2023 IPCC AR6 Summary For Policymakers: Last Warning

AR6 Synthesis Report

The Synthesis Report of the IPCC Sixth Assessment Report (AR6) has recently been released including a detailed 36-page Summary for Policymakers. Section A summarizes what is known of the observed warming, its causes and impacts. However just three short quantitative sentences allow readers to determine that there are only about 10 and 20 years to go before we reach warming of plus 1.5C and plus 2.0C, respectively, at the present rate of unchecked greenhouse gas (GHG) pollution.

Further, with the  continuing  global “Business As Usual” (BAU) the remaining 500 GtCO2-eq (500 billion tonnes of CO2-equivalent) “carbon budget”,  determined in 2020 for “a 50% likelihood of  limiting global warning to 1.5C” [1],  will be used up in a mere 7 years (i.e. in 2027 or in 4 years’ time). These quantitative estimates show that we are very badly running out of time to deal with the worsening climate emergency. Indeed atmospheric carbon dioxide (CO2) and methane (CH4) levels continue to rise at a record rate [1, 2].

Before succinctly addressing these quantitative estimates deriving directly from data in the AR6 Summary for Policymakers [1], it is useful to summarize the key findings on the causes  and impacts of the present warming  by means of edited quotes  from Section A of the report:

(1). Global warming causes and impacts.

The following are edited quotes from section A  of the Summary for Policymakers [1] that indicate the damage that is already being inflicted by climate change on Humanity and the Biosphere.

“(A). Current Status and Trends. Observed Warming and its Causes

A.1 Human activities, principally through emissions of greenhouse gases, have unequivocally caused global warming, with global surface temperature reaching 1.1°C above 1850–1900 in 2011–2020. Global greenhouse gas emissions have continued to increase, with unequal historical and ongoing contributions arising from unsustainable energy use, land use and land-use change, lifestyles and patterns of consumption and production across regions, between and within countries, and among individuals…

A.1.4 Global net anthropogenic GHG emissions have been estimated to be 59±6.6 GtCO2-eq in 2019, about 12% (6.5 GtCO2-eq) higher than in 2010…

A.2 Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred. Human-caused climate change is already affecting many weather and climate extremes in every region across the globe. This has led to widespread adverse impacts and related losses and damages to nature and people… Vulnerable communities who have historically contributed the least to current climate change are disproportionately affected…

A.2.1 It is unequivocal that human influence has warmed the atmosphere, ocean and land. Global mean sea level increased by 0.20 [0.15–0.25] m between 1901 and 2018… Evidence of observed changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical cyclones, and, in particular, their attribution to human influence, has further strengthened since AR5…

A.2.2 Approximately 3.3–3.6 billion people live in contexts that are highly vulnerable to climate change. Human and ecosystem vulnerability are interdependent. Regions and people with considerable development constraints have high vulnerability to climatic hazards. Increasing weather and climate extreme events have exposed millions of people to acute food insecurity and reduced water security, with the largest adverse impacts observed in many locations and/or communities in Africa, Asia, Central and South America, LDCs, Small Islands and the Arctic, and globally for Indigenous Peoples, small-scale food producers and low-income households. Between 2010 and 2020, human mortality from floods, droughts and storms was 15 times higher in highly vulnerable regions, compared to regions with very low vulnerability…

A.2.3 Climate change has caused substantial damages, and increasingly irreversible losses, in terrestrial, freshwater, cryospheric, and coastal and open ocean ecosystems… Hundreds of local losses of species have been driven by increases in the magnitude of heat extremes … with mass mortality events recorded on land and in the ocean… Impacts on some ecosystems are approaching irreversibility such as the impacts of hydrological changes resulting from the retreat of glaciers, or the changes in… Arctic ecosystems driven by permafrost thaw…

A.2.4 Climate change has reduced food security and affected water security, hindering efforts to meet Sustainable Development Goals… Ocean warming and ocean acidification have adversely affected food production from fisheries and shellfish aquaculture in some oceanic regions…Roughly half of the world’s population currently experience severe water scarcity for at least part of the year due to a combination of climatic and non-climatic drivers…

