This study investigates the El Niño‐Southern Oscillation (ENSO)‐related seasonal variations in precipitation extremes based on the observed daily precipitation dataset of 23 meteorological stations in Malaysia, spanning a period of 46 years from 1966 to 2011. The extreme indices were a subset of the Expert Team for Climate Change Detection and Indices (ETCCDI) that covers the duration, frequency and intensity aspects of precipitation extremes. Seasonal composites of ‘El Niño minus neutral’ and ‘La Niña minus neutral’ years of these indices were computed based on El Niño and La Niña occurrences during the period. The results showed that the ENSO‐related variations in precipitation extremes were generally coherent with the variations in total precipitation. Generally, dry (wet) precipitation extremes tended to enhance during El Niño (La Niña); however, this was dependent on season and location. The El Niño and La Niña influences on precipitation extremes were not entirely linear. While the impacts of El Niño and La Niña were generally opposite for most locations and seasons, there were cases where both exerted in‐phase influences. The impacts were also dependent on the intensity of the event itself. While the El Niño impacts were generally coherent across different intensities, La Niña can have entirely different impacts among different categories. During December–January–February (DJF), strong (moderate) La Niña caused a significant decrease (increase) in wet precipitation extremes over the Peninsular Malaysia. This was related to the broadening (narrowing and westward displacement) of the anomalous cyclonic circulation over the western north Pacific during strong (moderate) La Niña. Hence, the likelihood for widespread flooding over the east coast of the Peninsular Malaysia during DJF increases during moderate but not during strong La Niña events.

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The changes of soil organic carbon and soil carbon decomposition are in uenced by temperature and precipitation changes. In the present study, the changes of soil organic carbon under climate change scenarios were estimated by the Rothamsted Carbon model in di erent land-use areas in the north and northeast of Iran. The total soil organic carbon was observed 106.2 tC/ha in the study area. RothC model was used to simulate the change of SOC at 980 original 50 km 50 km grids under A2 and B2 climate scenarios during the upcoming decades the study area. Future temperature and precipitation data under both scenarios were predicted by LARS-WG weather generator model based on the IPCC AR4. The simulated results of soil organic carbon illustrated that over the period 2010-2065, SOC will decrease in the study area. The simulation of soil organic carbon strongly suggests that SOC levels will decline due to temperature increase and decline in precipitation, particularly in cultivated lands. SOC is expected to decrease under A2 climate scenario by 8.3 tC/ha and 13.36 tC/ha by the years 2030 and 2065, respectively. Likewise, under the B2 scenario, SOC will have decreased by 8.58 tC/ha and 13.81 tC/ha by the years 2030 and 2065, respectively.