How green is your summer holiday? Why emissions labels on flights risk greenwashing air travel

For a more modern example, you could start wagging your finger at them for going on holidays.

In recent years, experts and climate campaigners have targeted the aviation sector, and it's easy to see why.

Flying is one of the most polluting activities a person can do. A typical flight from Dublin to Spain produces about 200kg of CO₂ per economy passenger. That is roughly equivalent to the average annual carbon emissions of a person living in countries such as Ethiopia or Uganda. It is several years' worth of emissions for those living in even poorer countries.

All this carbon contributes to climate change, which (almost) everyone agrees we should stop. Therefore, reducing aviation emissions seems like a no-brainer.

But telling an Irish person to cut back on flying is unlikely to be met with a positive response.

First off, the ones doing the finger-wagging are often high polluters themselves. Climate summits where important politicians meet to discuss lowering emissions are notorious private jet-fests.

But more importantly, Ireland is an island. Unlike our neighbours on the continent, longer travel by land isn't an option. Any significant travel necessitates stepping on a plane.

This is where flight emissions labels come in. This is information shown when booking flights which gives the estimated greenhouse gas emissions which each passenger produces.

The idea is to nudge passengers towards lower-emission choices, with the hope being that they would prioritise emissions in the same way they do price.

If enough people did so, the change in behaviour could lead to airlines prioritising being as low-polluting as possible.

That's the theory anyway. There has been plenty of debate about whether emissions labels actually do their job, or whether they're just a smokescreen for 'greenwashing' - a practice which makes a business appear more environmentally friendly than it is in reality.

This ties into doubt around carbon offset programmes, where passengers can pay for projects, such as tree planting, intended to compensate for airline emissions.

Ryanair

One of the biggest sceptics, perhaps unsurprisingly, is Ryanair. Previously, the company offered passengers a carbon offsetting service, whereby they could pay €2 or so to partially compensate for the emissions their flight produced.

It also had a carbon calculator on its website, allowing consumers to fully offset the pollution if they chose to do so.

The airline dropped both, claiming there was "very little interest or uptake from passengers".

Other experts have also questioned the effectiveness of such schemes.

A Dutch regulator said at the time that even with CO2-compensation schemes, flying "remains a highly polluting way of travelling".

"Airlines may offer CO2 compensation schemes, but they cannot give the impression that CO2 compensation will make flying sustainable," it said.

The doubt around offset programs has led to greater scrutiny of emissions labels. Further questions over their effectiveness emerged in a new piece of research published last month by the Economic and Social Research Institute (ESRI).

It found that some emissions information made a small impact.

For example, when consumers were told the number of trees needed to absorb the difference in emissions between a higher-polluting flight and one with lower emissions, this led to a rise in the number of people selecting the lower-emitting option. But the effect was modest - a difference of just 4-6%.

And that was the best case scenario. The ESRI found that other types of emissions labelling risked confusing people.

For example, participants were asked which of three destinations was the lowest emitting: a journey from Dublin to one of Lisbon, Istanbul or Tokyo.

Initially, most correctly answered Lisbon. However, certain emissions labelling caused some uncertainty. One comparison caused just 47% of respondents to select Lisbon, while 37% chose Tokyo. This was due to a belief that the Tokyo flight delivered relatively larger carbon 'savings'.

The researchers said that the emissions labels could work in theory. In another exercise, participants were given various flight options to go to three destinations: New York, Santorini in Greece and Málaga in Spain.

If passengers all chose the lowest-emitting flights, emissions could have decreased by up to 14%. In reality, those surveyed chose flights with just a 3% emissions reduction.

With the positive effects modest and the potential for confusion deemed to be relatively high, the ESRI's verdict was ultimately downbeat.

"Overall, the findings imply that emissions labels, as currently implemented, are unlikely to reduce aviation emissions meaningfully," the ESRI said.

"[They] risk amplifying rather than correcting misperceptions by potentially greenwashing aviation."

Other studies on the topic have been more positive. Another study, published last month, looking at the US airline sector found that the labels had a better effect on consumers. It found that consumers were typically willing to pay more for flights if the result was lower CO2 emissions.

Another report from a few years back reached a similar conclusion, noting that this was quite impressive as the concept of emissions labelling and offsetting asks a lot of passengers.

"Unlike other household energy efficiency decisions (appliances, cars and buildings, for example), choosing more energy efficient flights has no private monetary return in the form of lower future energy bills," it said.

"It therefore represents a purer test of willingness to pay for a public good - a low CO2 environment."

But again, conclusions across research are mixed. Another report found that consumers are more likely to buy flights when emissions labels are present - but, they are not necessarily more likely to choose a lower-emission-labelled journey.

This goes back to the ultimate point made by the ESRI - emissions labels have to be very carefully designed to ensure they're actually pushing people to make more environmentally-friendly choices.

At their best, they can do this, even if the effect is small.

But at worst, emissions labels can cause confusion and give the impression that a company is being 'green' - even if that isn't the case.

This is particularly true for obscuring the impact of longer flights or exaggerating reductions on certain routes.

By itself, labelling won't move the needle. But it can be a useful nudge.

Done right, it can steer some passengers towards lower-emission flights and make a small, but positive, impact. It may not be much, but it can be a baby step in the right direction.

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