The ``Hockey Stick{''} Imprint in Northwest African Speleothems

Author(s)

Sha, Lijuan ^[1] ; Brahim, Yassine Ait ^[2] ; Wassenburg, Jasper A. ^{[3, 4]} ; Yin, Jianjun ^[5] ; Lu, Jiayu ^[1] ; Cruz, Francisco W. ^[6] ; Cai, Yanjun ^[1] ; Edwards, R. Lawrence ^[7] ; Cheng, Hai ^{[1, 5, 8]}

Affiliation

^[1] Xi An Jiao Tong Univ, Inst Global Environm Change, Xian - Peoples R China

^[2] Univ Basel, Dept Environm Sci, Basel - Switzerland

^[3] Inst Basic Sci, Ctr Climate Phys, Busan - South Korea

^[4] Pusan Natl Univ, Busan - South Korea

^[5] Chinese Acad Geol Sci, Key Lab Karst Dynam, MNR & Guangxi, Inst Karst Geol, Guilin - Peoples R China

^[6] Sao Paulo, Inst Geociencias Univ, Sao Paulo - Brazil

^[7] Univ Minnesota, Dept Earth Sci, Minneapolis, MN - USA

^[8] Chinese Acad Sci, State Key Lab Loess & Quaternary Geol, Inst Earth Environm, Xian - Peoples R China

• Document type: Journal article
• Source: Geophysical Research Letters; v. 48, n. 17 SEP 16 2021.
• Web of Science Citations: 0

Abstract

We present absolutely dated speleothem delta O-18 records spanning the past similar to 1.5 kyr, which provide new evidence of the transmission of an anthropogenic signal to natural climatic archives in NW Africa. Combined with three other speleothem delta O-18 records from SW Morocco, the results indicate unprecedentedly dry conditions during the 20th century, which developed more rapidly than those during the Medieval Climate Anomaly (900-1350 CE), likely due to rising atmospheric CO2 levels. The 20th century drying evident in the speleothem records is consistent with the ``Hockey Stick{''} pattern of increasing temperatures due to global warming. We demonstrate that this rapid drying is linked to warmer sea surface temperatures (SSTs) over the Azores High region, and cooler local SSTs off the coast of NW Africa. These changes intensified the Canary Current Upwelling, which promoted increased biological productivity in the surface water and enhanced the coastal fishing industry in Morocco. (AU)

• FAPESP's process: 17/50085-3 - PIRE: climate research education in the Americas using tree-ring speleothem examples (PIRE-CREATE)
• Grantee: Francisco William da Cruz Junior
• Support Opportunities: Research Projects - Thematic Grants