LIST OF EQUATIONS
2. Chapter 2 Impact of Climate Change on Pavement Resilience Resilience
2.2. Climate Change
2.2.3. Observations on Climate Change
Climate change can be seen in the form of changes in the temperature, precipitation and sea level, as discussed below.
2.2.3.1. Temperature
Based on the data from the IPCC, average global temperatures have increased by 0.74°C during the past 100 years (Qiao 2015). Results revealed that the increase in temperature over the most recent 50 years is almost double that of the past 100 years (Qiao 2015).
Estimation of temperature change by climate models shows a warmer forecast for the future. For example, based on the IPCC report, it is forecasted that average global warming will increase in the range from 1.1°C to 6.4°C by the end of the 21st century (see Figure 2-2). This phenomenon has recently been seen in the decline of the occurrence of cold days and nights and also the increase of hot days and hot nights.
Moreover, heat waves have become more regular occurrences (IPCC 2007;
Pavlopoulos 2010).
Figure 2-2: Global surface temperature change (IPCC 2007)
22 2.2.3.2. Precipitation
The International Panel on Climate Change (IPCC) report stated that precipitation across the world is varied. It has defined some areas, such as North and South America, northern Europe, and northern and central Asia that recorded a dramatic increase in precipitation between 1900 and 2005, whilst other places in the world such as the Mediterranean, southern Africa and parts of South Asia recorded less rainfall for the same period (IPCC 2007). An example of high precipitation occurred during a UK storm on 28 June 2012, which resulted in extensive disruption to the whole country, for instance, severing the main rail links between England and Scotland, causing delays of 10,000 minutes to services across the nation (Jaroszweski et al. 2015). It was also recorded that, within a period of five minutes, there were over 1000 lightning strikes in the UK and a total of over 50,000 were recorded during the day (Jaroszweski et al. 2015).
2.2.3.3. Sea Level Rise
The IPCC report indicates that the yearly increase in global sea level between 1961 and 2003 was at a rate of 1.8 mm with a total rise of 1.7 m in the 20th century (Pavlopoulos 2010). By considering the future impact of climate change on the global sea level rise, Church et al. (2008) stated that more increases will occur and could reach as much as 0.97 m by 2100 due to both glacial melting and thermal expansion.
Furthermore, Demirel, Kompil and Nemry (2015) stated that the degree to which the sea level rises is not constant across the globe. For example, an additional 15–20 cm could be added for the area of northern Europe. On the other hand, fluctuation in atmospheric pressure can also result in changes in the sea level, which may lead to catastrophic storms with strong onshore winds followed by very high coastal sea levels (storm surges) (Demirel, Kompil and Nemry 2015). Such an event was recorded on the United Kingdom’s North Sea coast, when a high tide level of more than 2 m occurred during the winter of 2013/2014. This storm resulted in severe damage in the east of England (Huntingford et al. 2014).
2.2.3.4. Snow and Ice
As was discussed earlier, the temperature has started to rise, and the consequences of this action will lead to snow and ice melting. Overall, the IPCC report defined that the annual average speed of ice retreat in the Arctic Ocean was found to
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be 2.7% per decade, which will eventually lead to increases in sea level (IPCC 2007;
Qiao 2015).
2.2.3.5. Extreme Weather
Extreme weather consists of heat waves, heavy precipitation and extremely high sea levels (Pavlopoulos 2010). This phenomenon has become more frequent in the last 50 years. For example, cyclones (typhoons and hurricanes) could become more intense, with more significant peak wind speeds and heavier precipitation (IPCC 2007).
Based on the highlighted literature, part of the research is to examine the emerging role of temperature in the context of climate change impact. Therefore, the research only considers the element of increases in temperature. More details are explained in sections 3.2.1 and 5.11.2
2.2.4. Impact of Climate Change in the UAE
2.2.4.1. Background
The UAE lies in a hot and water-scarce (water deficit rises every day) arid region. The country’s climate is classified by high temperature in summer, moderate winter, deficient rainfall, high evaporation rate and limited non-renewable groundwater (Chowdhury, Mohamed and Murad 2016). In the UAE, the months of summer are April to September. These months are extremely hot as temperatures reach 48˚C in coastal cities and 50°C in the southern desert area (AlRustamani 2014).
Moreover, the humidity levels reach 90% in coastal cities and drop in the southern desert area. According to statistics, the average yearly rainfall can be 140-200 mm and sometimes reach 350 mm in the mountainous regions along the north-east coast (Chowdhury, Mohamed and Murad 2016). Most of this rainfall occurs between December and April (Chowdhury, Mohamed and Murad 2016). It has also been forecasted that the temperature in the UAE will rise by between 2.79 oC and 3.8 oC (AlRustamani 2014; Chowdhury, Mohamed and Murad 2016).
2.2.4.2. Climate Change Projection in the UAE
According to the IPCC (2013), global warming is virtually guaranteed. For instance, in 2016, the world experienced the hottest year ever (Venturini et al. 2017).
The Environment Agency - Abu Dhabi (EAD) in conjunction with the United Nations
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Environment Programme (UNEP) developed the Weather Research and Forecasting (WRF) model and Regional Ocean Model (ROM). The findings of the WRF model in conjunction with the IPCC for the UAE are summarised as shown in Table 2-1.
Table 2-1: UAE climate change model outcomes by Venturini et al. (2017) Climate
parameter
Expected change Rate of change
Temperature Suggests a strong upward trend in average
temperature in the UAE
Increase of between 2 and 3°C during the summer months by 2060-2079
1°C by 2020 and between 1.5 and 2°C by the 2040s
Humidity Suggests an increase in humidity
Suggests an increase in humidity of about 10%
over the entire Arabian Gulf by 2060-2079 Precipitation Suggests an increase in
average annual
precipitation. This trend is stronger during the usually drier summer months and is associated with a reduction in the number of ‘wet days’
Possible increases of up to 200% in the annual maximum 1-day precipitation
Marine and coastal
Suggests that the Sea Surface
Temperatures (SSTs) of the Arabian Gulf could be warmer
1°C to 2°C by the end of the century
Sea level Sea level globally is likely to rise
Around 0.06 m by mid-century (1.5 mm per year over the next 40 years)
Storms There is some evidence that the Arabian Gulf coast of the UAE could
be exposed to tropical cyclones in the future
Tropical cyclones could be less frequent but more intense (2-11% increase) and produce substantially higher rainfall rates (10-15%)
Finally, the UAE is not isolated from climate change impacts. The signs of variations in temperature, precipitation and sea level conditions can be observed as such impacts are already being felt by people living in the country. The main climate change risk facing the UAE can be seen as heat and water stress. The area is strongly prone to rising temperatures and lack of water. UAE climate change model outcomes highlighted by Venturini et al. (2017) are applied in this research. More details are provided in sections 3.2.1and 5.10 .