Exceeding 1.5°C Global Warming Could Trigger Multiple Climate Tipping Points
Science, 2022 · paper · Earth science
Reassesses climate tipping elements and the warming thresholds at which they tip. It finds current warming of about 1.1°C is already within some uncertainty ranges, and that six tipping points become likely at 1.5 to under 2°C.
Checked: PDF from dspace.library.uu.nl, fetched 4 Oct 2026. Page numbers are those of that PDF.
11 findings
Substance LABC/SPG: "GMST feedback of ~0.5°C (regional ~−3°C) (low confidence)" lacks the minus sign; Table 1 gives the global impact as "-0.50", so it should read ~−0.5°C.
- p. 7 LABC section, best estimates sentence
back of ~0.5°C (regional ~−3°C) (low confidence)
- p. 5 Table 1, LABC row, Maximum impact Global
-0.50
- p. 7 LABC section
potential global cooling of
- p. 7 LABC paragraph, last sentence
GMST feed-back of ~0.5°C (regional ~−3°C)
Judge's note: Page 7 crop shows "~0.5°C" with no sign while the regional value right beside it shows "~−3°C", so this is not a lost glyph. Table 1 (page 5 crop) has -0.50 global and -3.0 regional for LABC. The other cooling feedbacks carry their signs in the text (AMOC "−0.5°C", BORF "~−0.18°C"), and warming ones carry "+". The surrounding paragraph speaks of cooling, which limits the harm, but the printed value has the wrong sign as written.
Second check: another model agreed
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Substance BORF: "[regional ~−0.5 to 2°C (low confidence)]" lacks the minus sign on the upper bound; Table 1 gives "-0.5 to -2", so it should read ~−0.5 to −2°C.
- p. 8 Boreal forest BORF
[regional ~−0.5 to 2°C (low confidence)]
- p. 5 Table 1 BORF
-0.5 to -2
Judge's note: Page 8 crop shows "~−0.5 to 2°C" with a minus only on the first number; Table 1 (page 5 crop) shows "-0.5 to -2". The paper does not use a shared-sign shorthand for negative ranges: the AMOC sentence prints both signs ("regional −4 to −10°C"). As written the range reads as spanning zero up to +2°C.
Second check: another model agreed · checked by hand
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Reference or label "alongside potential tipping points in table 4.10 of (23) and box 12.1 in table 1 of (28)": box and table are transposed; a table sits inside a box, so it should read "table 1 in box 12.1 of (28)".
- p. 4 (Ir)reversibility section
box 12.1 in table 1 of (28)
Judge's note: Page 4 crop shows the text as quoted. A box cannot be inside a table, and the parallel pointer in the same sentence uses the normal "table 4.10 of (23)" form. The exact title of the box in the cited IPCC chapter cannot be checked from the files, but the nesting as printed is malformed either way.
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Reference or label TUND: "leads to a net GMST feedback of +0.14°C per °C (regional ~+0.5 to 1°C)", whereas Table 1 gives the TUND global impact as an absolute "-6 GtC / net +0.14°C"; the "per °C" appears to be a wrong unit.
- p. 8 Boreal forest (BORF/TUND) section, last sentence
to a net GMST feedback of +0.14°C per °C
- p. 5 Table 1, TUND row, Maximum impact Global
+0.14°C
Only the authors can say what is right here.
Judge's note: Page 8 crop shows "+0.14°C per °C". Table 1 (page 5 crop) lists "net +0.14°C" under "Maximum impact (°C)", and its footnote reserves "°C per °C" for abrupt permafrost thaw. The parallel BORF sentence gives "~−0.18°C" with no rate unit, and the TUND value follows from a one-off uptake of ~6 GtC. The text unit is inconsistent with the table; the authors should confirm that the absolute value is intended.
