Online Briefing report 1 Introduction
Climate is changing, both globally and in the UK. The Fourth Assessment Report (AR4) from the IPCC (Intergovernmental Panel on Climate Change) in 2007 said that “it is very likely that anthropogenic greenhouse gas increases caused most of the observed increase in global average temperatures since the mid-20th century”, and more recent research has increased confidence in this statement. Changes projected by climate models are likely to result in significant impacts on the UK. And, because of the inertia of the climate system, current global emissions, and those over the past few decades, have already committed us to future climate change which cannot now, in any practical sense, be avoided.
These three factors: the high likelihood that mankind has already begun to change the earth’s climate, the projections of significant impacts in the future, and the commitment to further change over the next few decades irrespective of any emission reductions in the short term, argue very strongly for a strategy of adaptation to minimise the consequences, and maximise the opportunities, of climate change. To adapt effectively, planners and decision-makers need as much good information as possible on how climate will evolve, and supplying this is the aim of the new projections of UK climate change in the 21st century, known as UKCP09. They are one part of a UK government programme of work to put in place a new statutory framework on, and provide practical support for, adaptation.
The projections have been designed as input to the difficult choices that planners and other decision-makers will need to make, in sectors such as transport, healthcare, water resources and coastal defences, to ensure the UK is adapting well to the changes in climate that have already begun and are likely to grow in future. The underlying projections are in the form of numerical data that can be explored and downloaded with a purpose-built User Interface; this can also be used to visualise the data in the form of maps and graphs.
The UKCP09 projections are supported by several publications, primarily online, in particular:
- The climate of the United Kingdom and recent trends
- UK Climate Projections science report: Climate change projections
- UK Climate Projections science report: Marine and coastal projections
- UK Climate Projections science report: Projections of future daily climate for the UK from the weather generator
This report, and the science reports on which it is based, have been reviewed by the project Steering Group and User Panel. Reviewers’ comments have been taken into account in improving the report. The methodologies used to generate the UKCP09 projections were reviewed by an international panel of experts.
This Briefing Report aims to summarise the information in the four reports, for those requiring a general awareness of UK climate change. It begins by summarising recent observed changes in UK climate, in Section 2. It next turns to projections of change, where a major improvement in UKCP09 is the way in which uncertainty is dealt with. Because this is done differently for climate variables (temperature, rainfall, etc.) than it is for those in the marine and coastal environment (e.g. sea level and waves) the Briefing Report also follows this separation. Thus Section 3 summarises the methodology used to quantify uncertainties in climate variables, Section 4 describes the information provided in the probabilistic projections, and Section 5 shows some example projections of changes in temperature and precipitation. Section 6 presents the same sort of summary for the marine and coastal environment.Figure 1 (see below) summarises all the information, in different forms, available to support the projections. The process of developing UKCP09 has included consultation with both climate experts and potential users, through its Steering Group and Users’ Panel. Hence, the projections are designed to be aligned as closely as is possible with what users need to support their assessments of risk and choice of adaptation measures.