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What is success? COP26 and beyond

“What’s COP?”, asked my friend last week. It’s a bit unfair of me to quote him: he lives abroad, where media coverage is likely to be less blanket-like than in the UK; I didn’t use the full acronym “COP26”; and I gave no context (in fact, he was asking about my health).

But it’s a useful reminder that other people’s worlds are not revolving around the two week event that started today in Glasgow. For many of us working in climate change, life is currently consumed by COP26: reading about it, worrying about it, teaching about it; organising and writing talks for events there and elsewhere; talking to the news and recording podcasts; writing blog posts and opinion pieces about…well, what, exactly?

If you’re not sure exactly what COP26 is, or why this meeting is particularly important — if you don’t know your NDCs from your UNFCCCs — then skip to the end for a short explainer.

I’ve also put lists of my COP26-related podcasts and news interviews, and COP26 events, after the main blog post.

What will “success” at COP26 look like? Glasgow is different from Paris: it is not about signing a single treaty, but about the sum of its parts: the accumulated pledges of each country, the Nationally Determined Contributions (NDCs).

So I suppose the obvious reply might be: COP26 will be a success if climate scientists crunch the numbers of the final NDCs and find the predicted warming successfully meets the Paris Agreement target. But this is difficult to define, for a few reasons.

First, there are officially two targets: to limit warming “well below” 2°C, and to “pursue efforts” to limit at 1.5°C. So would success mean a predicted warming of 1.8°C? 1.7°C? 1.6°C?

Second, many would say these targets are not strong enough. We are already seeing changes to our weather at our current warming of 1.1°C. Each further tenth of a degree will make these changes more frequent and severe, and will make it more likely to trigger irreversible, long-term changes such as collapse of the West Antarctic ice sheet. A strong narrative has built up that we must limit warming to 1.5°C — rather than “pursuing efforts” to, which implies something higher — to limit the damage as much as possible.

Third, predictions of warming are inherently uncertain. Warming could be higher or lower than the central prediction. So only a central prediction below 1.5°C would have a better than 50:50 chance of limiting warming to 1.5°C.

Fourth, pledges are not the same as policies: the nuts-and-bolts plans of how to cut emissions using tools such as laws, taxes, grants, and encouraging behavioural change. The UK published their long-term strategy just-in-time before COP26, but few countries have plans with as many details. And they must be credible: Australia’s plans, for example, appear to be neither accurate nor physically possible. Without detailed and realistic plans for how to cut emissions by 2030, all talk is just…hot air.

And policies are not the same as reality: they must be successfully implemented, effectively enforced. There can be good surprises too, of course: faster-than-expected improvements in technology, energy efficiency, behaviour change. Future implementation is not necessarily something by which we can judge the success of COP26, but it is important to consider when assessing those Nationally Determined Contributions and any plans to achieve them.

Finally, there are other important aspects to COP26 that I haven’t discussed here (see explainer below): progress on these, or lack of, will also add to the bigger picture feelings of hope or disappointment.

I’m never a fan of binary thinking. The outcomes of COP26 will lie on a sliding scale, where it is unlikely we can reach the end — and the end is not clearly defined — but even a near-miss could be seen as successful in the stated aim to “keep 1.5 alive”. I agree with Christiana Figueres (former Executive Secretary of the UNFCCC and legend of the Paris Agreement) that some people will judge it a relative success and others an abject failure. This is inevitable when different groups are applying, at best, different value judgements and aims, and at worst, simplistic binary thinking, to outcomes that are not completely straightforward to categorise. I also agree with Chris Stark, Chief Executive of the Climate Change Committee which advises the UK government, who has said that COP26 will be seen as successful if people describe it as successful: in other words, if this is the dominant narrative emerging afterwards. We should ask, of course, which groups will determine that narrative?

It’s important to acknowledge that much of the progress of this COP26 has been made well before the meeting itself. Countries have been stating net zero aims and converting these into short-term targets and official Nationally Determined Contributions for the past few years. Without any action, we had been heading for a world 4°C warmer, or more. But given the policies we have already put in place, we are predicted to be heading for just under 3°C, perhaps a little lower. Under the official pledges updated before last month — if successfully translated into effective policies — we would limit warming to around 2.5°C. And since then, another 25 countries have updated their pledges.

Progress, yes, but by the minimum metric of limiting warming to below 2°C, nowhere near enough. Global emissions under the Nationally Determined Contributions are predicted to flatline or slightly increase this decade — China, for example, only aims to peak by 2030 — but limiting warming to 1.5°C requires us to cut global emissions by around half by 2030. By this measure, it is extremely unlikely we will see a prediction of 1.5°C warming for the final NDCs after COP26, though I remain hopeful we can improve beyond the current 2.5°C once they are all submitted and final. Keep an eye on that Climate Action Tracker

Glasgow is a very important push point, but not the only point at which we can make progress. After COP26, countries can always increase their ambition outside the five year update points of the Paris Agreement (most obviously, when governments change, as for the USA). Countries responsible for around three quarters of the world’s greenhouse gas emissions have adopted, or are considering, targets to reach net zero by 2050 or 2060: if successful, the predicted warming would be around 2°C (and if we were very lucky with the climate, perhaps as low as 1.5°C). This isn’t enough yet either, but it shows that this month’s pledges are not the only part of the story.

