Linking Future Hydroclimatological Changes With Past Climatic Conditions In Southeastern Iran: Insights From Models And Observations

We compare the predicted results of future hydrological changes based on a thirty-year (1989-2019) weather dataset with paleoclimatic changes inferred based on established proxies from the Jazmurian playa in southeastern Iran. Parallels between expected changes in the future were compared to past climatic conditions to trace the impact this region has undergone in the distant past. The study area is affected by the Indian Ocean Summer Monsoon (IOSM) and the Mid-Latitude Westerlies (MLW). The maximum and minimum temperatures and precipitation were predicted for the future (2061- 2080) by statistical downscaling outputs of 5 GCM models (EC-EARTH, GFDL-CM3, HadGEM2-ES, MIROC5, MPI-ESM-MR) under RCP 4.5 and RCP 8.5. The results show that the 20-years average of the mean temperatures ((Tmax + Tmin)/2) will increase in the range of 3.2 to 4.6 °C under RCP 8.5 compared to the base period. The trends suggest that the region will experience drier conditions than the baseline period in the future under both scenarios. In addition, the GCM predicts a considerable decline in MLW precipitation and little change in future IOSM precipitation under both scenarios compared to the baseline. The decrease in MLW precipitation is consistent with other GCM predictions and real paleoclimatic changes that happened during past warm/wet periods in the region. However, considering the close relationship between the increase in the Earth’s radiation budget and enhanced IOSM precipitation in southeast Iran since the late Pleistocene, we postulate that more intensive IOSM activity can be expected in the future.

Mineral magnetic properties of loess–paleosol couplets of northern Serbia over the last 1.0 Ma

We conducted the first detailed mineral magnetic investigation of more than nine loess–paleosol couplets of the composite Titel-Stari Slankamen loess section in Serbia, which provides one of the longest and most complete terrestrial record of paleoclimatic changes in Europe since ~1.0 Ma. The results show that the ferrimagnetic mineral assemblage of the loess units is dominated by partially oxidized multidomain (MD) and pseudo-single domain (PSD) magnetite; however, with an increasing degree of pedogenesis, the eolian contribution is gradually masked by pedogenic superparamagnetic(SP) and single-domain (SD) ferrimagnets (mainly maghemite). The overall consistency of ferrimagnetic grain-size parameters indicates an absence of dissolution of the fine-grained ferrimagnetic fraction despite changes in climate regime over the past 1.0 Ma. The variations of normalized dJ/dT@120K and normalized χheating@530°C reflect a long-term stepwise increase in aridity during glacials with a major step at ~0.6–0.5 Ma, over the last 1.0 Ma. Overall, the results provide an improved basis for the future use of the magnetic properties of Serbian loess deposits for paleoclimatic reconstruction.

Nonuniform Late Pleistocene glacier fluctuations in tropical Eastern Africa

Today’s ice caps and glaciers in Africa are restricted to the highest peaks, but during the Pleistocene, several mountains on the continent were extensively glaciated. However, little is known about regional differences in the timing and extent of past glaciations and the impact of paleoclimatic changes on the afro-alpine environment and settlement history. Here, we present a glacial chronology for the Ethiopian Highlands in comparison with other East African Mountains. In the Ethiopian Highlands, glaciers reached their maximum 42 to 28 ka thousand years ago before the global Last Glacial Maximum. The local maximum was accompanied by a temperature depression of 4.4° to 6.0°C and a ~700-m downward shift of the afro-alpine vegetation belt, reshaping the human and natural habitats. The chronological comparison reveals that glaciers in Eastern Africa responded in a nonuniform way to past climatic changes, indicating a regionally varying influence of precipitation, temperature, and orography on paleoglacier dynamics.

High diversity, inbreeding and a dynamic Pleistocene demographic history revealed by African buffalo genomes

Genomes retain records of demographic changes and evolutionary forces that shape species and populations. Remnant populations of African buffalo (Syncerus caffer) in South Africa, with varied histories, provide an opportunity to investigate signatures left in their genomes by past events, both recent and ancient. Here, we produce 40 low coverage (7.14×) genome sequences of Cape buffalo (S. c. caffer) from four protected areas in South Africa. Genome-wide heterozygosity was the highest for any mammal for which these data are available, while differences in individual inbreeding coefficients reflected the severity of historical bottlenecks and current census sizes in each population. PSMC analysis revealed multiple changes in Ne between approximately one million and 20 thousand years ago, corresponding to paleoclimatic changes and Cape buffalo colonisation of southern Africa. The results of this study have implications for buffalo management and conservation, particularly in the context of the predicted increase in aridity and temperature in southern Africa over the next century as a result of climate change.