4817USGS: Getting Warmer? Prehistoric Climate Can Help Forecast Future Changes
- Nov 26, 2008The first comprehensive reconstruction of an extreme warm period
shows the sensitivity of the climate system to changes in carbon
dioxide (CO2) levels as well as the strong influence of ocean
temperatures, heat transport from equatorial regions, and greenhouse
gases on Earth's temperature. ...
Since CO2 levels during the mid-Pliocene were only slightly higher
than today's levels, PRISM research suggests that a slight increase
in our current CO2 level could have a large impact on temperature
change. Research also shows warming of as much as 18°C, bringing
temperatures from -2°C to 16°C, in the high latitudes of the North
Atlantic and Arctic Oceans during the mid-Pliocene.
Warming in the Pacific, similar to a present day El Niño, was a
characteristic of the mid-Pliocene. Global sea surface and deep
water temperatures were found to be warmer than those of today,
impacting the ocean's circulation system and climate. Data suggest
the likely cause of mid-Pliocene warmth was a combination of several
factors, including increased heat transport from equatorial regions
to the poles and increased greenhouse gases.