Back at the start of May I was invited to speak at a business networking event run by Moral Fairground on the theme ‘The Unseen Cost of Travel’, alongside Intrepid Travel co-founder Geoff Manchester and Janine Hendry of Reho Travel. The invitation came about as a result of my posts here last year on the climate impacts of air travel. My brief was to cover the implications of carbon offsetting.

Here’s what I had to say, under the rough title ‘Carbon offsets or carbon penances? What a finite emission budget means for air travel and tourism futures.’

For a period pretty much identical to my own lifetime, travel for most rich-world citizens has effectively been synonymous with flying. In broader historical terms that’s a very small blip, and I’ll come back to that at the end in thinking about how those of us who take climate change seriously might deal with the dilemma that commercial aviation presents.

This dilemma has its origins in the fact that, at least for those of us who don’t have the means to travel around the place on our own private superyachts, flying is the most energy and emission intensive activity we will ever engage in.

This is often disguised when emissions from different modes of transport are compared on a per kilometer basis. That’s a misleading measure. To get the proper picture, we need to look at emissions per hour. Here, jet flight is the undisputed leader. If I spend an hour flying somewhere in a commercial jet aircraft, the emissions for which I’m responsible will be at least 10 to 20 times higher than if I was to spend that hour travelling by car.

Aviation’s climate impact is so high not because of the emissions per kilometer, but because flying allows us to travel a great many more kilometres in a given period of time than any other mode of transport. People simply wouldn’t be able to consume travel services in the way that they do today, if it wasn’t for the power of jet flight to fundamentally alter the relationship between space and time at the human scale.

The challenge that this poses for travel in the age of climate change is immense, because there is simply no technically feasible alternative to petroleum-fuelled aviation for fast, long-distance, transport on the massive scale available today. If you want to travel to Thailand for a week-long holiday, then for that trip alone the quantity of greenhouse gas emitted will be greater than the annual emissions per person for most of the world’s population.

So this has big climate implications, but it also has big implications for social justice. This is particularly so when we take into account that flying to Thailand for a week is an option only available to the world’s most affluent citizens, who’ve already enjoyed vastly unequal benefits from past emissions. Meanwhile, the climate impacts are born disproportionately by the world’s poorest citizens.

It’s within this context that governments and businesses in the rich world have turned to carbon offsets as an apparent panacea. The idea goes that by spending a few dollars on initiatives for which it’s hoped future emissions will be reduced elsewhere, or by hopefully shifting sufficient carbon from the atmosphere to forests, the climate impacts of that trip to Thailand might be cancelled out.

But while this way of dealing with the situation has institutional and political legitimacy, its scientific legitimacy is far more dubious. In fact, when you bring a systems view to the science it’s basically without legitimacy. This is not particularly controversial, it’s just that you won’t hear it articulated very often because thinking in systems often leads to views that are not at all convenient for established interests. For more on this, I highly recommend the work of UK climate scientist Kevin Anderson.

In a moment I’ll run through the case for why offsetting is without scientific legitimacy. But to set the scene for that, consider the following statements, from a number of sources that actually endorse offsetting:

• This first one’s from the Australian Government’s Carbon Neutral Program: “To achieve carbon neutral certification organisations must [first]…reduce [emissions] where possible…”
• Here’s another, from a renowned environmental scientist of 40 years standing, in a personal email to a colleague a few weeks back: “It would of course have been better not to have produced that CO2 in the first place.”
• A well-known adventure travel company says this about its own carbon neutral certification: “Whatever emissions can’t be avoided are offset…”
• Even the electricity retailer Powershop says of the carbon offsets it purchases in connection with the electricity it sells: “We know these aren’t a perfect solution…”

Or consider the very visually appealing section about offsetting on the Qantas website, where you can read about the strict international standards that their offsets meet. What you won’t find there is anything about what purchasing those offsets means for the actual physical climate impact of your flight.

