Experiments

In this section you will be introduced to the use of Global future by a couple of example scenarios. If you prefer, you can drop the experiments and try out the program directly yourself and, if you so wish, return to the examples later.

A. Using the model default scenario

The default scenario is a very simple experiment. It is based on a representation of the world status as described within the model framework at the beginning of year 2015, and compute the development through the next 50 years assuming the current political trends to continue unchanged.

 

To start the experiment, click the Run link at the end of this section. The stock variable values from which the computations strart are as far as possible based on official statistics and referring to the end of 2014. In some cases, however, these values are extrapolated from older statistics or roughly estimated.

Another set of entities called Policy parameters (Fig 1), are also displayed in the menu. The 3 first reflect how much of the Gross World Product (GWP) is assumed to be allocated to investment in industrial capital (p1), in cultivation of agriculture land area (p2) and in development of renewable energy resources (p3). The fourth parameter (p4) is an adjustment of the investment in new renewable energy resources when the energy needs are saturated to obtain a more smooth development. Examples will be e given below.

Note that the parameter values refer to the world aggregates and that there can be substantial regional and national variations.

Figure 1: Policy parameters

Do not make any changes in the menu, but go to the end of the menu and click Compute. Values for 100 years for 21 variable are computed and you are offered to display results in graphical and tabular form. It is recommended that you start reviewing the computational results by displaying graphs.

When selecting a presentation form, a menu for selecting variable series will be displayed (Fig.2). You can specify a view window (first year and the number of years within the 100 years horizon) which will determine the graph/table to be displayed. In the current experiment, leave the the two default values, i.e. 1 year and 50 years.

 

Figure2: Select series to be display

 

The graphical option generates a graph menu, in which you can specify a period at which you will focus. The default period is the first 50 years, and it is recommended that you start with this period. The next step is to select the variable series you want to inspect.You can select among 21 variable series, but you must restrict the selection to maximum 4 series for each graph.You are free to view as many graphs as you wish.

To use the graph space in an effective way, the minimum and maximum values for each variable are identified and each variable series is scaled so that the minimum point is at the bottom and the maximum at the top of the graph. Each series can be distinguished by its color.

As a first selection you may select the stock variables Population, Capital, Renewable resources available and Greenhouse gas concentration. The graph (Fig. 3) indicates that Population (red curve) will grow from 7335 Million at the end of 2015 to 8849 Million at the end of 2065 (the 50th year), and in parallel with the Capital (green curve). With the decided policy, the Renewable resources available (blue curve) grows steadily for about 40 years. At that time it seems to cover the energy demand and the Greenhouse gas concentration (black curve) stops growing.

Figure 3: Stock variable graph

Also the flow variable can be displayed as graphs. From the graph above, it will be of interest to see how the model will indicate the outlined future development will affect the human life. For the next graph (Fig. 4), the flow variables Food production (green curve), Consumption (blue curve), Global temperature (red curve) and human Welfare (black curve) are selected.

Figure 4: Flow variable graph

The graph indicates that the global temperature anomalies will increase from 0.6 to 2,6 decrees C during the 50 year period. The maximum temperature will occur after about 35-40 years. After that time the renewable energy recourses seem to cover the energy demand and growth of greenhouse gas concentration ends. Both food production as well as consumption increase during the period. However, the global welfare drops from a maximum of 96 points in 2015 to about 61 points in the next 25-30 years before it starts increasing again.

Note that the IPCC recommends to keep the temperature increase within 2 degrees C. Also keep in mind that the global welfare index is rather arbitrary. The welfare drop is obviously related to the increase in temperature, but we have no basis for interpreting how serious the drop from 96 to 61 points is.

By selecting tabular display of the computation results, we can get a more detailed view of the computed development. Selecting year 30 as the start year and 10 years as the tabulation period, we get the following table (Fig. 5):

Figure 5: Table from the default scenario

The table shows that the Non-renewable energy resources left starts to flatten out in year 37, and the Greenhouse gas concentration and the Temperature both obtain their maxima in the same year, while the Global welfare indicator reaches its minimum already in year 30.

 

 

 

B. Second scenario with faster investment in renewable energy resources

Let us investigate the effects of a faster expansive energy policy. The default scenario implied that 1% of the GWP each year was spent on expanding the renewable energy resource capacity. This is probably an optimistic estimate.

A possible alternative action can be to initiate a faster development of these resources, for example by raising the investment in renewable energy to 2% of GWP per annum. However, to maintain the starting level of consumption, another investment item has to be reduced accordingly which in turn can reduce productivity and make the GWP smaller. Let us choose to investigate an increase in investment of renewable energy from 1% to 2% and compensate for this increase by reducing general investment from 18% to 17%. Selecting again the graph presentation, we get another development (Fig. 6).

Figure 6: Second scenario with faster introduction of renewable energy resources.

Subject to the assumptions on which the model are based, the computed results show a more rapid fall in global welfare, but the fall is not as deep in this as in the default scenario. The rise in temperature is also faster, but reaches a maximum of 153 centidegrees. According to the model, the investment policy introduced in this compared with the default scenario seems to give a more preferred temperature and welfare development in the long run. The price to be paid would be a faster drop in the welfare in the first 10-15 years.

 

 

C. A scenario based on a more refined policy

The consumption and the welfare curves of the 2 previous scenarios show a cyclic development. The explanation is that when the needs for energy can be covered by the renewable resources, further development of these resources is discontinued. The investment meant for developing renewable energy resources can instead be consumed, and the consumption and welfare curves will increase. At the same time the GWP continue to grow and so does the need for more energy. After some time, this will again require new investment in renewable energy resources, and the consumption and welfare will be reduced accordingly.

Substituting the 0 default value of the policy parameter p4 with a value 0 < p4 <= 1 where p4 denotes a fraction of the investment in renewable resources the previous year (RDev(t-1)), the cyclic movements can be reduced on the sacrifice of consumption.

In this scenario, we use the parameter setting of scenario B with the exception that the default value of p4 is substituted by p4=0.85.

Figure 7: Development with adjusted investment in renewable resources

The graph in Figure 7 indicates that a smooth development can be obtained if the investment policy is adjusted. Even with much less values for p4 most of the cycles can be avoided. In the real world, these cycles may not be any problem because of the variation of the investment rate from region to region.

 

 

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