A.2.5 In all regions increases in extreme heat events have resulted in human mortality and morbidity… The occurrence of climate-related food-borne and water-borne diseases… and the incidence of vector-borne diseases… have increased. In assessed regions, some mental health challenges are associated with increasing …  trauma from extreme events… and loss of livelihoods and culture… Climate and weather extremes are increasingly driving displacement in Africa, Asia, North America…  with small island states in the Caribbean and South Pacific being disproportionately affected relative to their small population size…

A.2.6 Climate change has caused widespread adverse impacts and related losses and damages to nature and people that are unequally distributed across systems, regions and sectors. Economic damages from climate change have been detected in climate-exposed sectors, such as agriculture, forestry, fishery, energy, and tourism. Individual livelihoods have been affected through, for example, destruction of homes and infrastructure, and loss of property and income, human health and food security, with adverse effects on gender and social equity.

A.2.7 In urban areas, observed climate change has caused adverse impacts on human health, livelihoods and key infrastructure. Hot extremes have intensified in cities. Urban infrastructure, including transportation, water, sanitation and energy systems have been compromised by extreme and slow-onset events, with resulting economic losses, disruptions of services and negative impacts to well-being. Observed adverse impacts are concentrated amongst economically and socially marginalised urban residents…” [1].

Things will only get worse, and especially for the global poor in Developing Countries who are already suffering the greatest impacts [1] but have contributed least of all to GHG pollution as set out in Gideon Polya,  “Climate Crisis, Climate Genocide & Solutions” [2].

(2). Three short, key sentences in the 36-page Summary for Policy Makers enable estimates of the time line to catastrophe.

In relation to the proposition “We are running out of time”  the  key  statements in  the Summary for Policy Makers are as are as follows: “A.1.4 Global net anthropogenic GHG emissions have been estimated to be 59±6.6 GtCO2-eq in 2019, about 12% (6.5 GtCO2-eq) higher than in 2010” … B.5.2 For every 1000 GtCO2 emitted by human activity, global surface temperature rises by 0.45°C… The best estimates of the remaining carbon budgets from the beginning of 2020 are 500 GtCO2 for a 50% likelihood of limiting global warming to 1.5°C and 1150 GtCO2for a 67% likelihood of limiting warming to 2°C” [1].

The following 3 sections 3-5 use this information to estimate the years left before critical targets are exceeded.

(3). Business As Usual (BAU) estimates of plus 1.55C by 2034 and plus 2C by 2043

Assuming the estimates given by the IPCC AR6 report, and assuming  Business As Usual (BAU) when will we  reach a disastrous plus 1.5C and a catastrophic plus 2.0? In short, we will reach plus 1.55C in 2034 (i.e. in 11 years’ time) and a catastrophic plus 2C in 2043 (i.e. in 20 years’ time). The calculation is as follows:

The IPCC Sixth Assessment Report (AR6) Summary for Policymakers states: “A.1.4 Global net anthropogenic GHG emissions have been estimated to be 59±6.6 GtCO2-eq in 2019, about 12% (6.5 GtCO2-eq) higher than in 2010…” and further states that “B.5.2 For every 1000 GtCO2 emitted by human activity, global surface temperature rises by 0.45°C” [1].

Assuming a constant growth rate of the global greenhouse gas (GHG) pollution of plus 12% per decade, the annual GHG pollution in Gt CO2-equivalent (Gt CO2-eq) was 59 (2019), 66.1 (2029), 74.0 (2039), and 82.9 (2049).

The average annual GHG pollution in Gt CO2-eq  was 62.6 (2020s), 70.1 (2030s) and 78.5 (2040s).

From this we can readily estimate that an extra 1000 Gt CO2-eq would have to be emitted so that a plus 1.1C + 0.45C = plus 1.55C would be reached in 2034 (in 11 years’ time).

Similarly, a further 1,000 Gt CO2-eq would have to be emitted so that  a plus 1.55C + 0.45C =  plus 2C would be reached in 2043 (in 20 years’ time).

