New Research Reveals Plants Caused Ice Ages

New research reveals how the arrival of the first plants 470 million years ago triggered a series of ice ages. Led by the Universities of Exeter and Oxford, the study is published in Nature Geoscience.

The team set out to identify the effects that the first land plants had on the climate during the Ordovician Period, which ended 444 million years ago. During this period the climate gradually cooled, leading to a series of 'ice ages'. This global cooling was caused by a dramatic reduction in atmospheric carbon, which this research now suggests was triggered by the arrival of plants.
 
Among the first plants to grow on land were the ancestors of mosses that grow today. This study shows that they extracted minerals such as calcium, magnesium, phosphorus and iron from rocks in order to grow. In so doing, they caused chemical weathering of Earth's surface. This had a dramatic impact on the global carbon cycle and subsequently on the climate. It could also have led to a mass extinction of marine life.
 
The research suggests that the first plants caused the weathering of calcium and magnesium ions from silicate rocks, such as granite, in a process that removed carbon dioxide from the atmosphere, forming new carbonate rocks in the ocean. This cooled global temperatures by around five degrees Celsius.
 
In addition, by weathering the nutrients phosphorus and iron from rocks, the first plants increased the quantities of both these nutrients going into the oceans, fuelling productivity there and causing organic carbon burial. This removed yet more carbon from the atmosphere, further cooling the climate by another two to three degrees Celsius. It could also have had a devastating impact on marine life, leading to a mass extinction that has puzzled scientists.
 
The team used the modern moss, Physcomitrella patens for their study. They placed a number of rocks, with or without moss growing on them, into incubators. Over three months they were able to measure the effects the moss had on the chemical weathering of the rocks.
 
They then used an Earth system model to establish what difference plants could have made to climate change during the Ordovician Period.
 
One of the lead researchers, Professor Tim Lenton of Geography at the University of Exeter said: "This study demonstrates the powerful effects that plants have on our climate. Although plants are still cooling the Earth's climate by reducing atmospheric carbon levels, they cannot keep up with the speed of today's human-induced climate change. In fact, it would take millions of years for plants to remove current carbon emissions from the atmosphere."
 
"For me the most important take-home message is that the invasion of the land by plants -- a pivotal time in the history of the planet -- brought about huge climate changes," said Professor Liam Dolan of Oxford University, one of the lead researchers. "Our discovery emphasises that plants have a central regulatory role in the control of climate: they did yesterday, they do today and they certainly will in the future."
 
The study was carried out by a team from the Universities of Exeter, Oxford and East Anglia and the John Innes Centre.

Download Center

  • Monitoring and Reporting on Air Emissions for Regulators and the Real World

    When it comes to managing compliance and regulatory issues surrounding air emissions, there are no easy jobs. With interviews from practitioners from American Electric Power, Red Cedar Gathering, Trinity Consultants, and Cority, this eBook provides practical advice to advance your air emissions monitoring and reporting programs.

  • What Every EHS Professional Should Know About ESG

    Join experts from Arcadis and Cority on April 27th to learn the most common ESG reporting frameworks and how technology can help you improve reporting efficiency, identify areas for improvement, and create defensible audit trails.

  • Green Quadrant EHS Software 2021

    Read the new report by independent analyst firm, Verdantix, to get an unbiased comparison of the 22 most prominent EHS software vendors in the industry.

  • RFP Template for Waste Management Software

    Learn the essential questions to ask when evaluating waste management software solutions with this free, ready-to-use RFP template

  • 5 Keys to Best-in-Class Chemical Management

    Running a safe chemical program is challenging and complex: from knowing what's on-site to proper handling and disposal - all while navigating regulatory changes. Learn the best ways to mitigate chemical risk, get the most value out of your data, and gain buy-in for a chemical management solution.

Featured Webinar