According to new research on past climates, the average temperature of Earth’s surface 500 million years ago was much warmer than today.
During this evolutionary period for terrestrial animals and plants, the global average temperature fluctuated around 24°C and sometimes reached as high as 36°C. This is in stark contrast to the current temperature, which is approximately 14°C to 15°C.
Emily Judd, from the Smithsonian National Museum of Natural History in Washington, D.C., stated that their new research indicates that temperatures during greenhouse climate periods (characterized by high CO2 concentrations) could have been even warmer than previous studies suggested.
Simulation image of the Cretaceous period. (Photo: MasPix).
Specifically, during the hottest periods, the average temperature in the tropics could reach up to 42°C, making some areas too hot for both plants and animals to survive. Even polar regions during this time experienced average temperatures exceeding 20°C, significantly higher than today.
Judd noted: “Over the past half billion years, there may have been times when certain areas were uninhabitable or had very low biodiversity, severely impacting ecosystems and life on Earth at that time.”
Her team also discovered a strong correlation between atmospheric carbon dioxide (CO2) levels and global average temperatures. Over an extended period, the team had anticipated that this relationship would weaken due to factors like sunlight. However, research results indicated that the correlation between CO2 and temperature remains very strong.
“This is quite surprising,” Judd remarked. “It implies that atmospheric carbon dioxide levels may play an even greater role in regulating Earth’s climate than previously thought.”
Experts have long been aware that for most of the past 500 million years—an era known as the Paleozoic Era—Earth was warmer than it is today and did not have any major ice sheets.
Judd emphasized that the fact that the climate was once much warmer than now does not mean that humanity should not be concerned about climate change. What matters is the rate of change.
In the past, periods of rapid climate change led to mass extinctions because species could not adapt quickly enough. The current rate of warming is even faster than those historical periods.
Currently, global warming and climate change present significant challenges for humanity, including dwindling water resources, stronger and more frequent storms, rising sea levels, and a reduction in habitable and arable land.