(4). Check and revision: methane-based revised Business As Usual (BAU) estimates of plus 1.55C by 2033 (10 years’ time) and a catastrophic plus 2C by 2042 (19 years’ time).

In 2009 World Bank analysts Robert Goodland and Jeff Anfang revised global GHG pollution upwards by properly considering animal production and land use: “When uncounted tons are added to the global inventory of atmospheric GHGs, that inventory rises from 41,755 million tons to 63.803 million tons [CO2-eq]”  [3] i.e. 63.803 x 0.907 = 57.9 billion tonne = 57.9 Gt CO2eq.

Assuming a constant growth rate of the global greenhouse gas (GHG) pollution of plus 12% per decade, the annual GHG pollution in  Gt CO2-equivalent (Gt CO2-eq) was 57.9  (2009),  64.8 (2019), 72.6 (2029), 81.3  (2039), and 91.1 (2049).

The average annual GHG pollution in Gt CO2-eq  was 61.4 (2010s), 68.7 (2020s), 77.0 (2030s), and 86.2 (2040s).

From this we can roughly estimate that an extra 1000 Gt CO2-eq (giving an extra 0.45C)  would have to be emitted so that a plus 1.1C + 0.45C = plus 1.55C would be reached in 2033 i.e. (in 10 years’ time).

Similarly a further 1,000 Gt CO2-eq would have to be emitted so that  a plus 1.55C + 0.45C =  plus 2C would be reached in 2042 (i.e. in 19 years’ time).

(5). With BAU the remaining 500 GtCO2-eq  carbon budget determined in 2020 for a 50% likelihood of  limiting global warning to 1.5C will be used up in 7 years (i.e. in 2027 or in 4 years’ time). 

Using the data in (4) above, the average annual GHG pollution was  68.7 Gt CO2-eq  in the 2020s, and the remaining 500 GtCO2-eq carbon budget in 2020 for a 50% likelihood of  limiting global warning to 1.5C will be used up in 500 GtCO2-eq  /(68.7 GtCO2-eq per year) = 7.3 years or about 7 years (i.e. by 2030).

Thus an inspired and idealistic young scientist determined to help  save the world, and enrolling at a university in 2020 for successive relevant undergraduate and postgraduate degrees, could  be submitting his/her  PhD thesis in 2027, precisely when the carbon budget runs out.

Further, the carbon budget of “1150 GtCO2-eq for a 67% likelihood of limiting warming to 2°C” [1] will be used up in roughly 1150 GtCO2-eq  /(72.9 GtCO2-eq per year) = 15.8 years or about 16 years (i.e. by 2036 ,  in a mere 13 years ).

Of course, the obvious question remains: would you board a plane if it had a 67% or 50% chance of crashing? Unfortunately, as outlined above  we are running out of time, and there is no Planet B.

(6).  The Summary for Policymakers refers to the need for carbon dioxide removal (CDR) but not to its cost (the Carbon Price) nor the required transparency.

The Summary for Policymakers: “ B5.1… Reaching net zero GHG emissions primarily requires deep reductions in CO2, methane, and other GHG emissions, and implies net-negative CO2 emissions. Carbon dioxide removal (CDR) will be necessary to achieve net-negative CO2 emissions (see B.6)” [1]. However there is no mention of the cost of CDR i.e. of the Carbon Price. According to Professor James Hansen (Columbia) the cost of CDR by an advanced system is $200 per tonne CO2-eq [4]. Consonant with this estimate is the damage-related Carbon Price of $200 per tonne CO2-eq estimated by Dr Chris Hope (Cambridge) [5]. Indeed the International Monetary Fund (IMF) has recommended urgent action to get to a Carbon Price of $75 per tonne CO2-eq emplaced globally, noting that the average global applied Carbon Price is a mere $2 per tonne CO2-eq [6, 7].

