The Phanerozoic Eon has witnessed considerable changes in the climate system as well as abundant animals and plant life. Therefore, the evolution of the climate system in this Eon is worthy of extensive research. Only by studying climate changes in the past can we understand the driving mechanisms for climate changes in the future and make reliable climate projections. Apart from observational paleoclimate proxy datasets, climate simulations provide an alternative approach to investigate past climate conditions of the Earth, especially for long time span in the deep past. Here we perform 55 snapshot simulations for the past 540 million years, with a 10-million-year interval, using the Community Earth System Model version 1.2.2 (CESM1.2.2). The climate simulation dataset includes global distributions of monthly surface temperatures and precipitation, with a 1° horizontal resolution of 0.9° × 1.25° in latitude and longitude. This open access climate dataset is useful for multidisciplinary research, such as paleoclimate, geology, geochemistry, and paleontology.

Earth's climate has undergone large variations in the past 250 million years (Myr), with alternating warm and cold intervals (Scotese, 2015;Scotese et al., 2021). A warm greenhouse climate state lasted from the latest Permian to the late Triassic (∼250 to 200 million years ago [Ma]), followed by a cooler climate state during the middle and late Jurassic (∼174-145 Ma), and a pronounced greenhouse warming persisted from the late Cretaceous to the early Eocene (∼100-56 Ma). Then, a cooling trend prevailed from the early Eocene to the present.Many studies have suggested that Earth's climate is primarily regulated by greenhouse gas (principally CO 2 ) concentrations over tectonic timescales (

Coals and evaporites are commonly used as qualitative indicators of wet and dry environments in deep-time climate studies, respectively. Here, we combine geological records with climate simulations to establish quantitative relationships of coals and evaporites with temperature and precipitation over the Phanerozoic. We show that coal records were associated with an average temperature of 25°C and precipitation of 1300 mm yr−1 before 250 Ma. Afterwards, coal records appeared with temperatures between 0°C and 21°C and precipitation of 900 mm yr−1. Evaporite records were associated with average temperature of 27°C and precipitation of 800 mm yr−1. The most remarkable result is that net precipitation associated with coal and evaporite records remained constant across time. The results here have important implications for quantifying climate conditions for other lithologic indicators of climate and for predicting exogenetic ore deposits.

Stratospheric water vapor (SWV) variations play an important role in influencing the Earth's energy budget. Here, we investigate the SWV variations in the past 250 million years (Myr) using a fully coupled Earth System Model. It is found that both CO2 concentration and paleogeography have prominent influences on the SWV variations, while solar insolation plays a minor role. The SWV increases with surface warming and stratospheric moistening rate is accelerated during the warm periods in the past 250 Myr except for the Pangea supercontinent stage. The ratio of stratospheric moistening to surface warming is smaller in the warm Pangea supercontinent stage compared to that during the warm Cretaceous Period, which is due to the ascending and consequent cooling of the tropical tropopause layer associated with the severe surface warming over the tropical Pangea supercontinent. Our results suggest that paleogeography is an important factor in regulating SWV variations in deep‐time climate.

<p>The El Niño–Southern Oscillation (ENSO), originating in the central and eastern equatorial Pacific, is a defining mode of interannual climate variability with profound impact on global climate and ecosystems. Although ongoing coordinated community efforts have offered insights into how ENSO will change in the future under anthropogenic warming, the geological history of ENSO remains intricate. In particular, there is a clear lack of systematic study on how ENSO has evolved in response to vast variations in land-sea distributions and climate mean states over geological timescales. To unravel this, we analyze a series of time-slice coupled climate simulations forced by changes of paleogeography, atmospheric CO<sub>2</sub> concentrations, and solar radiation in the past 250 million years (Myr). Our simulations for the first time demonstrate that ENSO is the leading mode of tropical Pacific sea surface temperature (SST) in the past 250 Myr. Further, the amplitude of ENSO is predominantly captured by the zonal advective feedback and thermocline feedback, both of which are primarily regulated by eastern equatorial Pacific climatological SST. These findings highlight the significance of climate mean states in interpretation of the amplitude of ENSO during the deep past, and provide enlightening implications for constraining future climate change.</p>