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Real zero: four awkward truths about reaching net-zero

16 September 2022

The only way to reach net zero is to change the way we live — and fast, says Julian Allwood


COMPARED with our confusion, misunderstanding, and ignorance about climate mitigation, the doctrine of the Trinity looks like a walk in the park. Essentially, we all know that climate change is real, that it arises from the blanket effect of the greenhouse gases in the atmosphere, and that it’s a problem.

But we don’t know what to do about it.

The trouble is not just that there isn’t an agreed plan for making the climate safe, but that everyone talking about it has an angle, as it is secondary to the future prosperity of their own institutions.

Government ministers want us to believe that they have it under control, so we vote for them again. The highest emitting businesses, in oil, flying, steel, and cement, tell us they’re on course to deliver “net zero” by 2050, and we can continue to buy their products without concern. The finance sector tells us not to worry: we just need more investment. Even the scientists and engineers tell us we just need to spend more on science and engineering.

So, let’s take a blunt sword and hack a path of truth through the confusion.


Truth 1: There’s no business as usual

Climate change is a terminal threat to human beings. Not because of sea-level rise, higher temperatures, extreme weather, or drought, although they all matter. The real problem is food.

If emissions continue to rise (they’re up 50 per cent since we agreed to act, at the United Nations in 1992), then around a billion people will starve to death this century in countries near the equator. Crop yields are a function of temperature, water, and technology (seed development, fertiliser, and so on). Since 1980, average temperatures in most countries have risen by about a degree, and in warmer countries this rise, also linked to water shortage, is now defeating agrotechnology.

If we don’t act, by the end of the century many equatorial countries will not be able to grow the food that they need, or afford to buy it. As populations starve or migrate, there will be a world war over food, and the suffering will expand. Acting on climate change will change our lives, but not acting will end them.


Truth 2: New technologies aren’t going to solve the problem

Everybody would like it if we could invent a new technology to take the problem away. But we won’t, because dealing with climate change isn’t an Apollo mission. Doing something once is irrelevant. We need scale, not invention.


All solutions to climate change depend on just three physical resources: biomass, carbon storage, and emissions-free energy.

We can’t expand our use of biomass, because we’ll need it for food.

After 20 years’ discussion, and with the support of the world’s oil and gas industries, our total capacity for carbon storage is just 0.08 per cent of global emissions, growing at a steady 0.004 per cent per year. This is so small that it should be considered a research and development project, not a feature of serious climate policy.

Therefore, our only substantial resource will be emissions-free energy from nuclear, wind, solar, and hydro generation.

We will have more such generation by 2050, perhaps enough to replace all today’s fossil-electricity, but it takes a long time to expand large energy infrastructure.

From political commitment to operation, it takes more than 20 years to build a nuclear power station, and ten to 15 years for a large offshore wind farm. These projects need time for consultation on public finance, land rights, access, environment, safety, and regulation even before their complex construction. There isn’t time to introduce a new infrastructure technology and have it scale to global levels by 2050.

As a result, we are unlikely to have any significant negative emissions technologies. (We have negligible storage, and trees planted now won’t be mature by 2050 — just count the rings on a stump next time you take a walk in the woods.)

We won’t be able to continue with emitting activities and “offset” them, because we must have no emissions at all. And we can’t expect to repair the atmosphere after it has warmed, because we have never intervened at scale in the ecosystem without unforeseen, unwanted consequences.


Truth 3: The solution is about restraint

By 2050, we must have phased out all existing cement kilns, steel blast furnaces, and all ruminants (lamb, beef, dairy), because they all cause emissions regardless of how they are powered or fed.

We will phase out fossil aeroplanes and fossil ships and there aren’t any credible alternatives. Everything else must be electrified, but we’ll only have half as much electricity as we’d like.

