If the world is to meet the Paris climate agreement objective of limiting global warming to well below 2°C , it will have to reduce greenhouse gas emissions from the energy and industrial system to net zero across the world by around 2060. That is undoubtedly technical possible and at a relatively small economic cost.
But on current trends, as the latest report from the International Panel on Climate change (IPCC) makes clear, the world is still heading towards 3°C of global warming by 2100, a level never seen in human history spanning over 1 million years, and one likely to produce catastrophic harm to human welfare.
There is a dangerously high probability that the world will fail the climate change challenge, not because it is technically impossible or prohibitively expensive, but because governments, industry and consumers do not take the action required.
Getting to net zero emissions will of course require profound changes to energy supply and use, but as the Energy Transitions Commission’s recent report, Mission Possible, sets out, it is certainly achievable given technologies that are already on our radar.
All feasible paths to a low-carbon and eventually zero carbon economy require a massive increase in the role of electricity, with electricity’s share of final energy demand growing from around 20% today to something like 60% by mid to late century, and with total global electricity generation rising dramatically from today’s 20,000 terawatt hours (TWh) per year to as much as 100,000 TWh.
That electricity in turn must come from low carbon sources, and while nuclear power and gas generation offset by carbon capture may play a role, the lion’s share - 70% or more - will likely have to come from renewable sources.
That may seem like a daunting challenge. But less than 1.5% of the global land surface area could produce all the renewable electricity the world needs. With battery and other energy storage costs falling, and huge potential for the smart management of electricity demand, it will become possible to run grids that rely on intermittent renewables for 85-90% of their power, while still delivering electricity when needed, and at a cost below that of current fossil fuel generation. The big question is not whether the required end point is technically and economically feasible, but whether we will get there fast enough. Achieving this requires 40 years of investment in renewables at about 5 times the current annual level.
Three promising technologies
Three other sets of technologies will also be essential. First, a greatly expanded role for hydrogen, with annual hydrogen consumption growing from 60 million tonnes a year today to around 450-650m tonnes by mid century, and an increasing share produced via electrolysis. In steel production, hydrogen could replace coking coal as the reduction agent: ammonia produced from hydrogen and burnt in existing engines may be a route to the decarbonisation of shipping. Hydrogen may also play a major role as a chemical feedstock input.
Second, a significant role for bioenergy - power derived from organic materials - which could, for instance, provide zero-carbon aviation fuel, or feedstock for plastics production. The total scale will need to be carefully managed to avoid harmful impacts on ecosystems and food supply.
Third, at least some role for carbon capture and either storage or usage, in particular in cement production, where alternative routes to decarbonisation are currently unavailable, and as the least cost route to steel decarbonisation in regions where renewable electricity is more expensive.
Some aspects of a zero-carbon economy will make consumers better off. Within 10 years, electric cars will not only be cheaper to operate than diesel or petrol, but will also be cheaper to buy. In heavy industry and transport, where it is harder to reduce CO2 emissions, some additional costs are unavoidable but often the consumer impact will be trivial: making cars from zero-carbon steel would add no more than 1% to a typical car price. But in some specific sectors, material price increases may be unavoidable: if bio-based aviation fuel costs 50-100% more to produce than conventional jet fuel, that would add up to 20 per cent to ticket prices.
Overall however the ETC estimates that achieving zero emissions in the most difficult to decarbonise economic sectors - heavy industry and long distance transport - would make the global economy at most 0.5% smaller than it would otherwise be. For all sectors of the global economy, the cost is unlikely to exceed around 1%. The impact on global living standards of achieving a zero carbon economy will be trivial.
The promise - and the peril
Building a zero carbon economy will of course require significant investment – in power production and transmission, new industrial plants, and more efficient energy-using equipment. But at the macro level the challenge is far from daunting. The recent IPCC report estimates that required additional global investment, over 2015 to 2050, could run at $900 billion a year. That may seem a startlingly high figure, but compared to global GDP which stands at $100 trillion today and which with 3% annual growth could reach $260 trillion by 2050, it implies that the world needs to invest less than 0.6% of our income over the next four decades to avoid potentially catastrophic harm.
But while a zero-carbon economy is undoubtedly technically and economically feasible, it will not be achieved without strong public policies supported by responsible companies and consumers. And there is a real danger that self-interested lobbying and a short-term focus in both politics and business means we still fail and leave the world facing 3° warming within the lifetime of children alive today.
If that happens there will be no excuse: we cannot claim the task is impossible or even, within the context of what previous generations of humanity have achieved, all that difficult or expensive. So we need to make sure it doesn’t.