Accomplishments of the Earth System Evolution Program

• CIFAR researchers have been major contributors to the Snowball Earth hypothesis, which proposes that the entire Earth was ice-covered for long periods 600-700 million years ago, and that each glacial period lasted for millions of years, ending violently under extreme greenhouse conditions. These climate shocks may have triggered the evolution of multicellular animal life. This hypothesis has opened a whole new field of inquiry that seeks to understand the extreme climatic conditions that could have led to this scenario.
• Program member Sean Willett co-authored an article that has opened up an entirely new area of study: the relationship between earthquakes and climate. This research showed that earthquakes are significantly larger after erosion sediments cover subduction zones, places where one tectonic plate meets and slides underneath another. It seems that the weight of the sediment keeps the underlying wedge of the plate from bending. This rigidity translates into a zone where earthquakes of great magnitude regularly occur. Since sediments produced by erosion are largely a function of local weather conditions, this research reveals climate’s direct effect on subsequent geological events.
• Program Director Jerry Mitrovica contributed to a study confirming that an ocean covered one-third of the surface of Mars at least two billion years ago. There had been some doubt as to whether long, undulating geological features on Mars could mark the remnants of ancient shorelines because there were mountain-sized variations in their elevation, unlike the relatively flat shorelines on Earth. The new research shows that the difference between Earth and Martian shorelines is explained by a 50-degree shift of Mars’ spin axis at some point in its past. The change in the planet’s orientation resulted in the deformation of its landscape and shorelines.