Remaining carbon budget (Resource)

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Description: This page provides a summary and review of the remaining (global) carbon budget; as assessed by the Intergovernmental Panel on Climate Change (IPCC) of the United Nations (UN).

Remaining carbon budget

The following is a summary of the remaining carbon budget (RCB) based on various global temperature targets and confidence intervals. The remaining carbon budget figures as of January 1, 2018, originate from the Intergovernmental Panel on Climate Change (IPCC) 2018 Special Report on the impacts of global warming of 1.5 °C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty (SR15). In the first table below, only figures in the first column, "Jan 1, 2018 (GtCO2)," correspond with figures from Table 2.2 titled: "The assessed remaining carbon budget and its uncertainties."[1] Also note that this first table excludes all uncertainties and variations, including all non-CO2 greenhouse gases (GHGs); as such, this first table is the RCB for exclusively Carbon dioxide (CO2) and Earth System Feedbacks (ESF). Refer to The Big Three for detail on the three primary greenhouse gases, and Greenhouse gas conversion factors.

IPCC SR15 Assessed remaining carbon budget (RCB) for exclusively Carbon dioxide (CO2) and Earth System Feedbacks (ESF)
Budget

Abbrev.

Target warming and confidence percentile IPCC RCB

(excl. ESF)

1/1/2018

(GtCO2)[1][2]

Adj. RCB

(excl. ESF)

1/1/2020

(GtCO2)[3]

BAU

Years

Remaining[4]

Adj. RCB

(incl. ESF) 1/1/2020

(GtCO2)[5]

BAU

Years

Remaining[4]

1.5°C (67%) Remaining Carbon Budget^ for 67% TCRE probability of limiting warming to 1.5°C[6] 420 335 8 yrs 235 5 yrs
1.5°C (50%) Remaining Carbon Budget^ for 50% TCRE probability of limiting warming to 1.5°C 580 495 12 yrs 395 9 yrs
1.5°C (33%) Remaining Carbon Budget^ for 33% TCRE probability of limiting warming to 1.5°C 840 755 18 yrs 655 15 yrs
1.75°C (67%) Remaining Carbon Budget^ for 67% TCRE probability of limiting warming to 1.75°C 800 715 17 yrs 615 14 yrs
1.75°C (50%) Remaining Carbon Budget^ for 50% TCRE probability of limiting warming to 1.75°C 1,040 955 22 yrs 855 20 yrs
1.75°C (33%) Remaining Carbon Budget^ for 33% TCRE probability of limiting warming to 1.75°C 1,440 1,355 32 yrs 1,255 29 yrs
2.0°C (67%) Remaining Carbon Budget^ for 67% TCRE probability of limiting warming to 2.0°C 1,170 1,085 25 yrs 985 23 yrs
2.0°C (50%) Remaining Carbon Budget^ for 50% TCRE probability of limiting warming to 2.0°C 1,500 1,415 33 yrs 1,315 31 yrs
2.0°C (33%) Remaining Carbon Budget^ for 33% TCRE probability of limiting warming to 2.0°C 2,030 1,945 45 yrs 1,845 43 yrs

Uncertainties and variations affecting the remaining carbon budget

The table below incorporates the uncertainties and variations range (low-base-high) into the remaining carbon budget for the following three remaining carbon budget (RCB) outcomes and probabilities: (i) 1.5°C (50% probability), (ii) 1.75°C (50% probability), and (iii) 2.0°C (50% probability). For example, in the case of the 1.5°C (50%) and 1.75°C (50%) RCB outcomes: If the maximum, i.e., High, range of uncertainty and variation occurs, then 920 GtCO2 is deducted from either RCB, resulting in a final remaining carbon budget of (428.3) GtCO2, i.e., less than zero (budget exceeded), and 31.7 GtCO2, respectively. For reference, in 2017 an estimated 42.4 GtCO2 was emitted into the atmosphere.[7]

Assessed remaining carbon budget with key uncertainties and variation:

