text: var conversionFactor = 0.67; // converts cubic metres to kg
  
  facTerm = 1 + factorCoefficient * timeAbandoned;
  
  fac = Math.pow(facTerm, factorExponent);
  
  ch4Emissions = ((emissionsRate * fac) - recoveredMethane) * conversionFactor;
  
  // fetch GWP
  ch4GWP = dataFinder.getDataItemValue('planet/greenhousegases/gwp', 'gas=CH4', 'GWP');
  co2eEmissions = ch4Emissions * ch4GWP;
  
  returnValues.putValue('CH4', 'kg', 'year', ch4Emissions);
  returnValues.addNote('comment', 'CH4 emissions converted to CO2e using a global warming potential of '+ch4GWP);
  returnValues.putValue('CO2e', 'kg', 'year', co2eEmissions);
  returnValues.setDefaultType('CO2e'); 
  