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Reference or label Fig. 2 caption: "(green, SSP1-1.9; yellow, SSP1-2.6; orange, SSP2-4.5; red, SSP3-7.0; purple, SSP5-8.5)" does not match the panel B legend, which shows SSP5-8.5 red, SSP3-7.0 orange, SSP2-4.5 yellow, SSP1-2.6 teal and SSP1-1.9 blue.
- p. 10 Fig. 2 caption
(green, SSP1-1.9; yellow, SSP1-2.6; orange, SSP2-4.5; red, SSP3-7.0; purple, SSP5-8.5)
- p. 10 Fig. 2B legend
SSP5-8.5
- p. 10 Fig. 2B legend
SSP5-8.5 / SSP3-7.0 / SSP2-4.5 / SSP1-2.6 / SSP1-1.9
Judge's note: Compared the caption with the legend and curves in panel B on the page 10 image. The legend colours are red, orange, yellow, teal and blue from highest to lowest scenario; no purple line is drawn and the blue line has no caption entry. The caption colours are shifted by one scenario, so a reader relying on the caption would misidentify the scenarios in panels B and C. Green appears in the figure for the Paris range bar.
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Reference or label Reference 10 (Joughin et al., "Science 344, 735–738 (2014). doi: 10.1002/2014GL060140") is printed with the same DOI as reference 9 (Rignot et al., "Geophys. Res. Lett. 41, 3502–3509 (2014). doi: 10.1002/2014GL060140").
- p. 11 Reference 10
Science 344, 735–738 (2014). doi: 10.1002/
- p. 11 Reference 9
(2014). doi: 10.1002/2014GL060140
- p. 11 Reference 10
Antarctica. Science 344, 735–738 (2014). doi: 10.1002/ 2014GL060140
- p. 11 Reference 10
Science 344, 735–738 (2014). doi: 10.1002/ 2014GL060140
Judge's note: Both entries read on the page 11 image; the DOI strings are identical. Two different articles in different journals cannot share a DOI, and the string carries the "GL" stem that fits the Geophys. Res. Lett. entry, so the DOI on reference 10 is the wrong one. The correct DOI for reference 10 is not in the files.
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Reference or label Reference 47 (Yu et al., "Geophys. Res. Lett. 46, 14539–14547 (2019). doi: 10.1002/2017GL072514") is printed with the same DOI as reference 48 (Arthern and Williams, "Geophys. Res. Lett. 44, 2352–2359 (2017). doi: 10.1002/2017GL072514").
- p. 11 Reference 47
14539–14547 (2019). doi: 10.1002/2017GL072514
- p. 11 Reference 48
Lett. 44, 2352–2359 (2017). doi: 10.1002/2017GL072514
- p. 11 Refs 47 and 48
doi: 10.1002/2017GL072514
- p. 11 Reference 48
44, 2352–2359 (2017). doi: 10.1002/2017GL072514
Judge's note: Both entries read on the page 11 image; the DOI strings are identical. The two entries are different articles (volume 46 in 2019, volume 44 in 2017), so one DOI is wrong. The "2017GL" stem fits reference 48, which points to reference 47 as the wrong one. The correct DOI for reference 47 is not in the files.
Second check: another model agreed
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Reference or label Reference 55 (Vaks et al., "Science 340, 183–186 (2013). doi: 10.1038/nature14338; pmid: 25855454") repeats the DOI and PMID of reference 54 (Schuur et al., "Nature 520, 171–179 (2015). doi: 10.1038/nature14338; pmid: 25855454").
- p. 11 Reference 55
doi: 10.1038/nature14338; pmid: 25855454
- p. 11 Reference 54
nature14338; pmid: 25855454
- p. 11 Reference 54
carbon feedback. Nature 520, 171–179 (2015). doi: 10.1038/ nature14338; pmid: 25855454
- p. 11 Reference 55
Science 340, 183–186 (2013). doi: 10.1038/nature14338; pmid: 25855454
Judge's note: Both entries read on the page 11 image; DOI and PMID are identical in the two. They are different articles in different journals and years, and the "nature" DOI fits the Nature entry, so the identifiers on reference 55 are copied from reference 54. The correct identifiers for reference 55 are not in the files.
