There are five aspects of development proposals that should be considered when managing for adaptation to climate change:
- Heat island effect in urban areas
- Thermal comfort within the building
- Drainage and flood risk
- Water use and availability
- Building fabric resilience to climate change
Heat Island Effect
It is a well document fact that the ambient temperature within cities is significantly higher than in the surrounding area. It is estimated that on a warm summer’s day the difference between central London and the greenbelt can be as much as 8°C.
Thermal comfort in buildings
The appropriate cooling and heating demands for buildings has always played a major part of high rise and large commercial buildings, but it is now becoming a more general issue.
The low energy efficiency of buildings built fifty years ago, had at least a benefit in providing sufficient informal ventilation to allow for cooing during warmer periods in the year. Increased air tightness to reduce heating demand of buildings in combination with the predicted changes in temperature as a result of climate change has now put a formal consideration of thermal comfort firmly on the agenda.
Air conditioning is a very energy intensive form of cooling and although it can very effective for the building form a cooling perspective its overall effect is that it worsens the situation both through increased greenhouse gas emissions and heat emissions that exaggerate the heat island effect.
Drainage and flood risk
Although the current projections are that on average the annual amount of rainfall does not dramatically change as a result of climate change, there are great changes to the pattern of rainfall. The summers will see much more frequent and longer dry spells, whereas winters will be wetter and more intense rainfall will occur.
These changes will have an effect on the requirements of drainage capacity. It will need to perform well under circumstance of much higher intensity rainfall as well as with greater fluctuations on the capacity demand.
Water use and availability
Although the current projections are that on average the annual amount of rainfall does not dramatically change as a result of climate change, there are great changes to the pattern of rainfall. The summers will see much more frequent and longer dry spells, whereas winters will be wetter and more intense rainfall will occur. This will put a strain on managing adequate levels of available potable water in many areas in the south of England, which is already under severe pressure.
Building fabric resilience
With regards to building fabric resilience there are two main aspects that can be affected by climate change: structural stability and weather proofing.
Structural stability
The greater variability in rainfall intensity with short spells of higher intensity alternated by longer spells of drought, will increase the risk of subsidence to some building projects. Higher temperatures may also effect the strength of structural materials. This can be a positive change: it has been noted that steel actually gains in strength with higher temperatures.
Increases in storm activity may increase the wind load on buildings, although the current climate change projections are very limited in their predictive capacity of this element.
Weather proofing of materials
There are a number of climate change factors that may have an effect on the durability and weatherproofing of materials. Firstly the increased occurrence of high intensity rainfall may lead to increased erosion of building materials, for instance that of cement mortars in brick walling. The increased rain intensity may also lead to higher levels of water penetration as saturation of building materials is reached sooner and before a dry spell can restore the materials to normal again.
Higher sunlight intensity will also lead to more exposure of materials to UV light and its deteriorating effect on certain materials.