One of the most puzzling questions in modern human origins has been why the dispersal of modern Homo sapiens out of Africa was so delayed after their first appearance in East African fossil record...
Abstract: Global mean temperature has risen for the past century and is projected to rise even more in response to the increasing atmospheric CO2 concentrations. Precipitation change is of vital importance to societies but precipitation projections are intrinsically challenging as they change sign from one region to another. Recent studies show that in the tropics, radiatively forced...
This talk will highlight the relative importance of internally-generated vs. externally-forced climate trends at local and regional scales over North America and Eurasia based on a 30-member ensemble of the Community Earth System Model over the period 1920-2100. Each member is subject to the same historical and future (RCP8.5) radiative forcing scenario, but starts from a slightly different atmospheric state....
Abstract: We argue for a pervasive link between cold climates and polar ocean stratification. In both the Subarctic North Pacific and the Antarctic Zone of the Southern Ocean, ice ages were marked by low productivity. The accumulated evidence from sediment cores points to an increase in density stratification that reduced the supply of nutrients from the ocean interior into the sunlit surface in both of these regions.The last ice age was associated with stratification of the Antarctic...
