Last year was the warmest since the Last Interglacial Period 125,000 years ago, when sea levels were 6 to 9 meters higher than they are today.
One can only speculate about the long-term effects of the unfolding climate drama, but – judging from recent news reports – rising temperatures, wildfires and irregular rainfall patterns evidently are now a permanent part of the big picture.
According to a summary of scientific research on rainfall patterns, an increase of 22 millimeters per decade of “wet-day rainfall” in Southeast Asia was reported some time ago by the Intergovernmental Panel on Climate Change. The increase has been marked by increased frequency of heavy rainfall and decreased frequency of “light rain events”.
In October, Severe Tropical Storm Kristine brought unprecedented rainfall to Bicol, resulting in landslides in Bato and heavy flooding in Albay, where 413 millimeters of rain fell in 17 hours – equal to two months of average precipitation.
Daet, Camarines Norte, recorded 528.5 millimeters of rain in a 24-hour period, surpassing records dating back to the 1920s.
Similarly, Naga City experienced approximately 700 millimeters of rain, leading to widespread flooding that affected 70 percent of its population.
These changes in rainfall patterns are expected to affect agricultural practices and productivity. This is especially true in the “rice belt” of central and southern Luzon, including the Bicol Region.
Scientific research on rainfall patterns in the Philippines is scarce. One reason for this is the wide variations in terrain, which affect rainfall patterns and limit broad generalizations.
Also, some parts of the Philippines, including the Bicol Region, are affected by both the Southwest Monsoon and the Northeast Monsoon, while other regions are affected by only one or the other. Finally, there is a paucity of scientifically collected meteorological data.
In any case, a few meteorological studies exist, and they reveal significant changes in rainfall patterns across southern Luzon. For the next two months, for example, rainfall in Catanduanes is expected to be “above normal” or “way above normal”, according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).
These changes are driven by shifting cloud cover patterns that experts say could reshape agricultural practices.
In a review of scientific research on the matter, the Philippine Journal of Science reports that the recurrent rainfall incidence in the Philippines greater than 350 millimeters has been recorded more in the last decade, compared to 275 millimeters during the 1960s and 1970s.
The journal said there is “an increasing trend in the cumulative rainfall across timescales in most stations in the region, which has an implication on the timing of the optimum cropping patterns in agricultural areas and on the hydrology of the watershed in the region.”
Overall, the research shows an increasing trend in total rainfall, which has “an implication on the timing of the optimum cropping patterns in agricultural areas and on the hydrology of the watersheds in the region.”
Aside from adjustments in crop calendars, the journal recommends provisions for adequate drainage, flood control and erosion control.
On a more positive note, the amount of rainfall affects hydroelectric power generation. In Catanduanes, where power blackouts are commonplace, three hydroelectric power stations generate most of the island’s total power demand of 6.5 megawatts, but only if the reservoirs have enough water.
Individuals seeking the latest information on rainfall in the Bicol Region may visit the website “Bicol Region Precipitation Monitoring”. A “Maproom” on the website shows the last day of available rainfall date for the Region.
Bryce McIntyre, PhD, resides in San Andres. He holds a doctoral degree from Stanford University, Palo Alto, California, USA