Arwa Aburawa is a filmmaker whose work focuses on race, the environment, and the enduring legacies of colonialism. www.arwaaburawa.co.uk
In his book ‘Exterminate All the Brutes’ (1), the writer Sven Lindqvist carefully and meticulously traces the European colonial legacy of extermination and genocide as he treks across North Africa. And yet, he starts the book with a simple quote:
You already know enough.
So do I.
It is not knowledge we lack.
What is missing is the courage to understand what we know and to draw conclusions.
As I look over the previous editions of the CO2 newsletter that Marc wants to explore and examine, I know his work is guided by one quest: to carefully and meticulously trace how long we’ve known about the carbon dioxide and global warming problem.
And yet, we all know that the answer, sadly, is much too long.
Kevin Anderson states that since the newsletter’s publication, “humanity has become extraordinarily adept at observing and quantifying the world it is reshaping. With increasing accuracy, we can measure, model, and project the climate system, supported by ever more sensitive instruments, richer datasets, and stronger scientific confidence. Yet this growing clarity has not led to restraint or correction.” Michiel van den Broeke, reflecting on an article on glacial melts in the third edition states that it was “remarkably accurate.” So all the newsletters reveal, in great detail, is how even back in the 1980s we knew enough.
You did. And so did I. So it is not knowledge we lack.
But courage to understand what we know and to draw conclusions.
What does it mean to understand what we know and draw conclusions in this context?
It means to take action. To transform ourselves and our societies.
It’s to ask the same question the writers of this newsletter asked, to ask the same question Dr Abi Perrin asked, the same question that Marc’s work is ultimately shaped by: When should the studying stop and political action begin?(2)
The newsletter once again gives us another answer; long ago.
And yet here we are. So once again we are forced to look for the courage to ask why we have failed to take action and draw conclusions about that too.
When Lindqvist asks himself to draw conclusions and confront a reality he already knew – the roots of European colonialism, white supremacy, and genocide – he asks himself to really know and understand his society. To understand what is at the heart of his world and what drives it.
We must find a way to do the same thing. To confront the murderous, genocidal, white supremacist society which continues to accept the horrendous consequences of the climate crisis. A society where billionaire elites fight information, fact and science not with countering information but with a steady stream of confusion and distraction to destabilize us and rob us of any real clarity of what we might do next.
Ruth Wilson Gilmore defined racism as a premature exposure to death(2). I think that its also a fitting definition for the climate crisis and global warming. Colonialism never went away. It is here with us right now. It’s mutated, evolved into the same world which has failed to act on the climate crisis,
And so it’s time, once again, to look for that courage Lindqvist talked about, and draw conclusions.
(1) A book Marc introduced me to many, many years ago now
(2) I think it’s rather telling that the first option mentioned in the newsletter as a course of action for Energy and environmental planners in the U.S. was to “Postpone the decision to halt the CO, buildup (inaction itself may be a form or action)”
Michiel van den Broeke, Professor of Polar Meteorology at Utrecht University (longer bio at end of post) very kindly agreed to read William Barbat’s article “Glacier melt: How soon? How fast?” and explain what Barbat got right (and wrong) and where the science has gone in the almost 50 years since then. It’s a brilliant (imo) piece, and I hope you learn as much as I did. Please do share it, comment on it.
Professor van den Broeke
In the March 1980 edition of the CO2 NEWSLETTER, William Barbat reported about the threat of melting ice sheets and the rapid, multi-metre sea level rise that could ensue. Undoubtedly, Barbat had been triggered by the 1978 scientific publication of British glaciologist John Mercer (1922-1987), then employed at (what would later become) the Byrd Polar Research Centre of Ohio State University (Mercer, 1978). In his Nature article: “West Antarctic ice sheet and CO2greenhouse effect: a threat of disaster“, Mercer pointed out that the increase in CO2 concentration in the Earth’s atmosphere caused by the burning of fossil fuels would result in strong Antarctic warming, potentially leading to the disintegration of the large Ross and Filchner-Ronne ice shelves. In the absence of their buttressing effect, the West Antarctic ice sheet would collapse, raising global sea levels by several metres.
Today’s cryospheric research relies heavily on three complementary techniques: in situ observations, satellite observations and numerical models. In situ observations are often scattered in space, but to their credit have relatively long time series (typically decades in the Polar Regions), indispensable for trend detection. They moreover provide ground truth for satellites and serve to evaluate/calibrate climate and ice sheet models. Satellites, on the other hand, with their limited mission lifetime of typically 5-10 years, produce short time series, but they have the advantage of near-complete spatial coverage, filling in the spatial gaps left by the in situ observations. Numerical models, once evaluated and/or calibrated with the in situ and remotely sensed observations, can help us isolating the physical processes at work and, when they perform satisfactorily, make credible future projections.
