Last Update: 04/05/2026 at 2:50 PM EST
Snowball Earth Still Showed Climate Cycles
Coverage from EarthSky, EurekAlert!, and others
Articles
6
Latest Article
02/20
Active Days
23
Executive Summary
Scottish varves and climate models show Snowball Earth still had recurring climate cycles when small ice-free ocean patches remained
- Researchers analyzed about 2,600 varves from the Garvellach Islands in Scotland
- The rocks date to the Sturtian glaciation during the Cryogenian period
- Layer thickness patterns show annual to centennial climate cycles
- Some signals resemble El Nino-like oscillations and solar cycles
- Models found a fully ice-sealed ocean would suppress most oscillations
- Climate interactions could resume if about 15 percent of the ocean stayed ice-free
- The findings support brief tropical oases or slushball states during Snowball Earth
Quick Facts
- What: Ancient varves and models revealed Snowball Earth oscillations
- Where: Garvellach Islands and Port Askaig Formation in Scotland
- Why: Small ice-free ocean patches could sustain climate variability and refuges
- Who: University of Southampton researchers led the study
- When: During the Sturtian glaciation about 720 to 660 million years ago
Coverage Timeline: 23 Days
Featured Article
University of Southampton researchers report climate oscillations during Snowball Earth based on varved rocks near Garvellach Islands, Scotland, dating to the Sturtian glaciation.
Additional Articles
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University of Southampton researchers report in Earth and Planetary Science Letters (2020s) that Garvellach varves and models show tropical ice-free oases and climate oscillations during Snowball Earth in Scotland.
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University of Southampton scientists report climate oscillations during Snowball Earth in Scotland during the Sturtian glaciation
Scientists model ancient climate to show seafloor weathering may control duration of Snowball Earth events.
In February 2026, University of Southampton scientists reported that Scottish Cryogenian varves and climate models reveal active climate oscillations during Snowball Earth when limited tropical oceans stayed ice-free.
In February 2026, University of Southampton scientists reported that Scottish Cryogenian sediments and climate models reveal intermittent climate oscillations during the Sturtian Snowball Earth glaciation.