Greenhouse gasses which result in global warming may result in biological, climatological, and other major changes across the world. The chemical composition of Nuttalides truempyi, which are tiny ancient sea creatures were analyzed by the researchers Richard Norris and Flávia Nunes belonging to the Scripps Institution of Oceanography at the University of California, as a part of the research. The samples were collected from 14 different sites across the world.
They probed a four- to seven-degree warming period some 55 million years ago during the closing stages of the Paleocene and the beginning of the Eocene eras, and used data for constructing a monumental reversal in the circulation of deep-ocean patterns around the world.
Researchers said that the study in effect says that changes in the earth's environment can trigger long lasting changes as had happened 55 million years ago, which changed the environment for close to 20,000 years.
"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 anthropogenically induced global warming) could lead to dramatic changes to our planet," Nature quoted Prof Nunes as saying.
They said that the global warming of 55 million years ago, known as the Paleocene/Eocene Thermal Maximum (PETM), emerged in less than 5,000 years and set in motion a host of important changes around the globe, including a mass extinction of deep-sea bottom-dwelling marine life.
Fossil records indicate key migrations of terrestrial mammal species during this time-including evidence of the first horses and primates in North America and Europe, which were possibly allowed by warm conditions that opened travel routes which were not possible under previously colder climates, the study said.
Researchers said that modern carbon dioxide input from fossil fuel sources to the earth's surface was approaching the same levels estimated for the PETM period, and this was a matter of concern.
They said that man-made changes might have lasting effects not only on the global climate, but in deep ocean circulation as well.
"Overturning is very sensitive to surface ocean temperatures and surface ocean salinity. The case described in this paper may be one of our best examples of global warming triggered by the massive release of greenhouse gases. It gives us a perspective on what the long-term impact is likely to be of today's greenhouse warming that humans are causing," said Prof. Norris.
"Overturning"-a conveyor belt-like process in which cold and salty water exchanges with warm surface water-drives the warm water to the deep sea, releasing stores of methane gas that leads to further global warming and a massive extermination of deep-sea marine life, they said.