The sources of greenhouse gas emissions are well understood and can be dissected in a number of ways. Thinking about them sectorally, and decomposing them into sub-sectors, sub-sub-sectors and so on, offers one way of identifying mitigation opportunities. This is the way that national greenhouse gas inventories are structured.
One branch of the ‘emissions tree’, relating to energy emissions. Credit: based on the IPCC’s 2019 Refinement to the 2006 Guidelines for National Greenhouse Gas Inventories
Another branch of the ‘emissions tree’, relating to emissions from the metals industry. Credit: based on the IPCC’s 2019 Refinement to the 2006 Guidelines for National Greenhouse Gas Inventories
Each of these sectors, and its constituent sub-sectors, has its own specific characteristics, dynamics and actors. Whereas some mitigation policies – such as those that apply a price on carbon emissions through a carbon tax or an emissions trading scheme – can, in principle at least, be applied as a generic measure across multiple sectors, most need to be tailored to the sector at hand. ‘Policy stacks’, incorporating suites of hopefully (but not always) complementary policy and regulatory measures, are usually required.
But back to the inventories.
Inventories are arguably the bedrock of the UNFCCC and, looking forward, of the Transparency Framework of the Paris Agreement; without reliable GHG data, the entire system would break down. Over three-quarters of NDCs, for example, contain emissions targets expressed in GHG terms as opposed to, say, megawatts of renewable power generation or hectares of planted forest. To track progress to targets, it’s necessary to track emissions. If Internationally Transferred Mitigation Outcomes (ITMOs) are quantified in terms of tonnes of CO2-equivalent, as seems likely, inventories will be key.
National reporting of inventories has until now been through National Communications (NCs) from all Parties, Biennial Update Reports (BURs) from non-Annex I (developing country) Parties, and Biennial Reports (BRs) and annual GHG inventories from Annex I (developed country) Parties. This will change under the Transparency Framework, with BURs and BRs giving way to Biennial Transparency Reports (BTRs).
Approved GHG estimation methodologies, ‘good practice guidance’, reporting templates and accounting software provided by the IPCC serve to standardise, more or less, the inventories submitted to the UNFCCC by individual countries. To the extent possible – and, for more on that, see below – inventories should be transparent (with clear data sources, assumptions and calculations), well documented, complete, comparable and consistent over time. Uncertainties should be noted and, where possible, reduced. Key category analysis – to accord greater accuracy to more important emissions sources – should ideally be employed.
National inventories are also subject to a complex, acronym-rich system of verification. In the case of Annex 1 Parties, this has hitherto gone under the names of International Assessment and Review (IAR) and Multilateral Assessment (MA); for Non-Annex 1 Parties, International Consultation and Analysis (ICA) has been followed by Facilitative Sharing of Views (FSV). Under the Transparency Framework, the process will be standardised for all Parties as Technical Expert Review (TER) and the wonderfully-titled Facilitative Multilateral Consideration of Progress (FMCP).
Financial and technical support to developing countries to periodically update their inventories is provided by the Global Environment Facility – through its support to ‘enabling activities’ and through the Capacity Building Initiative for Transparency (CBIT) – as well as from the UNFCCC Secretariat, the Consultative Group of Experts (CGE) and an array of international organisations and donors. The UNFCCC’s Greenhouse Gas Information System compiles the data supplied by Parties and breaks it down along various axes (country, sector, gas, etc.).
So far, so good.
The problem is, the inventory system is no longer fit for purpose. Submitting periodic National Communications – and ‘periodic’ means once only in the case of Angola (2012), Grenada (2000), Iraq (2017) and Myanmar (2012), to take but 4 examples – may have been pragmatic stipulation in the 1990s, when the UNFCCC was finding its way and carbon trading was but a glint in policy-makers’ eyes.
But it seems strangely, well, periodic in today’s world of always-on information, not to mention climate urgency. The real-time price of stocks and shares on the Mauritian Stock Exchange or today’s weather in Oymyakon, the most remote settlement in Siberia, or the hourly carbon intensity of the UK national grid are but mouse-clicks away. But the last official GHG inventory data for Algeria, Africa’s largest country, date from 2000. Qatar, the world’s largest liquified natural gas exporter, has not provided updated figures since 2007. Libya, home of the largest proven oil reserves in Africa, has never even submitted an inventory.
Periodic reporting not only creates data gaps, it creates institutional inefficiencies. Inventory teams come and go, rarely consisting of the same individuals. Documents are misplaced; assumptions and calculations are lost to history. As much work goes into understanding how the last report’s figures were estimated as goes into calculating the next set of figures. It all has a rather ad hoc, belts-and-braces flavour to it.
The recent and ongoing requirement on countries to supply biennial reports (including inventory updates) is clearly a step in the right direction – although it should be noted that, as of October 2019, over 100 Non-Annex 1 countries have yet to submit one.
It’s also hard to shake off the impression that most inventories remain decidedly low-tech. Amidst excited chatter about how artificial intelligence can transform the fight against climate change, and how GIS / satellites / drones / smart phones / the Internet of Things / insert your technology of choice can revolutionise data collection and processing, the fact remains that most inventories are built on patchy and out-of-date activity data and generic (often Tier 1) emission factors – sometimes excluding entire economic sectors (notably AFOLU) on the grounds of cost or complexity – and sit in flat-file Excel spreadsheets on individual computers. It’s hardly the Brave New World of data analytics.
Consider the example of China, a country that has a relatively good track record of GHG reporting, having submitted three National Communications and two BURs over the past 15 years. China’s total emissions in 2014 are estimated as 11 Gt CO2e (i.e. 11 billion tonnes CO2e). However, the error margin on the estimate of GHG emissions from China’s agriculture and LULUCF sectors, which together account for roughly 20% of total emissions, is, according to China’s own BUR, approximately +/- 20%; the uncertainty in the waste sector is even higher, +/-23%.
To give a sense of what this means, an under-count of 20% in the Chinese agricultural sector – equivalent to 165 Mt CO2e – is larger than the national emissions of 20 of the 28 member states of the EU. And this is by no means an isolated example. The uncertainty on methane emissions in the UK’s inventory, which can reasonably be characterised as a best-in-class inventory, is acknowledged to be 16%, with nitrous oxide uncertainty at 28% and nitrogen trifluoride uncertainty reaching 47%.
It should be noted that the uncertainty estimates cited in national inventories are typically generated using the IPCC’s fairly conservative approach to assessing uncertainty. There is also the underlying assumption that any errors that arise are innocent consequences of poor data rather than deliberate manipulation – typically under-reporting – of emissions figures, which is generally but not universally the case.
Frankly, GHG inventories deserve better. They undoubtedly represent the bedrock of the Transparency Framework. But, to perhaps stretch the analogy too far, bedrock exists largely out of sight and is covered by intervening layers; it’s easily ignored or forgotten. It has been a long time since inventories were the darlings of climate policy-making; they have long been neglected, and it’s beginning to show.
Without reliable inventory data, we cannot track our emissions, we cannot gauge the success of our mitigation policies, trust between countries is eroded, carbon markets cannot work. So, let’s hear it for the humble greenhouse gas inventory: after all, you can’t manage what you can’t measure.