Last week, I wrote about a study that had found warmer waters reaching the glaciers of Greenland, helping to melt those glaciers from below while warm temperatures melt them from above. This scenario presents numerous dangers for societies around the world. Faster melting glaciers means faster rising sea levels, which means more impacts sooner.
Today, I will write about a scenario that is potentially more threatening than glaciers melting faster than expected. New research demonstrates that the oceans are acidifying more quickly than has happened naturally for tens of millions of years. The threat that presents is when the last similar acidification event occurred, upwards of 50% of marine life went extinct. It took hundreds of thousands to millions of years to recover from this catastrophe. It is known as the Paleocene–Eocene Thermal Maximum, or PETM, and it happened 55 million years ago. The event saw global temperatures rise by around 6°C (11°F) over 20,000 years, with a corresponding rise in sea level as the whole of the oceans warmed. To put that warming in context, climatologists are warning that global temperatures could rise by a similar amount over ~200 years. That’s 100 times faster than the last rapid global warming event of similar magnitude.