Is planting trees the answer to offsetting the impact of plane travel?

‘I plant a lot of trees.’ That was the essence of actress Dame Emma Thompson’s reply when asked how she could justify flying 5,400 miles from Los Angeles to help bring London to a standstill in the Extinction Rebellion protests. ‘Unfortunately, sometimes I have to fly,’ she stated. ‘But I don’t fly nearly as much as I did, because of my carbon footprint, and I plant a lot of trees… If I could fly cleanly, I would.’

Jet-setting chief executives and their communicators take note. Is the response to allegations of environmental hypocrisy really as simple as providing uncosted, unquantified claims of personal reforestation? Stand by, perhaps, for a welter of arboricultural proclamations about Ryanair chief executive Michael O’Leary’s penchant for pines or British Airways’ ultimate boss Willie Walsh’s wistful wisteria.

Air travel accounts equates for two per cent of global carbon dioxide emissions, according to the International Air Transport Association, yet predicted consumer demand could see this escalate to ten per cent by 2036. But is tree-planting now a zero-sum game to justify personal and corporate carbon footprints? Will that really wash with environmentalists, staff and consumers? And are all emissions really equal?

I don’t agree with being blasé about your travel emissions just because you are offsetting. It’s the wrong approach because the first step should always be to change behaviour and reduce our own emissions

Dame Emma is far from alone. The Duke and Duchess of Sussex were recently accused of hypocrisy after flying by private jet while campaigning for the environment. Sir Elton John finally revealed that he had made personal contributions to offset the Duke and Duchess’s private jet emissions. However, Doug Parr, Greenpeace’s chief scientist, then declared that such schemes make no ‘meaningful’ inroads towards the goal of a world of net zero carbon emissions. ‘There’s no way any current tech deals with the load of CO2 you’ve released on a personal level,’ Parr commented.

Indeed, non-governmental organisation Carbon Positive Life estimates that it would take 321 years for a single tree to absorb the seven tonnes of emissions from the royal return private jet flights to Ibiza and Nice.

For many, Dame Emma’s tree-planting justification therefore poses more questions than it answers. ‘Prove it,’ demands Clive Jackson, founder and chief executive of Alyssum Group, owner of private jets company Victor Jet. ‘Did she pay for the CO2 offset and was it the lowest level or at the highest level? And did she offset her life in other ways which are fully transparent and accessible to scrutiny? Too many high-profile public people feel their presence is enough to amplify a message which has well-placed goals but have not yet taken the time to fully understand the issues.’

Despite such criticism, Dame Emma’s tree-planting remarks were in tune with current thinking around climate change mitigation. Research published in July by the Swiss Federal Institute of Technology in Zurich found that there are 1.7 billion hectares of treeless land on which 1.2 trillion native tree saplings would naturally grow – a land mass equivalent to the total size of China and the US combined. It states that a worldwide tree-planting programme on such land could absorb and store a ‘mind-blowing’ two-thirds of all historic emissions caused by human activities.

‘[Forest] restoration isn’t just one of our climate change solutions; it is overwhelmingly the top one,’ Professor Tom Crowther, who led the research, told The Guardian. Martin Noponen, chief executive of The Rainforest Alliance, agrees, referencing a 2017 study that found that natural climate solutions such as tree-planting can deliver up to 37 per cent of the emission reductions needed by 2030 as part of the Paris Climate Agreement.

In addition, he cites research claiming that better land stewardship could cut emissions by 11.3 billion tonnes by the 2030 deadline – equivalent to calling a complete halt to all burning of oil worldwide. However, he adds: ‘I don’t agree with being blasé about your travel emissions just because you are offsetting. It’s the wrong approach because the first step should always be to change behaviour and reduce our own emissions.’

Offsetting is a complex business. On one level, customers simply pay an extra fee on top of their fare, which is donated to a carbon offset scheme. However, calculating the risk-reward profile of offsetting by tree-planting, as opposed to other environmental schemes, is more complicated. A single tree can absorb as much as 48lbs of carbon dioxide, reaching one tonne of the gas by the time it is 40 years old. Yet, the types of trees selected, the method of planting and density of spacing all need to be factored in. Many types of trees grow very little in their first few years, so passengers will still be offsetting their flights years after they took them. Additionally, urban trees have an average lifespan of less than 20 years, while farmed ones are typically harvested after double that time.

Such vagaries threatened to curtail offset tree-planting when it first emerged as a mooted partial solution for climate change more than a decade ago. In 2003, The Rolling Stones staged a ‘carbon neutral’ tour in the UK, planting one tree for every 60 tickets sold – 97 per cent of its tour’s emissions arise from fans travelling to the venue – while a year earlier Coldplay paid for 10,000 mango trees to be planted in southern India to offset the environmental impact of the band’s second album. However, many of Coldplay’s trees died within five years and the offset movement was further damaged by a 2007 study by North Carolina’s Duke University which bathed plots of pine trees in extra carbon dioxide every day for a decade but found that only those trees receiving the most water and nutrients stored enough carbon dioxide to offset global warming effects.

