jonathan overpeck

Surprises from Past Could Spell Longer Droughts, Rising Sea Levels

Abrupt climate changes could lead to decade-long droughts and massive sea-level rise, according to a University of Arizona geoscientist who studies the climate of the distant past. Factors that influence the climate system, such as natural changes in the Earth’s orbit or rising carbon dioxide emissions from cars and power plants, can result in dramatic climate shifts, says Jonathan Overpeck, a professor of geosciences and director of the UA Institute for the Study of Planet Earth. Scientists studying natural climate records, such as the variations in tree rings and gas bubbles trapped in the polar ice caps, find ample evidence of these types of rapid changes in the past — sometimes occurring in a decade or less.

Global Warming, Climate Changes May Make Mass Extinction Unavoidable

Worldwide efforts to protect plant and animal species may not be enough to avoid a mass extinction in the face of unexpected climate changes and global warming, says an international team of researchers. While the Earth’s climate is never stable, natural records of the past — such as fossils, ice cores, corals, and lake sediments — reveal that the species and ecosystems of today evolved within a specific range of climate conditions. The scientists are concerned that human activities, such as increased carbon dioxide emissions into the atmosphere, may push the climate outside of its current range, with devastating impacts on species around the globe.