A few decades ago there as a time, when scientists thought that the cloud formation over the Pacific waters can set the temperature level. At the same time, they thought that the cloud formation can also decide the how hot tropical areas can get. Therefore, they introduced a thermostat hypothesis model that time. 

Though, recently scientists have claimed that there is no need of such model. At the same time, they have also shown that there is a possibility that the temperatures may have exceeded the hypothetical limit 56 million years ago.

The concept of thermostat hypothesis was first proposed back in the year of 1991. When this hypothesis was introduced scientists and researchers across the world gave warm welcome to it. At that scientists have claimed that there is no chance that the sea level temperature will be greater than the average temperature 31 deg celsius. It is mainly because of the cloud formation over the tropical areas.

But the reality is completely different. Recent stats have shown that the temperature in the tropical areas has raised above the average temperature of 31-degree celsius at regular intervals. 

According to a report from Purdue University, an evidence is shown which tells during a period called the 'Paleocene-Eocene Thermal Maximum' (PETM) it has been the warmest sea in the world. The PETM existed on the planet earth over 100 million years ago.

As stated in the Science Advances, if there was no tropical thermostat the world would not witness this huge amount of biodiversity. At the same time, the human population in the world would get affected by a significant amount. The most affected places would be tropical rain forests, Brazil and India.

Till now, there are few confusions over the temperature of tropical seas. But this confusion can be easily cleared with some additional research in future.