Longer-term, I think few people are aware that climate scientists also talk about the possibility of overshooting and then coming back. If could limit our rise above 1.5°C to just a couple of decades, this will be a better outcome than the fixed final temperature that I think most people imagine.

To put it more succinctly:

“It’s never too late to do as much as we can”

— Greta Thunberg, The Andrew Marr Show, 31st October 2021

So 1.5 is still alive, but it’s on life support. We need to bring it out of critical care and into recovery: getting stronger month on month, year on year.

What does success look like elsewhere? I’ve been extremely fortunate over the past three years, with opportunities like co-authoring the first part of the IPCC Sixth Assessment Report and a related study, co-presenting the BBC Radio 4 series 39 Ways to Save the Planet, and co-directing an expanding MSc Climate Change.

But it hasn’t been sustainable, especially with the post-chemo fatigue (cognitive and physical) that seems persistently worse since February, so I went part-time in September. It’s been a time of tying up loose ends and passing things on. I think the hundred or so masters students are starting to settle in, with grateful thanks to co-director James Porter for helping them so much. I’ve taught four of my five weeks of climate science this term to them and our first year undergraduates. The King’s Climate Hub research network is going from strength to strength, thanks to incredible support by new coordinator Rachel Harrington-Abrams. The 39 Ways series is done. I’ve talked to interesting groups in the run-up to COP26, ranging from a huge, exciting event hosted by Stowe School (Schools’ Climate Action) to a lunchtime event for general counsel lawyers who want to make their business resilient to climate-related risks, as well as recording podcasts and other interviews (links below). In the next two weeks I’ll finish the teaching, travel to Glasgow to do a few events (also below), then round it off with a talk to a lot of vets.

I certainly haven’t yet been successful in going part-time. But I’m saying no to new events, projects and roles to make up the difference and rest after COP26. Success for me will therefore mean not a flatlining of activities, nor a slight increase, but substantial cuts: though hopefully not year-on-year until 2030.

This post is dedicated to the wonderful human and climate scientist Geert Jan van Oldenborgh (1961–2021), whose work has been essential to our field, and whose open and frank conversations with me about terminal illness and treatment meant a great deal.

Here are lists of my COP26-related recordings and COP26 events.

COP26 interviews by recording date

22nd September
Podcast: COP26: we got this — King’s College London and Australian National University
The climate science
We talk about the IPCC, and different types and audiences of climate science communication.
“I feel like we’ve got to fall in love with nature again; we do incredible things for each other when we fall in love.”Mark Rylance

23rd September
David Ferguson Lecture — The Ivors Academy
Music & The Climate Emergency (Facebook log-in required)
A 10 minute talk about current climate change and IPCC predictions for the future [at 34:00]. Also featuring Brian Cox [00:15] and Brian Eno [47:00].

8th October
Podcast: Brain Food for General Counsel — Pinsent Masons
COP26: our ‘last best chance’
A podcast for lawyers, but also of general interest. Also featuring former MP Douglas Alexander.

26th October
Podcast: How did we get here? Explaining the news — Channel 5 News
What is COP26? A guide to Glasgow’s climate talks
Interviewed by Andy Bell.
One review: “Even your reactionary uncle who thinks it’s all tree-hugging lefty rubbish and wants “proper 100W light bulbs and decent Hoovers” back will sit up and pay attention.”

29th October
News interview: BBC News channel.
With Lukwesa Burak. Video here (apologies for low quality).

Events during COP26

Wednesday 3rd November, 1-2pm
EU Polar Cluster session panel event — COP26 European Union Side Events
“Polar warming, global warning”
Panel event on polar impacts of climate change. Also featuring Prof Dame Jane Francis (Director, British Antarctic Survey), Larisa Lorinczi (European Commission), and three other polar scientists. Details:  

Update 3/11/21: watch the event recording here ->

Saturday 6th November, 9:30-10:30am
Science Pavilion – Blue Zone
“The future of the ocean and cryosphere in our hands” 
Panel event on oceans and cryosphere science, including the IPCC Sixth Assessment Report, featuring several scientists. 

Sunday 7th November, 12-1pm
BBC Radio 3
Private Passions
Talking about my career and classical music (live broadcast plays full pieces; podcast version only has snippets).

