Learn More
During the warm early Pliocene (approximately 4.5 to 3.0 million years ago), the most recent interval with a climate warmer than today, the eastern Pacific thermocline was deep and the average west-to-east sea surface temperature difference across the equatorial Pacific was only 1.5 +/- 0.9 degrees C, much like it is during a modern El Niño event. Thus, the(More)
The Earth's climate has undergone a global transition over the past four million years, from warm conditions with global surface temperatures about 3 degrees C warmer than today, smaller ice sheets and higher sea levels to the current cooler conditions. Tectonic changes and their influence on ocean heat transport have been suggested as forcing factors for(More)
The Paleocene-Eocene Thermal Maximum (PETM) has been attributed to a rapid rise in greenhouse gas levels. If so, warming should have occurred at all latitudes, although amplified toward the poles. Existing records reveal an increase in high-latitude sea surface temperatures (SSTs) (8 degrees to 10 degrees C) and in bottom water temperatures (4 degrees to 5(More)
Deep-time palaeoclimate studies are vitally important for developing a complete understanding of climate responses to changes in the atmospheric carbon dioxide concentration (that is, the atmospheric partial pressure of CO(2), p(co(2))). Although past studies have explored these responses during portions of the Cenozoic era (the most recent 65.5 million(More)
[1] Thirteen laboratories from the USA and Europe participated in an intercomparison study of Mg/Ca and Sr/Ca measurements in foraminifera. The study included five planktonic species from surface sediments from different geographical regions and water depths. Each of the laboratories followed their own cleaning and analytical procedures and had no specific(More)
SCIENCE sciencemag.org I n June, the Obama Administration unveiled its proposal for a Clean Power Plan, which it estimates would reduce carbon dioxide (CO 2 ) emissions from existing U.S. power plants 30% below 2005 levels by 2030 (see the chart). Power plant emissions have declined substantially since 2005, so the plan is seeking reductions of about 18%(More)
IN THE 16 SEPTEMBER 2011 issue, Science published the Report “Unclicking the click: Mechanically facilitated 1,3-dipolar cycloreversions” by J. N. Brantley et al. (1). After concerns were raised in an e-mail to the editors from a reader, the corresponding author supervised a comprehensive evaluation of all data presented in the original manuscript by(More)
  • 1