Carbon Cycle Model

globals [
  lithosphere               ;to set up lithosphere
  atmosphere                ;to set up atmosphere
  hydrosphere               ;to set up hydrosphere
  litho-carbon              ;amount of carbon in lithosphere
  atmo-carbon               ;amount of carbon in atmosphere
  hydro-carbon              ;amount of carbon in hydrosphere
  bio-carbon                ;amount of carbon in biomass
  fossil-carbon             ;amount of carbon in fossils fuels
  ppm                       ;used for calculating ppm
  gigaton-carbon            ;amount carbon in atmosphere in gigatons
  ppm-old                   ;used for calculating ppm
  ppm-new                   ;ppm carbon in atmosphere
  gigaton-change            ;change in atmospheric carbon
  scenario-increase         ;used for registering an increase in human emissions over time
  scenario-decrease         ;used for registering a decrease in human emissions over time
  est-global-temp           ;the estimated global average temperature worldwide
  ]

breed [carbons carbon]
breed [plants plant]
breed [outliners outliner]

to set-up                   ;sets up world
  clear-all
  reset-ticks 
  setup-world
  setup-res
  setup-volcano
  add-algae
end  

to setup-volcano            ;sets up volcano
  crt 1 
  [
    set shape "volcano"
    set size 16
    setxy -1 3
    set heading 0
  ]
end 

to setup-world                                                                    ;create spheres 
  set atmosphere max-pycor - 32
  set lithosphere max-pxcor - 32
  ask patches [                                                                   ;first layer to make lithosphere
    if pxcor <= lithosphere + 10 [ 
      set pcolor scale-color brown pycor -30 10] ]
    ask patch -6 -14 [set plabel word "Lithosphere Res: " initial-litho-carbon
    set plabel-color white]
  ask patches [                                                                   ;add a line for plants 
    if pycor = 0
    [set pcolor green] ]
  ask patches [                                                                   ;thickens line of plants
    if pycor = -1 
    [ set pcolor green]]
  ask patches [                                                                   ;thickens line of plants
    if pycor = 1
    [set pcolor green] ] 
  ask patches [                                                                   ;second layer to make hydrosphere
    if pxcor > lithosphere + 10 
    [set pcolor scale-color blue pycor -32 10] 
  ]
  ask patch -15 11 [set plabel word "Biomass Carbon: " initial-bio-carbon
    set plabel-color black]
  ask patch 31 -14 [set plabel word "Hydrosphere Res: " initial-hydro-carbon
    set plabel-color white]
  ask patches [                                                                   ;last layer to make atmosphere
    if pycor > atmosphere 
    [set pcolor scale-color sky pycor 32 0]
      set atmo-carbon 817
    ask patch 10 29 [set plabel word "Atmosphere Res: " atmo-carbon
    set plabel-color white]
  ask patch -6 -29 [set plabel word "Fossil Carbon: " initial-fossil-carbon]
  ]
 crt 1 [set shape "smokestack" set size 7 set color gray setxy -14 2]
  ask patch -26 5 [sprout-plants 1 [set size 9
      set color green
      set shape "tree border"] ] 
    
  set initial-hydro-carbon 44000                                                  ;sets default initial carbon amounts
  set initial-bio-carbon 550        
  set initial-litho-carbon 2300
  set initial-fossil-carbon 10000

 set ppm-new (0.074131 * (e ^ (0.0042584 * (2008 + (ticks / 12)))))               ;sets initial ppm to show before simulation starts
end 

to setup-res                                                                      ;sets up colors of reservoirs and sun
  ask patches [if pycor < -25 and pxcor <= 10  [set pcolor 31]]
  ask patches [if pycor > 25 [set pcolor black]]

 crt 1 [set shape "sun" setxy -26 29 set color yellow set size 7]
end 

to go                        ;carries out the functions of the simulation
  initial-setup
  scenario
  ask carbons [fd 2]
  calculations
  human-emission
  respiration
  photosynthesis
  soil-carbon
  decomposition
  air-exchange
  sea-exchange
  update-values
  update-labels
  wait .1
  tick
end 

to initial-setup                            ;initial setup before go
  if ticks = 0 [
  set hydro-carbon initial-hydro-carbon
  set bio-carbon initial-bio-carbon
  set litho-carbon initial-litho-carbon
  set fossil-carbon initial-fossil-carbon
  ]
end 

to human-emission                                         ;visually sets up the flow of human emissions into the atmosphere reservoir
  if ticks mod 12 = 0 [ ask patch -15 4 [
    sprout-carbons round (emission-multiplier + .49)[
      set shape "carbon arrow"
      set color orange
      set heading -20 + random 40 ] ] 
  ask carbons [
    if pcolor = white - 1
     [die]]
  ]
end 

to respiration                                            ;visually sets up the flow from biomass reservoir to atmosphere reservoir
  if ticks mod 2 = 0 [ ask patch -25 8 [
    sprout-carbons 1 [
      set shape "carbon arrow"
      set color blue
      set heading 0 + random 30] ] 
  ask carbons [
    if pcolor = black
    [die]]
  ]
end 

to photosynthesis                                         ;visually sets up the flow from atmosphere reservoir to biomass reservoir
  ask patch -31 25 [
    sprout-carbons 1[
      set shape "carbon arrow"
      set color green
      set heading 160 + random 20]
  ask carbons [if pcolor = green
    [die]]]
end 

