Impact case study database

We present two instances where research (illustrated below) has led to quantifiable impact:

1. Evidence for production of an illegal ODS, banned under the Montreal Protocol, resulting in enforcement by Chinese authorities and a change in ODS monitoring policy

2. Enhancing the UK’s global reputation as a lead nation on climate policy by improving the transparency and accuracy of the national GHG emissions inventory

(I). Enforcement of global CFC-11 production ban resulting from atmospheric monitoring

University of Bristol modelling, along with global atmospheric data, identified an increase of around 10,000 tonnes per year in the global emissions of one of the primary substances responsible for ozone depletion, CFC-11 [6]. This study prompted the addition of an agenda item by the EU representative at the 40^th Open-ended Working Group (OEWG) of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer (2018), who also cited the work in the discussion, “ The study, entitled ‘An unexpected and persistent increase in global emissions of CFC-11’ [6] , revealed that emissions of CFC-11 had increased in recent years despite the reported elimination of CFC-11 production under the Montreal Protocol.” [a1]. Concerns and actions were passed to the subsequent 30^th Meeting of the Parties (MOP) delegates who expressed “ … widespread dismay that CFCs were once again being produced and used despite the efforts of the past 30 years, thereby threatening the reputation and success of the Montreal Protocol, until now widely hailed as the most successful global multilateral environmental agreement” [b1]. At the 31^st MOP in November 2019 [b2], delegates noted that a subsequent Bristol-led paper using global and eastern Asian AGAGE data “ (published in Rigby et al. [ 3] … *) had determined that 40-60% of these global emission increases had originated in eastern China.*” Until publication of our work, certain parties felt that “ *it was troubling that, for at least five years, there had been substantial amounts of unexplained emissions of CFC-11 that were not consistent with actions taken under the Montreal Protocol.*” Calculations presented at the 40^th OEWG noted that a sustained future release of CFC-11 of the magnitudes identified in our papers “ would delay… the recovery of the ozone hole by 30 years.” [a1] In addition to their impact on the ozone layer, these unexpected emissions had an influence on climate equivalent to around one fifth of the UK’s annual carbon dioxide emissions.

Following our initial publication [6], on-the-ground investigation by media and a non-governmental organisation confirmed that “ factories in China… have ignored a global ban and kept making or using the chemical, CFC-11, mostly to produce foam insulation for refrigerators and buildings.” [c1, d]. Furthermore, at MOP30 [b1], MOP31 [b2], and meetings of the UN Multilateral Fund [e], delegates from China outlined law enforcement activities that had been initiated after our publications (“ Noting that numerous cases of illegal production facilities had been found in China [b2]”), resulting in the closure or demolition of several illegal production facilities, the confiscation of some ODS, including CFC-11, and legal proceedings against perpetrators [a2,b1,b2,e]. To ensure that such breaches of the Montreal Protocol are detected and stopped more rapidly in the future, China has taken actions “ including strengthening legislation and building capacity, including through improved access to monitoring equipment, inspections of plants and establishment of a monitoring plan” [b2].

Preliminary findings presented at the 31^st MOP [b2] and subsequently reported in the media [c2] suggest that global and Chinese CFC-11 emissions dropped during 2018 or 2019, implying that enforcement activities initiated following our research have been successful.

(II). Ensuring the UK leads the world in the accuracy of its national GHG emission reports

The UK is one of only four countries in the world to use atmospheric observations to evaluate its National Inventory Report (NIR) to the United Nations Framework Convention on Climate Change (UNFCCC) [f] and was the first to pioneer this approach . The Bristol-led DECC network [1] provides extensive atmospheric observations and model interpretation to give robust transparent verification of the UK’s national inventory. The UK’s Department for Business, Energy and Industrial Strategy (BEIS) states that “ The largest impact of the Bristol-led DECC network is the benefit it provides to the UK’s international standing. DECC network staff have… been central to drafting new best practice guidance for inventory compilation... the UK’s successful example of bringing together policy makers, inventory compilers and atmospheric scientists will provide further opportunities to lead the world in this field” [g]. Indeed, the Bristol-led DECC network has been highlighted as an exemplar in the World Meteorological Organisation (WMO) Integrated Global Greenhouse Gas Information System (IG³IS) [h1], and in the International Panel on Climate Change (IPCC) 2019 Refinement to the 2006 Guidelines for National Greenhouse Gas Inventories [h2]. The WMO IG³IS calls for other countries to “ build on the example of ‘early mover’ countries like UK” in its implementation plan [h1], which has been adopted by the Subsidiary Body for Scientific and Technological Advice (SBSTA) to the UNFCCC [h3].

Bristol research has led to significant revisions of the UK GHG inventory, which demonstrates the UK’s commitment to international “best practise”. Our measurements and modelling [2], for example, showed that the UK’s “ estimates of the fluorinated gas (F-gas) HFC-134a were ... significantly higher than those from the DECC network” [g]. Based on this work, the BEIS “GHGI team and inventory agency at Ricardo Energy and Environment began an in-depth investigation into our F-gas models to find the cause of its mis-estimation of emissions of HFC 134a. They found that the GHGI’s assumptions on mobile air conditioning were overly simplistic and conservative” [g]. In the UK’s 2020 NIR, it is noted that “ Revisions to the refrigeration and air conditioning model… have been made, and this comparison is now in better agreement” with the emissions derived from DECC network data [f]. Such changes enabled by the close links between Bristol-led research and BEIS, which “ have demonstrated world-leading science and fulfilled UNFCCC best practice requirements to continually improve our inventory” [g].

The example provided by the UK has inspired other countries to adopt similar methodologies. India became the first non-Annex-1 (developing) country to report emissions of the GHG, methane, based on a Bristol-led study utilizing space-based data [5]. In India’s Second Biennial Update Report (BUR) [i], it states “A paper published in Nature Communications (Ganesan et al., 2017) [5] investigated India’s methane emissions using a top-down approach and concluded that the magnitude of India’s methane emissions was consistent with that reported in First BUR.” The incorporation of this information provides Indian inventory compilers and policy makers with independent information with which to evaluate their emissions, thus improving the accuracy of their submissions. This research demonstrates a methodology that can be applied in the very large number of developing countries that do not have extensive data collection and is noted in the 2019 Refinement to the IPCC’s 2006 Guidelines for National Greenhouse Gas Inventories [h2].