This award will provide travel funding for participants of the Workshop on Synthesis of Transient Climate Evolution of the last 21-kyr (SynTraCE-2). Newly developed CCSM3 simulations will be used as a base for a data synthesis and model comparison workshop that will focus on critical themes in tropical paleohydrology, global deglacial temperature change, and coupled climate-vegetation changes during the last 21,000 years. The workshop will feature group discussion and working group activities that will develop the critical themes into targeted questions that can be answered through data synthesis and model comparison, and developing clear strategies for addressing those questions.
This workshop will bring the community together to chart a path towards addressing some of the most important topics in paleoclimate in the last 21,000 years. Attention will be paid to ensure participation and attendance by underrepresented groups.
Global climate models predict that anthropogenic greenhouse gas emissions will cause significant global warming along with a host of other climate changes. Yet the accuracy of these models is difficult to test, and many of the effects of greenhouse gas additions to our atmosphere will not be felt for decades. Paleoclimate datasets provide a key testing ground for the predictions of global climate models (GCMs) through experiments in which GCMs are used to simulate past climate change and compared directly against paleoclimate data. Paleoclimate data-model testing has made rapid advances in recent years. This is due to rapid improvements in the accuracy and spatial coverage of paleoclimate reconstructions, and to advances in computational power that allow GCMs to be run in ‘transient’ mode in which past climate changes are simulated in a time-continuous fashion. To this end, this award funded a SynTRaCE-21 (Synthesis and Transient Climate Evolution of the last 21 kyr) workshop in Providence, RI, from Nov. 4-7, 2012 to plan new syntheses of paleoclimate records of the major features of global climate of the last 21,000 years, recent and ongoing GCM transient simulations, and to plan for future data-model comparison activities. Forty-three participants from five countries attended the workshop, and brought expertise in the Pleistocene and Holocene history of the oceans, atmosphere, and land surfaces, and climate dynamics and paleoclimate modeling. We combined presentations of ongoing research with breakout discussions to identify novel areas for paleoclimate data-model comparison in the coming year. Most paleoclimate data-model comparison studies using fully coupled, state-of-the-art GCMs have investigated climate changes at high latitudes and/or global sea surface temperature changes of the last 21,000 years. However, past climate change included large changes in tropical hydrology, continental climate and vegetation changes, and changes in deep ocean circulation. Workshop participants identified these as critical issues to address in paleoclimate data-model comparison studies in the coming year. In particular, we identified the following key questions: 1) How did greenhouse gas and orbital forcing affect tropical atmospheric circulation during the last 21,000 years? 2) What are the mechanisms that link high and low latitude climate changes? 3) Where does water derived from glacial melting go in the oceans, and how might it impact ocean circulation? 4) What changes did the ocean circulation experience during the last deglaciation? 5) Can models simulate rapid changes in vegetation in the past, and if so, how do those changes affect regional climates? Workshop participants are now engaged in research on these questions, including paleoclimate data syntheses and data-model comparisons.