to soil-carbon                                            ;visually sets up the flow from biomass reservoir to lithosphere reservoir
  ask patch -24 -3 [
    sprout-carbons 2[
      set shape "carbon arrow"
      set color brown + 2
      set heading 160 + random 20] 
  ask carbons [if pcolor = 33 or pcolor = 33.25
     [die]]
  ]
end 

to decomposition                                          ;visually sets up the flow from lithosphere reservoir to atmosphere reservoir
  if ticks mod 2 = 0 [ ask patch -23 4 [
    sprout-carbons 1 [
      set shape "carbon arrow"
      set color brown - 2
      set heading 5 + random 20] ] 
  ask carbons [
    if pcolor = black
     [die]]
  ]
end 

to air-exchange                                           ;visually sets up the flow from atmosphere reservoir to hydrosphere reservoir
  if ticks mod 4 = 0 [ask patch 15 25
    [sprout-carbons 3 [
      set shape "carbon arrow"
      set color white
      set heading 175 + random 5] ]
  ask carbons [
    if pycor <= -12
     [die]]
  ]
end 

to sea-exchange                                           ;visually sets up the flow from hydrosphere reservoir to atmosphere reservoir
  if ticks mod 4 = 0 [ask patch 30 1
    [sprout-carbons 3 [
      set shape "carbon arrow"
      set color blue + 2
      set heading -10 + random 10] ] 
  ask carbons [
    if pcolor = black
    [die]]
  ]
end 

to scenario                                                                                           ;registers variation due to activation of scenarios
  ifelse scenario-increase = true and ticks mod (per * 12) = 0
  [set emission-multiplier (emission-multiplier + increase-or-decrease-by)]
  [ifelse scenario-decrease = true and (emission-multiplier - 0.1) > 0 and ticks mod (per * 12) = 0
    [set emission-multiplier (emission-multiplier - increase-or-decrease-by)]
    [set emission-multiplier emission-multiplier]
  if scenario-decrease = true and (emission-multiplier - increase-or-decrease-by) < 0
    [set emission-multiplier 0] 
  ]
end 

to calculations                                                                                       ;formulas used to calculate increase of carbon in ppm in the resevoirs 
  set ppm (0.074131 * (e ^ (0.0042584 * (2008 + (ticks / 12))))) 
  set ppm-old (0.074131 * (e ^ (0.0042584 * (2008 + (ticks - 1) / 12)))) 
  set gigaton-change ((ppm - ppm-old) * 2.13)                                                         ;calculates gigaton-change over time
  set gigaton-carbon (ppm-old * 2.13)
  set ppm-new (ppm-old + ((gigaton-change * (emission-multiplier - 1)) / 2.13) ) 
  set est-global-temp (ppm-new + 948.83) / 90.787                                                     ;temperature calculation
end 

to update-values                                                                                      ;updates the value of carbon in Gt for all labels
  set atmo-carbon round (gigaton-carbon + (gigaton-change * (emission-multiplier)))
  set hydro-carbon hydro-carbon + (((2 / 9) * gigaton-change))                                        ;distributes carbon 
  set litho-carbon litho-carbon + (((3 / 9) * gigaton-change))
  set bio-carbon bio-carbon + (((0 / 9) * gigaton-change))
  set fossil-carbon fossil-carbon - (gigaton-change * emission-multiplier)
end 

to update-labels                                                                                      ;adds lithosphere, hydrosphere, atmosphere, fossil, and biomass patch labels 
  ask patch -6 -14 [set plabel word "Lithosphere Res: " round litho-carbon]
  ask patch 31 -14 [set plabel word "Hydrosphere Res: " round hydro-carbon]
  ask patch 10 29 [set plabel word "Atmosphere Res: " round atmo-carbon]
  ask patch -6 -29 [set plabel word "Fossil Carbon: " round fossil-carbon]
  ask patch -15 11 [set plabel word "Biomass Carbon: " round bio-carbon]
end 

to erupt                                                                                              ;creates an eruption from the volcano
  ask patch -1 7 [ sprout-carbons 1 [                                                                 ;creates a smoke cloud
      set shape "cloud"
      set size 7
      set color gray - 2
      set heading 0
    ] ]
  set gigaton-carbon gigaton-carbon + .00001                                                          ;adds miniscule amount of carbon to atmosphere
end 

to add-algae                                                                                          ;generates algae on the surface of the hydrosphere
  ask n-of 4 patches with [(pycor = 0 or pycor = 1) and pxcor >= 11][                                 ;four algae plants
          sprout-plants 1                                                                             ;random places on a specific y cord
          [
            set color green
            set shape "plant small border"
            set size 4 
          ]]
end 

;Created by: 

;Amit Grewal amitgrewal97@yahoo.com Tracy High School 
;Evan Laufer evan.m.laufer@gmail.com San Ramon Valley High School 
;Joshua Abraham joshpabraham@gmail.com Tracy High School 
;Miguel Taruc miguelt17@comcast.net Tracy High School 
;Rowen Banton bantonrowen@gmail.com Monte Vista High School
;LLNL Computational Modeling TRA Level 3