We develop a self-consistent, large ensemble, high-resolution, bias-corrected global dataset of future climates for a set of four possible 21st century scenarios, which is suitable for assessing local-scale climate change impacts and climate policy benefits from a risk-based perspective across different applications. Four emission scenarios represent the existing energy and environmental policies and commitments of potential future pathways, namely, Reference, Paris Forever, Paris 2°C and Paris 1.5°C. We employ the MIT Integrated Global System Modeling (IGSM) framework, which consists of the MIT Earth System Model (MESM) of intermediate complexity and the Economic Projections and Policy Analysis model (EPPA). The EPPA characterizes detailed economic activities to track inter-sectoral and inter-regional links, while the MESM represents key physical, chemical, and biological components of the Earth system that are impacted by human activity. Such integrated framework ensures consistent treatment of interactions among population growth, economic development, energy and land system changes and physical climate responses, which can provide improved assessments of climate impacts and climate policy benefits across multiple sectors. The MESM contains a two-dimensional (zonally averaged) atmospheric model with interactive chemistry coupled to the zonally averaged version of Global Land System model and an anomaly-diffusing ocean model. This architecture allows for conducting a large ensemble of climate simulations for robust uncertainty analyses at significantly less computational cost than state-of-the-art climate models. In addition, we apply a combined spatial disaggregation (SD) – bias correction (BC) delta method with SD for achieving the high resolution and BC for correcting the biases inherent in the MESM future climate projections. The delta method adds the anomalies or deltas (future climate trends) onto a historical, detrended climate that is based on the third phase of the Global Soil Wetness Project (GSWP3, http://hydro.iis.u-tokyo.ac.jp/GSWP3/). The anomalies or deltas are derived by spatially disaggregating the IGSM zonal climate projections based on regional hydroclimate change patterns from the 18 Coupled Model Intercomparison Project Phase 6 (CMIP6) climate models. For each emission scenario, a distribution of plausible trajectories is provided by a 50-member ensemble to represent the uncertainty in the Earth system (e.g., the climate sensitivity, rate of heat uptake by the ocean, uncertainty in carbon cycle), allowing for constructing a 900-member ensemble of regional climate outcomes. The dataset contains nine key meteorological variables on a monthly scale from 2021 to 2100 at a spatial resolution of 0.5°x 0.5°, including precipitation, air temperature (mean, minimum and maximum), near-surface wind speed, shortwave and longwave radiation, specific humidity, and relative humidity. A technical evaluation indicates the dataset well represents the expected large-scale climate features across various regions of the globe and can meet various needs associated with climate impact assessments, including uncertainty analyses, risk quantification, climate policy mitigation, and driving climate impact models which require monthly data inputs, on both global and regional scales. There is no model version. But all the developed models are available online (https://globalchange.mit.edu/research/research-tools/earth-system-model) and have relevant licenses. On the website you could find the following information: The source code of the MESM is publicly available for non-commercial research and educational purposes via github (i.e. github.com:mit-jp/igsm.git). Under this open source protocol, we have also established a software license through the MIT Technology Licensing Office. As the MESM has embedded models developed at three other institutions, appropriate copyright clearances for the third-party code are required.

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ModE-Sim (short for Modern Era Simulations) is a medium-size ensemble of model simulations using the ECHAM6 atmosphere general circulation model (model version 6.3.5p2, doi:10.17617/2.1810480). Its setup is based on the PMIP4 experiments, but uses a forced AGCM rather than a fully coupled model. ModE-Sim was originally designed to form the a-priori state for a climate reconstruction (Modern Era Reanalysis, ModE-RA, to be found as separate experiment within this WDC project) that uses an offline data assimilation technique to combine the output of ModE-Sim with historical climate information. However, beyond its original purpose ModE-Sim on its own can be used as a tool to study climate variability, providing a high number of posible climate states that are physically plausible under the given forcings and boundary conditions. This might include, e.g. the separation of internal variability from the response to externally forced signals, understanding of teleconnection patterns, or the study of extreme events. The ensemble uses observed/reconstructed forcings and boundary conditions, while accounting in uncertainties in these. For 1420 to 1850 we provide a 60 member ensemble grouped in three subsets. The subset 1420-3 provided in this dataset group has 20 members and uses PMIP4 radiative forcings. As ocean boundary condition 20 different realizations of SST reconstructions were used and for sea ice a climatology was computed from the years 1850-1900 from HadISST2 sea ice.

