b'FLUXES The European Greenhouse Gas BulletinThe Greenhouse Gas Inventories - calculating country-level emissionsIn the labyrinth of climate data, where every number tells a story, the national greenhouse gas inventories serve as an important information source for the Global Stocktake. The inventories typically rely on estimations, but ground-based measurements can contribute to the verification of these.By Charlotta HenryE stimates, data and reports form theStatistics versus measurementsscientific core of the Global StocktakeThe greenhouse gas inventories not only show what the (see page 42). At the centre of thiscountries are releasing into the atmosphere in terms of operation are the national greenhouse gasemissions but also calculate carbon sinks and carbon inventories. Dirk Gnther, the Head of theremoval from land use change and forestry. In Germany, Emission Situation Section at the German Environmentthis is done every decade. In between, a forest carbon Agency, explains how the inventories are produced: stocktake is also done every five years and carbon We calculate emissions based on national officialremovals are calculated on an annual basis using official statistical data. The calculation is pretty simple. We takeforest and timber statistics. the activity data, for example the amount of producedEvery 10 years, we do an inventory of our forests steel, animals in the agricultural sector and the amountwith actual measurements, where people go to the of coal burned in power plants and multiply this with awoods, measuring the trees on certain reference points. specific emission factor of a gas or pollutant.Then, there is a model for calculating the increase or The greenhouse gas inventories are the monitoringdecrease of the forest sinks based on the statistics, the and reporting building blocks of the UNFCCC MRVharvesting and weather extremes, says Gnther.system. The verification consists of an internationalActual measurements and observational ground-technical review of the inventories by a team ofbased data can also add to the estimations and international experts that produces a report for eachcalculations of the greenhouse gas inventories. country with recommendations or encouragements.However, for most emission categories, the calculation The inventory needs to be transparent, and theis more accurate than the observation:calculation has to be plausible. One also needs to beGround-based observations cannot distinguish able to follow how the calculation has been made. Thewhether the methane emission source is the cattle farm calculation needs to be accurate and comparable,or the waste disposal site. In the iron and steel industry, Gnther explains. we have to distinguish between five different sources'