Global Temperatures To Rise To Levels Not Seen In 50 Million Years By 2300

Researchers have found that under the business-as-usual scenario, by 2300, the planet will see global temperatures reach a level that hasn’t been seen in 50 million years. Scientists compiled a climate record on Earth extending up to 66 million years into the past, the first time this has been done.

Published in the peer-reviewed journal Science last week (September 10), the new study examined past climate variations since the great extinction of the dinosaurs 66 million years ago. The research involved scientists from 12 different international laboratories using sample material collected from the ocean floor over the past five decades. It represents the first study to record a continuous and accurate trace of how the planet’s climate has changed. 

Using mathematical models and analysis, the scientists found four climatic states, which they dubbed Hothouse, Warmhouse, Coolhouse and Icehouse. Crucially, they found that while the Earth has previously experienced warm climate states, these were caused by extreme climate events and the warming that we’re experiencing now is anthropogenic and exceeds the natural variability seen in the past 66 million years. 

According to the scientists, our current levels of greenhouse gas emissions and other human activities causing ecological damage are driving the planet towards the Warmhouse and Hothouse states that haven’t been seen since the Eocene epoch that ended around 34 million years ago. During this period, there existed no polar ice caps and temperatures on the planet averaged around 9 to 14 degrees celsius higher than that of today. 

The IPCC projections for 2300 in the ‘business-as-usual’ scenario will potentially bring global temperature to a level the planet has not seen in 50 million years. In an extreme greenhouse world with no ice, there won’t be any feedbacks involving the ice sheets, and that changes the dynamics of the climate.

James Zachos, co-author of the study

“The IPCC projections for 2300 in the ‘business-as-usual’ scenario will potentially bring global temperature to a level the planet has not seen in 50 million years,” explained James Zachos, co-author of the study, distinguished professor of Earth and planetary sciences and Ida Benson Lynn Professor of Ocean Health at UC Santa Cruz.

“In an extreme greenhouse world with no ice, there won’t be any feedbacks involving the ice sheets, and that changes the dynamics of the climate.”

This latest study adds to the growing bed of scientific research providing evidence of the dire state the planet is in and what could happen on our current trajectory of climate inaction. Last week, a report from the Institute for Economics and Peace (IEP) found that as many as 1.2 billion people across 31 countries could face displacement within the next 30 years amid population growth and the effects of global heating. 

Another study, conducted by scientists at the Climate Impact Lab, finds that without a drastic reduction of carbon emissions, the number of deaths that will result from rising temperatures and more frequent and severe climate disasters could outnumber the loss of life from all infectious diseases combined. 

Lead image courtesy of picture alliance / M. Gann / McPhoto.