Influence of Dust on Climate during the Mesozoic

Dust in the atmosphere can affect climate by directly absorbing and scattering solar radiation. In present day, most of dust is emitted from the dry regions over North Africa and Arabian Peninsula, it has been shown that they impact on global mean surface temperature, African monsoon, number of tropical cyclones over the Atlantic Ocean, ENSO variability and the strength of Atlantic meridional ocean circulation (AMOC). During the Mesozoic, the continental configuration was very different from the present, the supercontinent Pangea gradually broke up and Atlantic Ocean formed during this time period. On a different continental configuration, the area and location of dry regions may be very different, so the dust emission and atmospheric dust loading is different too. In this work, we use the global Earth system model CESM1.2.2 to examine the influence of dust on climate during the Mesozoic. Specifically, we simulate the dust and climate at two time slices, 250 million years ago (Ma) and 80 Ma. Results show that the atmospheric dust loading in both periods was much higher than that of present day. Such dust induced significant cooling of the surface climate, especially over polar regions.