Some thoughts about net-zero

There’s been a reasonable vigorous, but pleasant, debate on Twitter about “net-zero”. It was largely motivated by a Conversation article by James Dyke, Robert Watson, and Wolfgang Knorr called Climate scientists: concept of net zero is a dangerous trap. The basic idea is that framing emission reductions in terms of reaching net-zero has allowed there to be plans that delay actual emission reductions on the basis of us being able to develop and implement negative emission technologies.

To be clear, I agree with the concern than we are using the net-zero framing to delay making actual emission reductions. What I don’t agree with is that this is some trap created by climate scientists. The requirement that we get (net) CO2 emissions to (roughly) zero emerges from the scientific evidence. As Kimberly Nicholas pointed out, this essentially means that we must no longer be adding CO2 to the atmosphere. It doesn’t, though, tell us how we should do so.

The simplest would be to simply stop emitting CO2 into the atmosphere. However, there are some sectors that are challenging to decarbonise, so we might need some kind of negative emission technologies that artificially remove as much CO2 as we emit. If it’s possible to implement these kind of technologies at a large enough scale, then we could also continue emitting CO2 under the assumption that these technologies could then be used to not only eventually balance our emissions, but to also allow us to end up in a position where our emissions are net negative.

This is where the problem comes in. By developing plans that rely on these kind of technologies, we’re not only gambling on these technologies being able to operate at scale, we’re also delaying making the kind of emission reductions that would potentially allow us to meet our targets without relying on these technologies. We can, of course, choose to take this risk, but we should be open about doing so.

So, yes, I do agree with people’s concerns about these types of plans and about the possibility that organisations can make promises about getting to net-zero that they may not be able to keep. However, I don’t think the problem is that scientists are pointing out that the requirement for stabilising global surface temperatures is that we need to get (net) CO2 emissions to ~zero.

In addition, I do think that scientists need to be careful. If people are misinterpreting scientific information, or making decisions that don’t seem consistent with that information, that doesn’t mean scientists should decide to change the information they present. Scientists shouldn’t, IMO, be second-guessing how information might be used and adjusting their messaging to steer things in a way that they regard as optimal.

I also think we should be careful of suggesting that the problem is how scientists have presented their information. Of course, scientists should aim to explain information as clearly as possible, but they’re not responsible for how that information is then used. This isn’t to suggest that we should avoid criticising scientists, but I do think we should be cautious of doing so because we disagree with how others are using the scientific information that is being presented.


Climate scientists: concept of net zero is a dangerous trap – Conversation article by James Dyke, Robert Watson & Wolfgang Knorr.

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15 Responses to Some thoughts about net-zero

  1. pendantry says:

    If it’s possible to implement these kind of technologies at a large enough scale

    That’s not just a big ‘if’, it’s enormous. And the ‘scale’ issue is proving to be insurmountable, making the ‘if’ even bigger.

  2. Ken MacClune says:

    Flashback to 25-years ago – “We can’t talk about adaptation. That will be giving up on mitigation.”

  3. Ken,
    There is another similarity, in that ~10-20 years ago some were arguing that we should rely on adaptation, rather than mitigation (which, I agree, did then influence how seriously others considered adaptation). Now we have people who are willing to develop net-zero plans, but that rely on future negative emissions technologies, rather than on emission cuts today.

  4. Tom Fuller says:

    The problem with a blanket condemnation of unorthodox solutions is that we are extremely unlikely to find a silver bullet that solves the climate problem. Instead we are quite likely to end up employing 50 2% solutions. Renewable energies will provide (are already providing) a handful of them. Electrifying transportation a well, as are afforestation and energy efficiency.

    But as a physicist, surely you can see the potential of technologies that reduce the energy imbalance at TOA, ranging from barium-laced white paint for rooftops to mylar shields blocking the sun from space. Others are iron seeding for the oceans, encouraging sea grass on shallow ocean floors, etc. But some are just common sense, like cleaning up black soot and letting the snow go back to doing what it’s best at.

    Some of these are science fiction and most would take time and money to scale up. But their original sin is that they don’t have any effect on emissions. Which is why I (of course) take issue with framing the problem as emissions-centric.

    Anthropogenic contributions to climate change involve much more than our emissions of greenhouse gases. Our solutions must as well.

  5. Eventual_Horizon says:

    Discussion on net-zero when CO2 emissions are accelerating and CH4 skyrocketed last year seem rather disconnected from reality. Rather like an obese chain smoker mulling training plans for a marathon. I know this reads cynical but 40 years of climate conferences haven’t bent the curve in any meaningful way. The COVID global economic collapse didn’t either. And we want to quibble on net-zero? Perhaps our sights should be set a little nearer.