Assessed remaining carbon budgets with uncertainties and variation[1] Low Base High
Remaining Carbon Budget (RCB) 1.5°C (50%) as of January 1, 2020 (GtCO2) 495 495 495
Total Uncertainties and Variations (U&V) (GtCO2e) (920)* (50)* 820
Net RCB 1.5°C (50%) -- Within/(Over) Budget (GtCO2e) (425) 455 1,315
Business As Usual (BAU) Years Remaining (Years) 0 yrs[8] 10 yrs 31 yrs
Remaining Carbon Budget 1.75°C (50%) as of January 1, 2020 955 955 955
Total Uncertainties and Variations (U&V) (GtCO2e) (920)* (50)* 820
Net RCB 1.75°C (50%) -- Within/(Over) Budget (GtCO2e) 35 905 1,775
Business As Usual (BAU) Years Remaining (Years) 1 yr 21 yrs 41 yrs
Remaining Carbon Budget 2.0°C (50%) as of January 1, 2020 1,415 1,415 1,415
Total Uncertainties and Variations (U&V) (GtCO2e) (920)* (50)* 820
Net RCB 2.0°C (50%) -- Within/(Over) Budget (GtCO2e) 495 1,365 2,235
Business As Usual (BAU) Years Remaining (Years) 12 yrs 32 yrs 52 yrs

* (Negative) values, i.e., a deduction from the remaining carbon budget.

The following uncertainties are not included in the above budget figures from the section, "Remaining carbon budget." The first table below, "Uncertainty and Variation," summarizes uncertainties and variations as per the IPCC SR15 (Table 2.2., "The assessed remaining carbon budget and its uncertainties").[1] The IPCC only provides binary ranges (low-high) for uncertainties and variations. The IPCC does not summarize these factors using a low-base-high range; such a three-scenario sensitivity analysis is common in value investing write-ups for publicly traded securities (stocks), and is useful in this case to see the midpoint of the binary range.[9] Note that the three-part sensitivity analysis below does not consider interdependence between factors of uncertainty and variation.

Key Uncertainties and Variation:

Uncertainty and Variation[1] Negative

GtCO2e

Base

GtCO2e

Positive

GtCO2e

Earth System Feedbacks (ESF)[10] (100)* (100)* (100)*
Non-CO2 scenario variation (250)* 0 250
Non-CO2 forcing and response uncertainty (400)* (100)* 200
TCRE distribution uncertainty 100 150 200
Historical temperature uncertainty (250)* 0 250
Recent emissions uncertainty (20)* 0 20
Total Uncertainties and Variations (U&V) (920) (50) 820

* (Negative) values, i.e., a deduction from the remaining carbon budget.

Notes on 1.5°C model pathway scenarios (P1, P2, P3, and P4)

The Special Report (IPCC, 2018), referred to as SR15, provides four pathways or scenarios to, "achieve the net emissions reductions that would be required to... limit[] global warming to 1.5°C with limited or no overshoot," titled P1, P2, P3, and P4. All pathways, except the first, rely on future deployment of, as yet, "unproven" CDR technologies, e.g., Bio-energy with carbon capture and storage (BECCS), or fossil fuel Carbon Capture and Storage (CCS).[1] Target global, annual carbon dioxide (CO2) emissions, i.e., excluding other greenhouse gases, in the year 2030, relative to global CO2 emissions in the year 2010A and 2019E, of each mitigation pathway, is projected as follows:

Annual carbon dioxide (CO2) emissions projected in Mitigation Pathways P1 P2 P3 P4
Global CO2 emissions change by 2030, % reduction relative to the year 2010[1] 58% 47% 41% 4%
Projected annual, global CO2 emissions in the year 2030[11] 16.1 20.3 22.6 36.7
% reduction relative to the year 2019[12] 63% 53% 47% 14%

These mitigation pathways rely on several factors, including Carbon dioxide removal (CDR) and reliance on nuclear energy, as follows:

Reliance on Carbon dioxide removal (CDR):

