Strange fluctuations in LUC emissions over 2020-2025

[debibooo]

Hi I ran the ref scenario and got the LUC emission by region results. However, no matter in which country, the LUC emissions rise remarkably from negative to positive emissions over 2020-2025, as shown in the following graph. My question is:

1. What causes this error?
2. How can I fix it? Thanks for any suggestions. LUC graph.docx

[pkyle]

The increase in net LUC emissions is driven by growth in agricultural production and by the introduction of bioenergy crops, which have low land carbon contents and may displace other land types with higher carbon contents. The growth in the crop production in general isn't something that's especially easy to modify as it's coming from the food demand module; as incomes increase, so do demands for animal commodities, and animal commodities are often produced with feed crops. Turning down the biomass production is comparatively simple; I believe if you reduce the default share assumptions in input/gcamdata/inst/extdata/aglu/A_bio_ghost_share.csv, that will reduce the amount of land switching to bioenergy crop production in the given time periods.

[debibooo]

I appreciate your suggestion. I utilized gcamdata and changed the ghost-share in land_input_4_IRR_MGMT XML files.

Also, I want to impose a forest protection policy in GCAM to depict China's reforestation plan for the future. Therefore, I modified every protected unmanaged forest and unmanaged forest part in the protected_land_input_3.xml by introducing a reduced_deforestation policy as follows:

           <LandNode name="ProtectedUnmanagedForest_Gobi">
                <relative-cost-logit>
                <logit-exponent fillout="1" year="1975">0</logit-exponent>
                </relative-cost-logit>
                <unManagedLandValue>1</unManagedLandValue>
                <UnmanagedLandLeaf name="ProtectedUnmanagedForest_Gobi">
                    <land-use-history>
                        <allocation year="1700">0</allocation>
                        <allocation year="1750">0</allocation>
                        <allocation year="1800">0</allocation>
                        <allocation year="1850">0</allocation>
                        <allocation year="1900">0</allocation>
                        <allocation year="1950">0</allocation>
                        <allocation year="1975">0</allocation>
                        <above-ground-carbon-density>5.6</above-ground-carbon-density>
                        <below-ground-carbon-density>13.9</below-ground-carbon-density>
                    </land-use-history>
                    <landAllocation year="1975">0</landAllocation>
                    <landAllocation year="1990">0</landAllocation>
                    <landAllocation year="2005">0</landAllocation>
                    <landAllocation year="2010">0</landAllocation>
                    <landAllocation year="2015">0</landAllocation>
                    <minAboveGroundCDensity>0</minAboveGroundCDensity>
                    <minBelowGroundCDensity>0</minBelowGroundCDensity>
                    <land-carbon-densities>
                        <above-ground-carbon-density>5.6</above-ground-carbon-density>
                        <below-ground-carbon-density>13.9</below-ground-carbon-density>
                        <mature-age fillout="1" year="1975">50</mature-age>
                    </land-carbon-densities>
                    <land-constraint-policy>reduced_deforestation</land-constraint-policy>
                </UnmanagedLandLeaf>
            </LandNode>

In the end, I added the sum protection targets (including all regions of China) for 2020 and 2050 as follows:

                       </UnmanagedLandLeaf>
                    </LandNode>
                </LandNode>
            </LandNode> 
        </LandAllocatorRoot> 
        <policy-portfolio-standard name="reduced_deforestation">
             <market>China</market>
             <policyType>subsidy</policyType>
             <constraint year="2020">2210</constraint>
             <constraint year="2050">2496</constraint>
        </policy-portfolio-standard>
    </region>
    <region name="EU-12">

I then changed the XML in the configuration file, but the iteration stalled in 2020. Do you know how I can fix it?

Any advice you can give would be greatly appreciated!