Belfast Climate Pack

Summary

This case study is a summary version of the original text which can be downloaded from the right-hand column. It highlights some of the climate pack’s key messages, but please access the downloadable resource for more comprehensive details and images/figures which have not been included.

Introduction

This City Pack was created in collaboration with Belfast City Council and Climate Northern Ireland as a product of the UK Climate Resilience Programme and published in August 2022. This City Pack provides high level, non-technical summaries of climate change projections for Belfast. It uses scientific research to provide robust climate information to help decision makers plan for the future, enabling cities and towns to become more resilient to climate change. Urban areas experience unique challenges from climate change. For example, urban environments contain surfaces which don’t soak up and store rainfall, such as tarmac and paving, which might increase flood risk. Urban areas are also affected by the urban heat island effect, which results in higher urban temperatures compared with surrounding rural areas.

What affects the region’s weather?

Belfast is located within Northern Ireland, which includes the six counties of Antrim, Armagh, Londondery, Down, Fermanagh and Tyrone. Here are some of the types of weather that the region experiences across a year:

Northern Ireland has a stable climate due to the moderating effect of the Atlantic Ocean, resulting in mild winters and cool summers. The indented shape of the coastline and the presence of high ground introduce localised differences in weather.

July is normally the warmest month in Northern Ireland, with mean daily maximum temperatures varying from about 17.5 °C in the upland areas and along the north coast to almost 20 °C in low lying areas south of Lough Neagh and in Fermanagh.

The wettest months in Northern Ireland are between October and January, although this seasonal trend is less marked in the drier southern and eastern areas. This results from a high frequency of winter Atlantic depressions and a relatively low frequency of summer thunderstorms.

Northern Ireland is one of the windier parts of the UK, with the windiest areas being over the highest ground and along the coasts of Counties Antrim and Down. At low altitudes in Northern Ireland, gales occur most frequently on the coasts of Antrim and Down with an average of around 15 days of gale each year.

Observed Changes

How are temperature and rainfall changing across the UK? These maps show changes in temperature (left) and rainfall (right) from 1991-2020 compared to a baseline period of 1961-1990. We can see that temperatures have risen in all areas across the UK. We can also see that whilst some areas have become drier, more areas have become wetter.

Projections used in the city pack

The City Pack uses the UK Climate Projections (UKCP) Probabilistic Projections at 25 km resolution.

High Emissions Scenario: 90th percentile in red indicates a 90% chance of the temperature being less than this result.

Medium Emissions Scenario: 50th percentile in green indicates that there is a 50% chance of being less than this result.

Low Emissions Scenario: Dotted line in blue. This City Pack does not focus on this scenario, as the world aims to limit warming through emission reductions, such as those or even greater than RCP2.6. However, it is good practice to consider the risks if this goal is not achieved.

Emission Scenarios

Our future climate is determined by ongoing and future greenhouse gas emissions, which are uncertain. To capture this uncertainty, we use emissions scenarios, such as the Representative Concentration Pathways (RCPs). RCPs describe possible future emissions based on assumptions about human activity.

The RCP pathways represent a broad range of possible futures and are neither forecasts nor policy
recommendations.

UK Climate Projections Results

Under a high emission scenario we could reach an increase in averge global temperatures of 4°C above a 1981-2000 baseline as soon as 2065. Under a medium emission scenario we wouldn’t expect to reach 4°C within this century. Under a low emissions scenario, with stronger mitigation, we may not reach 2°C of global warming. These dates are not forecasts, but simply offer possible futures for comparison. Global warming level dates may not always correspond with the City results below, due to differences in spatial scales. Global warming levels tell us about future temperature change at the global scale but not necessarily changes at the local scale.

Belfast

The map above shows the location of Belfast and the area in focus for this City Pack. Projection information provided within this City Pack is calculated as the average (mean) value across the smaller inset box (a 25 km grid cell). This box may include rural, coastal and mountainous areas as well as urban areas. As such, results for point locations within the grid box may differ from the average result of the box. At 25 km resolution, detailed urban effects are not represented in the model. For urban representation, a higher resolution model is required. The use of UKCP Local (2.2 km) may be more appropriate.

Belfast Climate projections

Table: Ranges in projects for the 25km grid box containing Belfast. Results are calculated as change from the baseline period: 1981-2000. Summer: June, July, August. Winter: December, January, February.

Time periods are 20-year time slices: 2020-2039, 2040-2059, 2070-2089. Precipitation is relative change (%) in mm per day.

The projections are provided as a ‘range’. The 1st number in the range is RCP 4.5 at the 50th percentile. The 2nd number in the range is RCP 8.5 at the 90th (except summer rainfall, which is the 10th percentile), calculated from UKCP 25 km Probabilistic Projections.

Results show changes in variables averaged over a season, and as such do not represent possible extreme conditions. For assessment of possible extremes, the use of UKCP Local (2.2km) may be more appropriate.

Understanding climate risk

We are already witnessing the impacts of a global average temperature rise of over 1°C compared to pre-industrial levels. Without global action to limit emissions, we may exceed even 4°C of global warming. The Paris Agreement says that we must limit global warming to well below 2°C, whilst aiming for 1.5°C. The Committee on Climate Change advises the UK to adapt to a 2°C rise in temperatures, whilst assessing the risk at 4°C. Following COP26, limiting warming to below 1.5°C above pre-industrial levels remains possible but will require bigger emission reductions than currently pledged by nations around the world. Current emission reduction pledges, made as part of nationally determined contributions, are likely to lead to warming above 2°C.

Definitions in the Climate Pack

To achieve Net Zero, and also prepare for the impacts of climate change, to which we are already committed, both mitigation and adaptation approaches are required. Mitigation includes efforts to reduce or prevent emissions of greenhouse gases, mitigation reduces the need for adaptation. Adaptation is Action that helps cope with and reduce the impacts of climate change. Adaptation is crucial in addressing the “locked-in” effects of climate change. Net zero and beyond: Ending contributions to global warming by balancing emissions released with emissions removed from the atmosphere. Co-benefits: The positive effects that taking climate action has on society.

Adaptation and mitigation both help to reduce the risk a city will face from climate change. Mitigation will help to limit the hazard, whilst adaptation can help to reduce exposure and vulnerability.

Further information

The City Climate Pack includes QR codes to access further information on the CIty Packs, datasets, factsheets, resources on adaptation and resilience. Please see the downloadable Pack in the right hand column.