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.

Greenhouse gasses, which result in global warming could result in biological, climatological, and other major changes across the world.

This study shows that the changes humans make to the earth today could lead to dramatic and irreversible changes on the planet.

The scientists induced a monumental reversal in the circulation of deep-ocean patterns around the world and analyzed the effects it had on the chemical composition of Nuttalides truempyi, tiny ancient sea creatures, which were collected from 14 different sites across the world.

Paleocene/Eocene Thermal Maximum (PETM) global warming that happened 55 million years ago emerged in less than 5,000 years and caused a number of important changes around the globe such as mass extinction of deep-sea bottom-dwelling marine life.

What the scientists are concerned about is that the today’s carbon dioxide input from fossil fuel sources to the earth's surface was approaching the same levels estimated for the PETM period.

The researchers came to conclusion that the massive release of greenhouse gases could leave long-term impact not only on the global climate, but in deep ocean circulation as well.