The SR15 includes the following statements regarding pathways and reliance on carbon dioxide removal[13] (CDR): "All pathways that limit global warming to 1.5°C with limited or no overshoot project the use of carbon dioxide removal (CDR) on the order of 100-1000 GtCO2 over the 21st Century;" relying on CDR to "neutralize emissions from sources for which no mitigation measures have been identified and, in most cases, also to achieve net negative emissions to return global warming to 1.5°C following a peak." As of the date of publishing: "CDR deployed at scale is unproven, and reliance on such technology is a major risk in the ability to limit warming to 1.5°C. CDR is needed less in pathways with particularly strong emphasis on energy efficiency and low demand" (IPCC SR15, p. 17 and 34). Three of the four illustrative pathways that limit global warming to 1.5°C require CDR (specifically: P2, P3 and P4). Carbon Capture and Storage (CCS), Bio-energy with Carbon Capture and Storage (BECCS), and Afforestation are forms of CDR. The following reflect total CCS and BECCS projected in the four pathways, as listed in Figure SPM.3b (p. 14).[1]

Carbon Capture and Storage (CCS) assumed in Mitigation Pathways[1] P1 P2 P3 P4
Sub-total Cumulative Bio-energy with CCS (BECCS) until Yr2100 (GtCO2) - 151 414 1,191
Sub-total Cumulative Non-BECCS until Yr2100 (GtCO2) - 197 273 27
Total Cumulative CCS until Yr2100 (GtCO2) - 348 687 1,218

Reliance on primary energy from nuclear power:

All four illustrative pathways that limit global warming to 1.5°C require operable civil nuclear power nuclear reactors to provide 50%-100% more energy than existing operable nuclear reactors by 2030, relative to 2010 (IPCC SR15, p. 14).[1] For reference: Total global electricity generation from nuclear energy has effectively flat-lined since the beginning of the 21st Century.[14] Currently, 53 reactors are under construction that will increase nuclear energy capacity by approximately 53.4 MWe; which reflects only a 13.6% increase relative to existing capacity of 394.0 MWe generated by 444 nuclear reactors.[14] By 2050, i.e., within 30 years, the four illustrative pathways that limit global waming to 1.5°C require operable civil nuclear power nuclear reactors to provide 98%, 150%, 468% and 501% more energy than existing operable nuclear reactors, i.e., the construction of 1.0x, 1.5x, 4.7x and 5.0x more nuclear reactors than are currently operable globally (IPCC SR15, p. 14).[1]

Historical Carbon dioxide (CO2) emissions (excluding other greenhouse gases)

The following figures originate from Le Quere, et al., Global Carbon Budget 2018. The first column, "Emissions (GtCO2)," includes emissions from fossil fuel and industry, land-use change, and budget imbalance (adjustment).[7] Refer to the Big Three for detail concerning greenhouse gas (GHG) types. The figures below do not include non-CO2 GHG emissions (e.g., CH4, N2O and Fluorinated gases); as are included in the recent UN Emissions Gap Report 2019.[15]

Alternatively, go to IPCC AR (Resource) for global total greenhouse gas emissions, by sector and activity, in 2010 as per IPCC WGIII AR5.

Year Emissions

from fossil fuel

and industry[7]

(GtCO2[2])

Emissions

from

land-use change[7]

(GtCO2)

FF&I

%

Total

LUC

%

Total

Carbon dioxide

emissions, Total[7]

(GtCO2)

Full Period[16]

Combined annual

growth rate (CAGR)

Trailing ten-year

(TTY)

CAGR

%

YoY[17]

1960 9.41 6.13 60.6% 39.4% 15.54 n/a n/a n/a
1970 14.85 4.84 75.4% 24.6% 19.69 2.4% 2.4% n/a
1980 19.39 3.98 83.0% 17.0% 23.37 2.1% 1.7% n/a
1990 22.18 4.84 82.1% 17.9% 27.02 1.9% 1.5% n/a
2000 24.56 4.82 83.6% 16.4% 29.38 1.6% 0.8% n/a
2010 33.07 5.20 86.4% 13.6% 38.27 1.8% 2.7% n/a
2011 34.36 4.97 87.4% 12.6% 39.32 1.8% 2.9% 2.8%
2012 34.92 5.86 85.6% 14.4% 40.78 1.9% 3.0% 3.7%
2013 35.21 5.65 86.2% 13.8% 40.86 1.8% 2.5% 0.2%
2014 35.51 5.87 85.8% 14.2% 41.37 1.8% 2.3% 1.3%
2015 35.46 5.95 85.6% 14.4% 41.41 1.8% 2.1% 0.1%
2016 35.68 4.76 88.2% 11.8% 40.44 1.7% 1.5% -2.3%
2017 36.15 5.09 87.7% 12.3% 41.24 1.7% 1.7% 2.0%
2018[18][19] 36.42 5.69 86.5% 13.5% 42.11 % % 2.1%
2019[20] 36.44 6.60 84.7% 15.3% 43.05 % % 2.2%
2020E[21] 34.1 (est.) 5.9 (est.) 85.3% 14.7% 39.9 % % (7.2%)
2021E[22] 35.8 (est.) 6.2 (est.) 85.3% 14.7% 41.9 % % 5.0% (est.)