  6. izen says:

    Net-zero looks like a delusion when we are unlikely to get Biden’s 50% cut in ten years.
    The economic forces that protect oil and gas are powerful and rich. Solar and wind cannot contend with a cartel of CO2 emitting industries.

  7. mrkenfabian says:

    I think we are better placed now than ever before to make strong commitments, just because building a whole lot of wind and solar in place of coal or gas is now cost effective. 20 years ago that must have looked very unlikely – or even 10 years ago. A tipping point on clean energy costs is being passed and nothing will be the same as a consequence. Solar installation for example is growing at above 40% per year, faster than the rate of growth of total energy. The point where energy supply grows and economies grow whilst fossil fuel use declines is already occurring in major nations like the US (despite Doubt, Deny, Delay and Deride being a mainstream climate “policy”). Reducing ongoing growth of fossil fuel use has to precede actual decline of fossil fuel use.

    That has to be cause for at least cautious optimism. It doesn’t make wind and solar the whole of problem solution – not anything near – but the RE boom is inducing change and I suspect it is is the sort of change that seems to happen very slowly… until clean energy is cheaper than FF energy when it can happen very fast. Nations that even a decade ago considered coal to be absolutely essential for electricity now cannot induce electricity generators to invest in them – but probably not because they care about climate.

    The growth of solar and wind is forcing change upon energy industries that have been resistant to it and that has shifted the Overton Window; the economically alarmist fear of climate activism – that committing to clean energy will ruin economies – is shown and known to be false and no longer has the potency to reign back emissions ambitions. The near absolute unity of captains of commerce and industry in opposing climate responsibility and accountability is no longer there. Climate science denial no longer resonates, clean energy pessimism no longer resonates.

    Opponents seems to be shifting to arguing strong policy is not required, because the solar and wind (they disparaged) appears able to grow without it may be the new battle ground, to ensure that as the capability to take stronger action grows that ambition grows with it.

  8. izen says:

    “Opponents seems to be shifting to arguing strong policy is not required, because the solar and wind (they disparaged) appears able to grow without it may be the new battle ground”

    Opponents seems to be shifting to arguing strong policy is required to prevent intermittent generators being unable to provide a consistent supply and persist in the inclusion of FFs in home supply to provide space heating.

  9. Ben McMillan says:

    Think scientists (or at least climate economists/policy academics) are substantially responsible for the idea that negative emissions are a big part of the solution. It isn’t a coincidence that this appeals to vested interests, they are active participants in things like IPCC and think tanks pushing for “realistic and gradual” solutions that don’t threaten their interests.

    I’m happy with “zero” but “net” would be better as a footnote, given the small role negative emissions are likely to play any time soon.

  10. mrkenfabian says:

    Izen, the pro coal and gas Australian government set up the Electricity Security Board in the certainty it would recommend prolonging the life of existing coal plants and the building of new gas plants, for the sake of energy reliability – a bit like the Texas situation. Now the ESB is saying batteries can cover the reliability requirements, at least in the near term, and does not recommend the new gas plants that seemed such a sure thing.

  11. I’d like to know what evidence there is that cutting emissions is more likely to bring about net zero than technofixes? I think a high energy using, nanotech enhanced world might be more likely to reach net zero than for the current world to adopt energy austerity, which might then prove futile.

    I’d also like to note that the world’s largest emitter of CO2, China, is not planning to start reductions until 2030:


    > President Xi Jinping announced in September the country’s carbon emissions would begin to decline by 2030, and reach carbon neutrality by 2060 — in four decades.

    > In the meantime, policymakers are making clear that economic growth remains a top priority — and that growth depends largely on coal power.

    >“Because renewable energy (sources such as) wind and solar power are intermittent and unstable, we must rely on a stable power source,” said Su Wei, Deputy Secretary-General of the National Development and Reform Commission. “We have no other choice. For a period of time, we may need to use coal power as a point of flexible adjustment.”

  12. Mike,

    I’d like to know what evidence there is that cutting emissions is more likely to bring about net zero than technofixes?

    Because if we’re actually cutting emissions, then we’re actually cutting emissions. Let’s not play “but China”.

  13. mrkenfabian says:

    Seems clear that developing clean energy abundance is already a credible option and a serious goal with strong support. Energy austerity apart from promoting efficiency is not a widely supported mainstream energy policy.

    Austerity by choice was never going to do the job and enforced austerity was never seriously an option at all – and the fears of globalist green dictatorships forcing it on the world were always alarmist BS.

  14. Pingback: Science-based targets | …and Then There's Physics

  15. Pingback: The concept of net-zero | …and Then There's Physics

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