So as these examples attest, it’s well recognised that offsetting is not equivalent to actually avoiding emissions in the first place. “Carbon neutrality” is an outcome of a certification process, and it means that a set of administrative requirements has been met.  But you’ll be hard pressed to find any legitimate provider or informed advocate saying that “carbon neutrality” is a physical fact. You won’t hear that offsetting physically cancels out the climate impacts of past emissions.

Now, there are various aspects to the case for why offsets are not equivalent to actually avoiding emissions. These relate to considerations around the extremely long time that carbon remains in circulation between the atmosphere and biosphere, once it’s released from stable stores in the earth’s crust; and the impossibility of making sufficiently accurate predictions about the behaviour of complex social and ecological systems over 100-year-and-beyond time periods.

There’s a broader context to all this though, that makes these more detailed issues somewhat academic. Climate science tells us that there’s a finite amount of greenhouse gas that can be dumped into the atmosphere, in order for a chance of remaining below a certain level of warming this century. This finite amount of greenhouse gas is known as the global carbon budget.

For an estimated better-than-even chance of staying below a 2^oC increase, the remaining budget is equivalent to less than 20 years’ worth of current global emissions. To avoid exceeding that limit, then by the time this budget’s used up, global emissions must reduce to zero.

So think for a moment now about what happens when you take a flight. The plane burns fuel, emitting carbon dioxide at a rate of something in the order of 100 kg per hour for each passenger. And the climate impact is equivalent to several times that amount. The warming effect of those emissions starts immediately, and will persist for many centuries.

For a return economy flight from Melbourne to London, the global carbon budget will be reduced by somewhere between 3 and 10 tonnes, depending on how the additional climate impacts are counted. Compare this with the typical per-person household emissions for Australia of around 8 tonnes per year.

There is no possible action that we can take that will increase the remaining global budget again by the same amount. It doesn’t matter how much someone else reduces their future emissions in compensation, or whether some of the carbon ends up temporarily in trees. That part of the budget is spent, effectively forever.

From this point of view, it’s clear that offsetting could, at very best, have the effect of reducing the rate at which the global budget is used up. It can’t undo any of the negative impacts associated with the emissions themselves. But even this slowing effect is highly questionable, when the flow-on social and economic consequences of the offset action are taken into account; or when the structural incentive to grow aviation services, provided by taking the flight in the first place, is considered.

So what does all this imply then for anyone who takes climate change seriously?

Firstly I would argue that we need to move right away from the language of offsetting or neutrality altogether. This doesn’t mean that re-forestation or renewable energy projects in poor countries aren’t worth supporting in their own right. But if they’re worth supporting, then why should that only be conditional on excusing rich people from responsibility for the climate damage their lifestyles cause?

If this support is, however, to be linked in this way with climate damage already incurred, then instead of calling them carbon offsets, it would be more honest to call them something like carbon reparations, or perhaps even carbon penances.

But if you really take climate change seriously, then why not go a step further? You could make the choice to avoid flying altogether, and donate the money saved directly to the very same causes, without the strings attached.

What does all this mean for travel? Well, go back to my opening point about just how historically strange the current situation is. If the age of mass flying were to end abruptly tomorrow, it wouldn’t mean the end of travel. The ways that people travel would just evolve accordingly. In fact, I’d suggest that commercial aviation has stifled our imagination for travel, at least as much as it has opened up new opportunities.

In 1966, four years before the Boeing 747 arrived on the scene, my dad set out from Australia by ship for what was then Ceylon. With him went an old BSA 650 motorcycle and sidecar, which he and a friend then rode via the overland route to the UK. A little later my mum travelled by ship to meet him and they were married there at the end of 1966. In 1970 they returned to Australia, this time driving back by the same route in an Austin mini van.

Slide shows and spoken stories from these adventures were staple entertainment for me growing up, and set the benchmark for what travel was all about. So you’ll perhaps appreciate why it’s no great stretch for me to suggest that flying a whole lot less in order to dissolve the climate dilemma of air travel can just as readily offer a pathway to more rather than less fulfilled lives.