Britain can get to net zero but time is short, says the head of the UK’s Climate Change Committee.

“We know enough now to say, confidently, that we can get to net zero and that’s not just a slogan,” Chris Stark, the chief executive of the CCC, told the Guardian by Zoom from Glasgow on the eve of Cop26.

The CCC published its report on the government’s net zero strategy on Tuesday, finding it achievable and affordable, and describing it as the most comprehensive in the G20 but pointing out that much more action was needed to protect those on low incomes from the costs of going green.

Diplomatic and tactical, with an ordered mind, Stark is careful to distinguish between boosterism (“I wouldn’t say I was optimistic,” he says) and determination (“but I would say I was positive about what can be done”). He is also realistic, acknowledging that it is one thing to know what to do but another thing to actually do it; that the UK’s record on emissions does not take into account the “broader footprint of what we import, so Greta [Thunberg] is right on that score” (she recently critiqued the UK government’s “blah” promises); that time is very short, and the picture would be a lot rosier if we had begun 30 years ago.

When he started the job four years ago, Stark found it “quite horrific. When you lift the bonnet on the impact of climate change, you can see how bad it really is. We’re going to have new, more extreme weather, more intense impacts … I’m afraid we’ve got a lot more still to come that’s baked in.” Yet as chilling as it has been to map the trajectory of the climate crisis, it has brought a new clarity and sense of possibility.

The CCC is an independent advisory body, though ministerially appointed, set up as part of the Climate Change Act of 2008, which is “still one of the most powerful bits of legislation you’ll find anywhere in the world”. It came about by political happenstance, driven by Ed Miliband but supported by David Cameron as part of an attempt to prove he was a new kind of Conservative. Parliamentary support was near-unanimous, and that consensus has, if anything, grown stronger. There is no serious opposition to net zero as a target – on Monday, the prime minister pledged that all Britain’s energy would be green by 2035.

That on its own will not get us to net zero, however: Stark scopes out the four things that need to happen. “Firstly and most importantly, you’ve got to be more efficient in your use of energy. There’s a huge shift required to make our homes more energy efficient and less draughty.” Second is cleaning up the energy supply. Third, we need to adopt low-carbon technologies in our everyday lives, and that will mean a revolution in what we make and sell – a boiler or a car might have a shelf life of 15 years, so by 2035, we need to have stopped producing petrol cars and traditional boilers.

“The fourth thing is the ‘net’ in net zero. It’s not just an energy story, we will have ongoing emissions from cows and sheep and planes, mainly. We’re not going to be able to get rid of all that, so it’s about what we do in the natural world to offset it.”

Renewable energy gets “better and better and cheaper and cheaper” all the time, Stark says, and he even manages to glean a positive from the pandemic, which demonstrated “that the population of this country is more prepared than we thought for a radical shift”.

The CCC estimates there will be a 20% cut in meat and dairy consumption over the next 15 years, and a 5% cut in kilometres driven. Stark hopes for a more dramatic shift to lab-made protein – synthetic meat: “That would be gamechanging: it would free you up from some of the difficult land use and agriculture scenarios that we worry about.”

Perhaps more surprising is Stark’s faith in the international picture. “Back in 2019, we published this huge report that led to the net zero target, and one of the things we said was we shouldn’t think of it as a unilateral target, because the UK’s decision to do this, as a major economy, will make it easier for other economies to do the same thing, and that’s exactly what we’ve seen. France, the EU, South Korea, some of the Asian economies, the US, China’s in now: when you look at Cop26, over two-thirds of global GDP is now sitting under these targets. That’s amazing, when you think of where we were a few years ago. When we start to deliver on that, then we’ll be motoring.”

Stark ends on a note of sober determination, remembering a talk he gave at his daughter’s primary school in Glasgow. “I worked out then that she in 2050 would be the same age as I was in 2019. It’s the gap between me and my daughter that we’ve got to fix this thing. It’s a human life, that’s the time we’ve got. And there’s loads to do.”