There are essentially two approaches to climate change: techno-optimism and the end of consumerism. The major difference is between the long term and the short term and between different areas of the economy and different forms of planetary limits. There are no constraints on sustainable electrification, but we have wasted precious time for the green transition and food remains a complex challenge. Techno-optimism is not out of place, but it is clear some of our behaviors will have to change.

Looking at climate change, it is clear that a radical change of action is required. In the energy industrial system, we must reduce co2 and other greenhouse gas emissions to around zero by mid century: and we must halt the destruction of the great tropical forests and other land or ocean ecosystems before it is too late. The question is not what we need to do but how. Two answers to the question of “how” prevail. The first we might label “techno-optimism” – the belief that technological progress will enable us to reach zero carbon emissions while continuing to enjoy our existing standards of living, and indeed while bringing all people across the world up to the living standards which rich countries currently enjoy. So that we can continue to drive our cars, fly off on holiday, and eat big steaks as long as the cars are electric, the planes use biofuels and the steaks are made without actual animals.

The second philosophy might be labeled “the end of consumerism”; this argues that current rich country living standards are inherently unsustainable – whatever the pace of technological progress – and that our demands for energy and materials will continue to take us far beyond sustainable planetary boundaries even if an increasing share of electricity comes from renewable sources. According to this reasoning, if we care about sustainability we have to get on our bicycles, stop flying and give up red meat.

Techno-optimism vs end of consumerism

Of course, like any binary choice, this one oversimplifies. Many sensible people rightly support a balanced mix of both approaches and philosophies. And there are crucial dimensions – such as how to build a circular economy with relentless recycling – which sit somewhat orthogonal to the choice I am highlighting here. Nevertheless, this choice does capture the debate about how to fix our sustainability problem; it highlights the difference, as it were, between the business elite and the Extinction Rebellion, between Elon Musk and Greta Thunberg.

Controversially perhaps, my own suggestion is that across many economic activities and forms of consumption, there are in the long term almost no relevant planetary boundaries. There is no limit to how much green electricity we can sustainably produce and consume, and therefore no long-term limits to how much we can heat or cool our homes, drive our electric cars, or fly.¹

Conversely, there are severe and immediate planetary boundaries in other sectors of the economy – in particular in relation to food and textile production. This may require dramatic behavioral change – in particular diet change – if we are to avoid disaster.

In terms of science, the distinction can be summed up as follows. In the arena of physics and inorganic chemistry – in the use of photons, electrons and ions to produce energy and heat (or cool), and in the minerals which make possible their effective manipulation – human kind faces no relevant longterm planetary limits to our ability to produce and use as much zero carbon energy as we could possibly want. But in the arena of organic chemistry and biology – that is, everything to do with life on earth, of photosynthesis and the production of complex hydrocarbon, carbohydrate and protein molecules, and the implications for land use – we must recognize inherent planetary boundaries. Indeed, we have already gone far beyond those limits. This distinction has important implications for policy.

Cheap green energy: Photons, Electrons and Ions

Energy production and consumption – in our industrial and transport systems, in our offices and homes – today account for the majority of all greenhouse gas emissions, about 30 gigatons (gt) per annum. That’s because 80% of our primary energy comes from fossil fuels, the stored product of photosynthesis over millions of years which we are releasing and burning in just a few hundred.

But the good news is that we know how to decarbonize all of this. And in the long term – indeed even within just 30-40 years – we can achieve a world of close to limitless, cheap zero carbon energy. So cheap and limitless, indeed, that in the second half of the twentieth century a focus on improving end-use energy efficiency may become largely irrelevant.

Ten years ago when I was the first chair of the UK’s climate change committee, this future was not so clearly visible. But over the last decade, the cost of solar and wind has collapsed dramatically: onshore wind costs are down over 60%, solar over 80%, and offshore wind costs are also now falling rapidly. When Germany first subsidized the installation of solar pv in the mid 2000s, it was paying German farmers over 40 eurocents per kilowatt-hour (c/kwh) to put panels on their roofs. A recent power auction in Portugal produced a price of 1.1 c/kwh: that’s a fall of 97%.