The fundamental reason for the appalling global inaction in the worsening Climate Crisis is that governments are presently simply not prepared to recognize, let alone address or meet, the full damage-related cost of greenhouse gas (GHG) pollution, otherwise known as the damage-related Carbon Price. In this terracidal (Earth killing) failure world governments are ignoring the advice of  science-trained Pope Francis in Section 195 of his 2015 encyclical “Laudato si’”: “Yet only when the economic and social costs of using up shared environmental resources are recognized with transparency and fully borne by those who incur them, not by other peoples or future generations,’ can those [economic] actions be considered ethical” [8-11]. Governments also continue to ignore  the crucial advice on “economic externalities” by eminent economist Sir Nicholas Stern (2007): “The problem of climate change involves a fundamental failure of markets: those who damage others by emitting greenhouse gases generally do not pay. Climate change is a result of the greatest market failure the world has seen. The evidence on the seriousness of the risks from inaction or delayed action is now overwhelming. We risk damages on a scale larger than the two world wars of the last century. The problem is global and the response must be a collaboration on a global scale” [2, 12, 13].

The existential dilemma facing  Humanity is succinctly stated by eminent physicist and one of the world’s greatest minds, eminent physicist the late Stephen Hawking (2018): “We see great peril if governments and societies do not take action NOW [my emphasis] to render nuclear weapons obsolete and to prevent further climate change” [2, 14]. The successive Reports of the Intergovernmental Panel on Climate Change (IPCC) have suffered from being consensus documents in which assertions are  qualified by statements such as “very high confidence”, “high confidence”, and “medium confidence”.  It is a pity that the fundamental reason for the climate crisis – lack of transparency over the Carbon Price – was not mentioned in the Summary for Policymakers.

The 2015 Paris Climate Change Conference committed to ideally less than a plus 1.5 degree Centigrade (+1.5C) temperature rise, and to no more than a catastrophic +2C. The  2021 Glasgow Climate Change Conference committed to “net zero emissions by 2050”. However presently there is still no decrease in our record greenhouse gas (GHG) pollution, gas, oil, and coal use, or cattle, cement, steel and iron ore production. We are surely doomed by remorseless inaction. There is no decrease in our presently peak global production of coal and methanogenic cattle. The atmospheric carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) are remorselessly increasing at record rates, as are oil and  gas use. Coal use has recently resumed increasing after flattening at a maximum rate in several COVID-19 Pandemic years. Greenhouse gas (GHG) producing cement, steel, and iron ore production are all increasing. Humanity should be radically decreasing these terracidal activities but, political rhetoric aside, is damning the planet through  catastrophic global inaction. The biodiversity loss is increasing catastrophically with a species extinction rate (speciescide rate) that is 100-10,000 times greater than the background extinction rate. While the rate of deforestation has decreased 3-fold since 1980, and net re-afforestation of temperate forests is now occurring, the deforestation rate in tropical forests levelled out to an appalling 50 million hectares per decade over the last 2 decades [15]. Unless something radical happens we are doomed, the planet is doomed, and Humanity and the Biosphere face decimation. Tackling climate change means decreasing and not increasing GHG pollution. In vain the climate scientists and biologists report the worsening realities, and plead for action with increasing desperation [2, 15-18].

UN Secretary General Antonio Guterres gave a stark warning at the November 2022 COP27 conference: “We are on a highway to climate hell with our foot still on the accelerator. To acknowledge the harsh truth, there is no excellencies. This UN climate conference is a reminder that the answer is in our hands. And the clock is ticking. We are in the fight of our lives, and we are losing. Greenhouse gas emissions keep growing, global temperatures keep rising, and our planet is fast approaching tipping points that will make climate chaos irreversible” [19, 20].

In March 2023 a passionate  Antonio Guterres commented thus on the latest IPCC AR6 Report  that has been described as a “last warning” to Humanity: “Our world is at a crossroads – and our planet is in the crosshairs. We are nearing the point of no return, of overshooting the internationally agreed limit of 1.5 degrees Celsius [2.7 degrees Fahrenheit] of global warming” [21].

