What was the climate like in the Tertiary Period?

The climate of the Tertiary Period: A Window into the Earth’s Past

The Tertiary Period, also known as the Age of Mammals, spanned from about 66 million years ago to 2.6 million years ago. It was a time of significant geological and climatic change, providing an important window into Earth’s past climate dynamics. This article examines the climate of the Tertiary Period and sheds light on the different climatic conditions that prevailed during this fascinating era.

The Early Tertiary: A Greenhouse World

During the Early Tertiary, the climate was characterized by a greenhouse effect, resulting in relatively warm global temperatures. The absence of permanent ice caps and the distribution of lush forests around the globe are indicative of the warm and humid conditions that prevailed during this period.

The primary driver of the warm climate during the early Tertiary was the high concentration of greenhouse gases, especially carbon dioxide (CO2), in the atmosphere. CO2 levels were significantly higher than they are today, leading to increased heat retention and amplification of the greenhouse effect. This resulted in an overall increase in global temperatures, making the early Tertiary a greenhouse world.

Middle Tertiary: Transition to cooler climates

The Middle Tertiary witnessed a transition from the warm greenhouse climate of the early Tertiary to relatively cooler conditions. This cooling trend was driven by a combination of factors, including changes in ocean circulation patterns, tectonic activity, and a gradual decrease in greenhouse gas concentrations.

During this period, the global climate became more variable, with the development of seasonal temperature fluctuations and the emergence of distinct climatic zones. The expansion of grasslands, particularly in the later part of the Middle Tertiary, was a significant vegetation change that had implications for both climate and biodiversity.

The Late Tertiary: A World of Ice

The Late Tertiary, specifically the last 2.6 million years known as the Quaternary, marked a significant shift in Earth’s climate. This period is characterized by the expansion of ice sheets and the onset of glaciations, leading to the formation of polar ice caps and the establishment of the current Ice Age.
The late Tertiary was characterized by a series of glacial-interglacial cycles, with alternating periods of ice advance and retreat. These cycles were driven by variations in Earth’s orbital parameters, known as Milankovitch cycles, which affected the amount and distribution of solar radiation reaching the planet’s surface.

Tertiary climate and biodiversity

The changing climate of the Tertiary had profound effects on biodiversity. As the climate shifted from a greenhouse world to a cooler, more variable climate, it influenced the distribution and evolution of plant and animal species.

For example, the formation of grasslands in the mid-Tertiary provided new ecological niches for grazers such as horses and rhinoceroses, which underwent significant adaptive radiation during this time. In addition, the emergence of cooler climates in the late Tertiary facilitated the evolution of cold-adapted mammals, including mammoths, mastodons, and early humans.
Understanding the climate of the Tertiary is critical to understanding the Earth’s climate system and its response to various forcings. By studying past climates, we gain insight into the mechanisms that drive climate change, which is invaluable for predicting and mitigating the effects of current and future climate change.

In summary, the Tertiary period witnessed a transition from a warm greenhouse climate to cooler, more variable conditions, ultimately leading to the establishment of the current Ice Age. This period played a pivotal role in shaping Earth’s climate and biodiversity, highlighting the interconnectedness of climate and the natural world.


What was the climate like in the Tertiary Period?

The climate in the Tertiary Period, which lasted from about 66 million to 2.6 million years ago, underwent significant changes. Overall, it was warmer than the present, with periods of both extreme warmth and cooling.

Did the Tertiary Period experience any ice ages?

Yes, the Tertiary Period did experience several ice ages, although they were not as extensive or severe as the ice ages that occurred in more recent times, such as the Pleistocene Epoch. These ice ages were characterized by the growth of ice sheets in polar regions and the expansion of glaciers in mountainous areas.

What were the dominant climatic conditions during the Tertiary Period?

During the Tertiary Period, the dominant climatic conditions varied across different epochs. In the early Tertiary, known as the Paleocene and Eocene, the climate was generally warmer and more tropical, with high global temperatures and high levels of carbon dioxide in the atmosphere. In the middle and late Tertiary, the climate became cooler, transitioning to more temperate conditions.

How did the Tertiary Period climate impact plant and animal life?

The changing climate of the Tertiary Period had a significant impact on plant and animal life. The warm and tropical conditions of the early Tertiary supported the development of diverse forests and the expansion of various plant groups. As the climate cooled during the middle and late Tertiary, grasslands and savannas became more widespread, leading to adaptations in both plant and animal species.

Were there any notable events or phenomena related to Tertiary climate?

Yes, there were several notable events and phenomena related to the Tertiary climate. One significant event was the Paleocene-Eocene Thermal Maximum (PETM), which occurred around 56 million years ago. During this period, there was a rapid and substantial increase in global temperatures, likely due to the release of large amounts of carbon dioxide and methane into the atmosphere. The PETM had profound effects on marine and terrestrial ecosystems.