Second check: another model agreed
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Reference or label Reference 98 (Rietkerk et al., "374, abj0359 (2021). doi: 10.1038/s41561-019-0310-1") is printed with the same DOI as reference 97 (Schneider et al., "Nat. Geosci. 12, 163–167 (2019). doi: 10.1038/s41561-019-0310-1").
- p. 12 Reference 98
374, abj0359 (2021). doi: 10.1038/
- p. 12 Reference 97
doi: 10.1038/s41561-019-0310-1
Judge's note: Both entries read on the page 12 image; the DOI strings are identical. They are different articles (2019 and 2021), and the "-019-" stem fits the 2019 entry, so the DOI on reference 98 is the wrong one. The correct DOI for reference 98 is not in the files.
Second check: another model agreed
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Reference or label Reference 98: "Evasion of tipping in complex systems through spatial pattern formation. 374, abj0359 (2021)." has no journal name between the title and the volume number.
- p. 12 Reference 98
pattern formation. 374, abj0359 (2021).
- p. 12 Reference 98
pattern formation. 374, abj0359 (2021). doi: 10.1038/ s41561-019-0310-1
- p. 12 Reference 97
doi: 10.1038/s41561-019-0310-1
- p. 12 Reference 98
Evasion of tipping in complex systems through spatial pattern formation. 374, abj0359 (2021). doi: 10.1038/ s41561-019-0310-1
Judge's note: Seen on the page 12 image: the bold volume "374" follows the title directly, with no italic journal title, so nothing was lost in extraction. Every neighbouring entry gives a journal name. Which journal it is cannot be confirmed from the files. Some reviewer notes in this cluster also raise the duplicated DOI on this entry; that part is covered by C029, and this verdict is for the missing journal name.
Second check: another model agreed
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Wording "Going from 3 to 5°C, EASB collapse becomes very likely", although the EASB maximum threshold is 6.0°C (Table 1: 3.0 / 2.0 / 6.0) and the paper ties "very likely" to passing the maximum estimate.
- p. 9 Implications section, 3 to 5°C paragraph
3 to 5°C, EASB collapse becomes very likely,
- p. 5 Table 1, EASB row, Threshold Est/Min/Max
3.0 2.0 6.0
- p. 9 Fig. 2A key
very likely
- p. 9 Implications for climate policy, paragraph on 3 to 5°C
Going from 3 to 5°C, EASB collapse becomes very likely
Only the authors can say what is right here.
Judge's note: Table 1 on page 5 gives EASB Est 3.0, Min 2.0, Max 6.0. The paper defines "possible" as beyond the minimum and "likely" as beyond the central estimate; the preceding paragraph on page 9 says maximum thresholds "are passed, suggesting that tipping them would become very likely", and the Fig. 2A key labels the region above the maximum "tipping: very likely". At 3 to 5°C EASB is above its central estimate but below its maximum, so "likely" is what the paper's own scheme supports. The same sentence uses "likely" for Amazon dieback, which has the same 6.0 maximum. No statement elsewhere in the article explains a looser use. Authors should say whether "likely" was meant.
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14 minor (typos and the like; most checked by the judge only)
Wording Discussion uses undefined acronyms: "(e.g., EQSC, ANOX, INSM, AABW, Congo rainforest)" and "(e.g., ENSO, JETS)"; EQSC, ANOX, INSM, AABW and JETS are not defined anywhere in the article.
- p. 9 Discussion, second paragraph
(e.g., EQSC, ANOX, INSM, AABW, Congo rain-
- p. 9 Discussion, second paragraph
(e.g., ENSO, JETS)
Judge's note: Page 9 image shows the acronyms as quoted. A search of the article text finds each of EQSC, ANOX, INSM, AABW and JETS only at this one place, with no expansion. The sentence ends "(see SM)", so they are presumably defined in the supplement, which was not provided; within the article the reader cannot resolve them. Minor.