When Mercer published his study almost 50 years ago, he had to make do with very limited observations and crude models. Although the density of in situ observations in the polar regions increased sharply after the 1957/58 International Geophysical Year (IGY, also referred to as the Third International Polar Year), observations remained very scarce notably in the ice sheet interiors. While some satellites for earth observation, notably Landsat, were available at that time, time series were less than a decade long. For Earth’s cryosphere, the satellite era started in earnest more than a decade later, with the launch of European Space Agency‘s radar-equipped ERS-1 in 1991. Finally, in the late 1970’s, climate and ice sheet models were still in their infancy; the model projections of future Antarctic warming used in Mercer’s study were from Syukuro Manabe, who in 2021 was co-awarded the Nobel prize in Physics for his pioneering contributions to climate modelling.
In spite of this, both Mercer’s 1978 Nature paper and William Barbat’s 1980 report in the CO2NEWSLETTER highlight the remarkable body of knowledge on the world’s ice sheets that had been gathered. Their reported total volume expressed in sea level rise equivalent of 66 m only deviates by 1% from today’s numbers1. Estimates of sea level stands of 6 m above present during the last interglacial (~125.000 years ago) fall well within the range of current estimates (6 to 9 m) (Dutton et al., 2015). Other remarkably accurate statements concern the approximately 50/50 partitioning of meltwater runoff and iceberg calving as sink terms in the mass balance of the Greenland ice sheet and the importance of ice shelf buttressing for grounded ice flow in Antarctica, which decades later was observationally confirmed after the sudden disintegration of Larsen B ice shelf in 2002 (Scambos et al., 2004). Mercer also correctly identified the apparent temperature threshold for the viability of Antarctic ice shelves, later corroborated by the demise of Antarctic Peninsula ice shelves after several decades of strong warming (Morris & Vaughan, 2013; Scambos et al., 2004). Also recently been confirmed is Mercer’s statement that a 5 K atmospheric warming could destabilize parts of the large Ross and Filchner-Ronne ice shelves (Van Wessem et al., 2023).
Inevitably, these early reports also have flaws and large uncertainties, which the authors frankly admit. Lacking direct observations, and realising that around 1980 mass changes of both ice sheets were significantly smaller than they are today (IMBIE, 2018, 2020), not much could be said about the magnitude of mass loss of the ice sheets, let alone the processes that caused them. It would take the launch in 2002 of the satellite pair of the Gravity Anomaly and Climate Experiment (GRACE) before mass loss from both ice sheets was convincingly demonstrated (Velicogna & Wahr, 2005; Velicogna, 2006). GRACE also showed that the recent mass loss in Antarctica is concentrated in the Amundsen and Bellingshausen Seas sectors, and is associated with ice shelf thinning owing to increased ocean melting at their base, rather than weakened buttressing of the Ross and Filchner-Ronne ice shelves. Making projections based on scanty information proved even harder. Mercer’s assumption that CO2 concentration in the atmosphere would double in 50 years was too pessimistic: atmospheric CO2 levels increased by 26%, from 337 to 426 parts per million, between 1979 and 2025. As a result, Antarctic warming remains far from the values reported in his paper.
This begs the question: if we were in Mercer’s shoes today, would we do much better in projecting the future of the Earth’s big ice sheets? Based on the latest IPCC report (IPCC, 2021), my take is that the uncertainties are still surprisingly large and not so dissimilar to what they were in 1978. Since then, our knowledge and technical (observational, modelling) capabilities have of course expanded tremendously, but we have also identified numerous new unknowns. The net result is that future ice sheet mass change and associated sea level rise remain highly uncertain, and that we still may be in for unpleasant surprises from nonlinear processes leading to tipping points that are currently not or poorly understood. Given the complex interactions between atmosphere, ocean and ice sheets that straddle several orders of magnitude in temporal and spatial scales, it is clear that this deep uncertainty will not be resolved anytime soon. It thus seems fitting to conclude with the statement made by Mercer in his 1978 paper, which still firmly stands: “…despite the crudities and inadequacies of present techniques for modelling the climatic effects of increasing atmospheric CO2content and the resultant doubts […], we cannot afford to let the atmosphere carry out the experiment before taking action because if the results confirm the prognosis, and we should know one way or the other by the end of the century, it will be too late to remedy the situation…”.
Bibliography
Dutton, A., Carlson, A. E., Long, A. J., Milne, G. A., Clark, P. U., DeConto, R., Horton, B. P., Rahmstorf, S., & Raymo, M. E. (2015). SEA-LEVEL RISE. Sea-level rise due to polar ice-sheet mass loss during past warm periods. Science, 349(6244), aaa4019. https://doi.org/10.1126/science.aaa4019
IPCC. (2021). Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.), Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. https://doi.org/10.1017/9781009157896.