Historical Carbon dioxide and other greenhouse gas emissions

The following approximates total greenhouse gas emissions, of which there are over two hundred types. Carbon dioxide, consistently, accounts for 75% of total, global human-caused greenhouse gases. Refer to The Big Three for detail on the three primary greenhouse gases, and Greenhouse gas conversion factors.

Year Carbon dioxide

(CO2)

emissions,

Sub-total

(GtCO2)

Other

greenhouse gas

(GHG)

emissions

est.,

Sub-total[23]

(GtCO2e)

TOTAL

GHG emissions[23]

(GtCO2e)

CO2 Other

GHGs

TOTAL
1960 15.54          6.66 22.2 70% 30% 100%
1970 19.69          7.66 27.4 72% 28% 100%
1980 23.37          8.64 32.0 73% 27% 100%
1990 27.02          9.01 36.0 75% 25% 100%
2000 29.38          9.79 39.2 75% 25% 100%
2010 38.27        12.09 50.4 (49.0[24]) 76% 24% 100%
2011 39.32        13.11 52.4 75% 25% 100%
2012 40.78        13.59 54.4 75% 25% 100%
2013 40.86        13.62 54.5 75% 25% 100%
2014 41.37        13.79 55.2 75% 25% 100%
2015 41.41        13.80 55.2 75% 25% 100%
2016 40.44        13.48 53.8 75% 25% 100%
2017 41.24        13.75 55.0 75% 25% 100%
2018[18][25] 42.11        14.04 56.2 75% 25% 100%
2019[26] 43.05        14.35 57.4 (59.1[27]) 75% 25% 100%
2020E[28] 39.9        13.31 53.3 75% 25% 100%
2021E[29] 41.9        14.00 55.9 75% 25% 100%

