The UN now accepts that global warming will exceed 1.5°C, and climate scientists conclude that the rate of warming has roughly doubled in the past decade. The concern is that the climate may be nearing tipping points: thresholds past which a change feeds itself. In 2018 a team led by Earth system scientist Will Steffen warned that continued emissions and biodiversity loss could set off a cascade of feedbacks leading to Hothouse Earth, a state much warmer than today that humans could not reverse by cutting emissions. Examples of feedbacks include melting ice exposing darker surfaces that absorb more heat, and warming that dries forests and releases stored carbon. The harder warming gets, the more these loops push, so each increment is harder to undo.

Hampi is a UNESCO World Heritage Site in Karnataka, India, with more than 1,600 surviving remains spread over 4,100 hectares. It was the capital of the Vijayanagara Empire from 1336 to 1565. Travellers from Persia and Portugal described it as a prosperous, wealthy and grand city with temples, markets and farms along the Tungabhadra River. By 1500 it was estimated to be the world's second-largest city after Beijing, and probably India's richest at the time. In 1565 a coalition of Muslim sultanates defeated the Vijayanagara Empire, its capital was conquered and destroyed, and the city was left in ruins. Hampi remains a religious centre, with the active Virupaksha Temple at its heart.