Abstract
Initial land cover distribution varies among Earth system models, an uncertainty in initial conditions that can substantially affect carbon and climate projections. We use the integrated Earth System Model to show that a 3.9 M km2 difference in 2005 global forest area (9–14% of total forest area) generates uncertainties in initial atmospheric CO2 concentration, terrestrial carbon, and local temperature that propagate through a future simulation following the Representative Concentration Pathway 4.5. By 2095, the initial 6 ppmv uncertainty range increases to 9 ppmv and the initial 26 PgC uncertainty range in terrestrial carbon increases to 33 PgC. The initial uncertainty range in annual average local temperature of −0.74 to 0.96 °C persists throughout the future simulation, with a seasonal maximum in Dec-Jan-Feb. These results highlight the importance of accurately characterizing historical land use and land cover to reduce overall initial condition uncertainty.
| Original language | English |
|---|---|
| Article number | e2019GB006383 |
| Journal | Global Biogeochemical Cycles |
| Volume | 34 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 1 2020 |
Funding
This work is supported by the US Department of Energy, Office of Science, Office of Biological and Environmental Research under Award Number DE-AC02-05CH11231 as part of the Multi-Sector Dynamics and Earth System Modeling Programs and with additional support from the E3SM project. X. Shi is also supported by the Biogeochemistry-Climate Feedbacks Scientific Focus Area project funded through the Regional and Global Climate Modeling Program in the Climate and Environmental Sciences Division (CESD) of the Biological and Environmental Research (BER) Program in the US Department of Energy Office of Science. Oak Ridge National Laboratory is managed by UT-BATTELLE for DOE under contract DE-AC05-00OR22725. The Pacific Northwest National Laboratory is operated for DOE by Battelle Memorial Institute under contract DE-AC05-76RL01830. This project used resources of the National Energy Research Scientific Computing Center (NERSC), which is a DOE Office of Science user Facility. The CESM project is supported by the National Science Foundation and the Office of Science (Biological and Environmental Research) of the US Department of Energy. Major long-term support for GCAM development comes from the U.S. Department of Energy, Office of Science, as part of research in Multi-Sector Dynamics, Earth and Environmental System Modeling program. The authors declare that there are no real or perceived financial conflicts of interest. Model outputs corresponding with the figures are available as supplemental datasets at http://doi.org/10.5281/zenodo.3701867, and the raw model outputs will be archived for at least five years from publication. Please contact the corresponding author to obtain access to the raw model outputs. The iESM code is available at https://github.com/E3SM-Project/iESM. Each fully coupled simulation used about 1.5 M processor hours each on the Edison supercomputing cluster at NERSC, and were charged twice this amount due to a 2X charge factor. This manuscript has been authored by an author at Lawrence Berkeley National Laboratory under contract No. DE-AC02-05CH11231 with the U.S. Department of Energy. The publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for U.S. Government purposes. This work is supported by the US Department of Energy, Office of Science, Office of Biological and Environmental Research under Award Number DE‐AC02‐05CH11231 as part of the Multi‐Sector Dynamics and Earth System Modeling Programs and with additional support from the E3SM project. X. Shi is also supported by the Biogeochemistry‐Climate Feedbacks Scientific Focus Area project funded through the Regional and Global Climate Modeling Program in the Climate and Environmental Sciences Division (CESD) of the Biological and Environmental Research (BER) Program in the US Department of Energy Office of Science. Oak Ridge National Laboratory is managed by UT‐BATTELLE for DOE under contract DE‐AC05‐00OR22725. The Pacific Northwest National Laboratory is operated for DOE by Battelle Memorial Institute under contract DE‐AC05‐76RL01830. This project used resources of the National Energy Research Scientific Computing Center (NERSC), which is a DOE Office of Science user Facility. The CESM project is supported by the National Science Foundation and the Office of Science (Biological and Environmental Research) of the US Department of Energy. Major long‐term support for GCAM development comes from the U.S. Department of Energy, Office of Science, as part of research in Multi‐Sector Dynamics, Earth and Environmental System Modeling program. The authors declare that there are no real or perceived financial conflicts of interest. Model outputs corresponding with the figures are available as supplemental datasets at http://doi.org/10.5281/zenodo.3701867 , and the raw model outputs will be archived for at least five years from publication. Please contact the corresponding author to obtain access to the raw model outputs. The iESM code is available at https://github.com/E3SM‐Project/iESM . Each fully coupled simulation used about 1.5 M processor hours each on the Edison supercomputing cluster at NERSC, and were charged twice this amount due to a 2X charge factor. This manuscript has been authored by an author at Lawrence Berkeley National Laboratory under contract No. DE‐AC02‐05CH11231 with the U.S. Department of Energy. The publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a non‐exclusive, paid‐up, irrevocable, world‐wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for U.S. Government purposes.
Keywords
- ESM
- carbon
- climate
- land cover
- land use
- uncertainty