4.1T1 Training Materials: Video "Human Demand" (original) (raw)
Video: "Human Demand"
In the following link you may find the video on "Human Demand":
Welcome to this video on the first calculation step of the FABLE model: “Computation of the targeted human demand”. Our objective is to help you learn: How human demand is calculated? Through which tables and worksheets? And what are the main inputs and outputs of the first calculation worksheet?
The first important distinction relevant for all calculations in the FABLE model is the difference between “targeted” and “feasible”.
This graph shows the calculation of human dietary consumption, in terms of daily food intake per capita. You can notice that there are three columns: the red colored ones, which measure historical values, the dark blue columns, which measure feasible consumption, and the lighter blue columns, which measure targeted consumption. The next thing you will notice is that both feasible and targeted consumption in this graph have approximately the same values.
So why calculate them separately? The difference between targeted and feasible values of consumption in the FABLE calculator is the difference between what is the modeled consumption which results from the scenario choices of the user (or targeted consumption) versus what is the consumption that is possible (or feasible), given the constraints included in the model, such as available land for agriculture and pasture, or imports.
This next graph shows the user that the scenario selection and definition that she has chosen leads to an infeasibility of dietary consumption: the dark blue columns are shorter than the light blue columns, signaling a need to adapt her scenario choices.
The computation of human demand is the first step of the FABLE Calculator. This means that all computed changes in the food and land-use systems modeled in the FABLE Calculator are caused by human demand. This represents an important underlying assumption of the model, where human demand is the key driver of change in the food and land-use system.
Human demand, or human consumption, has three components: the demand for food, for biofuels, and for other non-food products. Most of the agricultural products in the FABLE Calculator are food products but can also be used for other purposes. Also, some agricultural products are not fit for human consumption (for example, fiber crops).
Let us take a closer look at this figure: When an arrow passes through a box or is sourced from more than one, it means that two parameters are used together to compute the next value. For example, the way the calculator obtains values for the population is through a multiplication (blue colored-connection) of the population shifter times the historical population for the same year. In the same manner, the population is multiplied times consumption per capita and then added to biofuel use, which then results in the targeted total human consumption.
The numbers within the blue hexagons refer to the scenario tables, called from the worksheet Scenarios Selection, as they have been labeled in the Open FABLE Calculator 2020. For example, hexagon number 1 means that the scenario selection in Table S.1 will affect the values of this GDP Shifter. Please note that the numbers may differ in other versions of the FABLE Calculator, different from the Open FABLE Calculator, version 2020.
Now let us see how this looks in the FABLE Calculator. Are you ready for action? 😊
Human demand is calculated in the FABLE model in the green calculation worksheet called 1_calc_human_demand, using data from the respective gray worksheet called 1_data_demand. We will now explore through a panoramic view what happens in these worksheets.
First, you will see that the calculations done in this worksheet are all carried out through Table 1.A through 1.I. In Table 1.A, the scenarios that have been selected by the user are imported in the respective columns, with a VLOOKUP Excel function.
The VLOOKUP Excel Function is one of the most utilized formulas in the calculator because it serves to call values from tables in other worksheets of the same file. However, one of its limitations is that the modeler needed to organize her data so that the value she looked up was always to the left of the return value.
For this reason, in many tables of the FABLE Calculator, the first calculation step is actually at the end of the table. For human demand, this would be the last column of this first set of tables, in Table 1.E, called [pop2000]. Thus, once the scenario choices are imported to this worksheet, the first step is to calculate the population.
Several calculations of the FABLE model start with a base year, in this case, the 2000 value of population, then calculate a shifter (next column), which as you can see in the formula, depends on a scenario (Table S.2, called POP_scen, which is also signaled by the respective column colored codification throughout the calculator), which results in a final value of population for each five-year step, from 2000 to 2050.
Table 1.D does the exact same calculation for GDP, which is later converted to GDP per capita.
Table 1.C draws several historical values from the worksheet 1_data_demand, namely of Table 1.2, named prod_balance. Each of these historical values for human consumption, food consumption, and non-food consumption are then combined with scenario-based food waste figures, resulting in column M [Final human demand per capita], following the formula:
=[@consononfood]+[@consofood]*(1+[@[food_waste]])
The output of these set of tables is the column entitled "Total human consumption" [consotot], which will be the main input of the next two worksheets to calculate livestock and crop supply (which we will revise in the next two videos).
Lastly, you can see in Table 1.B that these calculations are done for 88 products, each of which are used for every year included, giving a total of 968 rows.
There are two more main calculations in this worksheet:
Tables 1.F through 1.H calculate total minimum calorie consumption per age class and gender, which as we can see in the beginning, are scenario-dependent, specifically on the “Level of activity of the population” and the selected “Population projection”. The last column of table 1.H is the total minimum calorie consumption, which then feeds table 1.I in the last column, to standardize the minimum average calorie consumption, per capita and per day.
This value finally informs the [kcal_MDER] column in the Total_Results_diets Table of the FOOD results worksheet. As you can see from the formula, this is done with a SUMIF function, which is originally meant to sum cells based on a defined criterion, which if consisting of only one value, is a good alternative to the VLOOKUP function, without the restrictions on the position of the columns.
Thanks for watching this video on the FABLE Calculator. We hope to have provided you with a good overview of how the FABLE Calculator approximates Targeted Human Demand. The next videos in the relevant sections of this FABLE-Github Wiki will include more detail of every following worksheet on the calculator. Do not forget to visit our various websites, for more information on the FABLE Consortium! You will find their links in the comments below, in the FABLE YouTube Channel description, or in the FABLE Github Wiki where this video is also hosted.
For more information on the FABLE Calculator:
• https://www.abstract-landscapes.com/fable-calculator
• https://github.com/FABLE-Github/Fable-Calculator-Documentation-2020/wiki
For more information on the FABLE Consortium:
• https://www.foodandlandusecoalition.org/fable/
The 2020 FABLE Report:
• http://pure.iiasa.ac.at/id/eprint/16896/
------------------------------------------------------------ Content ---------------------------------------------------------------
0:00 - Welcome
0:33 - "Targeted" vs "Feasible" in the example of Daily Food Intake per capita
2:10 - Review: calculation steps
2:36 – Overview of how human demand is calculated
4:28 - How is the calculation of human demand done in the Excel model? Tables 1.A-1.G
8:49 – How is the calculation of human demand done in the Excel model? Tables 1.H-1.I
9:30 – Link between calc_human_demand and FOOD worksheets
10:05 – Links to FABLE Websites (to click on them, also included in the video description)