feat: add budget constants

co2calculator/constants.py

@@ -7,6 +7,40 @@
 import iso3166
 from co2calculator.data_handlers import Airports
 
+from dataclasses import dataclass
+
+KWH_TO_TJ = 277777.77777778
+
+
+@dataclass
+class BudgetOnePointFiveDegrees:
+    """
+    Dataclass for budget for 1.5 degrees scenario
+    All values are in tons
+    Source for budget values: https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM_final.pdf#page=33, Table SPM.2
+    Remaining carbon budget calculated using an equal-per-capita allocation
+    """
+
+    total_carbon_budget: float = 300_000_000_000
+    budget_per_person: float = 34.0
+    budget_per_person_and_year: float = 1.4
+    budget_per_person_and_year_long: float = 1.1
+
+
+@dataclass
+class BudgetTwoDegrees:
+    """
+    Dataclass for budget for 2 degrees scenario
+    All values are in tons
+    Source for budget values: https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM_final.pdf#page=33, Table SPM.2
+    Remaining carbon budget calculated using an equal-per-capita allocation
+    """
+
+    total_carbon_budget: float = 900_000_000_000
+    budget_per_person: float = 101.9
+    budget_per_person_and_year: float = 4.1
+    budget_per_person_and_year_long: float = 3.4
+
 
 class HeatingFuel(enum.Enum):
     """Enum for heating fuel types"""