About 245 million years ago, when all the continents on Earth were fused into one continent called Pangaea, North and South America were more closely packed together. The current shape of Mesoamerica (Middle America) began to emerge as Pangaea broke up, and North and South America separated, not to be rejoined again until about 3 million years ago. This reconnection happened as two tectonic plates moved against each other, causing volcanoes to erupt, which created islands. Sediment gradually filled in among the islands. This had an enormous impact on Earth’s climate, because it reconfigured the ocean currents. Since the Atlantic current could no longer flow into the Pacific Ocean, it turned north up the coast of North America and over to Europe, carrying warm water from the Caribbean that raised temperatures in Europe.