Since then, some other studies have produced conflicting results, while standards have been developed for the offsetting industry. Processes range from the ‘Gold Standard,’ set up by charities including the World Wildlife Fund, to the ‘Verified Carbon Standard’ developed by US quality assurance organisation Verra. California-based Climate Action Reserve meanwhile claims to operate the ‘premier carbon offset registry for the North American carbon market’.

Offsetting, while in principle good, is hard to measure and frankly we need faster mechanisms in place to shift the agenda. Otherwise, we’re just rearranging the deckchairs on the Titanic

Alyssum Group’s Jackson believes that reforestation can play a ‘major, if not pivotal’ role in addressing the effects of growing emissions, but he adds: ‘The questions are: how it is done, whether it is bona fide and open to genuine scrutiny and can there be a common standard? It has to be beyond reproach. Not all the providers are delivering anywhere near the standards that would pass close scrutiny.’

Kevin Drum, political blogger on the Motherjones.com website, is also sceptical, writing that even planting 500 billion trees would only capture about 205 gigatonnes of carbon. This is roughly equivalent to the planet’s expected carbon dioxide emissions over the next 20 years but less than half the 450 gigatonnes emitted since the start of the Industrial Revolution.

‘If we could really get all the countries of the world to plant trees on currently unused land that’s suitable for reforestation, that would be great,’ he writes. ‘But even if we went all out and got 100 per cent cooperation, it would take 50 or 60 years for these forests to grow to maturity. Unless we do something about actual emissions, we will have added at least 500 gigatonnes of additional carbon by then, bringing us to total emissions of about a billion gigatonnes of carbon. The trees would make only a small difference.’

Iain Patton, director of communications agency Ethical Team, believes offsetting is a dated approach. He explains: ‘I think ten years ago you could have said offsetting would be the right thing to do but now that the Government has declared a climate emergency, that argument doesn’t wash any longer. Most people are not offsetting their flights and the general consensus is that people should reduce flying and switch to slower travel such as the train. Offsetting, while in principle good, is hard to measure and frankly we need faster mechanisms in place to shift the agenda. Otherwise, we’re just rearranging the deckchairs on the Titanic.’

At the extreme end of such talk is a movement to demonise and reduce global flight travel. Extinction Rebellion has held protests at Heathrow Airport, France is said to be considering an eco-tax on air fares and a Swedish anti-flying movement is spreading through Europe. In Sweden, home of schoolgirl activist Greta Thunberg, new politically-correct vocabulary is emerging, ranging from ‘flygskam’ or ‘flight shame’ to ‘tagskryt’ (‘train brag’).

Carbon Positive Life estimates that it would take 321 years for a single tree to absorb the seven tonnes of emissions from the royal return private jet flights to Ibiza and Nice

‘Unchallenged, this sentiment will grow and spread,’ Alexandre de Juniac, head of the International Air Transport Association, told 150 chief executives at a three-day airline summit in Seoul, South Korea in June. Patton, who is supportive of tree-planting schemes, argues that technological advances such as potential electric flights and waste-based jet fuel plants can also become part of the solution. However, he still believes that campaigns to change flying behaviour can become ‘the equivalent of the anti-smoking lobby,’ demonising flying as people begin to realise its detrimental effects on others.

Naturally, the travel industry does not agree. Jackson argues that the aviation industry is doing its bit, with airlines seeking more fuel-efficient planes, wingtips and engines and airports trying to reduce air ground handling delays which cause aircraft to burn more fuel and pollute more. ‘In Europe last year 24 per cent of all flights were delayed by more than 15 minutes,’ he says. ‘The CO2 saving if we ran more efficiently is staggering.’

Victor, he says, pays to offset double its actual emissions and asks its customers to follow suit in a ‘beyond offset’ campaign. Two corporate clients have so far done so. Even self-styled ‘ethical’ travel companies find the idea of reduced personal aviation difficult to swallow. ‘People define ethical travel is so many different ways,’ says Bruce Poon Tip, founder of G Adventures, a travel firm committed to leading ‘socially, environmentally and culturally-responsible’ tours that reduce poverty. ‘You can limit your travel by your carbon footprint or by human rights, not going to places where there are violations. It is certainly about people changing their behaviour but there are lots of different behaviours to think about, from your mode of travel to the bottles you carry your water in. It’s not as simple as just saying you’re not going to fly.’

Indeed, Dame Emma’s comments did not cause much of a stir in the US, where Greta Thunberg’s campaign has yet to make inroads into a resistance to personal travel quotas that almost rivals gun ownership as a personal liberation issue. Nevertheless, an increased focus on personal responsibility, backed up by accurate measurement systems, seems to be the way to bet. ‘We don’t like to criticise people,’ says Christian Arno, founder of Pawprint, whose tracker app enables people to keep count of their carbon footprint. ‘It’s simply not the best way to encourage change. That said, it’s important we recognise the impact of flying. Reducing the amount of flying we do is one of the most impactful actions consumers can take. Offsetting flights is better than just flying and doing nothing, but not flying is even better.’