Morris, E. M., & Vaughan, D. G. (2013). Spatial and Temporal Variation of Surface Temperature on the Antarctic Peninsula And The Limit of Viability of Ice Shelves. In Antarctic Peninsula Climate Variability: Historical and Paleoenvironmental Perspectives (pp. 61-68). https://doi.org/10.1029/AR079p0061
Scambos, T. A., Bohlander, J. A., Shuman, C. A., & Skvarca, P. (2004). Glacier acceleration and thinning after ice shelf collapse in the Larsen B embayment, Antarctica. Geophysical Research Letters, 31(18). https://doi.org/10.1029/2004gl020670
Van Wessem, J. M., Van den Broeke, M. R., Wouters, B., & Lhermitte, S. (2023). Variable temperature thresholds of melt pond formation on Antarctic ice shelves. Nature Climate Change. https://doi.org/10.1038/s41558-022-01577-1
Velicogna, I. a. J. W. (2006). Measurements of Time-Variable Gravity Show Mass Loss in Antarctica. Science, 311(5768), 1754-1756. https://doi.org/DOI: 10.1126/science.1123785
Footnotes
1 Combining radar flight lines of ice thickness with mass conservation provide us with accurate estimates of the sea level equivalent volumes of the ice sheets of Greenland (7.4 m) and Antarctica (57.8 m), (Morlighem et al., 2017; Morlighem et al., 2019).
Michiel van den Broeke (Rotterdam, 1968) has been Professor of Polar Meteorology at Utrecht University since 2008, where he studies the interaction between the climate and the large ice sheets of Antarctica and Greenland. Between 2016 and 2022, Michiel served as Scientific Director of the Institute for Marine and Atmospheric Research Utrecht (IMAU), where around 90 people work on developing a fundamental understanding of all components of the climate system.
From 1979 to 1982 American geologist William N. Barbat published 18 issues of the CO2 Newsletter. His family have kindly supplied copies and given permission for these to be digitised and shared. Every three weeks or so, an issue will be uploaded. To accompany each issue there will be a brief commentary. For the second issue, Dr Abi Perrin (see interview here) has written with her customary clarity, insight and honesty.
Dr Abi Perrin
The second installment of William Barbat’s CO2 newsletter continues his mission to “aid enlightenment on the CO2 problem, to promote constructive and timely solutions, to reduce disagreement and to encourage cooperation”. It expands on the warnings distilled in the first issue and continues to cut through the noise of scientific discussions ongoing at the time, summarising them succinctly and effectively.
Barbat brings the role of ecosystems such as forests and oceans into focus, turning attention to the attractive idea that natural carbon sinks could “relegate the CO2 problem to a reversible status”. Detailing how a growing consensus amongst scientists was unfortunately not so optimistic, he surmises that “there is no safe allowable rate of CO2 output which could prevent temperature thresholds from being reached. Rather every single contribution of CO2 is likely to have a long-lasting effect.”
With an air of hopefulness and conviction that now feels enviable, Barbat seems confident that the dawn of the 1980s would be an inflection point, stating that his newsletter intends to be “informative of an impending revolutionary change to leaders in government and industry.” He celebrates the presentation of a report (an “impartial examination of the validity of CO2 forecasts”) to President Carter’s science adviser as a moment of progress: the next step towards the consideration of global warming in US energy policy.
Amidst optimism, he is not blind to some of the hurdles on the route to action and change. “The revolutionary energy policies which are now being considered by the scientific community to bring the CO2 buildup to an early halt would require much more cooperation between government and business than appears to exist”, he acknowledges. In his discussions of carbon sinks and their capacity (or lack thereof) to reverse the “CO2 problem” he seems to realise how alluring the more convenient or comforting ‘interpretations’ of the science can be, in a way that feels prescient of many of the popular narratives that have delayed necessary accountability and action to this day.
Looking back from 2026, a time where a rapid worldwide transition to renewable power is considered feasible and highly cost-effective, Barbat’s skepticism about the future of wind and solar is one thing that ages his writing. But perhaps the biggest is this: “Fortunately, the CO2 problem has not become an adversary issue. This issue is being treated rationally in the scientific community, in the news media, and in politics.” He identifies apathy as a problem – that’s still with us, but 46 years later we also have to contend with widespread, mounting adversariality and irrationality. In recent months we’ve seen not just denial but effective censorship of basic climate science in the US, while in UK newspapers the volume of editorials attacking climate action overtook those supporting it. Meanwhile global greenhouse gas emissions continue to rise defiantly, we continue to trash the lands and oceans that buffer us from even-more-deadly impacts, and announcements that we have passed specific points-of-no-returnreceive little attention.