Second check: another model agreed
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Typo Summary: "They occur when change in large parts of the climate system—known as tipping elements—become self-perpetuating beyond a warming threshold"; the subject is the singular "change", so the verb should be "becomes".
- p. 2 Research Article Summary, Introduction
tipping elements—become self-perpetuating
Judge's note: Read the crop of page 2. The sentence is printed as quoted. The article abstract on page 3 has the same sentence with "change in a part of the climate system becomes self-perpetuating", which shows the intended subject is "change". Grammar slip only.
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Typo Introduction: "The recent the Intergovernmental Panel on Climate Change (IPCC) AR6 WG1 report identifies up to 15 candidates" has a superfluous second "the".
- p. 3 Introduction, end of column 2 / top of column 3
The recent
- p. 3 Introduction, top of column 3
the Intergovernmental Panel on Climate Change
- p. 3
The recent theIntergovernmentalPanelonClimateChange (IPCC) AR6 WG1 report
- p. 3 Introduction, top of third column
the Intergovernmental Panel on Climate Change (IPCC) AR6 WG1 report identifies
Judge's note: Page 3 images: column 2 ends with "The recent" and column 3 begins "the Intergovernmental Panel on Climate Change (IPCC) AR6 WG1 report identifies". The duplication is in the print, not a reading-order artefact.
Second check: another model agreed
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Typo EASB: "timescales of 2 ky (500 y to 10 ky)" uses "y" where the parallel WAIS sentence on the same page has "2 ky (500 years to 13 ky)".
- p. 6 EASB best estimates
timescales of 2 ky (500 y to 10 ky)
Judge's note: Both forms are visible on page 6 (the C007 crop shows "500 y to 10 ky"; the C006-a crop shows "500 years to 13 ky"). Unit abbreviation inconsistency only; the value is unaffected and agrees with Table 1 (500).
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Typo Stray '<' in the PFAT timescale: 'a timescale of 200 years (100 to 300<years)' should read '(100 to 300 years)'.
- p. 7 Boreal permafrost section, PFAT best estimates
300<years) (medium confidence)
Judge's note: The crop of p.7 (Boreal permafrost section) shows '300<years' printed on the page, so this is not an extraction artefact. The '<' has no meaning in a range written as '100 to 300'. It is a typesetting slip.
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Typo Wrong article: 'historically has been a important sink for human CO2 emissions' should read 'an important sink'.
- p. 8 Amazon rainforest (AMAZ) section, first sentence
historically has been a im-
- p. 8
historically has been a important sink for human CO2 emissions
Judge's note: The crop of p.8 (Amazon rainforest section) shows 'has been a im-' followed by 'portant sink'. The article 'a' stands as a separate word before 'important', so this is a real grammatical slip and not an artefact of the line-break hyphen.
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Typo AMAZ: "to a GMST feedback of ~+0.1° (regional +0.4 to 2°C)" is missing the "C"; it should read ~+0.1°C.
- p. 8 Amazon rainforest (AMAZ) section, best estimates
GMST feedback of ~+0.1° (re-
- p. 8
to a GMST feedback of ~+0.1° (regional +0.4 to 2°C)
- p. 8 AMAZ best estimates
GMST feedback of ~+0.1° (re-gional +0.4 to 2°C)
Judge's note: Page 8 crop shows "~+0.1° (re-" with no "C" after the degree sign. Table 1 gives "0.1°C" for the partial Amazon dieback.
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Typo BORF: "Our best estimates for BORF is a threshold of ~4°C" has a plural subject with a singular verb; it should be "are".
