Friday, February 19, 2016

Hot days, warm nights to affect farming

The global warming observed worldwide may not be true for the Philippines, PAGASA says.

The current hot weather and dry spell is brought by the seasonal El Nino weather—and not by global warming, says Analiza S. Solis, a senior weather specialist at the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).

Hot as it was, 2015 wasn’t the hottest year. 2015 was only the fourth warmest year, with a mean temperature 0.82° Celsius above normal, based on PAGASA records from 1951 to last year. 2013 was the hottest, followed by 1998 then 2012, says Anthony Lucero, head of PAGASA’s Climate Information Monitoring and Prediction Section.

Worldwide, 2015 was likely to be the warmest on record, according to the World Meteorological Organization, based on its 2011-2015 Warmest Five Year Period record.

While there’s a global increase in mean temperature, both on land and ocean worldwide, “it’s not happening in the Philippines.” Solis says, adding that the hot days this December is brought by the El Nino weather.

The Fifth Assessment Report of the United Nations Intergovernmental Panel on Climate Change   indicates a global warming of 0.85°C from 1880 to 2012. In the Philippines, it’s just 0.65°C, Solis says, adding it’s even lower when average temperature is based on the period from 1951 to 2010 or 60 years of PAGASA observations.

What’s happening is that “night time temperature is now hotter by almost three times,” she explains. It impacts on agriculture because the plant makes its nutrients at night when there’s no solar radiation. Hotter nights will affect this process, she says.

In most parts of the country the frequency of hot days and warm nights are increasing at a clip that is “statistically significant,” she points out, adding that most parts of the country are experiencing   decreases in the frequency of cool days and cold nights.

Nor has global warming brought stronger typhoons. “The frequency of extreme tropical cyclones   with winds over 150 kilometers per hour does not show any significant trend,” she says. “However, the number of strong typhoons is on the rise or in its active phase.”

In December, Typhoon Nona was followed right after by Typhoon Onyok and, together with the northeast monsoon rains that flooded Cagayan Valley and Central Luzon, claimed nearly 50 lives, and damaged 300,000 houses, of which 100,000 were totally wrecked.

Ms. Solis defines climate as “a particular space in the atmosphere, in a particular space in time.” Typically, the Philippines has a humid equatorial climate.

“We can get as high as 400 millimeters of rain in a year,” Solis says. In all Philippines, Hinatuan, Surigao del Sur, gets the most rainfall, Gen San in South Cotabato, the least. In most areas “the intensity of rainfall is increasing and becoming more frequent,” she says.

PAGASA observations indicate “it is likely that rainfall will increase towards the end of both 2049 and 2079,” Solis says; rainfall will increase approximately 0.1 millimeter to 0.2 mm/year or as much as 50 percent in 2020-2049 and 2050-2079, especially in the Visayas and parts of central Mindanao.

Maximum temperature is likely to increase annually by 3.0° C in 2050-2079. Minimum temperature is likely to increase by 3.0° C each year in 2050-2079, suggesting warmer nights in the future. Daytime temperatures are likely to increase in central to southern Philippines. Days with heavy rainfall and consecutive dry days are likely to increase in most of Luzon; decreases are projected in Cebu and Bukidnon.

The Land-Ocean Temperature Index of the U.S. National Aeronautics and Space Administration (NASA) in mid-December showed that the global average temperature in November was 1.05 degrees Celsius warmer than the overall average global temperature recorded from 1880 to 2015. It was the second time the monthly index has climbed more than 1 degree Celsius above the average since records began in 1880.

A five-year analysis NASA also conducted in November showed that 2011 to 2015 was the hottest five-year period ever recorded. The U.S. National Oceanic and Atmospheric Administration predicted in June that 2015 was set to be the hottest on record. (SciencePhilippines)

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