CFC-11 emissions are declining as expected in Western Europe
Bibliographic record
Abstract
Abstract. Production and consumption of CFC-11 (trichlorofluoromethane, CCl3F), CFC-12 dichlorodifluoromethane, CCl2F2) and CCl4 (carbon tetrachloride) are controlled under the regulations of the Montreal Protocol and have been phased out globally for dispersive use since 2010. Only CCl4 is still widely produced under exemption as a chemical feedstock (non-dispersive use). After 2010, emissions of CFC-11 and CFC-12 should therefore mostly originate from existing banks (e.g. foams and refrigerators), however evidence emerged of an increase in global emissions of CFC-11, which was in part attributed to eastern China. Emissions of CFC-11, CFC-12 and CCl4 have subsequently declined in this region, however the total global increase in CFC-11 was not fully accounted for. The motivation for this work was to assess the emissions of CFC-11 and the associated gases, CFC-12 and CCl4, from Western Europe. All countries in this region have been subject to the controls of the Montreal Protocol since the late 1980s, and, as non-Article-5 Parties, have been prohibited from producing CFCs and CCl4 for dispersive use since 1995. Four different inverse modelling systems are used to estimate emissions of these gases from 2008–2021 using data from four atmospheric measurement stations: Mace Head (Ireland), Jungfraujoch (Switzerland), Monte Cimone (Italy) and Tacolneston (UK). The average of the four model studies found that Western European emissions of CFC-11, CFC-12 and CCl4 between 2008 and 2021 were declining at 3.5 (2.7–4.8) %, 7.7 (6.3–8.0) % and 4.4 (2.6–6.4) % yr−1 respectively. Throughout this period, the highest CFC-11 emissions were in Northern France and Benelux (Belgium, the Netherlands and Luxembourg). Emissions of CFC-12 co-located in this region were slightly higher than elsewhere in Western Europe, and also showed some enhancement of CCl4 emissions. However for CCl4, emissions were highest in the south of France. France had the highest emissions of CFC-11, CFC-12 and CCl4 over the period 2008–2021. Emissions from Western Europe (2008–2021) were on average 2.4 ± 0.4 Gg (CFC-11), 1.3 ± 0.3 Gg (CFC-12), 0.9 ± 0.2 Gg (CCl4). This study concludes that the emissions of CFC-11 from Northern France and Benelux are unlikely to be the result of new production. Our estimated decline in emissions of CFC-11 is consistent with a Western European bank release rate of 3.4 (2.6–4.5) %, which is in the upper half of the published range.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".