References

  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 (IPCC, 2018): Rogelj, J., D. Shindell, K. Jian, S. Fifita, P. Forster, V. Ginzburg, C. Handa, H. Kheshgi, S. Kobayashi, E. Kreigler, L. Mundaca, R. Séférian, and M.V. Vilariño, 2018: Mitigation Pathways Compatible with 1.5°C in the Context of Sustainable Development. In: Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial level and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty [Masson-Delmotte, V., P. Zhai, H.-O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okai, C. Péan, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. Zhou, M.I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, and T. Waterfield (eds.)]. In Press.[1]
  2. 2.0 2.1 Remaining carobn budget (RBC); Earth System Feedbacks (ESF); Gigatonne (Gt): One billion tonnes of carbon dioxide (CO2).
  3. Assumptions: Based on 41.241 GtCO2 emissions in 2017; using 2.0% year-over-year (yoy) increase, resulting in 42.1 GtCO2 emissions in 2018 (Est.); and holding 2.0% yoy increase, resulting in 42.9 GtCO2 emissions in 2019 (Est.). Cumulative projected emissions of 85.0 GtCO2 for the two-year period (2018 and 2019); this is the figure used to make the adjustment to the IPCC Budget. For more detail on historical emissions, refer to the last table on this page. Sources: (Le Quéré, et al., 2018); and (UNEP, 2019).
  4. 4.0 4.1 Business as usual (BAU) years remaining. Calculation: Remaining Carbon Budget as of January 1, 2020; divided (/) by 43 GtCO2.
  5. Note: Remaining Carbon Budgets after deducting Earth System Feedbacks (EST), which includes CO2 released by permafrost thawing or methane released by wetlands, totaling about (100 GtCO2) on a centennial timescale. The ( ) indicates a negative value, i.e., a deduction from the RBC (excluding EST). Source: (IPCC, 2018).
  6. Transient Climate Response to Cumulative Carbon Emissions (TCRE). Note: These budgets exclude additional earth system feedbacks; and exclude other key uncertainties and variations, including: Non-CO2 scenario variation (+/- 250 GtCO2), Non-CO2 forcing and response uncertainty (-400 to +200 GtCO2), TCRE distribution uncertainty (+100 to 200 GtCO2), Historical temperature uncertainty (+/- 250 GtCO2), and Recent emissions uncertainty (+/- 20).
  7. 7.0 7.1 7.2 7.3 7.4 Note: Actual annual emissions figures 1960-2017. This includes carbon emissions from fossil fuel and industry, and land-use change; it does not include the Budget Imbalance (adjustment). Carbon emissions were converted to CO2 using the CO2:C ratio of 44.009:12.001 (molecular weight of CO2 and Carbon). Source: Corinee Le Quéré, Robbie M. Andrew, Pierre Freidlingstein, Stephen Stich, Judith Hauck, Julia Pongratz, Penelope A. Pickers, Jan Ivar Korsbakken, Glen P. Peters, Josep G. Canadell, Almut Arneth, Vivek K. Arora, Leticia Barbero, Ana Bastos, Laurent Bopp, Frédéric Chevallier, Louise P. Chini, Philippe Ciais, Scott C. Doney, Thanos Gkritzalis, Danial S. Goll, Ian Harris, Venessa Haverd, Forrest M. Hoffman, Mario Hoppema, Richard A. Houghton, George Hurtt, Tatiana, Ilyina, Atul K. Jain, Truls Johannesen, Chris D. Jones, Etsushi Kato, Ralph F. Keeling, Kees Klain Goldewijk, Peter Landschützer, Nathalie Lefèvre, Sebastian Lienert, Zhu Liu, Danica Lmobardozzi, Nicolas Metzl, David R. Munro, Julia E. M. S. Nabel, Shin-ichiro Nakaoka, Craig Neill, Are Olsen, Tsueno Ono, Prabir Patra, Anna Peregon, Wouter Peters, Philippe Peylin, Benjamin Pfeil, Denis Pierrot, Benjamin Poulter, Gregor Rehder, Laure Resplandy, Eddy Robertson, Matthais Rocher, Christian Rödenbeck, Ute Schuster, Jörg Schwinger, Roland Séférian, Ingunn Skjelvan, Tobias Steinhoff, Adrienne Sutton, Pieter P. Tans, Hanqin Tian, Bronte Tillbrook, Francesco N Tubiello, Ingrid T. van der Laan-Luijkx, Guido R. van der Werf, Nicolas Viovy, Anthony P. Walker, Andrew J. Wiltshire, Rebecca Wright, Sönke Zaehle, Bo Zheng: Global Carbon Budget 2018, Earth Syst. Sci. Data, 2018b. <https://doi.org/10.5194/essd-10-2141-2018>.
  8. The scenario of High uncertainties and variations (negative), makes satisfying the 1.5°C (50%) Remaining Carbon Budget unfeasible; even with aggressive future carbon dioxide removal (CDR).
  9. See: Write-ups posted to Value Investors Club for example of low-base-high stock price valuations.
  10. Earth system feedbacks include CO2 released by permafrost thawing or methane released by wetlands. Note: The IPCC did not provide a range for this uncertainty (variable).
