Over the centuries, religions have been dramatically reshaped by sudden climate shifts. As the world faces an unprecedented ecological crisis, a historian sees the possible emergence of new religious movements and new faiths

Climate change and global warming are now an inescapable feature of the headlines, and that presence will only increase as the United Nations Climate Change Conference, COP26, draws closer. Whether arising from titanic volcanic eruptions, growing or shrinking levels of solar activity, or from changes in the El Niño cycle in the oceans, disasters arising from sudden climate shifts have remade history – and have reshaped the world’s religions.

These climate shocks have had a terrifying impact on the lives of ordinary people. When temperatures fell and farming became all but impossible, the results were swift and devastating. Famines and attendant plagues killed millions, while terrified and angry people sought scapegoats to blame for the mounting horrors they saw around. Rebellions, civil wars and massacres readily followed such ­climate crises. The Four Horsemen of Revelation rode unchecked. History offers a stark warning of some of the consequences we are likely to face in the near future.

There have been climate emergencies every century or so, but some were especially harrowing. One occurred around the year 1320, at the start of the Little Ice Age. That era is best remembered for the wild flowering of paranoia and conspiracy theories directed against outsiders and imaginary enemies of all kinds – against Jews, witches, lepers and heretics. In Catholic Europe, this was the time when the Church formally approved the ­theory that witchcraft was not just an underhand kind of supernatural malice, but a whole alternate religion of evil, with its satanic pacts and sabbats. The first of what would become the standard model of witch trials occurred at Kilkenny in 1324. This was also the time that extremely pious critics of the Church’s wealth found themselves condemned as heretics to be sought out and slaughtered: inquisitors literally demonised groups like the Spiritual Franciscans and the Beguines. Meanwhile, Islamic societies decided that it was the Christians who were inciting divine anger, and they inflicted ruinous purges and persecutions on the once mighty Churches of Egypt and Mesopotamia. For societies around the world, the years around 1320 were unforgettably horrible.