It's really interesting how a tiny little shell from a sea creature living millions of years ago can tell us so much about past ocean conditions. We can tell approximately what the temperature was at the bottom of the ocean. We also have an approximate measure of the nutrient content of the water the creature lived in. And, when we have information from several locations, we can tell the direction of ocean currents. |
The Earth is a system that can change very rapidly. Fifty-five million years ago, when the Earth was in a period of global warmth, ocean currents rapidly changed direction and this change did not reverse to original conditions for about 20,000 years. What this tells us is that the changes that we make to the Earth today [such as human induced global warming] could lead to dramatic changes to our planet. |