And these falls are bound to continue. A May 2020 report by Ramez Naam entitled “Solar’s future is insanely cheap” suggests that by 2050 solar electricity could cost less than 1.5 c/kwh, even in the less sunny locations, and below 0.5 c/kwh in sunnier climes. This may be towards the more optimistic end of expectations, but even in more conservative analyses the big picture is still very clear. Renewable electricity generation will in future be significantly cheaper than fossil fuel-based electricity today.

The crucial question therefore is no longer the cost of generation, but what to do when the sun doesn’t shine and the wind doesn’t blow.

In other words, how to balance supply and demand across the minutes, hours, days and weeks in a system dominated by intermittent renewables? But here too, improving technology and declining costs provide the answer.

Lithium ion battery costs have collapsed 85% in the last ten years and will keep on falling, providing an increasingly cost-effective way to balance supply and demand over the diurnal cycle.

Multiple technologies could play a role over longer durations, including pumped hydro storage, compressed air, liquid air, and flow batteries. And the cost of producing hydrogen from electrolysis of water is on the verge of the sort of collapse we saw in solar as well, making it economic to turn surplus electricity into hydrogen, and then to burn that hydrogen in gas turbines to produce electricity when needed.

As a result, we can now plan with certainty to build zero carbon electricity systems whose total cost of operation – including all the storage and flexibility needed – will be at least as low as existing fossil fuel systems – and in favorable locations significantly lower. With cheap zero carbon electricity, we should electrify as much of the economy as possible; as a result, we could automatically improve energy efficiency all over.

While even in the so-called hard to abate sectors of the economy (such as steel and cement, shipping or aviation) decarbonization is technologically and economically possible by 2050, and while carbon capture and storage and bioenergy will play some role, in the long term the key technologies will be electricity, hydrogen and hydrogen derivatives. With enough electricity, we can decarbonize almost all of our economy. True, there are some exceptions (we may never, for instance, be able to decarbonize cement production without capturing and storing the co2 inevitably produced), but the exceptions are at the margins: the big picture is that by the second half of the twenty-first century we can electrify our way to a zero carbon world. The Energy Transitions Commission’s scenario for 2050 therefore describes a world in which global electricity use increases from today’s 27,000 twh to as much as 100,000 twh, with electricity then accounting for about 65% of total final energy demand versus 20% today. Hydrogen and hydrogen derivatives could potentially account for another 15%.²

The trivial impact of living standards

Such a world is certainly technologically possible. Once we have achieved it, the cost to living standards – even if measured in conventional GDP terms – will be trivial, at most, and quite possibly less than nil.

In some sectors, such as road transport, green electrification is not only going to benefit the planet but is going to make people richer: electrical vehicles will be cheaper both to buy and to run than today’s cars. If we’re not careful, that could actually make congestion problems worse, but its impact on conventionally measured living standards will undoubtedly be a positive one.

In other sectors, such as shipping or steel, intermediate costs may increase significantly (a ton of steel might cost 25% more or freight rates might go up 50% or more), but when you work out what that implies for end-consumer prices, the net effect will be trivial.

In some specific sectors, such as aviation, decarbonization will probably require somewhat higher consumer prices, but the impact on consumers should be offset by other savings.

In the end, across all sectors, the impact will be no more than a 1% reduction in conventionally measured living standards in 2050, falling thereafter and probably at some time becoming negative, as green electricity gets relentlessly cheaper.

Limitless green energy

Not only is green electricity going to be cheap – it will also essentially be limitless. For many decades, some scientists have dreamt that nuclear fusion would be able to deliver limitless, zero carbon, safe, cheap electricity. And I don’t exclude the possibility that nuclear fusion may have a role to play in our limitless green energy future.

But the wonderful reality is that human beings already enjoy the benefit of limitless energy delivered from an unbelievably massive nuclear fusion plant, fortuitously placed at a safe 92 million miles away: the sun.

Each day, the sun shines down on earth 8000 times as much energy as all humans use; we only need to capture and use 1/80 of 1% of that energy to have a completely decarbonized energy system. To produce 100,000 twh of electricity, solar panels would only need to cover about 1% of the global land area, and even less if we could also use some of the surface of the oceans.

