Pity the poor Planning Inspectors. They spend years qualifying as a town planner and then find themselves asked to answer one of the most contentious questions in British politics – the future of aviation. That at least must be what it feels like to be the Inspector in charge of the current enquiry into Gatwick’s plan to expand using its northern runway. And Gatwick is just one of half a dozen airports with plans to increase capacity.

Expanding airports has never been easy but the list of challenges has got a lot longer in the last decade. Air quality and the path to Net Zero have joined noise and the local environment in the top tier of issues. And any major proposal to expand needs to show not just that it will meet a need and bring social and economic benefits, but that it is consistent with national policy and will mitigate any adverse effects.

Of all these issues the one where the stakes are now highest is climate change. And that’s true politically as well. Aviation is hard to decarbonise, but it’s also emotionally charged in a way that (let’s face it) grazing cattle or sheep are not – even though agriculture is actually responsible for more greenhouse gas emissions and far fewer jobs than aviation.

With Labour’s focus on the economy, and an industry that is ready to expand and create jobs and growth, it’s easy to predict some difficult debates about aviation if they form the next Government. And those debates are likely to focus above all on airport expansion: whether it’s the most important issue or not, it can be understood and it can generate feelings in a way that many other aspects of the environmental agenda cannot.

We can all see this risk coming, so what to do about it? Can we manage this debate any better, so that it is less likely to turn into a zero-sum argument played out in the media about climate vs growth? To its credit, the current Government has already started to do lots of things that I suspect any Government will want to do: set out an ambitious strategy for Sustainable Aviation Fuels, invest more in aerospace R&D to try to improve fuel efficiency, and lead efforts around new global mechanisms like CORSIA at ICAO.

There is lots more to do here to ramp up delivery, not least on SAF. But it’s also striking that other aspects of the debate are less well developed and more polarised – which is never a good sign.

Let’s look at positions on airport capacity. The Committee on Climate Change has recommended a new framework for managing this nationally. It says there should be no net expansion in airport capacity between now and 2050: if there is expansion in one location, capacity should be reduced elsewhere. Under the CCC’s model, by 2050 the capacity of Britain’s airports would basically match demand – there would be a 25% increase in passenger numbers over 2018 levels and every airport would be more or less full.

The Committee says there should only be a net increase in airport capacity if aviation reduces carbon use even faster than the Government is assuming – for example because of huge breakthroughs in SAF or electric flight. This would be a radical intervention in the economy – managing capacity across the country’s airports, closing some to open others. It obviously raises lots of practical questions (including costs), as well as focussing on airport capacity more than the underlying issue of carbon emissions.

The Government by contrast thinks that the path set out in its Jet Zero strategy should allow aviation both to decarbonise sufficiently and to increase capacity and passenger numbers, with a 70% increase by 2050. This is based on assumptions about the development of technology – mainly SAF and fuel efficiency – as well as major changes in the pricing of emissions globally through CORSIA, that would need international agreement. The CCC, and some others, think these assumptions are just too risky and optimistic.

It seems a shame if the debate is left there, as an argument about assumptions when the truth is no one really knows. What is striking to me, as someone who has been around the block on public policy, is that the underlying issue is not really about technology – it’s about how you deal with uncertainty and create enough confidence that future Governments will act to limit emissions. And those are issues that come up and get resolved not too badly in other areas of public policy – pensions for example.

A bit more thought about solving these problems might be time well spent. It just might make life easier for a new Government, never mind the people running airports and, yes, the poor planning inspectors.