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Projections on seasonal temperature increase and rainfall change, and total frequency of extreme events nationally and in the provinces using the mid-range scenario outputs are presented in this chapter. A comparison of these values with the high- and low- range scenarios in 2020 and 2050 is provided in the technical annexes.

It is to be noted that all the projected changes are relative to the baseline (1971-2000) climate. For example, a projected 1.0 C-increase in 2020 in a province means that 1.0 C is added to the baseline mean temperature value of the province as indicated in the table to arrive at the value of projected mean temperature. Therefore, if the baseline mean temperature is 27.8 C, then the projected mean temperature in the future is (27.8 C + 1.0 C) or 28.8 C.

In a similar manner, for say, a +25%-rainfall change in a province, it means that 25% of the seasonal mean rainfall value in the said province (from table of baseline climate) is added to the mean value. Thus, if the baseline seasonal rainfall is 900mm, then projected rainfall in the future is 900mm + 225mm or 1125mm.

This means that we are already experiencing some of the climate change shown in the findings under the mid-range scenario, as we are now into the second decade of the century. Classification of climate used the Corona's four climate types (Types I to IV), based on monthly rainfall received during the year. A province is considered to have Type I climate if there is a distinct dry and a wet season; wet from June to November and dry, the rest of the year. Type II climate is when there is no dry period at all throughout the year, with a pronounced wet season from November to February. On the other hand, Type III climate is when there is a short dry season, usually from February to April, and Type IV climate is when the rainfall is almost evenly distributed during the whole year. The climate classification in the Philippines is shown in Fig.16.  
 

Seasonal Temperature Change


All areas of the Philippines will get warmer, more so in the relatively warmer summer months. Mean temperatures in all areas in the Philippines are expected to rise by 0.9 C to 1.1 C in 2020 and by 1.8 C to 2.2 C in 2050. Likewise, all seasonal mean temperatures will also have increases in these time slices; and these increases during the four seasons are quite consistent in all parts of the country. Largest temperature increase is projected during the summer (MAM) season.

Seasonal Rainfall Change


Generally, there is reduction in rainfall in most parts of the country during the summer (MAM) season. However, rainfall increase is likely during the southwest monsoon (JJA) season until the transition (SON) season in most areas of Luzon and Visayas, and also, during the northeast monsoon (DJF) season, particularly, in provinces/areas characterized as Type II climate in 2020 and 2050. There is however, generally decreasing trend in rainfall in Mindanao, especially by 2050. 
 
There are varied trends in the magnitude and direction of the rainfall changes, both in 2020 and 2050. What the projections clearly indicate are the likely increase in the performance of the southwest and the northeast monsoons in the provinces exposed to these climate controls when they prevail over the country. Moreover, the usually wet seasons become wetter with the usually dry seasons becoming also drier; and these could lead to more occurrences of floods and dry spells/droughts, respectively.

Extreme Temperature Events

Hot temperatures will continue to become more frequent in the future. Fig.19 shows that the number of days with maximum temperature exceeding 35 C (following value used by other countries in the Asia Pacific region in extreme events analysis) is increasing in 2020 and 2050.
 

Extreme Rainfall Events

Heavy daily rainfall will continue to become more frequent, extreme rainfall is projected to increase in Luzon and Visayas only, but number of dry days is expected to increase in all parts of the country in 2020 and 2050. Figures 20 and 21 show the projected increase in number of dry days (with dry day defined as that with rainfall less than 2.5mm) and the increase in number of days with extreme rainfall (defined as daily rainfall exceeding 300 mm) compared with the observed (baseline) values, respectively. 

Climate Projections for Provinces

 

The projected seasonal temperature increase, seasonal rainfall change and frequency of extreme events in 2020 and 2050
under the medium-range emission scenario in the provinces in Region 1 are presented in Table a, Table b and Table c, respectively.

To use the tables and arrive at values of seasonal mean temperature and seasonal rainfall in 2020 and 2050 in any of the provinces
, the projections are added to the observed values (presented in each of the tables).

For example, in Pangasinan, the projected values in 2020 are:

DJF mean temperature = (25.0 C + 0.9 C) = 25.9 C;
DJF rainfall = {19.4mm+19.4(54.3%)mm} = (19.4+10.5)mm or 29.9mm;
number of days with Tmax > 35 C in Dagupan City during the 2006-2035 period (centered at 2020) = 2,265;
number of dry days in Dagupan City during the 2006-2035 period (centered at 2020) = 6,443; and
number of days with rainfall > 300mm in Dagupan City during the 2006-2035 period (centered at 2020) =13.
 
