The Blue Machine

Around 26,000 years ago, much of the Earth was extremely inhospitable by today’s standards. A quarter of all land was covered by permanent ice, and the average global temperature was 6 ° C lower than today. All of modern-day Canada and a significant chunk of the modern United States were covered by ice that formed a thick white barricade from the Atlantic to the Pacific. That water had come from the ocean, evaporated by the sun’s energy and then rained and snowed back down to freeze solid on land. So much water had been removed from the ocean and piled up on the continents that the sea level was around 120 metres lower than it is today. The Pacific Ocean was entirely cut off from the Arctic Ocean by new land which had been uncovered between Russia and Alaska. All the humans on the planet were on the western side of the vast Canadian ice barrier. 30 All of North and South America, with its giant sloths, sabre-toothed cats and woolly mammoths, lay on the other side.