The dramatic changes and unprecedented high UV levels caused early humans to seek shelter in caves, explaining the apparent sudden flowering of cave art across the world 42,000 years ago. The study draws together multiple lines of evidence that strongly suggest the effects were indeed global and far-reaching. Ancient New Zealand kauri trees that had been preserved in peat bogs and other sediments for more than 40,000 years were analyzed, revealing a prolonged spike in atmospheric radiocarbon levels caused by the collapse of Earth’s magnetic field.
As the Earth’s magnetic field weakens, its satellites start to fail. The Earth’s magnetic field protects life from cosmic rays, energetic particles that would otherwise arrive from space. However, as the Earth’s magnetic field weakens, its satellites start to fail, and cosmic rays start to bombard every living thing on Earth. The kauri trees are like the Rosetta Stone, helping us tie together records of environmental change in caves, ice cores, and peat bogs around the world. Using the newly-created timescale, researchers can now investigate what happened during this critical period in Earth’s history and understand the potential consequences of future changes in the Earth’s magnetic field.