climate change politics

How would you get Britain to net zero?

Britain has committed to reach net zero carbon emissions by 2050. Last week it added an intermediate target (and Nationally Determined Voluntary Contribution, in the language of the Paris Agreement) of a 68% reduction by 2030.

There are many ways to get there, and the government department with responsibility for climate change, the department for Business, Energy and Industrial Strategy, has illustrated this with an interactive challenge. Visitors to the website can move a series of levers to lower emissions, and choose a set of policies that will edge emissions towards zero – more nuclear power? More solar? What about hydrogen or forestry?

After just a couple of minutes of play, one thing that immediately jumps out is that it’s not a matter of what you choose to do, but what you choose not to do. Getting to zero takes action across the board. Everything has to change.

And there will be compromises. For those who don’t want to major on behaviour change, for example, you’ll have to make extra emission cuts somewhere else. Likewise, deciding against nuclear power, or hydrogen, all require more work in another sector.

Because it’s the government’s set of sliders, it shouldn’t be taken as comprehensive and some policies are left out. There’s no option for food choices. The wind slider keeps saying it’s ‘mostly offshore’ when I’d like more onshore. Worst of all is transport demand. The highest level of ambition the government can imagine has aviation declining by just 5%. On the other hand, it can imagine that 100% of planes are plug-in electric hybrids by 2050, which seems vanishingly unlikely to me.

Still, it’s an interesting and educational exercise, not least because it reflects what is considered politically possible. You might not be able to model your ideal pathway to net zero, but it will also point out idealism. It clearly shows how hard it is to reach net zero without some controversial measures, such as carbon capture and storage, or bioenergy. Environmentalists are going to have to make compromises too.

The model, which is called the MacKay Carbon Calculator, is available in two versions. There’s a simplified version called My 2050 where you can see a little animation showing your chosen changes pop up in the landscape. I might run it past my kids after school. Then for the geeks, there’s the more detailed version with graphs. You can make your own zero carbon pathway, and here’s a highly unsatisfactory one I made earlier.

(This calculator is actually a third third iteration of the idea. This previous version modelled Britain’s previous carbon target of an 80% reduction by 2050. A little comparison shows what has become possible in the last decade. For example, electric buses seemed like a longshot. Batteries were expensive. There was a slider for small scale domestic wind, which nobody has taken seriously since. On the plus side, it was hosted by the Department of Energy and Climate Change, before it was abolished. Can we have a climate change department back now?)


  1. Interesting – thanks! Just had a quick explore; some of the assumptions seem amazingly pessimistic/lacking in ambition on how people will change demand (e.g. all the INCREASES in domestic car use).
    I also really like that it’s named in honour of David Mackay. Somehow to me it seems very telling that his simple ‘back of the envelope’ approach, which most 16 year olds could manage, became so influential for DECC and beyond including his appointment as scientific advisor. That should take nothing away from David’s great contribution. But what does it say about the sophistication and vision of our government’s approach on climate over these past ~2 decades? Is that unfairly reading in criticism where it isn’t due?

    1. Yes, it is a pretty abject failure of the imagination, especially considering that car travel peaked in the 1990s. An accelerated decline of car use would be leaning into an existing trend, which shouldn’t be impossible to conceive of.

      What I do find interesting is that transport is still the sector where it seems hardest to get any kind of political traction. It’s the biggest source of emissions in Britain, the one sector where emissions haven’t fallen, and it’s the sector here with the lowest levels of ambition. Something is quite broken in the politics of transport.

      As for MacKay, yes, nice to see him memorialised there. And I would hope that this is a public facing engagement tool, and that there is more sophisticated modeling going on behind the scenes!

      1. The problem with transport is that it represents a failure of the state. People prefer car travel because it is reliable and comfortable, and cheaper than public transport. If you have to wait an hour for a bus in the rain as opposed to going home then of course you’ll take the car. You can’t persuade people out of cars until you take the trade unions out of transport.
        State provided services have failed at every level and we see the result. NHS is a disaster, so people take private health insurance, the police fail so people live in gated communities, the schools fail so people pay for private education (paying twice), and transport is a faliure too.

  2. “The highest level of ambition the government can imagine has aviation declining by just 5%. On the other hand, it can imagine that 100% of planes are plug-in electric hybrids by 2050, which seems vanishingly unlikely to me.”
    As someone with a degree in aeronautical engineering, “vanishingly unlikely” seems an understatement. Electric and hybrid-electric propulsion, even with significant technological advances, are expected to power only ultra-short and short-to-medium-haul planes. Island-hopping in the Hebrides and Channel Islands will be doable with battery power. Hybrid aircraft might be able to reach Spain or Portugal nonstop, but I wouldn’t be so sure about the Canary islands. Perhaps, by the 2050s, any long flights will involve multiple stopovers, like airplanes in the 1930s. Personally, I think it’s more likely that sustainable aviation fuels (SAFs) will be used, and that longhaul flights will achieve carbon neutrality that way – if, that is, SAFs are produced in sufficient quantities by then.
    That’s one of the reasons why I recently started a petition asking the government to force up demand for SAFs right now ( not only would it lead to immediate improvements in the aviation sector’s CO2 balance, directly in proportion to the amount of SAFs used, it would also ensure that the infrastructure for carbon neutral aviation is built. I’d be grateful for any signature and signal boost for the petition:

    1. Thanks, and I agree – hybrid or electric planes are most likely to make a difference with small (ie private) planes on domestic routes, which is exactly the kind of flying that could be done by other forms of transport.

      Thanks for the link to the petition.

  3. I don’t see why most flights cannot be eliminated entirely. In the US ee have sports teams and their fans flying all around the country all year. Eliminate these flights. Flights for vacation and visiting are not necessary. Most business flying is also unnecessary. There may be dome necessary flying done but I suspect it is very little. Most is for connivence and pleasure.

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