October 6, 2023 – A research study conducted by Hebrew University of Jerusalem (HU) Ph.D. candidate, Kaushal Gianchandani, under the guidance of Professors Nathan Paldor and Hezi Gildor from the Institute of Earth Sciences at Hebrew University, in collaboration with HU’s Prof. Ori Adam and Sagi Maor, along with Dr. Alexander Farnsworth and Prof. David Lunt from the University of Bristol, UK, unveiled a previously unknown mechanism that significantly influences Earth’s climate. This cutting-edge research, published in Nature Communication, applies a novel analytic model developed by the three Hebrew University researchers two years ago, focusing on wind-driven circulation at the ocean’s surface and highlighting the pivotal role of ocean basin geometry. 

The research primarily focused on the climate during the Cretaceous period, which occurred approximately 145 to 66 million years ago. This period is of interest because it was characterized by high levels of carbon dioxide in the atmosphere, which is a greenhouse gas that can influence global temperatures. The researchers looked at how big ocean swirls, which move warm water from the tropics to the poles, influenced the temperature difference between these two regions. This temperature difference is crucial for understanding why there were so many different kinds of plants and animals during the Cretaceous period. 

In their research, the scientists aimed to uncover the complex relationship between changes in ocean current patterns (gyral circulation) that result from the arrangement of continents on Earth and variations in temperature gradients during the Cretaceous era when dinosaurs roamed the Earth. To do this, they conducted a thorough analysis using computer models that simulate ancient climates. Their findings revealed that the movement of Earth’s continents during the Cretaceous period caused a slowdown in the large swirling ocean currents responsible for carrying warm water from the equator to the poles. This slowdown disrupted the way the ocean regulated its surface temperatures, resulting in a significant increase in temperature differences between the poles and the tropics during that time. These findings align with geological evidence from the Cretaceous era, providing a more comprehensive understanding of past climate dynamics. Understanding how these currents influenced temperature differences between the poles and the tropics is crucial for comprehending the biodiversity and climate of the Cretaceous period. 

While the study primarily focused on the Cretaceous period, it has implications for our understanding of contemporary climate systems. It highlights the importance of ocean gyres (circulation patterns) in shaping climate dynamics, both in the past and today. It underscores the complexity of Earth’s climate and the strong effect that processes other than CO2 concentration might have on it.  

This research helps gain insights into the complex relationship between ocean circulation patterns, equator-to-pole temperature differences, and past climate conditions. While it primarily contributes to our understanding of Earth’s ancient climate, it also underscores the significance of oceanic processes in shaping contemporary climate systems. This knowledge can potentially aid in modeling and predicting the impacts of climate change in the modern era, as ocean circulation patterns continue to play a crucial role in regulating global climate. 

The study, titled “Effects of paleogeographic changes and CO2 variability on northern mid-latitudinal temperature gradients in the Cretaceous” can be found at https://www.nature.com/articles/s41467-023-40905-7 

Research Team: Kaushal Gianchandani-1, Sagi Maor-1, Ori Adam-1, Alexander Farnsworth-2,3, Hezi Gildor-1, Daniel J. Lunt-2 & Nathan Paldor 

Institutions:
1- Institute of Earth Sciences, Hebrew University of Jerusalem 

2- School of Geographical Sciences and Cabot Institute, University of Bristol 

3-State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing