November 12, 2021, by Brigitte Nerlich

The concept of net zero hangs in the balance

‘Net zero’ has been in the air for a while and I let it waft over me without taking much notice. However, a few days ago I read Ken Rice’s thoughts on this matter on his And Then There’s Physics blog. He argues against a “recurring narrative that the concept of net-zero is flawed”, saying that rather than contending that the concept is flawed, one should look at how it is being used.

Ken highlighted the word ‘concept’ in bold. I began to wonder, as is my wont, when this concept began to be used, how it came to be viewed with suspicion, and is now sliding into the repertoire of the ‘delay climate change action’ discourse. I also wondered how a concept can flip so easily between having positive to having negative associations/connotations.

Net zero in the Oxford English Dictionary

Anyway, my first port of call was, of course, the Oxford English Dictionary. And, surprise, surprise, the word/concept is actually in there! Its rooted in the discourse of finance, but is now used in the context of dealing with global heating. The OED says:

net zero  n. (in the management of greenhouse gas emissions) an overall balance between the amount of carbon dioxide and other greenhouse gases produced and the amount removed from the atmosphere; a target of achieving this in order to mitigate the effects of global warming.
1989   Session to Establish National Energy Policy to Reduce Global Warming (Hearings before U.S. Senate Comm. on Energy & Natural Resources) […]   On a fuel cycle basis, an integrated biofuels energy system is probably the closest to being net zero for CO2 effects of all combustion based energy systems, due to the CO2 absorption of the growing feedstocks.
2005   Campaign 22 July 20/4   What this really means is you’ve assessed, reduced and then offset your CO2 emissions to net-zero.
2021   Daily Tel. (Australia(Nexis) 12 May 89   Last year the National Farmers Federation set a net zero goal for 2050, while the Meat and Livestock Association went further, pledging to reach net zero by 2030.”

So, there is talk of a balance, between something added and something removed. Surprisingly, there is no talk about the most important thing: about something not added in the first place or about stopping adding things. This focus on adding and removing might be at the root of some current misuses of the word, perhaps.

The other surprise was that the word began to be used almost as soon as climate change became a matter for politics rather than ‘merely’ science, namely in 1989, one year after the Intergovernmental Panel on Climate Change was established to provide policy makers with easy access to the latest climate science findings.

It seems then that scientists and policy makers have been talking about net zero for a long time. It’s not just a recent invention. Let’s see how it was used in the news after 1989.

Net zero enthusiasm

I searched the news database I on 6 November using search terms “net zero” AND “global warming” OR “climate change” and found tens of thousands of articles, most of them bunched between 2018 and 2021.

The very first articles using the phrase appeared at the end of the 1990s, again in reports on US hearings, as in 1989. Then there was quite a bit of attention around the time of climate change exuberance around 2006 and 2007. Finally, net zero was used in an IPCC special report commissioned after COP21 in Paris, SR15, which was published in 2018. The issue was discussed at COP24 in 2018, a COP where I believe Greta Thunberg was present for the first time. SR15 said: “The report finds that limiting global warming to 1.5°C would require ‘rapid and far-reaching’ transitions in land, energy, industry, buildings, transport, and cities. Global net human-caused emissions of carbon dioxide (CO2) would need to fall by about 45 percent from 2010 levels by 2030, reaching ‘net zero’ around 2050. This means that any remaining emissions would need to be balanced by removing CO2 from the air.” There is some talk about removal but it is not the focus of the statement.

In 2019 the UK’s Committee on Climate Change published a report entitled Net-Zero: The UK’s contribution to stopping global warming. In October 2020 the government published its Net Zero Strategy. And the media went crazy. Then there was, of course, COP26 in Glasgow, and the net zero discourse there deserves a separate analysis. ‘Net zero is not zero’ was for example projected by activists onto the venue.

Let’s go back to the 1990s. The first uses of the phrase ‘net zero’ appeared in 1998 reports on government hearings in the US in the context of discussions about replacing coal with biofuels. Keep in mind that this was a year after the Kyoto protocol which was signed in 2001 but not by the US. The Federal News Services quoted an expert on 11 March 1998 as saying: “Crops that you grow in the earth take CO2 out and then when you burn them they put the CO2 back. That’s a net zero in terms of our CO2 in the atmosphere, whereas coal, the coal stream produces the CO2 that has not been in the atmosphere. So what we say is that these renewable crops that we replace a small percentage of the coal with are net CO2 zero kinds of substances, and so from a climate perspective you can reduce emissions.” It’s interesting to note that almost all the mentions of ‘net zero’ appeared at that time in US news items.

On 16 September 1998 The Federal News Services quoted another expert who explicitly mentions the IPCC: “When these biomass fuels are burned, the carbon dioxide that is emitted becomes part of natural carbon cycle through tree photosynthesis. This cycle is a closed-loop: tree growth readily absorbs the emitted carbon. Hence there is no net atmospheric contribution of carbon dioxide. The IPCC recognizes the use of biomass fuel as a net zero contributor to greenhouse gas emissions.”

In 1999 the phrase appeared for the first time in a headline and after that it was used with great abandon, similar to the explosion of what we once called ‘carbon compounds’ a few years later – but we overlooked this version of a carbon compound. Lexical compounds are combinations of two or more words to create a new word or concept. In the case of ‘net zero’ I found a plethora of compounds in the early coverage. The later news coverage on the topic was too big for me to survey. Some of the compounds were:

Net zero emissions, net zero GHG emissions, net zero CO2 emissions, net zero carbon impact, net-zero carbon energy system, net zero carbon emission economy, net-zero carbon energy and emissions future, net zero energy buildings, net zero energy requirements, net zero energy standard, net zero design, net zero housing, near-net-zero-energy floating home, net-zero-energy condominium building, Net Zero Energy Healthy Housing Initiative, and, of course, a net zero climate-neutral lifestyle.

There was lots of talk about building energy efficient buildings around 2006/07 and about going ‘carbon neutral’, in the context of measuring carbon footprints, engaging in carbon offsetting and so on. The discourse then featured a lot of carbon compounds alongside net zero compounds.

One article from 2007 (Times Colonist, Victoria, British Columbia, 15 February, 2007) was entitled “Confused by all that green talk? We can help”. It goes on to say: “So admit it, you have no idea what they’re talking about, do you? Carbon neutral. Carbon sequestration. Offsets. Credits. Net zero emissions.” It defines net zero in the following way: “Net zero greenhouse gas emissions: Putting together everything we’ve learned so far, if your emissions are balanced by an equivalent investment in green energy or a number of newly planted trees, your net emissions equal zero. B.C. committed this week that all electricity produced will have net zero greenhouse gas emissions by 2016.” However, no mention of stopping emissions! The carbon offsetting discourse was quite dominant at the time.

Net zero, carbon neutral and zero carbon

Amongst all that linguistic confusion I began to wonder what the difference was between ‘carbon neutral’, ‘net zero’ and ‘zero carbon’? One website made the following distinction: “Net Zero is a similar concept to Carbon Neutral, however it goes beyond just carbon and is typically on a larger scale. Net Zero refers to when all greenhouse gases being emitted into the atmosphere are equivalent to the greenhouse gases being removed from the atmosphere on a global scale (ClimateSeed, 2021). In other words, net zero emissions will be achieved when human activity no longer causes global warming. Crucially, being Net Zero includes all greenhouse gases, not just carbon dioxide.” Again, the focus is mainly on removing stuff.

What about zero carbon? One definition I found made the following distinction: “Net zero is all about ‘balancing’ or cancelling out any carbon we produce. We reach net zero when the amount of greenhouse gas we produce is no more than the amount taken away. Zero carbon concerns the emissions produced from a product or service – it means no carbon is given off at all. In the context of energy generation, one example would be a wind turbine creating electricity.”

