Quantifying Greenhouse Gas Emissions

In this report, Quantifying Greenhouse Gas Emissions, the Committee on Climate Change assesses how the UK’s greenhouse gas emissions are quantified, where uncertainties lie, and the implications for setting carbon budgets and measuring progress against climate change targets. The report finds that:

• The methodology for constructing the UK’s greenhouse gas inventory is rigorous but the process for identifying improvements could be strengthened.
• There is high confidence over large parts of the inventory. A small number of sectors contribute most to uncertainty, and research efforts should be directed at improving these estimates.
• UK greenhouse gas emissions for 2014 were within ±3% of the estimated level with 95% confidence, which is a low level of uncertainty by international standards.
• Methodology revisions in recent years have tended to increase estimated emissions, but these changes have been within uncertainty margins.
• Statistical uncertainty in the current greenhouse gas inventory is low, but could rise in future.
• Uncertainty also arises from sources of emissions not currently included in the inventory and from potential changes to IPCC guidelines.
• Independent external validation of greenhouse gas emissions is important and new monitoring techniques should be encouraged.
• Government should continue to monitor consumption-based greenhouse gas estimates and support continued research to improve methodology and reduce uncertainty in these estimates.