ModE-Sim (short for Modern Era Simulations) is a medium-size ensemble of model simulations using the ECHAM6 atmosphere general circulation model (model version 6.3.5p2, doi:10.17617/2.1810480). Its setup is based on the PMIP4 experiments, but uses a forced AGCM rather than a fully coupled model. ModE-Sim was originally designed to form the a-priori state for a climate reconstruction (Modern Era Reanalysis, ModE-RA, to be found as separate experiment within this WDC project) that uses an offline data assimilation technique to combine the output of ModE-Sim with historical climate information. However, beyond its original purpose ModE-Sim on its own can be used as a tool to study climate variability, providing a high number of posible climate states that are physically plausible under the given forcings and boundary conditions. This might include, e.g. the separation of internal variability from the response to externally forced signals, understanding of teleconnection patterns, or the study of extreme events. The ensemble uses observed/reconstructed forcings and boundary conditions, while accounting in uncertainties in these. For 1420 to 1850 we provide a 60 member ensemble grouped in three subsets. The subset 1420-1 provided in this dataset group has 20 members and uses PMIP4 radiative forcings. As ocean boundary condition 20 different realizations of SST reconstructions were used and for sea ice analogues were picked from the HadISST2 sea ice, based on the reconstructed SST fields.

ModE-Sim (short for Modern Era Simulations) is a medium-size ensemble of model simulations using the ECHAM6 atmosphere general circulation model (model version 6.3.5p2, doi:10.17617/2.1810480). Its setup is based on the PMIP4 experiments, but uses a forced AGCM rather than a fully coupled model. ModE-Sim was originally designed to form the a-priori state for a climate reconstruction (Modern Era Reanalysis, ModE-RA, to be found as separate experiment within this WDC project) that uses an offline data assimilation technique to combine the output of ModE-Sim with historical climate information. However, beyond its original purpose ModE-Sim on its own can be used as a tool to study climate variability, providing a high number of posible climate states that are physically plausible under the given forcings and boundary conditions. This might include, e.g. the separation of internal variability from the response to externally forced signals, understanding of teleconnection patterns, or the study of extreme events. The ensemble uses observed/reconstructed forcings and boundary conditions, while accounting in uncertainties in these. For 1850 to 2009 ModE-Sim offers 36 members grouped in two subsets, all using PMIP4 radiative forcings. The subset 1850-2 provided in this dataset group has 16 members and uses linear combinations of HadISST2 realizations as SST and HadISST sea ice as ocean boundary conditions.

ModE-Sim (short for Modern Era Simulations) is a medium-size ensemble of model simulations using the ECHAM6 atmosphere general circulation model (model version 6.3.5p2, doi:10.17617/2.1810480). Its setup is based on the PMIP4 experiments, but uses a forced AGCM rather than a fully coupled model. ModE-Sim was originally designed to form the a-priori state for a climate reconstruction (Modern Era Reanalysis, ModE-RA, to be found as separate experiment within this WDC project) that uses an offline data assimilation technique to combine the output of ModE-Sim with historical climate information. However, beyond its original purpose ModE-Sim on its own can be used as a tool to study climate variability, providing a high number of posible climate states that are physically plausible under the given forcings and boundary conditions. This might include, e.g. the separation of internal variability from the response to externally forced signals, understanding of teleconnection patterns, or the study of extreme events. The ensemble uses observed/reconstructed forcings and boundary conditions, while accounting in uncertainties in these. For 1420 to 1850 we provide a 60 member ensemble grouped in three subsets. The subset 1420-2 provided in this dataset group has 20 members and uses a 20-member ensemble of perturbed volcanic forcings from the easy volcanic aerosol (EVA) model to account for uncertainties in the strength and the timing of volcanic eruptions. As ocean boundary condition 20 different realizations of SST reconstructions were used and for sea ice analogues were picked from the HadISST2 sea ice, based on the reconstructed SST fields.

ModE-Sim (short for Modern Era Simulations) is a medium-size ensemble of model simulations using the ECHAM6 atmosphere general circulation model (model version 6.3.5p2, doi:10.17617/2.1810480). Its setup is based on the PMIP4 experiments, but uses a forced AGCM rather than a fully coupled model. ModE-Sim was originally designed to form the a-priori state for a climate reconstruction (Modern Era Reanalysis, ModE-RA, to be found as separate experiment within this WDC project) that uses an offline data assimilation technique to combine the output of ModE-Sim with historical climate information. However, beyond its original purpose ModE-Sim on its own can be used as a tool to study climate variability, providing a high number of posible climate states that are physically plausible under the given forcings and boundary conditions. This might include, e.g. the separation of internal variability from the response to externally forced signals, understanding of teleconnection patterns, or the study of extreme events. The ensemble uses observed/reconstructed forcings and boundary conditions, while accounting in uncertainties in these. For 1850 to 2009 ModE-Sim offers 36 members grouped in two subsets, all using PMIP4 radiative forcings. The subset 1850-1 provided in this dataset group has 20 members and uses 10 different realizations of HadISST2 (two different ModE-Sim members share one realization of HadISST while they differ in their initialization) and according sea ice as ocean boundary conditions. In contrast to the other ModE-Sim sets, for set 1850-1 no forcings are provided within this dataset group. This is because for set 1850-1 only standard forcings and boundary conditions were used, i.e. PMIP4 volcanoes and HadISST sea surface temperatures and sea ice concentrations https://www.metoffice.gov.uk/hadobs/hadisst2/.