Seasonality of Rainfall
Seasonality of rainfall refers to the cycles of rain during a year, which produces predictable seasons of rainfall. It is important in regulating the distribution of species, and also planning planting and harvesting seasons. Changes in the seasonality of rainfall will disrupt this predictable pattern of seasons, with certain areas may become wetter or drier. This may alter the type of plants and animals living in an area, and disrupt agriculture.
Climate Extreme Indices on the Changes to Rainfall in Sabah under a +2.5°C Warming Scenario for 2071-2100
In Kampung Wangkod, the paddy planting community has begun describing rainfall patterns as unpredictable. Similarly, the community of Kampung Pulutan in Keningau feel a loss of regular seasonality, and claim that ordered cycles of “musim” is a thing of the past. Now four seasons can come at any time: cold; dry & hot; wet; and wet & hot.
Data layer download: Change in length of Dry Season, Number of days >20mm of rain, Heaviest 24-hour precipitation total
Research source: Climdex
Precipitation to Potential Evapotranspiration (P/PET) ratio
The Precipitation to Potential Evapotranspiration (P/PET) ratio is a way to understand the balance between water received from precipitation and the water that could be lost to evaporation and plant transpiration.
The ratio is a useful tool for understanding water availability and the health of ecosystems in a particular region. Knowing the ratio allows us to assess factors such as plant species availability and water availability for human use and agriculture.
P/PET ratio for End of Century
Projections for 2071-2100 average
Current Situation
Scenario at +2.5°C warming (2071-2100)
The projection shows that Sabah will experience longer months with a P/PET ratio below one, with certain areas such as Sook experiencing a <1 P/PET ratio for almost the entire year. Northern and eastern Sabah also will suffer a <1 P/PET ratio for about half a year according to the projections.
This can have major consequences to Sabah’s ecosystem and peoples; to the ecosystem it can result in a change in biome due changes in the water balance in the system, and to the communities the impacts can be felt to the water availability for rain-fed agriculture. A prolonged period of <1 P/PET ratio will result in water scarcity and the risk of drought stress, which can lead to poor harvests.
