The projected timing of climate departure from recent variability

Camilo Mora, University of Hawaiʻi at Mānoa
Abby G. Frazier, University of Hawaiʻi at Mānoa
Ryan J. Longman, University of Hawaiʻi at Mānoa
Rachel S. Dacks, University of Hawaiʻi at Mānoa
Maya M. Walton, University of Hawaiʻi at Mānoa
Eric J. Tong, Hawaiʻi Institute of Marine Biology
Joseph J. Sanchez, University of Hawaiʻi at Mānoa
Lauren R. Kaiser, University of Hawaiʻi at Mānoa
Yuko O. Stender, University of Hawaiʻi at Mānoa
James M. Anderson, University of Hawaiʻi at Mānoa
Christine M. Ambrosino, University of Hawaiʻi at Mānoa
Iria Fernandez-Silva, Hawaiʻi Institute of Marine Biology
Louise M. Giuseffi, University of Hawaiʻi at Mānoa
Thomas W. Giambelluca, University of Hawaiʻi at Mānoa

Abstract

Ecological and societal disruptions by modern climate change are critically determined by the time frame over which climates shift beyond historical analogues. Here we present a new index of the year when the projected mean climate of a given location moves to a state continuously outside the bounds of historical variability under alternative greenhouse gas emissions scenarios. Using 1860 to 2005 as the historical period, this index has a global mean of 2069 (±18 years s.d.) for near-surface air temperature under an emissions stabilization scenario and 2047 (±14 years s.d.) under a 'business-as-usual' scenario. Unprecedented climates will occur earliest in the tropics and among low-income countries, highlighting the vulnerability of global biodiversity and the limited governmental capacity to respond to the impacts of climate change. Our findings shed light on the urgency of mitigating greenhouse gas emissions if climates potentially harmful to biodiversity and society are to be prevented. © 2013 Macmillan Publishers Limited. All rights reserved.