  11. Using 38.27 GtCO2 emissions in the year 2010 (Quéré, et al, 2018).
  12. Using 42.91 GtCO2 emissions in the year 2019E; which is derived by applying year-over-year increases to the figures from (Quéré, et al., 2018).
  13. Carbon dioxide removal (CDR) refers to the process of removing CO2 from the atmosphere. It may sometimes be referred to as carbon capture and storage (CCS) or carbon capture and sequestration (CCS). Other forms of CDR include: Bioenergy with carbon capture and storage (BECCS) and afforestation. As well as removals in the Agriculture, Forestry and Other Land Use (AFOLU) sector, e.g., low-till farming, conservation agriculture, silvopasture, restorative agriculture, and permaculture (wilding, biomimicry). Many activities in AFOLU intersect.
  14. 14.0 14.1 "Reactor Database Global Dashboard." World Nuclear Association. Accessed November 21, 2019.<https://www.world-nuclear.org/information-library/facts-and-figures/reactor-database.aspx>.[2]
  15. Note: From the report, Figure 2.1, Global greenhouse gas emissions from all sources; of which Fossil CO2 is 37.5 Gt; and LUC around 3.9 Gt (estimated using 7.0% of total annual GHG emissions, i.e., 55.3 Gt CO2e). Source: United Nations Environmental Programme (2019). Emissions Gap Report 2019. UNEP, Nairobi.
  16. As of 1960 (17.5 GtCO2 base year emissions).
  17. Year-over-Year (YoY).
  18. 18.0 18.1 2018E used 2.0% yoy as per UNEP, Source 2. Note 1: From Slide 11/81: "Global fossil CO2 emissions [from hydrocarbons] are projected to rise by 2.7% in 2018" with a low/high range of "+1.8% to +3.7%." (Sources: CDIAC; Jackson, et al.; Le Quere, et al.; Global Carbon Budget 2018.) Source 1: Global Carbon Project. Presentation: Global Carbon Budget 2018. (Slide 11/81.) Published on December 5, 2018. Accessed: November 16th, 2019.[3] Note 2: The UNEP Emissions Gap Report 2019 provide 2.0% increase for fossil fuel CO2. Source 2: Second source: United National Environmental Programme (2019). Emissions Gap Report 2019. UNEP, Nairobi.
  19. Global Carbon Project. (2020). Supplemental data of Global Carbon Budget 2020 (Version 1.0) [Data set]. Global Carbon Project. <https://doi.org/10.18160/gcp-2020>. Accessed: January 5, 2022.
  20. Global Carbon Project. (2020). Supplemental data of Global Carbon Budget 2020 (Version 1.0) [Data set]. Global Carbon Project. <https://doi.org/10.18160/gcp-2020>. Accessed: January 5, 2022.
  21. Global Carbon Project. (2020). Supplemental data of Global Carbon Budget 2020 (Version 1.0) [Data set]. Global Carbon Project. <https://doi.org/10.18160/gcp-2020>. Accessed: January 5, 2022.
  22. Applying 5% year-over-year growth to 2020E figures from: Global Carbon Project. (2020). Supplemental data of Global Carbon Budget 2020 (Version 1.0) [Data set]. Global Carbon Project. <https://doi.org/10.18160/gcp-2020>. Accessed: January 5, 2022.
  23. 23.0 23.1 The quantity of other greenhouse gas (GHG) emissions is approximated using % ratios provided by (IPCC, 2014) and (EGR, 2019), available in The Big Three, applied to Carbon dioxide (CO2) emission figures provided by (Quéré, et al., 2018).
  24. Global greenhouse gas (GHG) emissions were 49 GtCO2e, of which 76% or approximately 37.24 Gt were exclusively Carbon dioxide (CO2), multiplying 49 x 76%, as per (IPCC, 2014), SPM.2 (p. 9) of IPCC WGIII AR5. Refer to IPCC AR5 (Resource).
  25. Global Carbon Project. (2020). Supplemental data of Global Carbon Budget 2020 (Version 1.0) [Data set]. Global Carbon Project. <https://doi.org/10.18160/gcp-2020>. Accessed: January 5, 2022.
  26. Global Carbon Project. (2020). Supplemental data of Global Carbon Budget 2020 (Version 1.0) [Data set]. Global Carbon Project. <https://doi.org/10.18160/gcp-2020>. Accessed: January 5, 2022.
  27. The 57.4 is an estimate is an estimate; (UNEP, 2020) lists total, global human-caused greenhouse gas emissions for the year 2019 as being 59.1 GtCO2e. United Nations Environmental Programme (2019). Emission Gap Report 2020. UNEP, Nairobi. <https://www.unep.org/emissions-gap-report-2020>.
  28. Global Carbon Project. (2020). Supplemental data of Global Carbon Budget 2020 (Version 1.0) [Data set]. Global Carbon Project. <https://doi.org/10.18160/gcp-2020>. Accessed: January 5, 2022.
  29. Applying 5% year-over-year growth to Year 2020 figures from: Global Carbon Project. (2020). Supplemental data of Global Carbon Budget 2020 (Version 1.0) [Data set]. Global Carbon Project. <https://doi.org/10.18160/gcp-2020>. Accessed: January 5, 2022.