We can save energy by using equipment less (taking the train, not the car, turning down the thermostat); designing better equipment (average cars in the UK now weigh 12 times more than the people in them, while most of our heating leaks out through walls and windows, and we can change these designs within existing supply chains); and by keeping things for longer (most commercial buildings are demolished before 50 years).


We need restraints, but they are specific. Some businesses, such as oil and gas distribution, conventional cement production, or manufacturing combustion engines must close, while others, such as upgrading homes, supplying plant-based foods, or developing apps to make better use of fewer vehicles, will grow.

The restraints do not presage economic collapse, however, or miserable lives. We can expand, not contract, almost all the activities we most value: living with zero emissions requires no restraint in time spent with our families, meals with friends, care and compassion, wonder, joy, singing, dancing, playing tennis, running, hiking, sailing, cycling, creativity, love, reflection, endeavour, expression, or splashing around in paddling pools.


Truth 4: The cost is an investment for our grandchildren

The champions of new energy infrastructure technologies believe that the trigger for action is spending. But there isn’t time for that to succeed; so we need to think differently about the “cost” of action.

Some restraints, such as not flying, not building, or turning the heating down, save us money. Some require us to buy new equipment, whether an electric car or an electric arc furnace, and, if this is beyond our private or corporate purse, we may be able to persuade government ministers to offer a subsidy.


For actions that become too expensive, we must do without. Instead, we could share cars, renew old buildings, and heat fewer rooms in winter.

Today’s public discussion about climate mitigation focuses on cost, as if we would prefer to avoid acting, but that’s wrong. The cost of not acting is much greater.

Eventually, we will have regulation to ban emissions just as we banned asbestos. Then, our understanding of cost will change, because we won’t make comparisons with emitting alternatives. Until then, our spending on mitigation is an investment, like a pension, to secure a better and safer future for our grandchildren.


THESE four truths are true, however much they are hidden in public discourse. Restraint is a natural topic for the Church Times, but unnatural for political or business leaders.

Like Lenten fasts, our choices about restraint will all be different. No one today would want to restrain someone from flying to visit a dying relative. Some people can afford an electric car now; others can’t. The journey is different for us all, but the end point is not: by 2050, we must have restrained ourselves entirely from emitting greenhouse gases.

Interpreting the four truths creates an agenda for action, which we can explore in different contexts. As individuals, only four choices really matter: we must stop using fossil planes, ruminants, fossil cars, and fossil boilers as rapidly as we can.

The C of E’s commitment to zero emissions by 2030 means that no church funds can be used to buy fossil-fuels (whether for transport, or heating), and any future construction must avoid conventional cement or new steel.

It is possible to electrify heating, but within its fair share of emissions-free electricity, the Church must plan to use much less heating. The best options are individual heaters for the most vulnerable, matched with additional warm clothing and blankets, shorter services in winter, and with as much movement as possible in the service.

Most of the Church’s use of cement and new steel is in extensions, which, after 2030, will have to draw exclusively on emissions-free materials. Maintenance with zero emissions is essential, but difficult. Like Portland cement, lime mortar is an emitting material, and, while it eventually re-absorbs a fraction of the emissions of its production, this takes a long time unless it is used only as a thin wash.

More broadly, the Church as an institution, and as a collection of motivated people, has influence. We all have more influence than we realise, especially when we co-operate in teams. By insisting on the need for restraint, we can collectively be agents of substantial change.

If it chose to do so, the C of E could be a source of good information and a broker of stories of action — revealing, connecting, and empowering a network of motivated individuals across the whole of UK society.

Above all, the Church could make a clarion call for action on zero emissions today based on restraint, to counter the cacophony supporting delay in the hope of innovation. We urgently need leadership demonstrating and celebrating the restraint that is our only credible path to real zero emissions.


Julian Allwood is Professor of Engineering and the Environment, and Director of the Use Less Group, University of Cambridge. He is hosting a live-stream event in conjunction with the Church Times at Ely Cathedral next Tuesday, 20 September, at 6.30 p.m. Details at churchtimes.co.uk/events

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