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A Summary of Climate Change Impacts in the West Midlands Combined Authority Area

Appendix B: Example Datasets

This section shows three example climate change vulnerability datasets, one for each of the themes considered in this summary (People, Infrastructure and Natural Environment). These show how data can be mapped and presented to visualise the impacts of climate change against certain metrics.

Example Dataset: IMD Decile

The IMD is the official measure of relative deprivation at a small local area (known as a lower super output area LSOA) level across England. The IMD Decile provides a rating for all LSOAs based on the 2019 IMD measure in England. ‘1’ represents the most deprived 10% of LSOAs (red), whilst ‘10’ represents the least deprived 10% of LSOAs (green). Across the WMCA, Birmingham, Sandwell, Walsall and Wolverhampton have greater levels of relative deprivation when compared with areas such as Solihull.

One of the key areas of exploration regarding the impacts to people relates to how climate change may disproportionally affect disadvantaged population subgroups. Because of the unequal distribution of environmental risks and related health outcomes, it’s important to identify those areas that are relatively more deprived.

Fluvial flood risk refers to flooding resulting from increases in the water levels of rivers and the sea, causing banks to overflow, spreading water to the surrounding area.

This type of flooding is not to be confused with pluvial flooding, which is flood risk associated with short periods of intense rainfall, overwhelming natural water infiltration rates, resulting in standing water unable to drain effectively. A combination of these flood risk categories has been analysed to show the overall flood risk in this impact assessment as both will likely be intensified by the impacts of climate change.

The outputs of this particular assessment alongside the range of other climate change impacts are shown within the climate vulnerability hotspots in the following section

Example Dataset: Fluvial Flood Risk Areas and Major Roads

There are a range of datasets used to help inform the impact assessment.

A key contributor to the climate impact assessment for infrastructure was the inclusion of the Environment Agency’s national classification of fluvial flood risk zones 2 and 3. Flood zone 2 refers to areas at risk of river flooding following between a 1 in 1000 and 1 in 100 year-flood event and flood zone 3 shows areas which are at risk in a 1 in <100-year event.

For the impact assessment, areas were categorised as at risk of flooding if they were in an area affected by either pluvial or fluvial flooding in a 1 in 100 year (medium flood risk) or above. Given that climate change is likely to seasonally affect precipitation rates, it is deemed that areas at risk of flooding will increase and it is likely that many areas currently at medium risk of flooding will be at high risk of flooding in the future. This dataset was used in all eight metrics for the impact assessment.

In Figure 16 it is evident that there are key corridors of Motorways and A Roads which are at risk of fluvial flooding. These can be seen in Central to Eastern Birmingham and a corridor running from Eastern Wolverhampton to Central Birmingham. Impacts from these roads at flood risk can create further risks such as increases in the likelihood of road traffic accidents.

The outputs of these datasets, along with others which have contributed to the assessment of infrastructure risks associated with climate change are shown in the following section.

Example Dataset: Climate Change Vulnerability

Within the natural environment impacts, one of the key areas of exploration relates to how climate change can induce habitat degradation/ loss. Due to the ranging interdependencies, conditions, strategic significance and biological composition of habitats within the WMCA, it is important to establish a metric which combines these factors into a tangible representation.

To achieve this, as part of their National Biodiversity Climate Change Vulnerability Model, Natural England created the Climate Change Vulnerability GIS layer.

The layer creates 200m x 200m squares, identifying locations of biodiversity habitats as identified by Natural England. It then uses a series of variables to define the vulnerability to biodiversity from climate change for each square. Each of the four characteristics used to define this vulnerability (habitat sensitivity, fragmentation, topographic heterogeneity and management/ condition) are scored out of three. The scale goes from least vulnerable (one) to most vulnerable (three), with the overall vulnerability being the average of all the scores combined. As seen on Figure 17, four categories have been used in the analysis, ranging from <0.75 in dark green to >2.25 in dark red for the highest climate vulnerability. These have been categorised to provide a further level of granularity in the analysis, highlighting at risk areas in greater detail. When looking across the WMCA, it is evident that the areas with the most vulnerable habitats to climate change centre around Walsall, North Wolverhampton,

Solihull and East Coventry when compared with areas with the least vulnerable habitats such as North and South Birmingham.

This dataset was used in two of the five metrics assessed during the development of this impact assessment combined with others, for example, flooding datasets, to identify areas of vulnerability. The outputs of how these datasets have contributed to the assessment of Natural Environment risks associated with climate change are shared in the following section.