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The Issue
For years, researchers believed most of Earth was uniformly impacted by abrupt climate change and subsequently recovered at the same rate. New research from the Institute for Geophysics says rainfall in the Philippines took centuries to feel the full effect of temperature change in Greenland. Likewise, tropical rainfall started recovering at the same time as temperature change in Greenland, yet required several centuries to return to normal.
The Research
For abrupt climate change, the poster child is the Younger Dryas. It’s a well-studied period of time approximately 12,000 years ago when Earth was experiencing a natural warming period, then took a sudden U-turn and started rapidly cooling.
“The questions are: how fast can that happen to us in the modern day, and what are the repercussions?” says Jud Partin, Research Associate at the University of Texas Institute for Geophysics. “It’s a serious problem that people worry about for obvious reasons. Greenland is melting.”
The possibility of icebergs melting and altering the ocean’s conveyer belt, thereby slowing the gulf stream’s flow of warm air and warm water, is nothing new. Scientists have studied it for decades. Where Partin’s research challenges previous beliefs is in identifying just how destabilizing abrupt changes could be to far-reaching regions of the globe.
His paper was published September 2 in Nature Communications in collaboration with 10 colleagues who aided in the research.
Traveling to world’s longest underground navigable river in Puerto Princesa Subterranean River National Park in Palawan, Philippines, Partin and colleagues were permitted to remove three stalagmites and bring them back to back to a lab in Austin. Cutting open and analyzing chemical changes in the stalagmites, Partin was able to determine rainfall patterns in the Philippines during the Younger Dryas.
But in using radiogenic isotopes to look closer at the timing, Partin realized even though the climate in the Philippines started changing at the same time as Greenland’s, it took the Philippines centuries to feel the full impact. And while Greenland’s climate recovered quickly, within 20 years, it took the Philippines approximately five hundred years to get back to normal rainfall.
“It’s a small ship versus a big ship,” says Partin. “Greenland is the small ship able to make sharp turns, while the Philippines are the big ship that take a long time to change course.”
For the Layperson
Partin’s research is especially noteworthy because it goes against decades of previously-held scientific beliefs. By taking such a strong stance, Partin opens the door for researchers to re-analyze their own data and establish new timelines of how the Younger Dryas affected different parts of the globe.
“We realized if we were going to buck the trend, we better come with some pretty good ammunition. We used models to confirm the mechanism and why the changes in Greenland happened so quickly. Then we objectively laid out the paper and came to this conclusion,” says Partin. “We’ve heard from other scientists saying they’ve seen the same thing in their research but didn’t have the resources to pursue it fully. So we’ll see what happens, it’s been pretty fun.”
The applications of Partin’s model to contingency plans may change the way society plans for abrupt climate change.
“If an event similar to the Younger Dryas does occur, it is a double-edged sword: if society were able to somehow act quickly enough to alleviate the temperature change, then we have the potential to prevent the impact on global rainfall,” says Partin. “However, the longer the circulation event lasts, the longer it will take for rainfall to recover. When you start talking about rainfall and monsoons being impacted to the point that people don’t have water to drink or food to eat, it’s going to be tougher to deal with than just a drop in temperature.”
The Study
Gradual Onset and Recovery of the Younger Dryas Abrupt Climate Event in the Tropics