Anyway, despite all the low carbon exuberance at the beginning of the millennium, the concept of net zero lay almost dormant until the IPCC special report put it on the map in 2018 and newspaper articles exploded.

I couldn’t look through the thousands of articles published in 2018 and beyond, but one article, a report on COP24 in Katowice in 2018, attracted my attention: “Citing a recent scientific report, the U.N. chief urged governments to aim for net zero emissions by 2050. Net zero emissions mean that any greenhouse gases emitted need to be soaked up by forest or new technologies that can remove carbon from the atmosphere.” (The Associated Press, 3 December 2018)

Here we get back to the curious fixation on removal also found in the OED. But the concept of net zero itself doesn’t stipulate that. It has drifted somehow into that semantic corner through its association with the concept of ‘balancing’ perhaps, which depends on adding or taking away stuff on a balance.

Net zero criticism

Recently, some climate scientists have followed these negative connotations to their logical conclusions and written, for example an article written in April 2021 and entitled “Climate scientists: concept of net zero is a dangerous trap”. They think that “the idea of net zero has licensed a recklessly cavalier ‘burn now, pay later’ approach which has seen carbon emissions continue to soar.’”

Net zero was, they argue premised on promises and technologies, such as CCS and BECSS for example, which move ever further into the future. And, what is more: “Once we realise net zero will not happen in time or even at all, geoengineering – the deliberate and large scale intervention in the Earth’s climate system – will probably be invoked as the solution to limit temperature increases.” So, in a sense, the idea of ‘net zero’ becomes, like geoengineering, a ‘moral hazard’ – it distracts from climate change mitigation. By focussing on removal, the idea of net zero was removed by some of those who used it from its idealistic moorings, I think. It was captured by carbon capture.

On 2 November 2021, Holly Jean Buck, a specialist on geoengineering, carbon capture etc. published a book entitled Ending Fossil Fuels: Why Net Zero is Not Enough. She argues, and I quote from a book review by Sibo Chen “that the net zero framework’s concentration on emissions diverts public and policy attention away from the more fundamental issue: effective and lasting climate change mitigation requires an unwavering end to the fossil fuel sector.”

On 10 November,  called net zero a “hollow promise”.

Net zero scepticism

In October 2021, a month before COP26, the Global Warming Policy Foundation “a climate sceptic lobby group”, which was founded in 2009, just before COP15 in Copenhagen, morphed into a new organisation that calls itself Net Zero Watch “which seeks to highlight the implications of “expensive and poorly considered climate and energy policies” (The Times, Scotland edition, 23 October). The focus here is here on raising the alarm about the cost of net zero and to raise doubts about net zero in the process.

Interestingly, when searching for ‘net zero scepticism’ (or ‘inactivism‘), which has replaced climate scepticism for some, I found this interesting tweet, posted from COP26 by Max Falkenberg on 8 November: “One of the big #COP26 takeaways for me is how prominent #climate and #NetZero scepticism is. We might not see it, but posts from sceptics are getting huge engagement, enough to put them in the top 150 COP influencers (see” And: “Three obs: 1. Engagement with COP amongst sceptics seems much higher than previous COPs. 2. Almost no one is shouting #ClimateHoax anymore. The narrative is now all about the #CostofNetZero. 3. There is a big overlap amongst these groups with anti vax/mask #COVID19 groups”.


The rise of this type of net zero scepticism, aligned with climate scepticism, needs much more research. It can thrive in a climate where the concept of net zero has moved from being seen as something to aspire to, to being portrayed as a danger, a trap, a hollow promise or a distraction to be wary of.

The semantic balance of ‘net zero’ has tipped from the relatively positive to the negative, a process precipitated, and now accelerated, by a focus on adding and, in particular (the promise of/cost of) removing greenhouse gases, rather than on ceasing to add them in the first place.

Image: Max Pixel

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