Naturally, it would never make sense to rely only on solar pv: an optimal renewable system would always use a mix of solar, wind and hydro. But some of the other resources also are abundantly available. The International Energy Agency estimates that the total technical potential for offshore wind is as much as 420,000 twh, which is at least ten times what we need in our future electricity system.³

Of course solar and wind developments may have local environmental and aesthetic impacts which will need to be managed. And local land availability may be a constraint in specific densely populated nations. China, for example, could easily meet mid-century electricity demand of 15,000 twh (twice current levels) while devoting only a trivial percentage of its large lightly-populated western provinces to solar PV. However, should Bangladesh (with a population density eight times higher) try to meet the same electricity demand per capita with solar pv, it would have to use over 15% of its total land area – and almost all the country’s land is already intensively used. Our future global zero carbon energy system will therefore need to involve a new zero carbon form of international energy trade, whether in the form of high voltage electricity transmission, or of hydrogen or ammonia. Still, there are no planetary limits here, and no unsustainability. There is no danger that by developing a green electricity system capable of producing 100,000 twh per annum – or even much more – we will degrade the capacity of the ecosystem to support human welfare in the future (the rebound effect notwithstanding).

Plentiful minerals

But what about all the minerals needed to build this huge zero carbon energy system? We need cobalt, magnesium, nickel and lithium for batteries; silicon for solar panels; rare earths such as neodymium and dysprosium for the magnets used in electric motors; copper for electrical transmission and distribution systems. And what about the 7,200 million tons of water which would be needed to produce 800 million tons of hydrogen in a world already facing significant water constraints?

Well, a detailed analysis will reveal that there are no inherent scarcities of supply for any of these materials. Water consumption for electrolysis is completely manageable as well as it is very small compared with that big water user – agriculture. While mining for the necessary minerals could impose local environmental impacts which need careful management, they remain far smaller than the environmental impacts imposed by the existing fossil fuel-based system.

Consider, for instance, the supply of lithium. Lithium is a crucial element in batteries. And if there are 2 billion cars on the road in 2050, each with a 60 kWh lithium ion battery, that means 120 TWh of battery capacity, which in turn implies something like 19 million tons of lithium. Even if we get really good, as we must, at recycling end-of-life batteries, there will always be some new lithium input needed, and thus a significant need for lithium mining. Lithium mining, if done badly, can have significant adverse local environmental impacts: toxic chemicals such as hydrochloric acid are used in extraction from rock deposits, and enormous quantities of water are needed to extract it from salt flats.

But there is no shortage of available lithium supply: indeed, lithium is one of the most abundant materials on land and in oceans. Furthermore, economically accessible resources of lithium are currently estimated by the US Geological Survey at 80 million tons – an estimate up from 53 million tons in 2018, reflecting a familiar pattern in which once a mineral becomes more valuable, more resources are identified. And the environmental impact of mining 1 million tons of lithium per annum is bound to be minimal compared with the local environmental impact – let alone the global climate impact – of mining 7,000 million tons of coal each year.

This is the pattern across all the material inputs we need for our green electric system: their adverse environmental impact is an order of magnitude, or two or three orders of magnitude, smaller than that of our old fossil fuel-based system.

An essentially renewable system

This is not just a happy accident. It is inherent to the very nature of the renewable system which we are building.We often use that word “renewable” but fail to reflect on how fundamentally different this system is from one based on fossil fuels.

Until now, to get energy, we have had to take massive amounts of fossil fuels out of the earth each year and burn them in chemical reactions. The process produces 30 billion tons of co2 every year. In a renewable system, by contrast, we take much smaller quantities of inorganic minerals and we put them into structures – silicon in the solar panels, copper in the wires, lithium in the batteries, rare earths in the motors. The photons of sunlight and the motion of the wind then generate streams of electrons, which we can use to heat or cool buildings, drive machines, or create hydrogen molecules. This all happens silently, and with almost no local pollution, let alone global atmospheric pollution. Most importantly, at the end of each year, those structures are largely unchanged, and already in place to do the same job all over again.

