It's a reality that people fly more and more regularly. Some have cut back on flying, a few have given up entirely. But, whether it's for work or to visit family abroad, flying, for many, is unavoidable.

What’s equally unavoidable is the climate impact of those flights.

We’re fortunate that in an increasing number of our consumer choices, we can choose the greener option. Electric cars, renewable energy, meatless diets and well insulated homes. But no “green option” exists for flying. (More below on why that’s the case.)

So for those wanting to fly, it leaves them in a bind, looking for a way to compensate for the climate damage they are causing. The answer being presented by some is to offset - to pay someone else to reduce their emissions, rather than reduce your own. For example, investing in renewable energy or tree-planting in some other part of the globe.

Do carbon offsets work?

Many have called them modern day papal indulgences, after the middle ages practice of paying priests to absolve you of your sins. I’m not a theologist, indeed I’m a (very) lapsed Catholic, so I’m no expert on whether indulgences will cleanse your soul. But we can be honest and say that, after decades of trying to make them work, offsetting most certainly will not wipe your carbon slate clean. The reasons are, unfortunately, a little complex but, briefly, there’s a reason they won't work in practice, and a reason they won't work in theory.

The “in practice” is easiest to explain. When you make a payment, you can’t be sure that the carbon-cutting activity you pay for actually takes place, or wouldn’t have taken place regardless of the payment. For example, whether those trees planted won’t burn down, or whether the solar plant was going to be built anyway. It’s known as “additionality” and the most comprehensive research has shown that most offsets don’t have it.

The theoretical problem is rooted in how the Paris Agreement has been designed. The agreement has a temperature and emissions target, but it lets each party set their own level of ambition. That leaves open the possibility that parties will set weak targets for themselves, and sell you any overachievement as an offset. No extra emissions are reduced, but you’re led to believe that you’re flying sustainably.

As a result, it's fair to say that offsetting, more generally, is incompatible with the Paris Agreement. That agreement is about all sectors and all parties bringing their emissions to zero.

Paying someone else to reduce emissions, while airlines keep burning fossil fuels, is incompatible with that objective.

Fitting offsetting into the Paris Agreement is like fitting a square peg into a round hole

Despite this apparent contradiction, the Paris Agreement does in fact have provisions relating to offsetting, contained in Article 6 of that agreement. The catch is that, four years after the Paris Agreement was signed, states still can’t agree how to operationalise these provisions. They failed again last month at the climate conference in Madrid. It's the only section of the agreement that negotiators have failed to operationalise.

And they are likely to continue to fail, because fitting offsetting into the Paris Agreement is like fitting a square peg into a round hole. Offsetting should be seen as a bug, not a feature, of the agreement.

How to cure climate guilt?

Where does all this leave the concerned citizen who wants to cure their climate guilt? They can offset, doing their best to find the most reputable suppliers. The transfer of any money from the well-off (and it is the well-off who fly most) to those most affected by climate change (and it's always the worst-off who’ll be most affected) should be welcome.

The unavoidable reality is that the limited benefits of offsetting will never be enough to offset the known damage of flying.

That hasn’t stopped industry from investing in them, even when they freely admit that offsetting isn’t a solution. And there are moves underway to finalise a global system where airlines will offset a portion of their emissions (called Corsia - the Carbon Offsetting and Reduction Scheme for International Aviation), though the problems inherent to offsetting mean it will never solve aviation’s climate problem. Yet airlines are pushing for this to be the only measure in place.

What governments need to do

So governments have a choice to make. Because, unlike individuals, who have limited choice and limited power, the options for governments are practically endless. They can tax, invest, ban, restrict, order and command. That’s why we have electric vehicles and clean power - because the power of the state was used to bend markets and drive innovation.

Offsetting by individuals is, at worst, ineffective.

Governments implementing offsetting schemes is something much worse - a distraction from effective policies that can actually reduce aviation emissions.

European Commission president Ursula von der Leyen and her new team seem to understand this. The European Green Deal makes no reference to aviation offsetting, but instead focuses on policies such as kerosene taxation, emissions trading and new fuels. All these have the potential to really cut emissions.

The test is whether she is able to follow through on these big promises. Some industries will try to distract focus by continuing to flog offsetting but VdL must continue to avoid such futile ideas. She has the political capital and the public demand to take real measures to cut aircraft emissions. Now is the time to act.