Climate change poses increasingly significant risks and challenges, including to churches and other buildings.
Church officers, architects and Quinquennial Inspectors, and other construction professionals working for parishes and churches, all need to understand these risks and how to mitigate them.
So far in the UK, climate change has mainly shown itself in higher temperatures, rainfall and river flooding.
Temperatures have become extreme, especially in the July 2022 heatwave, when the mercury reached more than 40 deg C.
In recent years there has also been an incidence of wildfires in the UK. On 19 July 2022, homes and businesses in Wennington on the outskirts of London (Chelmsford Diocese) suffered destruction to a number of homes and businesses. Such wild fires are mounting in scale and severity around many countries worldwide.
On average, UK temperatures have risen more or less in line with global heating, from the early 20th to the early 21st c.
Since 2014, global average temperatures have been shooting up alarmingly. The warmest years in the record (worldwide, so far) were 2016 and 2020, with 2019 close behind.
The UK is on the fringe of a relatively cool spot in the north Atlantic, possibly associated with a weakening of the Atlantic Meridional Overturning Circulation (AMOC, or the ‘Gulf Stream’). ‘The jury is out’ on whether that will in time cause net cooling in the UK, slow down the warming slightly – or even increase it.
Average increases from the 1910s to the 2020s are about 1.8% of the total temperature range that occurs in the UK, which is -27C to +40C (not in the same place, of course). That might seem a trivial amount of warming. However it is far from negligible, and can have and has had dramatic real world consequences.
There is about 4% more moisture in the clouds over the UK than the historic average, due to increased evaporation from the oceans. Rainfall has increased significantly towards the north-west of the UK mainland, relative to the 1961-1990 mean; on average it has decreased slightly towards the south-east, including in London.
Drought has been more prevalent in the south-east, though there have been major rainfall events as well. When rain comes, it seems to be getting more concentrated in sudden downpours. Time will tell how the pattern is shifting in the long-run. But the consensus is there will be major changes, with more rain on and flooding on average.
Weather extremes are already beginning to occur with greater frequency and the seasons are becoming more chaotic, especially Spring and Autumn. There are also periods where the pattern of weather becomes locked in by the position of the jet stream.
Some severe winters may still occur in the UK, in spite of the general warming; though they are expected to become less common worldwide. It is notable how temperature highs, lows and averages are all slowly rising, on a range of timescales. For example, the cold winters of 2008/9, 2009/10 and 2010/11 were much less severe than those of 1946/7 and 1962/3.
Heat waves are becoming more frequent, longer and more extreme – the July 2022 heat wave being the most extreme (a maximum of 4.4 deg C hotter than 2006 – though the heat wave in 1976 lasted longer, for 16 days). Unfortunately, heat wave definitions vary – and the Met Office updates them periodically – so it is difficult to compare like with like. Nonetheless the trend towards increasing extremes is clear.
Climate risks to churches and their buildings in London over the next few years may include the following:
Poor air quality is thought to be responsible for several thousands of excess deaths each year.
Although the London smogs caused by soot are a thing of the past since the Clean Air Acts, air pollution has become more notorious in recent years due to tailpipe emissions from vehicles, including oxides of nitrogen and particulates, being only partly controlled by the London Low Emissions Zones.
Lead has of course been eliminated from petrol, but there remains a degree of acidification in the rain.
Metal including iron, steel and bronze are at increasing risk of corrosion due to poor air quality.
Increasing adverse effects are expected from growth of bacteria, mosses, lichens, fungi and ivy on buildings of all kinds due to a warmer wetter climate.
Also we are seeing the introduction of new species (and the recession of others) as their habitats generally shift northwards.
Different kinds of action in response to climate and environmental threats can be divided into three categories:
All three kinds of action are needed. Buildings we build now must remain habitable in the event of extreme flooding and also high temperatures.
In some respects historic buildings, having survived a process of natural selection, are those best adapted to the range of climates they have so far encountered, so long as they remain well maintained. But now extreme weather is become more frequent and severe, and may soon move into no-analogue situations.
An assessment of any ancient building is advisable, for its capacity to withstand high wind loads and to handle high volumes of rainfall without overflow of gutters, hoppers and pipes. This may indicate upgrades that are necessary in individual cases. Some building elements may also require more frequent replacement even if on a like-for-like basis.
Traditional buildings need to move and need to breathe. Inappropriate imposition of insulation or over-rigorous draught exclusion can lead to heat stresses on the structure and/or condensation and mould growth.
Potential impacts on particular buildings should be assessed through quinquennial inspections (QIs).
Owing to successive PCCs, QIs and architects, over the last 30 years an immense volume of stone repairs has been completed in the Diocese. Steeples were rebuilt after being scraped of their soot – e.g. St Mary-le-Strand, St Clement Danes. Others had rusting iron ties replaced, e.g. St Mary Aldermary in the City.
However the job is not done. There is a catalogues of repairs needed now to churches. Some of these present greater risk in an extreme weather event. Incidences of severe and prolonged neglect have become apparent.
Has your PCC prioritised remaining essential repairs – especially to steeples, spires and finials? Sandstone and soft limestone or brick are the most vulnerable materials.
Where resources are tight, at least get a steeplejack’s survey and report. A photogrammatic survey may be considered, making any reconstruction easier.
Some more points for thought and action:
A report of 2003, ‘Climate Change and the Historic Environment’, May Cassar and Robyn Pender, University College London, advocates amongst its recommendations:
The EU’s project, with several UK universities including UCL, ‘Climate Change Impact on Built Heritage’, set out to map the likely impacts of climate change on heritage sites in different European regions, including the UK.
Intermediate results were presented in a conference in 2006. Qualitative conclusions included:
Data on insurance claims is among the evidence that climate change is real.
Always keep your insurers informed of significant events and action taken. Consult or at least inform them of impending works or other measures.
Parish Property Support Team
Head of Environment and Sustainability.
Flooding in churches
Climate Action Projects
Sustainable Building.
Sustainable Traditional Buildings Alliance.
Environment and Sustainability, front page.