Monday 8th November, 10-11:30am
Arctic Basecamp – Federated Hermes Fringe Festival, Skypark 
“Climate Risk and Tipping Points in the Polar Regions” 
Organiser: COP26 Universities Network. Also featuring several other scientists.
Register for the live stream:

Tuesday 9th November, 12:15-13:15
UK Pavilion – Blue Zone
“Inclusion is key: How gender equality improves science, tech and innovation for climate action” 
Chairing this panel discussion.  
Details and livestream:

About COP26

COP26 is shorthand for the 26th session of the “Conference of the Parties”. This is the twenty-sixth (sigh…) of the annual meetings set up as part of the “United Nations Framework Convention on Climate Change” (UNFCCC) that began in 1994, back when I was a spotty teenager starting to get interested in physics. The “parties” are, broadly speaking, all the countries of the world, and I refer to them as countries for simplicity, though the European Union acts as one party.

We’ll always have Paris

The 21st of these meetings was historic. Held in Paris in 2015, it led to the most important piece climate treaty ever signed — the “Paris Agreement” — in which the world agreed to:

– limit global warming to “well below 2 °C”
– “pursue efforts” to limit warming to 1.5 °C.

But — crucially — it didn’t say how. Instead, each country submitted a target for cutting their greenhouse gas emissions that was (a) decided by them and (b) voluntary. This enormous flexibility might seem insane, but is widely agreed to be one of the reasons the Paris Agreement was successfully adopted. The targets, or pledges, are called the Nationally Determined Contributions, or NDCs.

There are other very important parts of the Paris Agreement too, including monitoring of global climate, adapting to climate change, finance to support developing countries, and setting up a global market for trading carbon. But for the sake of (some) brevity, I will keep to the pledges themselves, and how we think they will translate into avoiding future warming.

Immediate, rapid and large-scale

How do we know how fast to cut emissions to meet those temperature targets? At a global level, this comes from a 2018 report by the Intergovernmental Panel on Climate Change (IPCC). To have a good chance of limiting warming to 1.5°C, with little or no overshoot, we need to:

– Cut global CO2 emissions by about half by around 2030.
– Reach “net zero” global CO2 emissions by around 2050.

“Net zero” means cutting CO2 emissions so much we can compensate the last part with methods such as planting trees or extracting it from the air. We only have a limited capacity to do this kind of compensation, so it has to be the last resort: reserved only for sectors for which it is very difficult or slow to reduce emissions to (about) zero.

The IPCC Sixth Assessment Report this summer confirmed that “unless there are immediate, rapid and large-scale reductions in greenhouse gas emissions, limiting warming to close to 1.5°C or even 2°C will be beyond reach.”


This COP, our COP in Glasgow, is a particularly important one, for a few reasons. First is that it is a special year. In the Paris Agreement, countries must update their NDCs every five years, increasing their ambition by promising deeper cuts in emissions. This is known as the “ratchet mechanism”: squeezing more from each pledge as our knowledge and technology improve. Last year would have been the first ratchet year, but it was delayed to 2021 by the pandemic.

Another is the breathtaking scale of the task: to limit warming to 1.5°C, global emissions must drop every year, year-on-year, this decade. The best time to start cutting emissions was a long time ago; the second best time is right now. This is our Sunday night deadline: we can’t avoid our homework any longer.

Finally, we have some momentum from the publication of the first part of the IPCC Sixth Assessment Report, giving an ever-more certain and comprehensive state of the climate and the possible future climates we can choose. The UK has a long history of founding ambitious, legally-binding targets for cutting emissions on scientific evidence, and should — in theory — be able to show leadership on this.

COP26 goals

The first of the UK’s four COP26 goals is based on the IPCC assessment: “Secure global net zero by mid-century and keep 1.5 degrees within reach” – or, more snappily, to “keep 1.5 alive”.

Boris Johnson memorably summarised four priorities as “coals, cars, cash and trees”, with key points that include:

  • Coal: “committing to phasing out coal power by 2030 (developed countries) or 2040 (developing countries), and to no new coal plants anywhere;”
  • Cars: “commit to ensuring all new car and van sales are zero emission vehicles by 2035 (advanced markets) or 2040 (all other markets);”
  • Trees: “Taking concrete steps to halt and reverse deforestation”

The “cash” priority is to provide the $100 billion/year of climate finance to developing countries. There are other aims, including adapting to climate change and setting up global carbon markets, but those above are the most commonly discussed.

  1. Thanks Tamsin for your very informative article.
    My concern with all the debate and number crunching is that we are distracted from the main point that burning stuff needs to be stopped as soon as possible.
    This requires; no investment in fossil fuels, no new FF, big tax on FF.
    Other measures can follow (using revenue from the tax)
    Due to the latent heat of fusion, we won’t see the restoration of glacial or arctic ice for millennia, so our current situation is precarious.
    Sorry, this not the kind of response you were looking for.

  2. A quick list of the extra things I did while up there (partly for my own reference):

    Monday 8th Nov

    “INSIDE:COP26” podcast by Sophie Schnapp for Clyde Built Radio (from 12:00):

    Tuesday 9th Nov

    Interviewed on camera by Joe Goodman of Carbon Brief for this piece, but didn’t make the cut (sorry! was too tired after my event to be coherent/interesting/specific):

    But I made it onto BBC Radio 4 Newscast, talking about the new Climate Action Tracker update (starts 10:40):

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