Scientists Identify Possible 'Tipping Point' of Global Warming

Scientists have long been concerned that global warming may push the Earth's climate system past a "tipping point," and a new study from Oregon State University (OSU) may have finally identified that threshold.

According to the research, synchronization of climate variability in the North Pacific and North Atlantic Oceans is that tipping point - where rapid melting of ice and further warming may become irreversible. This is what happened 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, published this week in the journal Science, suggests that this combined ocean warming may have forced the Earth's climate past the point of no return.

"Synchronization of two major ocean systems can amplify the transport of heat toward the polar regions and cause larger fluctuations in northern hemisphere climate," lead author Summer Praetorius, a doctoral student in marine geology at Oregon State, said in a press release. "This is consistent with theoretical predictions of what happens when Earth's climate reaches a tipping point."

For those nervous about our current predicament with global warming, Praetorius is quick to point out that this research doesn't necessarily mean that the same thing will happen in the future, "but we cannot rule out that possibility," she said.

Over a period of 10 years, the OSU team examined marine sediment cores recovered off southeast Alaska. These geologic records of climate change portrayed a detailed history of changing temperatures on a scale of decades to centuries over many thousands of years.

They found that once the North Pacific and North Atlantic were in sync with each other, they began to change more and more until both oceans experienced an abrupt warming event of several degrees within a few decades.

"As the systems become synchronized, they organized and reinforced each other, eventually running away like screeching feedback from a microphone," explained co-author Alan Mix, a professor in OSU's College of Earth, Ocean, and Atmospheric Sciences.

"Suddenly you had the combined effects of two major oceans forcing the climate instead of one at a time."

Mix notes that a tipping point for climate change can happen at any time, but it's likely that the Earth's climate system will take hundreds or even thousands of years to change in response.

Researchers hope that this study can provide useful information about the Earth's dynamics for the future, should we ever reach that tipping point.