We have aimed to keep our calculators as simple to use as possible, using the following sources to estimate figures for energy consumption and the carbon emissions generated. While these can help provide the average carbon emissions for everyday activities, we stress that these are a guide only, given the activities and environments relating to carbon emissions vary greatly, and that our calculators cannot account for every variable and circumstance.
We estimate the fuel consumption per kilometers driven using figures provided by the the Mexico Government's Portal of Vehicle Emissions and Efficiency, based on popular models for small/medium (30.58mpg), large (21.17mpg), and commercial (16.47mpg) vehicles. Our Vehicle Offset Packages assumes fuel consumption based on a small/medium car, and the average annual Mexican per vehicle mileage of 15000km (as provided by the Institute of Transport and Development Policy).
We then calculate the CO2 emissions generated from the fuel consumption per kilometer driven according to data provided by the US Environmental Protection Agency (8.89 kg of CO2 produced for each gallon of gasoline burned).
The CO2 emissions estimates for air travel are a guide only, given the exact fuel consumption levels per passenger per mile will depend on the type of plane, the number of people flying, the weight of the cargo, and other factors.
However, using the "GHG emissions from transport or mobile sources" calculator provided by the Greenhouse Gas Protocol, carbon emissions for air-travel have been estimated as follows:
Roundtrip domestic flight (less than 463km each way): 120kg CO2 (assuming 350km flight)
Roundtrip short haul flight (463-1107km each way): 148kg CO2 (assuming 800km flight)
Roundtrip long haul flight (over 1107km each way): 661kg CO2 (assuming 4000km flight)
These calculations account for the fact that planes burn more fuel at take off and landing, meaning that domestic and short-haul trips are less efficient per mile flown.
The Frequent Flyer Offset Package presumes 5 round trip short-haul flights: 148x5=740kg and the offset will round up to 1 tonne of Carbon.
We estimate the carbon emissions of each event guest as 10kg, based on an average distance travelled by car of 32km (driving calculations as above), and the preparation of 1-2 meals per person, (emissions estimates come from a review of widely used carbon calculators carried out by John Hopkins Bloomberg School of Health. This review provides six estimates of per capita food footprint in the US, which we have averaged then divided by 365 then by three to get CO2 emissions per meal).
Additional CO2 emissions for hotel stays have been calculated as 25 kg per guest per night, being the mid-point of CO2 produced for budget (16.8kg) and upscale Hotels (33.3kg), using figures provided by the Environmental Protection Agency and calculations performed by carbonfund.org.
The Individual Offset Package is calculated at 3.9 tonnes of CO2 ,this being the per- capita emission figure for Mexico in 2011 as provided by the US Energy Information Administration.
For our Individual Household calculator, we use the average residential per-capita electricity use for Mexico per year (435kWh for 2014 - sourced from Energydata via World Energy Council) as well as per-capita Natural Gas use for Mexico per year (609.045cm o 6813.248 kWh 609 cubic meters or 6813kWh, 2014 natural gas data sourced from the CIA World Fact Book and population data from indexmundi.com). We then estimate the CO2 produced from this energy usage using calculations developed by the US Environmental Protection Agency (0..690kg CO2 produced per kWh electricity, and 0.172kg CO2produced per kWh natural gas, conversion factors provided by UK Power and EIA).
A tonne, also known as a metric ton, is a unit of mass equaling 1,000 kilograms = 2205 pounds.