 
 
 
Note:
  • For northern La Union, use values of Vigan.
  • For southern La Union, use values of Dagupan.
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The projected seasonal temperature increase, seasonal rainfall change and frequency of extreme events in 2020 and 2050 under the medium-range emission scenario in the provinces in Region 2 are presented in Table a, Table b and Table c, respectively.

To use the tables and arrive at values of seasonal mean temperature and seasonal rainfall in 2020 and 2050 in any of the provinces, the projections are added to the observed values (presented in each of the tables).

For example, in Cagayan, the projected values in 2020 are:

DJF mean temperature in 2020 = (24.5 C+0.8 C) = 25.3 C;
DJF rainfall in 2020 = {284.4mm+284.4(6.9%)mm} = (284.4+19.6)mm or 304mm;
number of days with Tmax > 35 C in Aparri during the 2006-2035 (centered at 2020) = 1,276;
number of dry days in Aparri during the 2006-2035 period (centered at 2020) = 6,498; and
number of days with rainfall > 300mm in Aparri during the 2006-2035 period (centered at 2020) = 16. 
 



Note:
  • For northern Cagayan, use values of Aparri.
  • For southern Cagayan, use values of Tuguegarao.
  • For Isabela, use values of Tuguegarao.
  • For Nueva Vizcaya, use values of Tuguegarao.
  • For Quirino, use values of Baler.
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The projected seasonal temperature increase, seasonal rainfall change and frequency of extreme events in 2020 and 2050 under the medium-range emission scenario in the provinces in Region 3 are presented in Table a, Table b and Table c, respectively.

To use the tables and arrive at values of seasonal mean temperature and seasonal rainfall in 2020 and 2050 in any of the provinces, the projections are added to the observed values (presented in each of the tables).

For example, in Nueva Ecija, the projected values in 2020 are:

DJF mean temperature = (25.3 C+0.9 C) = 26.2 C;
DJF rainfall = {155.2mm+155.2(7.5%)mm} = (155.2+11.6)mm or 166.8mm;
number of days with Tmax > 35 C in Cabanatuan during the 2006-2035 period (centered at 2020) = 3,271;
number of dry days in Cabanatuan during the 2006-2035 period (centered at 2020) = 6,117; and
number of days with rainfall > 300mm in Cabanatuan during the 2006-2035 period (centered at 2020) = 2.




Note:
  • For Tarlac, use values of Clark.
  • For Bulacan, use values of Science Garden



The projected seasonal temperature increase, seasonal rainfall change and frequency of extreme events in 2020 and 2050 under the medium-range emission scenario in the provinces in Region 4-A are presented in Table a, Table b and Table c, respectively.

To use the tables and arrive at values of seasonal mean temperature and seasonal rainfall in 2020 and 2050 in any of the provinces, the projections are added to the observed values (presented in each of the tables). 

For example, in Quezon, the projected values in 2020 are:

DJF mean temperature = (25.1 C+0.9 C) = 26.0 C;
DJF rainfall = {827.7mm+827.7(-6.5%)mm} = (827.7-53.8)mm or 763.9mm;
number of days with Tmax > 35 C in Casiguran during the 2006-2035 period (centered in 2020) = 1,720; number of dry days in Casiguran during the 2006-2035 period (centered at 2020) = 4,520; and
number of days with rainfall > 300mm in Casiguran during the 2006-2035 period (centered at 2020) = 20.


Note:
  • For northern portion of Quezon, use values of Casiguran.
  • For middle part of Quezon, use values of Infanta.
  • For southern portion of Quezon, use Tayabas.
  • For Laguna, use values of Ambulong.

