the killings and disappearances of environmental defenders from 2012 through 2024 by monitoring news outlets, NGO reports and court records. Their methodology counts each verified incident where a person was killed, died in custody or disappeared after opposing projects related to land, water, forests or minerals. Over the thirteen‑year span, they recorded at least 2,253 cases, which averages to roughly three victims each week.

In February 2024, South Korea’s Constitutional Court heard a lawsuit filed by youth activists and NGOs who argued that the government’s greenhouse‑gas reduction goals violated the constitutional right to a healthy environment. The court examined scientific assessments showing the targets would fall short of limiting warming to 1.5 °C and concluded they were insufficient. It ordered the administration to enact legally binding cuts that will reduce emissions steadily through 2049, with interim milestones every five years.

The ruling marks the first time a high court in Asia has tied climate policy directly to constitutional rights, potentially shaping litigation elsewhere. Meanwhile, the persistent violence against defenders underscores that environmental progress often depends on individuals facing grave risk. Observers will watch how South Korea implements the court‑ordered cuts, whether other nations adopt similar rights‑based arguments, and if the annual Earth Day mobilizations continue to grow beyond the one‑billion‑person estimate reported in recent years.