The Sixth Mass Extinction—Earth’s first extinction event caused by a single species (us)—became shorthand for biodiversity collapse. The hashtag surged after the 2019 IPBES Global Assessment reported that 1 million species face extinction, extinction rates are 100-1,000x higher than background rates, and 75% of land and 66% of oceans are “severely altered.” Unlike past extinction events caused by asteroids or volcanism, this one has an agent: human activity (habitat destruction, overfishing, pollution, climate change, invasive species).

The Numbers and the Reckoning

Vertebrate populations declined 68% on average from 1970-2016 (WWF Living Planet Report). Insect biomass dropped 75% in 27 years (German study). Coral reefs faced 70-90% loss at 1.5°C warming, 99% at 2°C. 40% of amphibian species were threatened. The hashtag made abstract “biodiversity” concrete: fewer monarch butterflies, silent springs without bird songs, empty oceans. Scientists warned we’re undermining ecosystem services (pollination, water purification, carbon sequestration) that make human civilization possible.

The Insect Apocalypse

The “insect apocalypse” particularly alarmed. Studies showed catastrophic declines: 45% of insect species in rapid decline, 41% facing extinction. Flying insects decreased 75% in German nature reserves over 27 years. Puerto Rico’s rainforest insects (and the birds/frogs that ate them) plummeted 98% since 1970s. Causes: habitat loss, pesticides (especially neonicotinoids), light pollution, climate change. The hashtag’s wake-up call: insects aren’t gross—they’re the base of food webs and pollinate 75% of crops. If they collapse, we follow.

Half-Earth and Protected Areas

Conservation strategies evolved beyond protecting endangered species to protecting ecosystems. E.O. Wilson’s “Half-Earth” goal (protect 50% of planet’s surface) inspired the “30x30” campaign—conserving 30% of land and ocean by 2030, endorsed by 100+ nations at 2021 UN Biodiversity Conference (COP15). However, implementation questions loomed: Who decides what gets protected? Will Indigenous peoples be displaced? Can we protect ecosystems while feeding 10 billion people? The hashtag debated trade-offs between human needs and planetary health.

Climate Change Accelerant

The hashtag increasingly linked biodiversity and climate: forests sequester carbon, wetlands filter water, intact ecosystems resist climate shocks. Destroying ecosystems for palm oil or cattle both drives species extinction and accelerates warming. Conversely, climate change forces species migrations, disrupts phenology (timing of life events), and creates mismatches (pollinators emerging before flowers bloom). The hashtag’s sobering realization: climate and biodiversity crises are inseparable—solving one requires solving both.

Sources: IPBES Global Assessment 2019, WWF Living Planet Report, Nature insect decline studies, PNAS vertebrate extinction research, UN Convention on Biological Diversity COP15 documents, E.O. Wilson’s Half-Earth