Figure 5: Simulated Annual Rainfall from year 1980 – 2069 in the Cameron Highlands
Results and Discussion
Temperature Global increases in temperature are related to increases in greenhouse gases in the atmosphere. The global average surface temperature rose 0.6 ° C to 0.9 ° C between 1906 and 2005( CET, 2004). The rate of temperature increase has nearly doubled in the last 50 years. Temperature has an important impact on living and non-living things, including water resources.
In this study, the maximum, minimum and mean temperature from year 1980 – 2069 have been projected for the chosen study area. Figure 2 shows the results of simulated maximum, minimum and mean temperature from year 1980 – 2069 in the Cameron Highlands. This graph shows three equations correspondingly which are y = 0.0421x – 59.715 for maximum, y = 0.0249x – 30.786 for minimum and y = 0.0315x – 41.109 for mean. The model shows that in the next 100 years, the maximum, minimum and mean temperatures are expected to rise 4.2 °, 2.5 ° and 3.2 ° C respectively.
However in Figure 3, the observed maximum, minimum and mean temperatures show different slopes. Thus the equations y = 0.0282x – 33.99, y = 0.0113x − 7.176 and y = 0.0197x – 20.583 have a smaller gradient where the maximum, minimum and mean temperatures are estimated to increase 2.8 °, 1.1 ° and 2.0 ° C respectively in 100 years’ time. This complies with the observation in the field where local people commented“ warmer days, less cold days / nights”.
After bias corrections have been carried out, the maximum, minimum and mean temperature equations become y = 0.0383x – 54.178, y = 0.0283x – 38.62 and y = 0.0182x – 23.061. The degree of temperature rise after correction is smaller than simulated data. After correction, the maximum, minimum and mean temperatures are estimated to rise 3.8 °, 1.8 ° and 2.8 ° C in 100 years’ time as shown in Figure 4.
According to Stern et al( 2006), each degree of temperature rise brings a different level of impact. With an increase of 2 ° C, crop yields will drop by 5 % – 10 %. While with an increase of 3 ° C, increased flooding events will occur. A 4 ° C of temperature rise causes agricultural yields to drop 15 % – 35 %. This is a terrifying figure which could eventually lead to food shortage when over half of Malaysian vegetable demands are supplied by Cameron Highland farmers( Barrow et al, 2009).
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