@misc{MaslinBrierleyMilneretal.2014, author = {Maslin, Mark A. and Brierley, Chris M. and Milner, Alice M. and Shultz, Susanne and Trauth, Martin H. and Wilson, Katy E.}, title = {East African climate pulses and early human evolution}, series = {Quaternary science reviews : the international multidisciplinary research and review journal}, volume = {101}, journal = {Quaternary science reviews : the international multidisciplinary research and review journal}, publisher = {Elsevier}, address = {Oxford}, issn = {0277-3791}, doi = {10.1016/j.quascirev.2014.06.012}, pages = {1 -- 17}, year = {2014}, abstract = {Current evidence suggests that all of the major events in hominin evolution have occurred in East Africa. Over the last two decades, there has been intensive work undertaken to understand African palaeoclimate and tectonics in order to put together a coherent picture of how the environment of East Africa has varied in the past. The landscape of East Africa has altered dramatically over the last 10 million years. It has changed from a relatively flat, homogenous region covered with mixed tropical forest, to a varied and heterogeneous environment, with mountains over 4 km high and vegetation ranging from desert to cloud forest. The progressive rifting of East Africa has also generated numerous lake basins, which are highly sensitive to changes in the local precipitation-evaporation regime. There is now evidence that the presence of precession-driven, ephemeral deep-water lakes in East Africa were concurrent with major events in hominin evolution. It seems the unusual geology and climate of East Africa created periods of highly variable local climate, which, it has been suggested could have driven hominin speciation, encephalisation and dispersal out of Africa. One example is the significant hominin speciation and brain expansion event at -1.8 Ma that seems to have been coeval with the occurrence of highly variable, extensive, deep-water lakes. This complex, climatically very variable setting inspired first the variability selection hypothesis, which was then the basis for the pulsed climate variability hypothesis. The newer of the two suggests that the long-term drying trend in East Africa was punctuated by episodes of short, alternating periods of extreme humidity and aridity. Both hypotheses, together with other key theories of climate-evolution linkages, are discussed in this paper. Though useful the actual evolution mechanisms, which led to early hominins are still unclear and continue to be debated. However, it is clear that an understanding of East African lakes and their palaeoclimate history is required to understand the context within which humans evolved and eventually left East Africa. (C) 2014 The Authors. Published by Elsevier Ltd.}, language = {en} } @article{ComasBruHarrisonWerneretal.2019, author = {Comas-Bru, Laia and Harrison, Sandy P. and Werner, Martin and Rehfeld, Kira and Scroxton, Nick and Veiga-Pires, Cristina and Ahmad, Syed Masood and Brahim, Yassine Ait and Mozhdehi, Sahar Amirnezhad and Arienzo, Monica and Atsawawaranunt, Kamolphat and Baker, Andy and Braun, Kerstin and Breitenbach, Sebastian Franz Martin and Burstyn, Yuval and Chawchai, Sakonvan and Columbu, Andrea and Deininger, Michael and Demeny, Attila and Dixon, Bronwyn and Hatvani, Istvan Gabor and Hu, Jun and Kaushal, Nikita and Kern, Zoltan and Labuhn, Inga and Lachniet, Matthew S. and Lechleitner, Franziska A. and Lorrey, Andrew and Markowska, Monika and Nehme, Carole and Novello, Valdir F. and Oster, Jessica and Perez-Mejias, Carlos and Pickering, Robyn and Sekhon, Natasha and Wang, Xianfeng and Warken, Sophie and Atkinson, Tim and Ayalon, Avner and Baldini, James and Bar-Matthews, Miryam and Bernal, Juan Pablo and Boch, Ronny and Borsato, Andrea and Boyd, Meighan and Brierley, Chris and Cai, Yanjun and Carolin, Stacy and Cheng, Hai and Constantin, Silviu and Couchoud, Isabelle and Cruz, Francisco and Denniston, Rhawn and Dragusin, Virgil and Duan, Wuhui and Ersek, Vasile and Finne, Martin and Fleitmann, Dominik and Fohlmeister, Jens Bernd and Frappier, Amy and Genty, Dominique and Holzkamper, Steffen and Hopley, Philip and Johnston, Vanessa and Kathayat, Gayatri and Keenan-Jones, Duncan and Koltai, Gabriella and Li, Ting-Yong and Lone, Mahjoor Ahmad and Luetscher, Marc and Mattey, Dave and Moreno, Ana and Moseley, Gina and Psomiadis, David and Ruan, Jiaoyang and Scholz, Denis and Sha, Lijuan and Smith, Andrew Christopher and Strikis, Nicolas and Treble, Pauline and Unal-Imer, Ezgi and Vaks, Anton and Vansteenberge, Stef and Voarintsoa, Ny Riavo G. and Wong, Corinne and Wortham, Barbara and Wurtzel, Jennifer and Zhang, Haiwei}, title = {Evaluating model outputs using integrated global speleothem records of climate change since the last glacial}, series = {Climate of the past : an interactive open access journal of the European Geosciences Union}, volume = {15}, journal = {Climate of the past : an interactive open access journal of the European Geosciences Union}, number = {4}, publisher = {Copernicus}, address = {G{\"o}ttingen}, organization = {SISAL Working Grp}, issn = {1814-9324}, doi = {10.5194/cp-15-1557-2019}, pages = {1557 -- 1579}, year = {2019}, abstract = {Although quantitative isotope data from speleothems has been used to evaluate isotope-enabled model simulations, currently no consensus exists regarding the most appropriate methodology through which to achieve this. A number of modelling groups will be running isotope-enabled palaeoclimate simulations in the framework of the Coupled Model Intercomparison Project Phase 6, so it is timely to evaluate different approaches to using the speleothem data for data-model comparisons. Here, we illustrate this using 456 globally distributed speleothem δ18O records from an updated version of the Speleothem Isotopes Synthesis and Analysis (SISAL) database and palaeoclimate simulations generated using the ECHAM5-wiso isotope-enabled atmospheric circulation model. We show that the SISAL records reproduce the first-order spatial patterns of isotopic variability in the modern day, strongly supporting the application of this dataset for evaluating model-derived isotope variability into the past. However, the discontinuous nature of many speleothem records complicates the process of procuring large numbers of records if data-model comparisons are made using the traditional approach of comparing anomalies between a control period and a given palaeoclimate experiment. To circumvent this issue, we illustrate techniques through which the absolute isotope values during any time period could be used for model evaluation. Specifically, we show that speleothem isotope records allow an assessment of a model's ability to simulate spatial isotopic trends. Our analyses provide a protocol for using speleothem isotope data for model evaluation, including screening the observations to take into account the impact of speleothem mineralogy on δ18O values, the optimum period for the modern observational baseline and the selection of an appropriate time window for creating means of the isotope data for palaeo-time-slices.}, language = {en} }