Scientists have long been concerned that global warming may push Earth’s climate system across a “tipping point,” where rapid melting of ice and further warming may become irreversible – a hotly debated scenario with an unclear picture of what this point of no return may look like. A newly published study by researchers at Oregon State University probed the geologic past to understand mechanisms of abrupt climate change. The study pinpoints the emergence of synchronized climate variability in the North Pacific Ocean and the North Atlantic Ocean a few hundred years before the rapid warming that took place at the end of the last ice age about 15,000 years ago. The study suggests that the combined warming of the two oceans may have provided the tipping point for abrupt warming and rapid melting of the northern ice sheets. Results of the study, which was funded by the National Science Foundation, appear in Science. This new discovery by OSU researchers resulted from an exhaustive 10-year examination of marine sediment cores recovered off southeast Alaska where geologic records of climate change provide an unusually detailed history of changing temperatures on a scale of decades to centuries over many thousands of years.
