From the first birds and fish to pine trees, dinosaurs, woolly mammoths and humans, most life on Earth has evolved and flourished over the last roughly 500 million years. A new study documents how the Earth’s temperature changed in that time frame — carbon dioxide has been a driving cause of historic temperature increases. Using proxy data, geologic studies and climate models, researchers found that over the last 485 million years, the global mean surface temperature (GMST) of the Earth has varied between 11° Celsius (52° Fahrenheit) and 36°C (97°F). In other words, the average temperature of the Earth has stayed within that 25°C (45°F) degree window for the last half a billion years. High temperature periods often tracked with elevated atmospheric carbon dioxide (CO2) levels. “This research illustrates clearly that carbon dioxide is the dominant control on global temperatures across geological time,” Jessica Tierney, a paleoclimatologist at the University of Arizona and a co-author of the study said in a statement. “When CO2 is low, the temperature is cold; when CO2 is high, the temperature is warm.” The current GMST of the Earth is approximately 15°C (59°F). “Right now, we are still in an ice age,” Brian Huber, study co-author and paleobiologist with the Smithsonian National Museum of Natural History in the U.S., told Mongabay in a phone call. However, Huber added that based on what’s known from studies of past climate warming events, “we are warming the Earth faster than any other natural event that’s happened in geologic history.” Human-caused…This article was originally published on Mongabay
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