EcoBusinessLinks always looks for ways to help our visitors, our customers, and ultimately the environment. For that reason, we believe it is important to examine the quality of the information and services we present. For example, in our carbon offsetting survey we excluded those services that mostly relied on tree planting offsets due to their controversial nature and we separately listed those providers that did not provide independent verification for all of their offset products.

As part of our continuing effort to provide quality information we have released this new comparison survey of carbon offset flight calculators. We hope that this new study will be of further help to you with your offsetting evaluation.

From February 25 to March 1, 2009, EcoBusinessLinks.com conducted a survey of 30 voluntary carbon offset flight calculators in order to compare their results.

This analysis revealed:

The 30 calculators tested returned a wide variety of carbon footprint results for the same flight.

More than one-third of calculators surveyed likely under-report an individuals flight carbon footprint.

 The following summarizes the results of this study.

Flight Emissions Calculation Survey

We chose a round-trip flight from New Yorks LaGuardia Airport to Los Angeles International Airport as the sample and inputted this trip into the flight calculators of 30 carbon offset providers. The table below displays:
 

        The name of the offset provider.

        The calculators CO2 calculation in metric tons.

        The radiative forcing index* (if any) used by a calculator.

        The calculators total trip distance calculation in miles.

        Any additional information about a calculator deemed relevant to its results.

*The Radiative Forcing Index (RFI) is a numerical multiplier used to account for the total climate impact of all the different pollutants generated from a flight. Calculators that utilize RFI multiply their CO2 emissions calculation for a flight by a specific numerical factor to arrive at their final CO2 calculation. Previous estimates from the Intergovernmental Panel on Climate Change (IPCC) put this factor at approx. 2.0 to 4.0 with a estimate of 2.7 (IPCC 1999).  In 2007, the IPCC in its Fourth Assessment Report estimated that the RFI ranged from 1.9 to 4.7.

Results and Conclusions

As you can see from reviewing the data, there is a significant range of calculation results:

    Of the 30 calculators tested, the CO2 footprint results for a round trip flight from New York to Los Angeles ranged from a low of 0.84 metric tons to a high of 4.94 metric tons.

        The average CO2 metric ton calculation is 1.73.

        Out of the 30 calculators surveyed, there are only five instances where two calculators return an identical metric ton calculation.

       Of the eight providers using an RFI of 1.9 or 2.0, the metric ton calculation ranges from 1.21 to 2.00, with an average metric ton calculation of 1.61.

       Of the five providers utilizing an RFI of 2.7, the metric ton calculation ranges from 1.84 to 2.41, with an average metric ton calculation of 2.18.

       Six calculators provide CO2 calculations based on an individuals seat type: Carbon Planet, Clear, Enpalo, My Climate, Atmosfair, and The Carbon Reduction Institute.

        In addition to seat type, the Enpalo calculator also provides CO2 calculations based upon the airline selected.

        In addition to seat type, the Atmosfair calculator also provides CO2 calculations based upon (1) if the flight is a charter or commercial flight; and (2) which type of aircraft is used (43 different aircraft listed). 

        It is likely that more than one-third of the calculators tested in this analysis are under-reporting their emissions calculations.

In 2006-2007 the Tufts Climate Initiative published a study titled Voluntary Offsets For Air-Travel Carbon Emissions. This study examined carbon offset providers, flight calculators and the complex issues surrounding offsetting. For offset flight calculators, the TCI study found that in addition to distance traveled, the following factors affect the amount of CO2 an individual consumes (and must offset) on a particular flight:  (1) radiative forcing; (2) occupancy efficiency; (3) seat type; and (4) aircraft type. It is clear that the results of our survey vary so widely in large part because of these variables. It is notable that many of the calculators rendering the lowest CO2 results are those which do not appear to account for RFI in their calculation. Furthermore, the TCI study concludes:

Not all air travel emissions calculators are equally accurate. Here is a rule of thumb: A U.S. return flight from coast to coast produces about 2 – 3 tons of CO2 emissions per passengerIf the emissions calculator comes up with a much lower number, it is underestimating your emissions.

 After converting Tufts' estimate of 2 – 3 U.S. short tons into metric tons (1.81 – 2.72), it is likely that more than one-third of the calculators tested in this analysis are under-reporting their emissions calculations.

The TCI study recommends several offset providers based on their analysis of companies and calculators. Rather than making recommendations, the purpose of this survey is to show what calculation results are received for a specific flight across many providers. Beyond that, our hope is twofold: 

(1) Provide people with more information about the similarities and differences between carbon offset flight calculators.  

(2) That the publication of this survey will help enhance the credibility and quality of the voluntary carbon offset industry by encouraging carbon offset providers to increase the accuracy, disclosure, and standardization of their calculators. 

Methodology and Disclaimer

All the offset data contained in this report was obtained by recording the results from the online, publicly-available calculators provided by each of the organizations surveyed. This data was obtained directly from these calculators after inputting the specific parameters detailed in this survey. In each case, calculations were checked several times to confirm the results. In some cases, calculator results (such as kilometers, pounds and short tons) were converted into the units specified in this report (miles, metric tons) so they could be compared across all survey providers.

The flight calculators surveyed for this study were primary chosen from those carbon offset providers with flight calculators who are listed on EcoBusinessLinks' Carbon Emissions Offset Directory. A few additional offset companies were chosen because of their previous inclusion in other surveys and studies.

While every effort has been made to confirm the accuracy of the information and data displayed in this report, EcoBusinessLinks.com is not responsible for mistakes, inaccuracies or omissions in the data, statements, observations and conclusions detailed in this report. EcoBusinessLinks.com is not responsible for any potential or actual purchasing decisions and/or actions that are made by any party after reviewing any or all parts of this report and its contents. Inclusion or exclusion of providers and/or calculators from this survey and this report does not imply a recommendation or lack thereof. EcoBusinessLinks.com is not responsible for the content of external web sites.

This report is provided as a free service to visitors of EcoBusinessLinks.com. If any inaccuracies or omissions are discovered by anyone reviewing this report, including the organizations whose calculators where surveyed for this report, EcoBusinessLinks.com will correct and/or rectify such omission or inaccuracy.

The purpose of this report is to:

(1) Provide interested parties with more information about the similarities and differences between carbon offset flight calculators.

(2) Help enhance the credibility and quality of the voluntary carbon offset industry by encouraging carbon offset providers to increase the accuracy, disclosure, and standardization of their calculators. 

Copyright 2009 EcoBusinessLinks.com