Add definitions for Chapter 4 (#8)

definitions/region/common.yaml

@@ -4,7 +4,6 @@
 - Regions:
     - North America:
         description: United States and Canada
-    - China
     - Europe
     - Asia
     - Oceania

definitions/variable/tag_cdr-market.yaml

@@ -0,0 +1,15 @@
+- CDR Market Credit Type:
+     - Mixed (Mainly CDR):
+          description: carbon credits for carbon dioxide removal and avoided emissions
+              with the majority of credits from carbon dioxide removal
+     - Mixed (Mainly Avoided):
+         description: carbon credits for carbon dioxide removal and avoided emissions
+             with the majority of credits from avoided emissions
+     - Novel CDR:
+        description: carbon credits for novel carbon dioxide removal methods
+     - Conventional CDR:
+        description: carbon credits for conventional carbon dioxide removal methods
+     - Avoided Emissions:
+        description: carbon credits for avoided emissions
+     - Emission Reduction:
+        description: carbon credits for emission reductions

definitions/variable/variables.yaml

@@ -102,6 +102,47 @@
     description: Amount of investment in start-ups related to {Conventional CDR Method}
     unit: billion USD
 
+- Carbon Credits|Novel CDR|Tons Sold:
+    description: Quantity of credits sold (purchased) in the voluntary carbon removal market
+      using novel CDR methods
+    unit: Mt CO2
+- Carbon Credits|Novel CDR|Tons Sold|{Novel CDR Method}:
+    description: Quantity of credits sold (purchased) in the voluntary carbon removal market
+      using {Novel CDR Method}
+    unit: Mt CO2
+- Carbon Credits|Novel CDR|Tons Sold|Not Disclosed:
+    description: Quantity of credits sold (purchased) in the voluntary carbon removal market
+      where the removal method was not disclosed
+    unit: Mt CO2
+- Carbon Credits|Novel CDR|Tons Delivered:
+    description: Quantity of credits delivered in the voluntary carbon removal market
+      using novel CDR methods
+    unit: Mt CO2
+- Carbon Credits|Novel CDR|Tons Delivered|{Novel CDR Method}:
+    description: Quantity of credits delivered in the voluntary carbon removal market
+      using {Novel CDR Method}
+    unit: Mt CO2
+- Carbon Credits|Novel CDR|Tons Delivered|Not Disclosed:
+    description: Quantity of credits delivered in the voluntary carbon removal market
+      where the removal method was not disclosed
+    unit: Mt CO2
+- Carbon Credits|Conventional CDR|Tons Issued:
+    description: Quantity of credits issued in the voluntary carbon removal market
+      using conventional CDR methods
+    unit: Mt CO2
+- Carbon Credits|Conventional CDR|Tons Issued|{Conventional CDR Method}:
+    description: Quantity of credits issued in the voluntary carbon removal market
+      using {Conventional CDR Method}
+    unit: Mt CO2
+- Carbon Credits|Conventional CDR|Tons Retired:
+    description: Quantity of credits retired in the voluntary carbon removal market
+      using conventional CDR methods
+    unit: Mt CO2
+- Carbon Credits|Conventional CDR|Tons Retired|{Conventional CDR Method}:
+    description: Quantity of credits retired in the voluntary carbon removal market
+      using {Conventional CDR Method}
+    unit: Mt CO2
+
 - Planned Projects|Removal:
     description: Planned near-term projects for carbon dioxide removal
     unit: Mt CO2

nomenclature.yaml

@@ -0,0 +1,3 @@
+definitions:
+  region:
+    country: true