AN OVERVIEW OF GREENHOUSE GAS EMISSIONS IN SCOTLAND Royal Statistical Society Edinburgh Group Meeting 29 September 2015 Martin Macfie Climate Change Statistics Scottish Government 1

Outline of Presentation Latest statistics and Purpose of collecting data Headline results – source emissions Methodological Improvements, Revisions and Uncertainties

Latest Statistics and Purpose of collecting data

Latest statistics Latest Official Statistics: Scottish Greenhouse Gas Emissions (2013). Published June Contains results of Scotland’s greenhouse gas inventory What is a greenhouse gas inventory? Source sectors and different greenhouse gases Potency of different greenhouse gases – global warming potential

Why are we collecting and reporting on these figures?

Purpose of collecting data? The UK and other member states are required to collect emissions data to the United Nations Framework Committee on Climate Change (UNFCCC) Background to UNFCCC Devolved administrations inventory This forms the basis of reporting against Scotland’s Climate Change targets – with some consideration of Scotland’s share of EU wide emissions trading

Headline Results - Source Emissions

Sources of Scottish Greenhouse Gas Emissions, Values in MtCO 2 e 9

GHG emissions fell by 3.6% in 2013; and by 34.3% since Values in MtCO 2 e Comparison with the Rest of the UK 2.2% drop in latest year; and 26.7% fall since 1990

Between 1990 and 2013? Absolute changes (MtCO 2 e) and percentage changes 11

The drop in 2013 is mainly due to electricity production. Cockenzie Power Station’s closure is a big factor.

…but the start of 2013 was very cold. (and the heating system is still on aggregate relatively inefficient and carbon intensive)

…despite this, emissions from households and public sector buildings didn’t rise, but they flatlined.

…emissions from waste continued to fall sharply…

The only rise of any note in the latest year was Business and Industrial Process Emissions But this is typical of the normal year-on-year volatility in the series.

Methodological Improvements, Revisions and Uncertainties

How is the inventory compiled? (1) Covers a wide variety of anthropogenic (man made) sources Different approaches and sources Methods used consistent with IPCC requirements

How is the inventory compiled? (2) Most emissions estimates = activity data (e.g. fuel use) x emissions factor (e.g. CO 2 emitted per unit of fuel) Some point source data (e.g. plant specific data used for reporting in EU Emissions Trading System (EU ETS) Some more complicated models – e.g. for landfill emissions, for estimating the carbon dynamics in soils “Bottom-up” and “top down” estimates

Revisions to the greenhouse gas inventory In October 2014, we produced an Statistics paper on Revisions to the greenhouse gas inventory since the time at which the Climate Change targets were set ( ) nt/Publications/ghgrevisionshttp:// nt/Publications/ghgrevisions This paper outlined and explained the key revisions by sector, on both a year-on-year basis and on successive inventories Attend National Inventory Steering Committee. Where available, we consider the impact of likely future revisions in our latest stats publication This is of real importance in the context of our Climate Change Targets

The largest ever revision to base-year emissions in the 2013 stats

A key revision: increase in the global warming potential of methane with a knock-on effect on emissions from landfill (and agriculture). Impact on Baseline (a 5.2 MtCO 2 e (6.9% increase in the latest year)

Scottish Greenhouse Gas Emissions. Impact of revisions across time series. Values in MtCO 2 e

Scottish Greenhouse Gas Inventory Uncertainties Project Background to project: We were questioned about what appeared to be high uncertainty in the figures from some of our users Some statistical sampling error – but many other causes of error Project Report Published on the 9 June Thanks to our contractors at Ricardo-AEA, who lead up a consortium of inventory compilers: Publications/GHGUncertainties2013Summary

Scottish Greenhouse Gas Inventory Uncertainties Project: Causes of uncertainty USE OF MODELS – A major source of uncertainty LACK OF REPRESENTATIVENESS OF DATA – moderate to high uncertainty LACK OF DATA – Moderate uncertainty STATISTICAL RANDOM SAMPLING ERROR - Will affect all estimation to a greater or lesser degree MEASUREMENT ERROR – affects majority of source emissions to some degree MISREPORTING OF DATA / LACK OF COMPLETENESS OF DATA - Very small sources of uncertainty GHG Inventories adhere to International Reporting Requirements

Any questions? Contact details Martin Macfie