2020-04-01_Business_Traveller_UserUpload.Net

businesstraveller.com APRIL 2020

35

WHY ARE CARBON OFFSET
CALCULATORS SO DIFFERENT?
As you can see from the box on
the right, we compared a range of
calculators for a nonstop return
flight in premium economy
between London and Hong Kong.
We specified an aircraft type
(B777-300ER) because both BA
and Cathay Pacific, which serve the
route, use that aircraft for some of
the flights.
As you’ll notice, the results
vary by a lot. Dr Roger Tyers, a
research fellow at the University of
Southampton, explains why. “There
are two parts to this. First, there are
the emissions that the calculators
feed into the model. There are
different ways of counting these
emissions. For instance, they might
count only the carbon emissions, or
include the non-carbon emissionsas
well. Do they count radiative forcing
[see glossary overleaf ], and, if so, what
multiple should you use? Some say
it should be double the ground base
equivalent, while some say triple, and
some don’t use any because there’sno
hard consensus on what it should be.
“Then there’s the price attachedto
each tonne, and this depends on the
offset project. Why? Because some
are cheaper than others. An airline
might say that its offsets are cheaper
because they are buying them at
scale and so are achieving economies
of scale. There’s also differences in
how they are accredited. Of course,
you want accreditation, but there
are different levels, and they come
with different levels of expense, and
depending on what your aim is, you’ll
decide what level of accreditation is
necessary for your purpose.”
He adds: “If you are cynical, then
there are sliders that airlines can
move up and down in all of this

PremiumeconomyreturnHeathrow-HongKongflightona B777-300ER,March2-9

Climatecare 4.62 £34.63† Variousprojects

GreenTripper 3.68/6.74* £38.89/£71.16 Efficientcookstoves,

(incl.VAT) safewater,deforestation

PureLeapfrog 2.44 £12.68† Forestconservation,

efficientcookstoves

CathayPacific 2.08 £3.93† Efficientcookstoves,clean

energyfromwaste

Flightnook 3.86 £75.56-£1,064.44† Cleanerfuel,treeplanting

SouthPole 5.12 £9.58-£16.54† Efficientcookstoves,

windpower,hydropower

Atmosfair 4.98 £95.76† Efficientcookstoves,

renewableenergy

Compensaid 13.7 £23.84-£582.18† Biofuel,replantingtrees

Carbonfootprint 2.44/4.62* £27.65(ex.VAT)- Trees,variousprojects

£64.50(incl.VAT)

†Not

known

ifVAT

is

included

*Climate

impact

with

radiative

forcing

→

HOW DOES COMPENSAID CALCULATE EMISSIONS FROM YOUR FLIGHT?

“We collaborated with Myclimate to evaluate more than 43,000 individual flights

to provide a detailed picture of the CO2 consumption. From small regional jets to

big long-haul aircraft, we analysed the entire fleet to determine the total jet fuel

consumption of a given flight from gate to gate. The objective is to record the

different meteorological conditions as well as the rolling procedures on the ground

and the holding patterns and detours in the air. Using this information, Myclimate

developed an algorithm that calculates the corresponding CO2 emissions for each

flight. The selected flight class is also taken into account and assigned a value. The

algorithm is regularly updated with new flight data, most recently in 2018.”

WHY NO RADIATIVE FORCING?

“Along with CO2, air traffic causes other emissions – in particular, nitrogen oxides

and water vapour – which are considered to have an impact on the climate. At this

time, the scientific community is still unable to conclusively determine the exact

influence of these factors. This is why the CO2 calculator does not consider any

other emissions apart from CO2.”

ONE CALCULATOR EXPLAINS

CALCULATORS COMPARED

Carbon calculator Metric tonne C02Carbon offset price Causes to donate to