Understanding Sustax Climate Data / Climate’s Past and Future

Climate’s Past and Future

Last update: July 17, 2025

In:

Interactive Index

  1. CMIP6 Projections (1979-2080)
  2. ERA5 Reanalysis (1979-2022)
  3. Sustax Climate Offering

Sustax provides users with powerful tools to analyze climate change risks and opportunities, powered by robust data that seamlessly spans from the historical record (1979) deep into future projections (2080). Understanding the source and nature of this data is key to leveraging its full potential. This article explains the foundational approach used within the Sustax platform.

To present a comprehensive and scientifically sound picture of climate change, Sustax integrates two primary, best-in-class types of climate data:

CMIP6 Projections (1979-2080)

  • What is CMIP6? To project future climate change, Sustax utilizes data from the Coupled Model Intercomparison Project Phase 6 (CMIP6). CMIP6 is a collaborative international effort coordinated by the World Climate Research Programme (WCRP, [11]). It brings together dozens of climate modeling groups from around the world to run standardized climate model experiments. These models simulate the Earth’s complex climate system—including the atmosphere, oceans, land surface, and ice—based on fundamental physical laws and under various future greenhouse gas emission scenarios.
  • Why CMIP6? CMIP6 represents the latest generation of global climate models, offering the most up-to-date scientific understanding of potential future climate pathways. By using an ensemble of CMIP6 models, Sustax can provide not only projections but also insights into the range of possible outcomes and the inherent uncertainty in future climate scenarios.
  • What CMIP6 models? Sustax represents a comprehensive Big Climate Data initiative, integrating 7 CMIP6 SSP-RCP scenarios under a multi-model, multi-ensemble basis. Below is shown for each CMIP6 model/modeling center, the number of scenarios and the number of simulations/ensemble members used per scenario. 

ERA5 Reanalysis (1979-2022)

  • What is ERA5? For the historical period, Sustax relies on ERA5, the fifth generation ECMWF (European Centre for Medium-Range Weather Forecasts) atmospheric reanalysis of the global climate. ERA5 is a state-of-the-art global reanalysis dataset produced by the Copernicus Climate Change Service (C3S). It provides a detailed, hourly reconstruction of the Earth’s past weather and climate by combining vast amounts of historical observations (from satellites, weather stations, balloons, buoys, etc.) with advanced weather models using data assimilation techniques.
  • Why ERA5? ERA5 [12] is a globally recognized, high-quality historical climate dataset (1979-2022). Sustax uses this critical “ground truth” data for two primary purposes:
    • Training our bias-correction models: Ensuring our future projections align accurately with the observed past.
    • Validating the performance and the predictive accuracy of our climate projections against the historical record.
  • Accessing ERA5 Insights in Sustax: While Sustax projections extend well beyond 2022, the ERA5 available period in Sustax (1979-2022) forms the historical basis for understanding recent climate conditions and for the validation of our forward-looking models.

Thus, Sustax incorporates CMIP6 model outputs that simulate both the historical period (overlapping with ERA5, crucial for bias correction) and future projections out to 2080, under 7 distinct Shared Socioeconomic Pathways (SSPs) and Representative Concentration Pathways (RCPs).

Sustax’s Climate Offering

Ensuring a smooth and scientifically valid transition between historical observed/reanalysed data (ERA5) and model-driven future projections (CMIP6) is critical. It is important to mention that directly using future projections leads to structural errors and inconsistencies due to inherent model biases.

Powered by Geoskop Climate Intelligence [13], Sustax is built on top of advanced statistical techniques to achieve a reliable and accurate projection. This includes:

  • Bias Correction: CMIP6 model outputs are systematically compared against the ERA5 historical “ground truth” during their overlapping period. Geoskop’s proprietary bias correction [14] is then used to identify and correct systematic biases in the CMIP6 models, ensuring their historical simulations align more closely with observed reality.
  • Calibration: While CMIP6 models provide global coverage, their native’s spatial resolution can be coarse for most applications. Sustax’s models achieve superior spatial resolution and predictive accuracy because they are calibrated against real-world observations (i.e.: ERA5), not just flawed deterministic downscaling methods [15] [16]

Sustax’s climate change scenarios result in a unique climate big-data suite. Delivered as a climate dataset that is integrated and harmonised from a temporally and geospatial perspective.

A Harmonised Climate Model-Driven Timeline

Bias-Corrected CMIP6 Historical Simulations (1979-2022): CMIP6 models are run for the historical period and meticulously bias-corrected against ERA5. This ensures the entire climate change model aligns closely with observations.

Bias-Corrected CMIP6 Future Projections (2022-2080): The projection period extends the bias-corrected historical simulations up to 2080. The CMIP6 projection period is comparable to its respective historical simulations and to its analogous to ERA5. Providing a consistent view of potential future climate pathways for the seven SSP-RCP scenarios available in Sustax.

A Foundational Historical Context

We provide direct access to ERA5 reanalysis data (1979-2022). This high-quality reanalysis dataset serves as the “ground truth” for understanding recent climate. ERA5 static variables, such as geopotential height [17], soil type [18], and high/low vegetation types [19] [20] are also supplied to the user, to support advanced understanding of Sustax’s comprehensive climate change impacts. Static data is provided for free in any request

This turns Sustax into a set of SSP-RCP models whose resolution is 0.25 degrees (~31km2), providing more granular insights where appropriate and scientifically sound. Sustax’s employed bias correction approach creates a continuous, reliable CMIP6 dataset (historical and future) for assessing climate risks from 1979 to 2080, with rigorous ERA5-based harmonisation of past performance and projections delivering exceptional predictive accuracy [14] and consistency.