- p. 8 Boreal forest (BORF/TUND) section
mates for BORF is a threshold of ~4°C
- p. 8
Our best estimates for BORF is a threshold of ~4°C
Judge's note: Page 8 crop shows the sentence as quoted. The parallel sentences use the plural ("Our best estimates for AMAZ are", "For TUND our best estimates are").
Second check: another model agreed
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Typo "committing to WAIS and GrIS collapse near complete warm-water coral die-off, and abrupt permafrost thaw": the comma after "collapse" is missing (and "near complete" is unhyphenated), so the first two list items run together.
- p. 9 Implications section, 1.5 to 2°C paragraph
committing to WAIS and GrIS collapse near
- p. 9
committing to WAIS and GrIS collapse near complete warm-water coral die-off
- p. 9 Implications for climate policy, 1.5 to 2°C paragraph
committing to WAIS and GrIS collapse near complete warm-water coral die-off, and abrupt permafrost thaw
- p. 9 Implications for climate policy, 1.5 to 2°C
WAIS and GrIS collapse near complete warm-water coral die-off, and abrupt permafrost thaw
Judge's note: Read on the page 9 image: no comma follows "collapse" at the line end, so it was not lost in extraction. The sentence is a three-item list (ice sheet collapse; near-complete coral die-off; abrupt permafrost thaw).
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Typo "widespread Permafrost collapse": "Permafrost" is capitalised mid-sentence.
- p. 9 Implications, >5°C paragraph
widespread Permafrost collapse
Judge's note: Seen on the page 9 image. Elsewhere in the running text the word is lower case (for example "abrupt permafrost thaw", "large-scale permafrost collapse" in the same column).
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Typo Fig. 2 caption: "central (line, red)", whereas panel A marks the central estimate with a black dotted line inside the red part of each bar.
- p. 10 Fig. 2 caption
central (line, red)
- p. 10 Fig. 2A bars and key
central
Judge's note: On the page 10 image the key at the top left of panel A and the bars show the central estimate as a dark dotted line across a red band of the yellow-to-dark-red gradient. The caption may mean the red band around the line, so this is a loose description and not a mislabel that would mislead a reader. Judged at page-render resolution.
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Typo Reference 36: "D. Notz, S. Community, Arctic Sea Ice in CMIP6." lists "S. Community" as if it were a person.
- p. 11 Reference 36
D. Notz, S. Community, Arctic Sea Ice in CMIP6.
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: that the second author of this paper is a consortium (the SIMIP Community) and not an individual. The page 11 image shows "S. Community" as quoted, which reads like a group name parsed into initial and surname; the correct author form cannot be confirmed from the files.
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Typo Reference 35: "(The Univ. of New South Wales Climate Change Research Centre, 2009); https://www.ccrc.unsw.edu.au/sites/default/files/Copenhagen_Diagnosis_LOW.pdf)." ends with an unmatched closing parenthesis.
- p. 11 Reference 35
Copenhagen_Diagnosis_LOW.pdf).
Judge's note: Seen on the crop and page 11 image: the parenthesis is closed after "2009" and a second ")" follows the URL with no opening partner. Reference 29, in the same format, ends its URL with no parenthesis.
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Typo Reference 83 prints the author as "F. S. Chapin3rd", with the generational suffix fused to the surname and not superscripted (should read "F. S. Chapin 3rd" or "F. S. Chapin III").
- p. 12 Reference 83
F. S. Chapin3rd, Thresholds for boreal biome transitions.
- p. 12 Reference 83
F. S. Chapin3rd
Judge's note: Viewed both crops of PDF page 12. Reference 83 reads "M. Scheffer, M. Hirota, M. Holmgren, E. H. Van Nes, F. S. Chapin3rd, Thresholds for boreal biome transitions." The "3rd" is set at baseline in the same size as the surname with no space, so it is not an extraction artefact of a superscript. Purely typographic defect in the reference list (likely carried over from the PubMed-style author string); the citation is still identifiable.
Second check: none (judge only)