Washington: A much clearer picture of the Earth`s temperature nearly 50 million years ago, when Carbon Dioxide (CO2) concentrations were higher than current levels, has emerged.
A new study by researchers from Syracuse and Yale Universities may shed light on what to expect in the future if CO2 levels keep rising.
"The early Eocene Epoch (50 million years ago) was about as warm as the Earth has been over the past 65 million years, since the extinction of the dinosaurs," says Linda Ivany, associate professor of earth sciences at Syracuse University, who led the study, reports the journal Geology.
"There were crocodiles above the Arctic Circle and palm trees in Alaska. The questions we are trying to answer are how much warmer was it at different latitudes and how can that information be used to project future temperatures based on what we know about CO2 levels," she said.
Previous studies have suggested that the polar regions (high-latitude areas) during the Eocene were very hot - greater than 30 degrees centigrade (86 degrees Fahrenheit), according to a Syracuse statement.
However, because the sun`s rays are strongest at the Earth`s equator, tropical and subtropical areas (lower latitude) will always be at least as warm as polar areas, if not hotter. Until now, temperature data for subtropical regions were limited.
The Syracuse and Yale research team found that average Eocene water temperature along the subtropical US Gulf Coast hovered around 27 degrees centigrade (80 degrees Fahrenheit), slightly cooler than earlier studies predicted.
The new results indicate that the polar and sub-polar regions, while still very warm, could not have been quite as hot as previously suggested.