Part of Serpentine’s long-term climate crisis program, “Back to Earth” opens in London with arresting propositions. Works by Agnes Denes, Brian Eno, Carolina Caycedo, Formafantasma, Sissel Tolaas, and others present research, experiences, and interventions: A new edition of Alexandra Daisy Ginsberg’s Pollinator Pathmaker (2021), for example, algorithmically arranged 62 plant species in nearby Kensington Gardens to “serve the greatest diversity of pollinators.”