As estimated here using data from the IPCC AR6 Report Summary for Policymakers, the 1.5C limit will be exceeded within 10 years if BAU continues. Despite 6 major Reports since the foundation of the IPCC in 1988, the atmospheric CO2 and CH4 continue to  rise at record rates. A despairing world await the year when  the atmospheric levels of these greenhouse gases (GHGs) will have finally started to decrease. The atmospheric CO2 is presently at a record level of about 420 parts per million (420 ppm) and increasing at a record rate but numerous scientists  demand a return to the pre-Industrial  Revolution level of about 300 ppm for a safe and sustainable  planet for all peoples and all species [2, 22, 23]. Articulate climate heroine Greta Thunberg has been reduced to a famous  and indignant “How dare you!” and more recently to “Blah, blah, blah” in relation to the politicians who are destroying the planet. Decent people must (a) inform everyone they can, and (b)  urge and apply Boycotts, Divestment and Sanctions (BDS) against all people, politicians, parties, collectives, corporations and countries disproportionately involved in  the ongoing climate criminality and  terracide, the destruction of ecosystems and life on this planet. There is no Planet B.


[1]. Synthesis Report of the IPCC Sixth Assessment Report (ARC), Summary for Policymakers: https://report.ipcc.ch/ar6syr/pdf/IPCC_AR6_SYR_SPM.pdf .

[2]. Gideon Polya,  “Climate Crisis, Climate Genocide & Solutions”, Korsgaard Publishing, Germany, 2020.

[3]. Robert Goodland and Jeff Anfang, “Livestock and Climate Change: What If the Key Actors in Climate Change Are Cows, Pigs, and Chicken?”, World Watch, November/ December 2009: https://awellfedworld.org/wp-content/uploads/Livestock-Climate-Change-Anhang-Goodland.pdf .

[4]. James Hansen, “Climate change in a nutshell: the gathering storm”, Columbia University, 18 December 2018: http://www.columbia.edu/~jeh1/mailings/2018/20181206_Nutshell.pdf  .

[5]. Chris Hope, “How high should climate change taxes be?”, Working Paper Series, Judge Business School, University of Cambridge, 2011: http://www.jbs.cam.ac.uk/fileadmin/user_upload/research/workingpapers/wp1109.pdf  .

[6]. Gideon Polya, “Australia Rejects  IMF Carbon Tax & Preventing  4 Million  Pollution Deaths By 2030”, Countercurrents, 15 October 2019: https://countercurrents.org/2019/10/australia-rejects-imf-carbon-tax-preventing-4-million-pollution-deaths-by-2030/ .

[7]. International Monetary Fund (IMF), “Fiscal Monitor: how to mitigate climate change”. Executive Summary”, September  2019: file:///C:/Users/Gideon/AppData/Local/Temp/execsum-6.pdf   .

[8]. Pope Francis , Encyclical Letter “Laudato si’”, 2015: http://w2.vatican.va/content/francesco/en/encyclicals/documents/papa-francesco_20150524_enciclica-laudato-si.html .

[9]. Gideon Polya, “Pope Francis Demands “Fully Borne” Cost of Pollution (Carbon Price) To Prevent “Millions Of Premature Deaths””, Countercurrents, 29 July, 2015: http://www.countercurrents.org/polya290715.htm .

[10]. Gideon Polya, “Green Left Pope Francis Demands Climate Action “Without Delay” To Prevent Climate “Catastrophe””, Countercurrents, 10 August, 2015: http://www.countercurrents.org/polya100815.htm .

[11]. Gideon Polya, “Western Mainstream Media Censor Green Left Pope Francis’ “Laudato Si’” Message For Urgent Action On Climate Change”, Countercurrents, 20 August, 2015: http://www.countercurrents.org/polya200815.htm .

[12]. Sir Nicholas Stern, quoted in Alison Benjamin, “Stern: climate change a “market failure”, UK Guardian, 29 November 2007: http://www.guardian.co.uk/environment/2007/nov/29/climatechange.carbonemissions .

[13]. Gideon Polya, “Detailed Document Exposing Pro-gas Australia Climate Change Inaction”, Countercurrents, 15 March, 2011: https://countercurrents.org/polya150311.htm .

