I've recently read a paper from the journal Proceedings of the National Academy of Science, December 2018, that has me very concerned and, to be honest, more a bit shocked. I'll list the title and authors in full, as their credentials are very important:
Pliocene and Eocene provide best analogs for near-future climates
K. D. Burke
(a,1) J. W. Williams(
b), M. A. Chandler(
c,d), A. M. Haywood
(e), D. J. Lunt
(f), and B. L. Otto-Bliesnerg
(a)Nelson Institute for Environmental Studies, University of Wisconsin– Madison, Madison, WI 53706;
(b)Department of Geography and Center for Climatic Research, University of Wisconsin–Madison, Madison, WI 53706;
(c)Center for Climate Systems Research, Columbia University, New York, NY 10025; (
d)Goddard Institute for Space Studies, National Aeronautics and Space Administration (NASA), New York, NY 10025; (
e)School of Earth and Environment, University of Leeds, LS2 9JT Leeds, United Kingdom;
(f)School of Geographical Sciences, University of Bristol, BS8 1SS Bristol, United Kingdom; and
gClimate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO 80305
Edited by Noah S. Diffenbaugh, Stanford University, Stanford, CA, and accepted by Editorial Board Member Robert E. Dickinson November 6, 2018 (received for review June 29, 2018)
Quote:
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As the world warms due to rising greenhouse gas concentrations, the Earth system moves toward climate states without societal precedent, challenging adaptation. Past Earth system states offer possible model systems for the warming world of the coming decades. These include the climate states of the Early Eocene (ca. 50 Ma), the Mid-Pliocene (3.3–3.0 Ma), the Last Interglacial (129–116 ka), the Mid-Holocene (6 ka), preindustrial (ca. 1850 CE), and the 20th century. Here, we quantitatively assess the similarity of future projected climate states to these six geohistorical benchmarks using simulations from the Hadley Centre Coupled Model Version 3 (HadCM3), the Goddard Institute for Space Studies Model E2-R (GISS), and the Community Climate System Model, Versions 3 and 4 (CCSM) Earth system models. Under the Representative Concentration Pathway 8.5 (RCP8.5) emission scenario, by 2030 CE, future climates most closely resemble Mid-Pliocene climates, and by 2150 CE, they most closely resemble Eocene climates. Under RCP4.5, climate stabilizes at Pliocene-like conditions by 2040 CE. Pliocene-like and Eocene-like climates emerge first in continental interiors and then expand outward. Geologically novel climates are uncommon in RCP4.5 (<1%) but reach 8.7% of the globe under RCP8.5, characterized by high temperatures and precipitation. Hence, RCP4.5 is roughly equivalent to stabilizing at Pliocene-like climates, while unmitigated emission trajectories, such as RCP8.5, are similar to reversing millions of years of long-term cooling on the scale of a few human generations. Both the emergence of geologically novel climates and the rapid reversion to Eocene-like climates may be outside the range of evolutionary adaptive capacity.
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I've attached a grab from this paper as well. I really don't know what to think of all this. If the science is right we're heading towards some very rapid change. What do we tell our kids? What can we do?
Finally, here's another quote from the same paper:
Quote:
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These analyses also indicate that the Earth system is well along on a trajectory to a climate state different from any experienced in our history of agricultural civilizations (last 7 ka) (34) and modern species history (360–240 ka) (35). Climate states for which we have good historical and lived experience (e.g., 20th century, preindustrial) are quickly diminishing as best analogs for the coming decades, while being superseded by climate analogs drawn from deeper times in Earth’s geological history (Figs. 2 and 3). Future climates also tend to exhibit greater geographic separation from their closest analogs over the coming centuries (SI Appendix, Fig. S14). Efforts to keep the Earth within a safe operating space, defined as climates similar to those of the Holocene (11, 36), seem to be increasingly unlikely.
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I don't want to think about this too much, but I can't stop thinking about it. 2030 is 10 years away. 2050 is 30 years away.