There were many passages and statements in this newsletter that are frustrating and depressing by virtue of their relevance and repetition ever since. Lurking in one of the ‘Excerpts from recent reports’ was this one: “The problem facing us today is this: When should the studying stop and political action begin?” To see this kind of sentiment expressed a decade before I was born, 30 years before I cheerfully embarked on a career in scientific research, felt especially jarring. A very similar question motivated my exit from academia: was I describing a dying world at the expense of acting to protect it?
Reading these CO2 newsletters caused me to ask myself another uncomfortable question, about the communication work I’m involved with now: am I replicating the approach Barbat and others took for decades, but expecting different results? Concerted action on climate and nature must be empowered and underpinned by knowledge, but even with deadly impacts on our doorstep we cannot put our faith in awareness alone leading to proportionate, rational responses.
I have a list of people I am inviting to provide commentaries (you may be on it – nominate yourselves or other people!) I would send a pdf of the relevant issue and you read it then write (or draw? make a video? a song?) 600-900 words in response, to be published just after the issue goes up.
From 1979 to 1982 American geologist William N. Barbat published 18 issues of the CO2 Newsletter. His family have kindly supplied copies and given permission for these to be digitised and shared. Every three weeks or so, an issue will be uploaded. To accompany each issue there will be a brief commentary. First up, Professor Kevin Anderson, professor of energy and climate change at the Universities of Manchester (UK) and Uppsala (Sweden).
In the first edition of William Barbat’s CO2 Newsletter, he translates specialist climate research into accessible language, tracing the unchecked rise of atmospheric carbon dioxide, its primary cause in fossil fuel combustion, and its likely consequences, including “impending famine and social and political upheaval.” The edition offers a measured snapshot of contemporary understanding, written to “fill the communications gap” and inform the public and policymakers; all premised on the hopeful belief that knowledge would prompt action.
In the closing section of the Newsletter, Barbat turns to his two principal “solutions”, both aimed at reducing and ultimately eliminating fossil fuel use: constraining the growth of energy demand and the rapid deployment of nuclear power. Yet more significant than these, is the social and political context he sees as essential for any rational response. “Empathy and trust must be restored between politicians, administrators, businessmen[sic], and activist groups if the CO2 buildup is to be halted in timely fashion … When heated arguments give way to cool logic, we find that the overall goals of conservationists, humanists, and industrialists actually converge to represent the desires … of a fully enlightened public.” For Barbat, reason, cooperation, and compassion are not optional add-ons; they are prerequisites for action at the necessary scale.
Barbat’s calm, almost reassuring tone sits in stark contrast to the severity of his conclusions. He warns that “Nothing short of revolutionary changes in energy production and usage appear capable of averting the adverse impacts which are expected.” He is equally unambiguous about the dangers of delay: “If we wait to let the atmosphere perform the carbon dioxide experiment, … it will be too late to do much about it”. He frames the issue as a moral one: “If we harbor any sense of responsibility toward preserving spaceship Earth, and toward the welfare of our progeny, we can scarcely afford to leave the carbon dioxide problem to the next generation.”
Yet here we are in 2026. We have pumped an additional 1.5 trillion tonnes of carbon dioxide into the atmosphere (from fossil fuels and land use) and the combustion of oil, gas and even coal continue their seemingly relentless rise. Instead of “empathy and trust” we have chosen delusion, misinformation and lies. Worse still, this failure has spread into expert communities, where magical thinking is increasingly invoked to prop up an unstable status quo or is quietly endorsed through collective silence. The laws of physics, however, remain unmoved by rhetoric or omission.
Since the Newsletter’s publication, humanity has become extraordinarily adept at observing and quantifying the world it is reshaping. With increasing accuracy, we can measure, model, and project the climate system, supported by ever more sensitive instruments, richer datasets, and stronger scientific confidence. Yet this growing clarity has not led to restraint or correction. Instead, it has coincided with a profound inability to act on the damage we fully understand and knowingly accelerate, paralysed not by ignorance, but by convenience, power, and habit.
This is the defining contradiction of our age: a species capable of extraordinary insight, yet seemingly incapable of acting in its own long-term interest. Whether this failure is a temporary lapse or a terminal condition remains unresolved. History, and geology, will render the verdict. Humanity may yet prove itself resilient and adaptive. Or we may simply degrade into a genetic cul-de-sac: a brief, unmistakable stratum in the fossil record, marking a civilisation that could chart its own collapse with exquisite precision, issue increasingly urgent warnings to itself, and still choose, again and again, not to listen.
I have a list of people I am inviting to provide commentaries (you may be on it – nominate yourselves or other people!) I would send a pdf of the relevant issue and you read it then write (or draw? make a video? a song?) 600-900 words in response, to be published just after the issue goes up.