Of course some atomic and molecular structures undergo complex microscopic change and degradation (batteries, for instance, slowly lose capacity). This means that we need to repair, replace and recycle, with some new mineral flow required, to keep the system going. But the difference with the fossil fuel system remains fundamental. This future system is essentially a renewable system, and for that reason it faces no long-term planetary boundaries at a scale relevant to human energy demand.

Warding off disaster

If our focus remains solely on keeping our current industrial, transportation, heating and cooling systems up and running; on whether we can continue flying without guilt; and on whether air-conditioning should be used as freely in the tropics as heating is used along the higher latitudes, then the techno-optimists seem poised to win the day. But we remain on a path to climate disaster.

We must not ignore the fact that we are destroying our natural environment in an unsustainable and potentially irreversible fashion.

First of all, we have left it dangerously late to move away from our fossil fuel-based energy system. Secondly, in our use of land and oceans for food, textile and other organic material production, we are already exceeding planetary boundaries and – unlike in the energy and industrial systems – we do not yet have a clear vision of how to draw back from them.

The first problem is one of timing. If, 40 years ago, responding to early scientific understanding of the global warming threat, we had forcefully set out to build our technically possible renewable system, we could have done so in good time, without needing to change consumer behavior dramatically. But we didn’t. We allowed the stock of co2 in the atmosphere to keep rising. Today, if we are to have any hope of limiting global warming to non-catastrophic levels, we must not only achieve zero emissions by around mid century, but reduce emissions by something like 50% in the next decade. The latter goal is much more difficult than the former. Given 30 years and determined policy, we could change our capital stock to support zero carbon production almost entirely and at a very low economic cost: steel production can be zero carbon in 2050, as can shipping and long-distance trucking. But it’s much more difficult to achieve a 50% reductions via changes on the supply side of the economy within just one decade. Indeed, much of the capital stock we will use in ten years time is already in place. Therefore, changes in lifestyle and consumer behavior are essential to achieve emission reductions quickly. Ironically, those changes will be unnecessary once we get to the zero carbon renewable economy of 2050 and beyond.

The second problem is more fundamental, because it derives from the inherent inefficiencies of the photosynthetic process, and our current means of animal protein production. Each year, human beings use about 125,000 twh of non-food energy. In addition, if 9 billion people in 2050 were to each enjoy an adequate calorific intake of, say, 2200 calories per day, that would mean 7400 TWh of energy intake in the form of food. So the required food energy input is only about 6% of total human non-food energy use.

But unlike energy we use for heating/cooling and to operate our machines, we cannot substitute electrons for carbon-based molecules in the food we eat. We have to derive food from the photosynthesis of vegetable matter, and that’s a far less efficient way of converting solar energy into usable energy. Research for the World Resources Institute shows that even fast-growing sugarcane on highly fertile land in the tropics converts only around 0.5% of solar radiation into sugar; for corn grown in Iowa, the solar to biomass-energy conversion efficiency is just 0.3%. A field of solar panels, on the other hand, might achieve an average yield of 15%, and this figure is slowly increasing over time thanks to technological progress.⁴

Inevitably, therefore, photosynthesis to produce food requires large amounts of land, even though energy in food is only about 6% of our total requirement. And while we can improve the efficiency of the photosynthetic process by applying nitrogen fertilizer, for example, that in itself has a significant climate change effect, via the production of nitrous oxide. In addition, food production via photosynthesis in fields requires large water inputs.

Moreover and crucially, if we choose to consume food in the form of animal protein, we essentially take the vegetable product of photosynthesis and put it through some very inefficient processing machines called animals; some of these – in particular cattle and sheep – also produce methane gas as a byproduct. As a result, agriculture in total is currently responsible for about 11 GT of greenhouse gas emissions, only about 0.7 of which reflects the energy used in agricultural processes, with about 4 gt of co2 equivalent emission resulting from methane release, 1.5 GT from nitrous oxide, and about 5 gt from the land-use changes, which are primarily driven by agriculture and, above all, by meat production.⁵

Even if we could reduce energy system emissions by 50% by 2030, and reach zero by 2050, we would still be threatened by harmful climate change. We would still be destroying natural habitats and biodiversity in an utterly unsustainable fashion, and in a way which threatens to become self-reinforcing and irreversible.

