ACCESS-ESM1-5 forestation experiments

Earth System Experiments
1

Experiment title: ACCESS-ESM1-5 forestation experiments

Summary

Sensitivity experiments using ACCESS-ESM1-5 of forestation on croplands. They test the response of ACCESS-ESM1-5 to increases in forest plant functional types (PFTs) at the expense of croplands. If we can crop crops there we can plausibly grow trees. Under future sustainable development, natural lands should be preserved and much of the potential forestation will compete with agricultural lands. While many of these experiments are not realistic, they provide useful information on the behavior of ACCESS-ESM1-5’s land-use change.

Scientific motivation

  1. ACCESS’ response to land-use change as a whole in the global context is not well described. These experiments will demonstrate the response of the model in terms of the climate and the carbon cycle.
  2. There aren’t many experiments of forestation for Australia. The LUMIP forestation experiment does not have any future changes in forest cover for Australia. Forestation experiments are needed to answer question surrounding the CO2 removal potential of forests. and the impact on the climate. Would the CO2 removal be offset by local effects of darker trees? Furthermore, how would newly planted forests perform under different climate warming states?

Baseline global warming level

These experiments are based on the global warming level experiments. In these baseline global warming experiments ACCESS-ESM1-5 is run in emissions-driven mode for ssp585, and branched at future points in time every 5 years until 2060. At each branching point the emissions are set to 0 and the climate is allowed to stabilize.

Standard forestation

The forestation experiments branch from the global warming level experiments 400 years after the branching point, since the climate has approximately stabilized enough for doing short 100-year experiments. Forestation occurs instantly at the start of the simulation. Three tree PFTs are expanded (evergreen needleleaf, evergreen broadleaf and deciduous broadleaf) at the expense of of crops. If tree PFTs exist at a grid-cell, the proportions of existing tree PFTs are preserved in the forestation. If there are no existing tree PFTs, then the proportions are preserved using the nearest forested grid-cell.

PFT specific forestation

These simulations are based on the 2030 global warming level (approximately a present-day climate) and forestation occurs using only one tree PFT.

Effect of CO2 vs forestation area

The crop cover increases slightly over the period 2030–2060 in ssp585, therefore forested area increases for later branching points. This simulation branched at 2060 but uses the 2030 land cover map for forestation. This allows us to differentiate forestation area from the increase in CO2 over the period 2030–2060.

Partial forestation

These simulations are based on the 2030 branching point and offer a slightly more realistic forestation scenario. Forestation occurs in the same manner as the standard forestation experiments but only on 10% or 50% of crop lands, everywhere.

Biogeochemical vs. biogeophysical separation

The effects of increasing CO2 from land use change are separated from the biogeophisical effects of land use change using a 2030 no land-use change experiment in concentration-driven mode with the concentrations from the 2030 forestation experiment. This would represent the CO2-only effects of land-use change and the difference with the forestation scenario will reveal the biogeophysical effects of the land-use change.

Exp name Run length Branches from Forestation on Compared to
esm-esm-piNoCrops 100 years piControl all crops esm-piControl
Esm-esm-piNoCrops-02 50 years piControl all crops esm-piControl
GWL-NoCrops-B2030 200 years PI-GWL-t6 all crops PI-GWL-t6
GWL-NoCrops-B2030-02 200 years PI-GWL-t6 all crops PI-GWL-t6
GWL-NoCrops-B2035 200 years PI-GWL-B2035 all crops PI-GWL-B2035
GWL-NoCrops-B2040 200 years PI-GWL-B2040 all crops PI-GWL-B2040
GWL-NoCrops-B2045 200 years PI-GWL-B2045 all crops PI-GWL-B2045
GWL-NoCrops-B2050 200 years PI-GWL-B2050 all crops PI-GWL-B2050
GWL-NoCrops-B2055 200 years PI-GWL-B2055 all crops PI-GWL-B2055
GWL-NoCrops-B2060 200 years Pi-GWL-B2060 all crops Pi-GWL-B2060
GWL-NoCr-B2060-02 200 years Pi-GWL-B2060 all crops Pi-GWL-B2060
GWL-EqFor-B2060 200 years Pi-GWL-B2060 Only GWL-NoCrops-B2030 crops Pi-GWL-B2060
GWL-EGNL-B2030 200 years PI-GWL-t6 all crops PI-GWL-t6
GWL-EGBL-B2030 200 years PI-GWL-t6 all crops PI-GWL-t6
GWL-DCBL-B2030 200 years PI-GWL-t6 all crops PI-GWL-t6
GWL-50pc-B2030 200 years PI-GWL-t6 50% of croplands PI-GWL-t6
GWL-10pc-B2030 200 years PI-GWL-t6 10% of croplands PI-GWL-t6
GWL-CO2only-B2030 200 years PI-GWL-t6 all crops GWL-NoCrops-B2030

People: Tammas Loughran
Model: ACCESS-ESM1.5
Configuration:
Payu
CSIRO ksh scripts
Initial conditions:
Land use maps and UM restart files on gadi: /g/data/p66/tfl561/sensitivity_lu_map
Resources per year
Service Units: 995.20
NCPUs Requested: 384 NCPUs Used: 384
CPU Time Used: 493:16:10
Memory Requested: 288.0GB Memory Used: 183.22GB
Walltime requested: 02:30:00 Walltime Used: 01:17:45
JobFS requested: 800.0MB JobFS used: 8.16MB
Outputs: /g/data/p66/tfl561/ACCESS-ESM
Related articles:
Based on Global Warming Experiments:
King, A. D. et al. Studying climate stabilization at Paris Agreement levels. Nature Climate Change 11, 1006–1016 (2021).

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