The projected seasonal temperature increase, seasonal rainfall change and frequency of extreme events in 2020 and 2050 under the medium-range emission scenario in the provinces in Region 4-B are presented in Table a, Table b and Table c, respectively.
To use the tables and arrive at values of seasonal mean temperature and seasonal rainfall in 2020 and 2050 in any of the provinces, the projections are added to the observed values (presented in each of the tables). 
For example, in Oriental Mindoro, the projected values in 2020 are:

DJF mean temperature = (26.4 C+0.8 C) = 27.2 C;
DJF rainfall = {260.3mm+260.3(-3.2%)mm} = (260.3-8.3)mm or 252.0mm;
number of days with Tmax > 35 C in Calapan during the 2006-2035 period (centered in 2020) = 440;
number of dry days in Calapan during the 2006-2035 period (centered at 2020) = 7,057; and
number of days with rainfall > 300mm in Calapan during the 2006-2035 period (centered at 2020) = 4.




Note:
  • For main island of Palawan, use values of Puerto Princesa.
  • For Marinduque, use values of Calapan.

The projected seasonal temperature increase, seasonal rainfall change and frequency of extreme events in 2020 and 2050 under the medium-range emission scenario in the provinces in Region 5 are presented in Table a, Table b and Table c, respectively.
To use the tables and arrive at values of seasonal mean temperature and seasonal rainfall in 2020 and 2050 in any of the provinces, the projections are added to the observed values (presented in each of the tables). 
For example, in Albay, the projected values in 2020 are:

DJF mean temperature = (25.6 C+0.9 C) = 26.5 C;
DJF rainfall = {739.8mm+ 739.8(+0.5%)mm} = (739.8 +3.7)mm or 743.5mm;
number of days with Tmax > 35 C in Legaspi City during the 2006-2035 period (centered at 2020) = 683;
number of dry days in Legaspi City during the 2006-2035 period (centered at 2020) = 3,698; and
number of days with rainfall > 300mm in Legaspi City during the 2006-2035 period (centered at 2020) = 4.




Note:
  • For northern portion of Camarines Sur, use values of Daet.
  • For southern portion of Camarines Sur, use values of Legaspi.
  • For northern portion of Sorsogon, use values of Legaspi.
  • For south western portion of Sorsogon, use values of Masbate.
  • For south eastern portion of Sorsogon, use values of Catarman.

The projected seasonal temperature increase, seasonal rainfall change and frequency of extreme events in 2020 and 2050 under the medium-range emission scenario in the provinces in Region 6 are presented in Table a, Table b and Table c, respectively. To use the tables and arrive at values of seasonal mean temperature and seasonal rainfall in 2020 and 2050 in any of the provinces, the projections are added to the observed values (presented in each of the tables). For example, in Iloilo province, the projected values in 2020 are:

DJF mean temperature = (26.4 C+1.0 C) = 27.4 C;
DJF rainfall = {324.8mm+(324.8+1.2%)mm} = (324.8 +3.9) or 325.7mm;
number of days with Tmax > 35 C in Iloilo City during the 2006-2035 period (centered at 2020) = 1,431;
number of dry days in Iloilo City during the 2006-2035 period (centered at 2020) = 5,227; and
number of days with rainfall > 300mm in Iloilo City during the 2006-2035 period (centered at 2020) = 3.



Note:
  • For Aklan, use values of Roxas City.
  • For Antique, use values of Iloilo City.
  • For Negros Occidental, use values of Iloilo City.

The projected seasonal temperature increase, seasonal rainfall change and frequency of extreme events in 2020 and 2050 under the medium-range emission scenario in the provinces in Region 7 are presented in Table a, Table b and Table c, respectively. To use the tables and arrive at values of seasonal mean temperature and seasonal rainfall in 2020 and 2050 in any of the provinces, the projections are added to the observed values (presented in each of the tables). For example, in Bohol province, the projected values are:

DJF mean temperature = (26.6 C +0.9 C) = 27.5 C;
DJF rainfall = {376.1mm+376.1(9.8%)mm} = (376.1+36.9m) or 413mm;
number of days with Tmax > 35 C in Tagbilaran City during the 2006-2035 period (centered at 2020) = 1,710;
number of dry days in Tagbilaran City during the 2006-2035 period (centered at 2020)= 6,836; and
number of days with rainfall > 300mm in Tagbilaran City during the 2006-2035 period (centered at 2020) = 1.






Note:
  • For Siquijor, use values of Dumaguete.

The projected seasonal temperature increase, seasonal rainfall change and frequency of extreme events in 2020 and 2050 under the medium-range emission scenario in the provinces in Region 8 are presented in Table a, Table b and Table c, respectively.

