Wednesday, April 12, 2017

Tibet Sediments Reveal Climate Patterns from late Miocene, Six Million Years Ago (It Was Raining, People Were Crabby)

Ooops, it appears I've used that headline.*
Plus, 'people' hadn't really shown up up six million years ago.

From Archeology News Network:
The Tibetan Plateau in China experiences the strongest monsoon system on Earth, with powerful winds—and accompanying intense rains in the summer months—caused by a complex system of global air circulation patterns and differences in surface temperatures between land and oceans. 
These extreme weather patterns make this area an ideal location for climate scientists to study the delicate interconnected web of the global climate system.

Carmala Garzione, a professor of earth and environmental sciences at the University of Rochester, and Junsheng Nie, a visiting research associate at the University, surveyed sediment samples from the northern Tibetan Plateau's Qaidam Basin and were able to construct paleoclimate cycle records from the late Miocene epoch of Earth's history, which lasted from approximately 11 to 5.3 million years ago. They recently published their findings in Science Advances.

Reconstructing past climate records can help scientists determine both natural patterns and the ways in which future glacial events and greenhouse gas emissions may affect global systems.

Based on previous research on ice core, marine, and sediment records, researchers determined that for the past 800,000 years, Northern Hemisphere ice ages—in which vast areas of North America, Europe, and Asia are covered with thick sheets of ice—occurred about every 100,000 years. Prior to that period, ice ages occurred more frequently, on cycles of 41,000 years, and scientists believed this was the norm.

Using the sediment samples from the Qaidam Basin, Nie and Garzione show that the East Asian monsoon patterns in the late Miocene also follow similar 100,000 year cycles, with stronger monsoons peaking at 100,000 years and diminishing in the periods in between. This reveals a greater than 6 million earlier onset of these 100,000 year cycles than was previously documented.

"People have been thinking that the 100,000 year cycle was a later Quaternary [present-day] climate anomaly," Nie says. "But from our results, we see that it's not an anomaly, it was present many years before."...MORE
*World's Oldest Weather Report Found in Egypt: It Was Raining, People Were Crabby

Imagine That: Earliest Surviving Secular Song Is An English Guy Talking About The Weather
I grew up being told Sumer Is Icumen In was the earliest surviving but this one is a decade or two older, as the post points out.
Adios cuckoo, hello English guy griping* about the cold and wind....