E2.7 Enabling future land-use scenarios within E3SM

Abstract

Human land‐use and land‐use change are key drivers of change to the Earth’s carbon cycle and climate system. As a result, their accurate representation within Earth System Model (ESM) experiments is an increasingly important goal. The Land‐use Harmonization (LUH) connects historical land‐use reconstructions with future land‐use projections from Integrated Assessment Models (IAMs), attempts to preserve all future gridded changes depicted by the IAMs, computes associated land‐use transitions, and provides this data in a consistent format designed for use in ESMs. The 6th Coupled Model Inter‐comparison Project (CMIP6) recently made land‐use a required forcing, and the LUH2 dataset was made an entry card for participating in CMIP6 runs. LUH2 improves upon LUH1 in multiple ways, including finer spatial resolution (0.25 x 0.25 degrees), earlier model start date (850 AD), additional land‐use states and transitions including multiple cropland and pasture types, improved spatial detail for wood harvesting and shifting cultivation, and new data layers of land management information such as irrigation and fertilizer usage (Hurtt et al. in prep).

Over the past two years, the LUH team have participated in the E3SM project by enabling land‐use dynamics in E3SM code, providing key land‐use input datasets, and supporting modeling related coupled model experiments. Specially we have converted the LUH2 historical data for the years 1850‐2015 into an LUH1 format, modified the Land‐Use Translator code to use this data to produce new land‐cover transitions, and then generated consistent land surface files using makesurfdat for use in E3SM. We now turn our attention to the LUH2 future scenarios and are in the process of converting the LUH2 SSP5 RCP8.5 scenario into the format required for use in E3SM. This involves aggregation to 0.5 x 0.5 degrees gridded fractions of 5 land‐use states and all transitions between them, annually, for the years 2015‐2100; running these datasets through the Land-Use Translator in offline mode to generate a set of corresponding land‐cover transitions; and then running those land-cover transitions through makesurfdat to generate a corresponding surface file for use in E3SM. In combination with prior work, enabling E3SM to use this LUH2 future scenario will enable historical‐to‐future land and coupled model simulations in a consistent manner. In this poster we will show the current results from this dataset conversion.