Climate Change
With the current process of climate change, the whole world is expecting to face major challenges in order to adapt to and mitigate the consequences of severe weather conditions.
An increase in temperature can cause discomfort, economical loss, migration and increased mortality rates. In addition, there are predicted increases in extreme weather events (e.g. heat waves, floods, droughts, wildfires and windstorms), with several parts of the world predicted to be exposed to multiple climate hazards at once.
The urban climate often differs from the surrounding rural countryside as it is generally more polluted, warmer and less windy
This suggests that the effect of climate change with the predicted increase in temperature and more extreme weather events will be experienced to a greater extent in urban areas compared to the surrounding landscape. The changing climate might also exaggerate the negative effects of urbanisation already experienced, such as increased urban temperatures and flooding.
Effect on Urban Temperatures
Changing urban temperatures are driven both by large-scale climatic changes and ongoing urbanisation. The urban temperature is dependent on global development but is in general highly influenced by, e.g. the urban heat island (UHI) effect which is seen as a major problem of urbanisation .
There are three parameters of urbanisation that have direct bearing on UHI, namely,
- increasing amount of dark surfaces such as asphalt and roofing material with low albedo and high admittance,
- decreasing vegetation surfaces and open permeable surfaces such as gravel or soil that contribute to shading and evapotranspiration
- release of heat generated through human activity (such as cars, aircondition, etc.).
These factors are not equally distributed across the city, and hence, certain areas will experience the UHI to a higher degree. The effect will, for example, be higher for areas with a high degree of built-up land and little green space than for leafy suburbs and hence will effect the population differently within an urban area.
Effect on Urban Hydrology
With a changing climate, the frequency of flood peaks is predicted to increase in several regions. Estimations point towards an average doubling of severe flood peaks. In addition, this is matched by a rise in sea level that, together with a predicted increase in windstorm frequency, will lead to an increase in coastal flooding . As most of the urban areas are situated either on floodplains or along the coast, these two types of flooding will have a major impact across cities, translating also into more frequent basement floodings.
This means that the current urban drainage system will exceed its capacity more frequently, causing economic loss, increased discomfort and even loss of lives. This is why, the existing drainage systems need to be relieved hydraulicly.
Consequences
Heat waves and heavy rainfall events increase dramatically.
The health of humans and animals, especially in the cities is effected by an increasing number of heat waves and floods.
Due to floodings, urban wastewater usually reaches the nature untreated, because the sewer networks are overloaded.
We are the first generation to be able to end poverty, and the last generation that can take steps to avoid the worst impacts of climate change. Future generations will judge us harshly if we fail to uphold our moral and historical responsibilities.
– Ban Ki-moon, Secretary-General, United Nations.
Climate change is not a hoax. More droughts and floods and wildfires are not a joke. They are a threat to our children’s future.
– Barack Obama, President of the United States of America.
Climate change is no longer a far-off problem; it is happening here, it is happening now.
– Barack Obama, President of the United States of America.