Journal Article

The projected timing of climate departure from recent variability

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

2013

Overview

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. An ensemble of simulations indicates that ongoing climate change will exceed the bounds of historical climate variability some time in the mid to late twenty-first century and that the burden of rapid climate adaption will occur earliest in highly biodiverse and often economically challenged tropical areas. Tropics first in line for climate change woes Projections of warming are now a fixture of climate modelling exercises. Camilo Mora et al . have used an ensemble of these simulations to estimate when ongoing warming will exceed the bounds of historical climate variability. Depending on assumptions regarding future emissions in greenhouse gasses, this will occur sometime in the mid to late twenty-first century. This landmark event is likely to occur first in the tropics, where historical variability is low, and where biodiversity is highest. The new projections suggest that the often economically challenged areas in the tropics will face the highest burden of rapidly adapting to the biological effects of climate change. In an accompanying News & Views Forum, three climatologists discuss the significance of these results.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 704/106/694/2786 / Analysis / Animals / Biodiversity / Climate change / Climatic changes / Climatology. Bioclimatology. Climate change / Computer Simulation / Earth, ocean, space / Ecosystems / Emissions / Environmental aspects / Environmental impact / Exact sciences and technology / Experiments / External geophysics / Global Warming / Greenhouse gases / Humanities and Social Sciences / Low income areas / Meteorology / multidisciplinary / Science / Surface temperature / Time / Tropical environments / Variables