[14].  Stephen Hawking, “Brief Answers to the Big Questions”, John Murray, UK, 2018.

[15]. Gideon Polya, “Planet Doomed: No Decrease In Record GHGs & Gas, Oil, Coal, Cattle, Cement & Steel Production”, Countercurrents, 16 October 2022: https://countercurrents.org/2022/10/planet-doomed-no-decrease-in-record-ghgs-gas-oil-coal-cattle-cement-steel-production/ .

[16]. Gideon Polya, “Extrapolating 11,000 scientists Climate Emergency warning to 2030 catastrophe”, Countercurrents,   14 November 2019: https://countercurrents.org/2019/11/extrapolating-11000-scientists-climate-emergency-warning-to-2030-catastrophe .

[17]. Gideon Polya, “Inescapable $200-250 trillion global Carbon Debt increasing by $16 trillion annually”, Countercurrents, 27 March 2019: https://countercurrents.org/2019/04/inescapable-200-250-trillion-global-carbon-debt-increasing-by-16-trillion-annually-gideon-polya/ .

[18]. “Carbon Debt Carbon Credit”: https://sites.google.com/site/carbondebtcarboncredit/ .

[19]. Schroders, “COP27 live blog”, November 2022: https://www.schroders.com/en/us/insights/sustainability/cop27–live-blog-schroders-investors-climate-change-net-zero/ .

[20]. “UN Secretary-General warns world ‘on a highway to climate hell’”, Video transcript, Yahoo News, 8 November 2022: https://au.news.yahoo.com/un-secretary-general-warns-world-032528599.html .

[21]. “‘Planet in the crosshairs’: UN chief demands rapid emission cuts”, Al Jazeera, 13 March 2023: https://www.aljazeera.com/news/2023/3/13/planet-in-the-crosshairs-un-chief-demands-rapid-emission-cuts .

[22]. “300.org – return atmosphere CO2 to 300 ppm CO2”: https://sites.google.com/site/300orgsite/300-org—return-atmosphere-co2-to-300-ppm .

[23]. 300.org: . https://sites.google.com/site/300orgsite/300-org .

Dr Gideon Polya taught science students at La Trobe University, Melbourne, Australia over 4 decades. He published some 130 works in a 5 decade scientific career, notably a huge pharmacological reference text “Biochemical Targets of Plant Bioactive Compounds”. He has also published “Body Count. Global avoidable mortality since 1950” (2007, 2022) and “Jane Austen and the Black Hole of British History” (1998, 2008, 2023). He has recently published “US-imposed Post-9-11 Muslim Holocaust & Muslim Genocide” (2020), and “Climate Crisis, Climate Genocide & Solutions” (2020), and contributed to Soren Korsgaard (editor) “The Most Dangerous Book Ever Published – Dangerous Deception Exposed!” (2020). For images of Gideon Polya’s huge paintings for the Planet, Peace, Mother and Child see: http://sites.google.com/site/artforpeaceplanetmotherchild/  .

Support Countercurrents

Countercurrents is answerable only to our readers. Support honest journalism because we have no PLANET B.
Become a Patron at Patreon

Join Our Newsletter


Join our WhatsApp and Telegram Channels

Get CounterCurrents updates on our WhatsApp and Telegram Channels

Related Posts

Permafrost Showdown

"Deep below the glistening surface of a frozen Arctic lake, something is bubbling—something that could cause global warming to accelerate beyond all previous projections… Now the freezer door is opening,…

Tracking toward mass extinction

Where “Two plus two equals five if the party says so” (George Orwell) and when drilling methane wells reduces global warming Having turned a blind eye to climate science, ignoring…

Surprising Rising Seas “Must Reads”

Sea levels are surging along the US coastline, exceeding 30-year expectations. Scientists are confused, concerned, searching for answers. In that regard, an excellent new series by The Washington Post d/d…

Join Our Newsletter

Annual Subscription

Join Countercurrents Annual Fund Raising Campaign and help us

Latest News