New Study Reveals 16,000-Year Climate History Of Tropical Andes

Eddie Gonzales Jr. – MessageToEagle.com – A recent study on the tropical Andes’ climate history reveals that carbon dioxide levels and ocean currents influenced temperature and rainfall patterns over 16, 000 years, reflecting global climate events.

Mirrored lakes – Cajas National Park in Ecuador, near Cuenca. Image credit: Delphine Ménard (notafish} – CC BY-SA 2.0 fr

Led by Brown University researchers, the study marks the first high-resolution temperature record covering the past 16,000 years in the tropical Andes and could help scientists predict and mitigate future climate impacts in tropical regions of the planet.

“Usually when we study climate change in the past, we emphasize the Northern Hemisphere or Southern Hemisphere because of the outsized role they play in affecting climates all over the globe,” Boyang Zhao, a scientist in Brown’s Department of Earth, Environmental and Planetary Sciences and the study’s first author, said in a press release.

“One of the biggest questions we are getting at is what are the driving factors behind temperature history in this part of the tropics, so that we can begin to potentially apply that data and knowledge to other tropical regions.”

Along with future implications, the new study provides a unique look at the way distinct and distant parts of the world influence temperature and weather elsewhere, emphasizing how regional climates are connected to global climate changes.

“Our evidence here suggests that temperatures in this region of the world are more influenced by the Southern Hemisphere—so places like Antarctica,” Zhao said.

Brown-led researchers highlight 16,000 years of climate history in the tropical Andes, which includes areas like the Laguna Llaviucu in Cajas National Park in Ecuador. Credit: Mark Bush

The study focused on an analysis of sediment samples from Laguna Llaviucu, a lake located in Ecuador’s Cajas National Park. The measurements from the sediment samples showed that temperature variations in the tropical Andes closely aligned with climate events that saw the planet’s temperatures rise and fall during the past 16,000 years.

Overall, the evidence showed that the main driver in these temperature fluctuations was the concentration of CO2. Researchers saw evidence that the tropical Andean temperatures track with Antarctic temperatures, which are mainly controlled by carbon dioxide concentrations. The findings showed that about 17,000 to 14,000 years ago, tropical Andean temperatures rose when carbon dioxide increased, and that the temperatures remained relatively stable about 12,000 years ago when carbon dioxide levels remained relatively stable.

Zhao said that the findings support previous research identifying carbon dioxide as a key driver of global temperature changes since the last Ice Age.

The study highlighted ocean currents moving warm water from tropics to the North Atlantic. During the Antarctic Cold Reversal 14, 500 years ago, a strengthened northward current transported more heat, cooling southern sea temperatures. This cooling effect reached the tropical Andes.

To reconstruct past climate conditions, the researchers analyzed lipid biomarkers and hydrogen isotopes collected in 2009 from Laguna Llaviucu by scientist Mark Bush from the Florida Institute of Technology. Lipid biomarkers are chemical compounds that provide clues about past temperatures and rainfall patterns. The high-resolution data, combined with accurate dating techniques, allowed the team to create a detailed timeline of climate changes over the past 16,000 years.

According to the researchers, this is the first time organic biomarkers have been used to put together a quantitative climate history for tropical South America. It is traditionally difficult to reconstruct temperatures from the tropics.

The study highlights regional variations in temperature patterns, such as cooling in the tropical Andes and Southeast Asia during certain periods, while Africa remained unchanged. It also examines how local factors might offset global CO2-driven warming by comparing past temperature models with sediment data.

“Mountain environments are some of the most sensitive regions on Earth to climate change,” said James Russell, a professor of Earth, environmental, and planetary sciences at Brown who oversaw the new research. “In fact, in the near future, high tropical mountains, such as the Andes, are predicted to experience a rate of warming second only to the Arctic, which is the fastest warming part of the planet.”

The researchers from Brown plan to continue to explore past temperature patterns in this part of the world.

Paper is published in the Proceedings of the National Academy of Science.

Written by Eddie Gonzales  Jr. – MessageToEagle.com Staff Writer