To use the tables and arrive at values of seasonal mean temperature and seasonal rainfall in 2020 and 2050 in any of the provinces, the projections are added to the observed values (presented in each of the tables). 

For example, in Leyte province, the projected values in 2020 are:

DJF mean temperature = (26.4 C + 0.9 C)=27.3 C;
DJF rainfall = {689.5mm+689.5(3.0%)mm} = (689.5+20.7)mm or 710.2mm;
number of days with Tmax > 35 C in Tacloban City during the 2006-2035 period (centered at 2020) = 1,398;
number of dry days in Tacloban City during the 2006-2035 period (centered at 2020) = 5,199; and
number of days with rainfall > 300mm in Tacloban City during the 2006-2035 period (centered at 2020) = 7.





The projected seasonal temperature increase, seasonal rainfall change and frequency of extreme events in 2020 and 2050 under the medium-range emission scenario in the provinces in Region 9 are presented in Table a, Table b and Table c, respectively.

To use the tables and arrive at values of seasonal mean temperature and seasonal rainfall in 2020 and 2050 in any of the provinces, the projections are added to the observed values (presented in each of the tables). 

For example, in Zamboanga del Sur province, the projected values in 2020 are:

DJF mean temperature = (26.8 C+0.9 C) = 27.7 C;
DJF rainfall = {294.5mm+294.5(11.2%)mm} = (294.5+33.0)mm or 327.0mm;
number of days with Tmax > 35 C in Zamboanga City during the 2006-2035 period (centered at 2020) = 114;
number of dry days in Zamboanga City during the 2006-2035 period (centered at 2020) = 7,058; and
number of days with rainfall > 300mm in Zamboanga City during the 2006-2035 period (centered at 2020) = 1.



Note:
  • Zamboanga Sibugay, use values of Zamboanga City.

The projected seasonal temperature increase, seasonal rainfall change and frequency of extreme events in 2020 and 2050 under the medium-range emission scenario in the provinces in Region 10 are presented in Table a, Table b and Table c, respectively.

To use the tables and arrive at values of seasonal mean temperature and seasonal rainfall in 2020 and 2050 in any of the provinces, the projections are added to the observed values (presented in each of the tables). 

For example, in Bukidnon province, the projected values in 2020 are:

DJF mean temperature = (25.1 C+1.0 C)= 26.1 C;
DJF rainfall = {329.7mm+329.7(2.9%)mm} = (329.7+9.6)mm or 339.3mm;
number of days with Tmax > 35 C in Malaybalay during the 2006-2035 period (centered at 2020) = 477;
number of dry days in Malaybalay during the 2006-2035 period (centered at 2020) = 3,977; and
number of days with rainfall > 300mm in Malaybalay during the 2006-2035 period (centered at 2020) = 1.





Note:
  • For western portion of Misamis Occidental, use values of Dipolog City.

The projected seasonal temperature increase, seasonal rainfall change and frequency of extreme events in 2020 and 2050 under the medium-range emission scenario in the provinces in Region 11 are presented in Table a, Table b and Table c, respectively.

To use the tables and arrive at values of seasonal mean temperature and seasonal rainfall in 2020 and 2050 in any of the provinces, the projections are added to the observed values (presented in each of the tables). 

For example, in Davao del Sur province, the projected values in 2020 are:

DJF mean temperature = (26.9 C+0.9 C) = 27.8 C;
DJF rainfall = {288.1mm+288.1(18.1%)mm} = (288.1+52.1)mm = 346.2mm;
number of days with Tmax > 35 C in Davao City during the 2006-2035 period (centered at 2020) = 2,981;
number of dry days in Davao City during the 2006-2035 period (centered at 2020) = 4,789; and
number of days with rainfall > 300mm during the 2006-2035 period (centered at 2020) = 0.





Note:
  • For Davao del Norte, Davao Oriental and Compostela valley, use values of Davao City.

The projected seasonal temperature increase, seasonal rainfall change and frequency of extreme events in 2020 and 2050 under the medium-range emission scenario in the provinces in Region 12 are presented in Table a, Table b and Table c, respectively.

To use the tables and arrive at values of seasonal mean temperature and seasonal rainfall in 2020 and 2050 in any of the provinces, the projections are added to the observed values (presented in each of the tables). 

