19


3.3 The emissions gap in 2030


The emissions gap for 2030 is defined as the difference between global total GHG emissions from least-cost scenarios that are consistent with the 2°C and 1.5°C temperature limits and the estimated total global GHG emissions resulting from full implementation of NDCs. To allow for a more nuanced interpretation of the Paris Agreement’s temperature targets, this assessment includes a below 1.8°C scenario. This section updates the gap based on estimated levels of GHG emissions in 2030 for the scenarios described in section 3.2. Table 3.1 provides a full overview of 2030 emission levels for all seven scenarios considered in this assessment, as well as the resulting emissions gap. Figure 3.1 illustrates the emissions gap in 2030.


Table 3.1 indicates that in the absence of further climate action since 2005, that is, under a no-policy baseline scenario, the total global GHG emissions in 2030 would be 65 GtCO2


e (range of 60–70 GtCO2 e). Current policies


lower than the 2017 estimate, which is within rounding precision. The lower and upper limit of the range for the current policy estimate has decreased by 2 GtCO2 and 1 GtCO2


There are no substantive updates to these estimates compared with the 2017 assessment. The median current policy estimate for 2018 is roughly 0.5 GtCO2


are estimated to reduce global emissions in 2030 by around 6 GtCO2


e respectively due to lower projections


(see chapter 2, section 2.4). Overall, this implies that studies have not identified significant and unambiguous progress in the implementation of policies that would allow the NDCs to be achieved by 2030. However, the estimates of global emissions in 2030 under the current policy scenario have decreased slightly since 2015, from 60 GtCO2 2015) to 59 GtCO2


indicating that some studies show slight progress in policy implementation since the adoption of the Paris Agreement.


e (range of 58–62 GtCO2 e (range of 56–60 GtCO2


Table 3.1: Total global greenhouse gas emissions in 2030 under different scenarios (median and 10th range), temperature implications and the resulting emissions gap.


Scenario (rounded to the nearest gigatonne)


No-policy baseline


Current policy


Unconditional NDCs


Conditional NDCs


Below 2.0°C (66% chance)


Number of


scenarios in set


Global total emissions in 2030 [GtCO2


e] Estimated temperature outcomes 50% chance 179 4 12 10 65 (60–70) 59 (56–60) 56 (52–58) 53 (49–55) Peak: 29 40 (38–45) 1.7–1.8°C


In 2100: 1.6–1.7°C


Peak:


Below 1.8°C (66% chance)


Below 1.5°C in 2100


(66% chance) 43 34 (30–40) 1.6–1.7°C


In 2100: 1.3–1.6°C


Peak: 13 24 (22–30) 1.5–1.6°C


In 2100: 1.2–1.3°C


Assessment Report. The NDC and current policy emission projections may differ slightly from the presented numbers in Cross-Chapter box 11 of the IPCC Special Report (Bertoldi et al., 2018) due to the inclusion of new studies after the literature cut-off date set by the IPCC. Pathways were grouped in three categories depending on whether their maximum cumulative CO2 and 1,300 GtCO2 from 2018 onwards until net zero CO2


Note: The gap numbers and ranges are calculated based on the original numbers (without rounding), which may differ from the rounded numbers (3rd column) in the table. Numbers are rounded to full GtCO2


2nd emissions are reached, or until the end of the century if net zero is not reached before. Pathways emissions were less than 600 GtCO2 , between 600 and 900 GtCO2


assume limited action until 2020 and cost-optimal mitigation thereafter. Estimated temperature outcomes are based on the method used in the IPCC 5th Assessment Report.


, or between 900 Peak: 1.9–2.0°C


In 2100: 1.8–1.9°C


Peak: 1.7–1.8°C


In 2100: 1.5–1.7°C


Peak: 1.6–1.7°C


In 2100: 1.4–1.5°C


Peak: 2.4–2.6°C


In 2100: 2.3–2.5°C


Peak: 2.1–2.3°C


In 2100: 1.9–2.2°C


Peak: 2.0–2.1°C


In 2100: 1.8–1.9°C


e. GHG emissions have been aggregated with 100-year global warming potential values of the IPCC 18 (16–20) 15 (12–17) 13 (9–15) 24 (22–25) 21 (17–23) 19 (15–20) 35 (32–36) 32 (28–34) 29 (26–31) 66% chance 90% chance to 90th percentile


Emissions Gap in 2030 [GtCO2


e]


Below 2°C


Below 1.8°C


Below 1.5°C in 2100


e) (UNEP, e) in 2018, e


e compared with the no-policy scenario. e


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112