Equable Climate? What Does That Mean?

During various points in the Earth's history, the global climate has been equable. You are probably wondering what an equable climate is. Simply put, it is a period in Earth's history when the temperature was roughly equal everywhere in the world. In the past, this state existed because the poles were significantly warmer than they are currently, while the Tropics remained at roughly present day temperatures. For a more in-depth explanation, click on the "Climate" tab above.

How Do We Know About Equable Climates?

Scientists have been able to determine that the Earth's climate was equable in the past by using the natural records left by plants, animals, and rocks. People have found ancient fossils in regions where the organisms would not be able survive today because the areas would be too cold for them. Additionally, the chemical composition of ancient sea organisms' shells differs from the composition of their present-day equivalents in a way that suggests the poles were warmer. By using natural records like these examples, scientists have been able to ascertain that certain periods in Earth's history had equable climates. Click on the "Evidence" tab above to learn more about this topic.

Why Would The Climate Have Become Equable?

Some event or mechanism must have triggered the transition of the climate to an equable state, but scientists have not determined the instigating event or mechanism yet. It is challenging to determine the cause because the change in the climate was regionally specific. As a result, any explanation for the change must alter only the high-latitudes' climate and must not affect the climate in the low-latitudes. Scientists have proposed a number of theories that explain how more heat could have been carried to the poles or how the poles could have absorbed more heat, but they have not reached a consensus yet. Thus, the cause of equable climates is still open for debate. Click on the "Theories" tab to read more about possible explanations for equable climates.