Wildfires are burning through the carbon budget that humans have allocated themselves to limit global heating, a study shows. The authors said this accelerating trend was approaching – and may have already breached – a “critical temperature threshold” after which fires cause significant shifts in tree cover and carbon storage. …Forests are going up in smoke in Brazil, the US, Greece, Portugal and even the Arctic Circle amid the Earth’s two hottest years in recorded history. Each fire has a double impact on the global climate: first, by emitting carbon from the burned trees, and second, by reducing the capacity of forests to absorb carbon dioxide. …Other research showed the Amazon is undergoing a “critical slowing down”, with more than a third of the rainforest struggling to recover from drought after four supposedly “one-in-a-century” dry spells in less than 20 years. These compounding impacts are turning forests from carbon sinks into carbon sources.