In the agricultural system as it is currently organized, we truly have gone beyond planetary boundaries, and we need a strategy for drawing back.

Such a strategy could entail a mix of three elements:

First, non-radical change in food production technologies and systems. These could play a significant but still only partial role. New forms of animal feed, for instance, may be able to reduce methane emissions to some degree. Nitrogen fertilizer could be used more efficiently, and a nitrogen tax would help create incentives to do so. Perhaps most importantly, better incentives could encourage more effective land use, even with largely unchanged technologies. It’s a striking fact that total global land use for agriculture is not actually increasing, but harmful land-use change still occurs: we are simultaneously destroying natural habitats to create new agricultural land, and abandoning existing agricultural land, which has been degraded by harmful practices, or which is simply more expensive to use than taking new land.

A second way forward is diet change: people must be encouraged, persuaded and incentivized to reduce their consumption of red meat and dairy. Such a diet change has been urged, for example, by the wwf’s report Eating for 2 degrees, which shows that a major change in uk diets, including in particular a more than 50% reduction in red meat consumption, could reduce the country’s carbon footprint from food consumption by 30%, even without a change in technology.

A third way forward is radical changes in the technology of food production. This could include vertical controlled-environment farming to produce green vegetables with 90% less water and 99% less land. It could include breeding insects as feedstock for fish production or as direct human food and/or synthetic production of carbohydrates, such as being developed by Solar Foods Finland. It could include synthetic meat protein production, using precision fermentation and energy inputs to produce meat equivalents while using 100 times less land and 1/10 as much water as those inefficient animal processing units called cows.

Such a shift would make food production more like non-food energy production: an input to human welfare and consumption without planetary boundary limits. After all, knowledge is limitless and electricity can become so. A September 2019 Food and Agriculture Report by RethinkX explains how the technology of precision fermentation improves every year while the traditional technology of the cow remains as inefficient as ever. And if one technology is relentlessly improving while another is staying still, it is simply a matter of time before the new beats the old.

But that takes us back to the issue of timing: we have technologies which will make planetary boundaries close to irrelevant by the late twenty-first century, yet we still face an ecological disaster today.

Four implications for action

In sum, to beat climate change, I see four particular implications for action, whether by governments, companies or individuals. First, we must build the future zero carbon electricity system as fast as possible, decarbonizing electricity production and electrifying as much of the economy as possible.

Second, we must get emissions down fast over the next ten years, and we must therefore persuade as many people as possible to make responsible consumption choices today even if those choices will be unimportant after 2050. Cutting down or cutting out red meat and dairy, traveling by train rather than plane wherever possible, bicycling and using public transport rather than private cars, avoiding unnecessary purchases of clothes – all of this must be part of the story.

Third, we should aim for radical new technologies in food production, and quickly, in order to render the sector sustainable.

Finally, we must motivate big flows of finance to support ecosystem restoration, reforestation, and less destructive land-use practices.

We are running out of time, both to prevent climate change and to avert an irretrievable loss of the biodiversity and the beauty of the natural world.

  1. One possible caveat to this hypothesis arises from the “rebound effect”, in which, if energy or any other intermediate product or service gets cheaper, human beings simply use more of it. But the strong distinction between the severity of planetary boundaries arising from different areas of human consumption remains necessary.
  2. “Making Mission Possible: delivering a net-zero economy”, Energy Transitions Commission, September 2020.
  3. World Energy Outlook 2019, iea, November 2019, chapter 14.
  4. Tim Searchinger and Ralph Heimlich, Avoiding bioenergy competition for food crops and land, World Resources Institute, January 2015.
  5. See “Making Mission Possible”, box A, p. 30, for a breakdown of agriculture and land-use emissions

This article is drawn from the author’s Keele World Affairs Lecture, held on November 12, 2020 and also appeared in

Aspenia international 93-94

Adair Turner

Lord Adair Turner, a British academic and businessman, has called himself a “technocrat”. He is currently Chair of the Energy Transitions Commission, among other positions.

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