For example, in South Cotabato province, the projected values in 2020 are;

DJF mean temperature = (27.7 C +1.0 C) = 28.7 C;
DJF rainfall = {183.3mm+183.3 (10.1%)mm} = (183.3+18.5)mm or 201.8mm;
number of days with Tmax > 35 C in General Santos City during the 2006-2035 period (centered at 2020) = 3,748;
number of dry days in General Santos City during the 2006-2035 period (centered at 2020) = 7,526; and
number of days with rainfall > 300mm in General Santos City during the 2006-2035 period (centered at 2020) = 0.







The projected seasonal temperature increase, seasonal rainfall change and frequency of extreme events in 2020 and 2050 under the medium-range emission scenario in the provinces in Caraga are presented in Table a, Table b and Table c, respectively.

To use the tables and arrive at values of seasonal mean temperature and seasonal rainfall in 2020 and 2050 in any of the provinces, the projections are added to the observed values (presented in each of the tables). 

For example, in Surigao del Norte province, the projected values in 2020 are:

DJF mean temperature = (26.3 C+0.9 C) = 27.2 C;
DJF rainfall = {963.3mm+963.3 (4.0%)mm} = (963.3+38.5)mm or 1001.8mm;
number of days with Tmax > 35 C in surigao City during the 2006-2035 period (centered at 2020) = 225;
number of dry days in Surigao City during the 2006-2035 period (centered at 2020) = 6,054; and
number of days with rainfall > 300mm in Surigao City during the 2006-2035 period (centered at 2020) = 2.






The projected seasonal temperature increase, seasonal rainfall change and frequency of extreme events in 2020 and 2050 under the medium-range emission scenario in the provinces in ARMM are presented in Table a, Table b and Table c, respectively.

To use the tables and arrive at values of seasonal mean temperature and seasonal rainfall in 2020 and 2050 in any of the provinces, the projections are added to the observed values (presented in each of the tables). 

For example, in Maguindanao province, the projected values in 2020 are:

DJF mean temperature = (27.6 C +1.0 C) = 28.6 C;
DJF rainfall = {225.3mm+225.3 (6.3%)mm} = (225.3+14.2)mm or 239.5mm;
number of days with Tmax > 35 C in Cotabato City during the 2006-2035 period (centered at 2020) = 3,382;
number of dry days in Cotabato City during the 2006-2035 period (centered at 2020) = 5,471; and
number of days with rainfall > 300 days in Cotabato City during the 2006-2035 period (centered at 2020) = 3.






The projected seasonal temperature increase, seasonal rainfall change and frequency of extreme events in 2020 and 2050 under the medium-range emission scenario in the provinces in CAR are presented in Table a, Table b and Table c, respectively.

To use the tables and arrive at values of seasonal mean temperature and seasonal rainfall in 2020 and 2050 in any of the provinces, the projections are added to the observed values (presented in each of the tables).


DJF mean temperature = (27.6 C +1.0 C) = 28.6 C;
DJF rainfall = {225.3mm+225.3 (6.3%)mm} = (225.3+14.2)mm or 239.5mm;
number of days with Tmax > 35 C in Cotabato City during the 2006-2035 period (centered at 2020) = 3,382;
number of dry days in Cotabato City during the 2006-2035 period (centered at 2020) = 5,471; and
number of days with rainfall > 300 days in Cotabato City during the 2006-2035 period (centered at 2020) = 3. 





The projected seasonal temperature increase, seasonal rainfall change and frequency of extreme events in 2020 and 2050 under the medium-range emission scenario in the provinces in NCR are presented in Table a, Table b and Table c, respectively. To use the tables and arrive at values of seasonal mean temperature and seasonal rainfall in 2020 and 2050 in any of the provinces, the projections are added to the observed values (presented in each of the tables). For example, in Metro Manila, the projected values in 2020 are:

DJF mean temperature = (26.1 C+1.0 C) = 27.1 C;
DJF rainfall = {107.5mm+107.5(-12.8%)mm} = (107.5-13.8)mm or 93.7mm;
number of days with Tmax > 35 C in Quezon City during the 2006-2035 period (centered at 2020) = 1,984;
number of dry days in Quezon City during the 2006-2035 period (centered at 2020) = 6,302; and
number of days with rainfall > 300mm in Quezon City during the 2006-2035 period (centered at 2020) = 8.