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 ).
43