A recent study published in the journal Science unveils a curve of global mean surface temperature that provides insights into Earth’s temperature variations over the Phanerozoic Eon, a period when life diversified, populated land, and experienced mass extinctions. The temperature curve also demonstrates a strong correlation between Earth’s temperature and the levels of carbon dioxide in the atmosphere. The study focuses on the last 485 million years due to limited geological data before that period.
The researchers utilized an approach called data assimilation to combine data from the geologic record and climate models to develop a comprehensive understanding of ancient climates. This method allows for hindcasting ancient climates, refining scientists’ understanding of how Earth’s temperature has fluctuated over time and providing essential context for studying modern climate change. The team found that global temperatures varied more significantly over the past 485 million years than previously assumed, with extreme heat periods typically associated with elevated levels of carbon dioxide.
The study emphasizes the critical influence of carbon dioxide on global temperatures throughout geological time, with lower CO2 levels corresponding to colder temperatures and higher CO2 levels leading to warmer temperatures. While the Earth’s current global temperature of 59 degrees Fahrenheit is cooler than much of the Phanerozoic period, human-driven greenhouse gas emissions are rapidly warming the planet, posing risks to species, ecosystems, and causing a rapid rise in sea levels. The rate of warming is surpassing even the fastest warming events of the past, potentially triggering mass extinctions.
The researchers warn that moving towards a warmer climate could pose dangers to humans who have adapted to a narrower range of global temperatures compared to the larger span observed in the last 485 million years. The planet has been warmer before, but the rapid pace of climate change driven by human actions outpaces the ability of humans and animals to adapt. The study highlights the urgency of addressing human-caused climate change to mitigate its adverse impacts on the planet and its inhabitants.
The collaboration between researchers at the University of Arizona and the Smithsonian aimed to create a curve presenting Earth’s global temperature over the Phanerozoic Eon. By gathering and combining data from various sources, including ancient temperature estimates and climate simulations, the team constructed a comprehensive and accurate picture of how Earth’s temperature has evolved over the past 485 million years. The findings provide valuable insights into climate sensitivity and the consistent relationship between carbon dioxide and temperature across geological time.
Overall, the study sheds light on Earth’s complex climate history and the significant role of carbon dioxide in dictating global temperatures over millions of years. By comparing past temperature variations to the current warming trend driven by anthropogenic activities, the research underscores the urgent need to address climate change to safeguard ecosystems, species, and humanity from the severe consequences of rapid global warming. The study’s findings offer a compelling case for immediate and coordinated action to curb greenhouse gas emissions and mitigate the impacts of climate change on the planet.