Calculating Long-haul Air Freight CO₂ Emissions

This knowledge base document describes how to calculate Carbon Dioxide (CO₂) emissions for long-haul air cargo transport, and provides an example that can be used for similar calculations.

For any type of transport, CO₂ emissions are a matter of weight, distance and mode of transportation.

For example, depending on year and model, your car emits about 160 g CO₂ per kilometer 1. For a 140 kilometer round trip that totals to 22.4 kg CO₂. (Imp: 87 miles driving emitting 50 lb CO₂).

We are going to calculate the amount of emissions caused by long-haul air freight.

Air Freight

Because take-off and landing cause seriously higher emissions than cruising speed flight, long-haul flights have lower emissions averages per km than short-haul flights. For any calculation, long-haul and short-haul air freight are different modes of transportation, using different emissions figures.

Air Freight CO₂ Calculation

Long-haul air freight CO₂ emissions are about 500 g CO₂ per 1,000 kg cargo per 1 km 2. This is for long-haul above 5,000 km, with a large cargo plane using modern engines. Our example uses such a plane on an intercontinental long-haul.

We have 3.9 kg cargo travelling between Miami and Bangkok. It's 15,611 km by air freight.  (Imp: 8.6 lb cargo air freighting 9,700 miles).

How much CO₂ does this emit? Again, specifically for long-haul:

Air freight 1,000 kg cargo for 1 km: 500 g CO₂.
Air freight 1 kg cargo for 1 km is: 500/1,000 = 0.5 g CO₂

Air freight 1 kg cargo for 15,611 km is: 0.5 x 15,611 = 7.81 kg CO₂
Air freight 3.9 kg cargo for 15,611 km is 7.81 x 3.9 = 30.46 kg CO₂

The 3.9 kg air shipment going 15,611 kilometers emits 30.46 kg CO₂ emissions. 

Actually, you can do this type of weight calculation yourself now. For different transportation modes find the appropriate CO₂/km averages. You'll see that slower types of transport have notably lower CO₂ emissions.

One way to counter CO₂ emissions is to plant trees. An average tree absorbs approximately 22 kg CO₂ per year. JEDI has planted over 1,500 trees on own ground, with villagers planting another 1,000 trees on their own and public ground, for a total of about 55,000 kg (55 tonnes) of annual CO₂ absorption.

CO₂ Price

While the planet very likely knows what trees do, it has no relation to human material value labels like "carbon emissions cost", price, allowance, or tax. Any monetary valuation of CO₂ emissions should therefore be taken with three grains of salt.

On 24 August 2018 the official European Emission Allowance "price" for CO₂ was 23.93 USD per tonne (20.55 Euro) 3. This is equivalent to 0.02 ¢ per kilogram. It is significantly up from about 5.82 USD per tonne (5.00 Euro) a year earlier, and before that. Note that these allowances are priced artificially based on governments creating papers 4 with text like "Carbon Emission 1 tonne" and allowing "free" markets to decide their value. Initially too many of these papers were issued, they were unpopular, there was some talk of fraud, so their price dropped so low that your friendly neighborhood café was better off buying these allowances for its soda maker than getting the real thing.

In 2015 the US government calculated the social cost of carbon emissions at 37.00 USD per tonne, while Stanford University, taking wider economic effects into account, estimated 220.00 USD per tonne 5.

CO₂ and CO₂e

CO₂ stands for Carbon Dioxide, a colorless gas containing one carbon atom double bonded to two oxygen atoms. It exists naturally as a trace gas, and as a man made gas mainly through burning fossil fuels. It acts as a greenhouse gas, responsible for heating up earth's surface and lower atmosphere.

CO₂e stands for Equivalent Carbon Dioxide. It shows the "global warming potential" (GWP) of any other greenhouse gas as in terms of what it would be when expressed as CO₂. So, CO₂ itself has a global warming potential of 1. The greenhouse gas methane is 25 times stronger in global warming potential than CO₂, so its GWP is 25.

Refrigerants

Those other "e" gases have clout.

The most destructive of these are manufactured refrigerant gases used in air conditioners and refrigerators, such as the conventionally used Freon 6, 7 gases. These are fluorocarbon (CFC,HCFC, HFC) gases that 1) deplete the earth's ozone layer and 2) have global warming potentials of thousands to tens of thousands greater than CO₂. An early example was Freon CFC-12 /R-12, highly destructive to the ozone layer, with a global warming potential about 10,000 times greater than CO₂. Some improvements have been made, reducing the ozone depletion effect, while current Freon variants have global warming potentials of about 1,300 to 4,000 times greater than CO₂ 8.

Newest Freon variants are hydrofluoroolefins (HFOs). They have zero effect on the ozone layer, and a lower global warming potential, yet still still hundreds of times greater than CO₂. The newest version for automobiles goes by the name HFO-1234yf / R-1234yf. Its technical advantage is its use as so-called "drop-in" replacement of the conventional R-134a refrigerant. Its monetary advantage is that it is patented by the same Freon manufacturers, allowing for continued shareholder profit 9.

Best to go back to the natural refrigerants 10 that were in widespread use before pernicious Freon became a household term. These natural refrigerants are carbon dioxide (CO₂) itself, ammonia, and hydrocarbon refrigerants, specifically propane, iso-butane and propylene. Many large industrial refrigeration facilities never abandoned their natural refrigerants, since they are patent-free, widely available, inexpensive, and have very low to zero global warming potential. They do require specifically designed cooling hardware, but that's about it.

Most European automobile brands have now redesigned their vehicle air conditioners to use natural refrigerant CO₂ 11, also known as R-744, with global warming potential 1.

It may very well be possible for you to raise your own environmental contribution by converting, or switching to an air conditioner with refrigerant that has low or no atmospheric impact 12.

Related

Norway's plan for a fleet of electric planes - 2018-08-22
http://www.bbc.com/future/story/20180814-norways-plan-for-a-fleet-of-electric-planes ... (link is external)

Footnotes

  1. https://www.eea.europa.eu/data-and-maps/daviz/average-emissions-for-new-cars-4
  2. https://timeforchange.org/co2-emissions-shipping-goods
  3. https://markets.businessinsider.com/commodities/co2-emissionsrechte
  4. http://www.climateactionprogramme.org/news/carbon_prices_reach_new_low_with_bureaucratic_delay_and_oversupply
  5. https://news.stanford.edu/2015/01/12/emissions-social-costs-011215
  6. Also referred to as F-gases. Patented, trademarked, and manufactured, monopolized by Honeywell and DuPont /Chemours. It includes Freon type aerosol propellants like the Donald's hair spray, gases used in foam production, and solvents used in cleaning products.
  7. Various Freon variants, such as CFC-12 /R-12, were banned and replaced with newer versions due to their depletion effects on the earth's ozone layer. Only much later was global warming potential considered.
  8. Widely used HFC-134a /R-134a is at about 1,500 times greater than CO₂.
  9. "Always sell at the highest possible profit" Ferengi Rule of Acquisition #55, the profit being for Honeywell, DuPont, Chemours
  10. https://theintercept.com/2018/08/25/chemours-epa-coolant-refrigerant-dupont/
  11. http://mercedesblog.com/mercedes-goes-eco-with-co2-air-conditioning-the-systems-explained, https://www.mahle.com/en/research-and-development/research-and-development-highlights/r744-air-conditioning-system/
  12. But not so easily in Thailand, where low/no GWP refrigerants are not yet generally introduced. See http://www.ozonediw.org/attach/159/ThailandStageIIPreparation.pdf

Disclaimer: This is an internal knowledge base document. Its content may or may not be correct or updated, and may or may not apply to your own situation.