Chiang Rai Province CC Threat overview AAS1109 Mekong ARCC This threat overview relies on projections of future climate change in the Mekong Basin for the period 2045-2069 compared to a baseline of 1980-2005. Statistical downscaling for 166 temperature and precipitation stations was used to develop these projections using IPCC scenario A1B and six GCMs. The results of the downscaling were incorporated into a basinwide hydrological model which computed changes in precipitation, evapotranspiration, PET, soil moisture, river discharge and runoff for every 5x5km grid cell in the Mekong Basin. THREAT OVERVIEW Chiang Rai Province is projected to experience some of the largest increases in precipitation within the Mekong Basin with annual precipitation increasing by 9 18%. Temperature increases are mostly moderate across the province (between 5-8%). Chiang Rai Province has a large variation in elevation between the lowlands running north to south through the centre of the province and the higher elevations to the east and west. This elevation range causes a minor variation in temperature within Chiang Rai. A more important variation in precipitation occurs north to south with some areas in the north receiving up to 2000mm more annual precipitation than areas in the south. For the lower parts of the province: Daily maximum temperatures (Map 1-3 and Figure 1-2):): Under baseline conditions maximum temperatures vary on average between 25.7 to 35.5 Deg C during the year, with temperatures peaking in April, averaging 34.7 Deg C and dropping to a minimum in December. With climate change, temperatures will continue to follow a similar pattern; however there will be positive shift in the mean temperature of 1
2.0 Deg C. Under baseline conditions, average daily maximum temperatures do not exceed 42 Deg C, in the future with climate change average daily maximum temperatures will reach 44Deg C. Daily Minimum Temperatures (Figure 3-4): Under baseline conditions average daily minimum temperatures range between 11.3 23.8 Deg C, peaking in June. With climate change, temperatures will continue to follow a similar pattern; however there will be a positive shift in the average of 1.5 Deg C (19.1 to 20.6) and a shift of the peak temperature to occur in July. Precipitation (Figure Map 4-6 and Figure 6-8): Lowland areas of Chiang Rai show a strong seasonal pattern characterized by the monsoon rains from May to October. Peak rainfall occurs in August accounting for about 20% of the total annual rainfall. With climate change annual rainfall will increase from 1,600 mm/yr to 1,740 mm/yr (+140 mm/yr). Peak monthly rainfall in August will increase from 325 to 345 mm/yr. The largest percentage increases in rainfall will occur during December (close to 50% increase in monthly rainfall), while the largest reduction in rainfall will occur in February (over 20% reduction in monthly rainfall). Storms (Map 7 and Figure 9): Chiang Rai province experienced one of the lowest rates of storms of tropical depression strength or stronger in the period between 1956-2009, only 0-2 storms in the whole 53 year period. Intense storms are projected to become more intense under future climate conditions. Comparison of the ranked annual highest rainfall events for the 25 years of baseline and climate change shows that the large rainfall events will be increasing in size. Under baseline conditions a daily rainfall event of over 10 0mm occurred on average once every 25 years. With climate change storms over 100mm will twice as often, on average once every 12 years. Droughts: Comparison of monthly rainfall and Potential Evaporation (PET) conditions gives an agricultural definition of drought. Under historic conditions drought is a typical occurrence between November to April and occurs in some years in May and October. This pattern of drought will be unchanged with projected climate change. Soil water availability: Soil moisture is an important parameter for terrestrial plants as it measures the amount of water available in the shallow and deep soil layers. The impact of climate change on soil moisture in Chiang Rai will be minor and vary throughout the year from a maximum increase of 0.6% to a maximum decrease of 1.4 % 2
CLIMATE CHANGE THREAT DETAIL List of maps and figures The following maps and figures are provided below to aid intrepation of climate threats in the province: Map 1 - Annual average maximum temperature Map 2 Dry season average maximum temperature Map 3 Wet season average maximum temperature Map 4 Annual average precipitation Map 5 Dry season average precipitation Map 6 Wet season average precipitation Map 7 Historical storm tracks Figure 1 Maximum temperature typical year time series in lowland area Figure 2 Maximum temperature seasonal ranges in lowland area Figure 3 Minimum temperature typical year time series in lowland area Figure 4 Minimum temperature seasonal ranges in lowland area Figure 5 Temperature seasonal ranges in lowland area Figure 6 Monthly precipitation for a typical year in lowland area Figure 7 Percentage change in monthly precipitation for a typical year in lowland area Figure 8 Precipitation seasonal ranges in lowland area Figure 9 Ranking of annual maximum rainfall events Definitions Typical year: The daily values (temp, rainfall etc) for a typical year is calculated as an average of that day over the 25 years of modelled data. Comfort zone: The range of precipitation or temperature that was experienced during 50% of the baseline around the mean. It can be assumed that the system is not stressed within this temperature and precipitation range. 3
Daily maximum temperature (Deg C) 50 Maps and figures legend The box 45 and whisker graphs represent the following statistics: 40 Maximum 35 30 75 th percentile Median 25 th percentile 25 20 Minimum The following shading is used to mark the wet seasons and the comfort zone: 15 Wet season Baseline Wet Season (Jun-Nov) CC Wet Season (Jun-Nov) Comfort zone Baseline Dry Season (Dec - May) CC Dry Season (Dec - May) In the maps the green dot represents the location of the point time series data used to create the figures: 4
Map 1 - Annual average maximum temperature 5
Map 2 Dry season average maximum temperature 6
Map 3 Wet season average maximum temperature 7
1-Jan 11-Jan 21-Jan 31-Jan 10-Feb 20-Feb 2-Mar 12-Mar 22-Mar 1-Apr 11-Apr 21-Apr 1-May 11-May 21-May 31-May 10-Jun 20-Jun 30-Jun 10-Jul 20-Jul 30-Jul 9-Aug 19-Aug 29-Aug 8-Sep 18-Sep 28-Sep 8-Oct 18-Oct 28-Oct 7-Nov 17-Nov 27-Nov 7-Dec 17-Dec 27-Dec Maximum temperature (Deg C) 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 Figure 1 Maximum temperature typical year time series in lowland area BL BL min BL max GCM average GCM min GCM max Wet season Typical year 8
Daily maximum temperature (Deg C) Figure 2 Maximum temperature seasonal ranges in lowland area 47.5 Figure 5 42.5 37.5 32.5 C.Z. C.Z. 27.5 22.5 17.5 12.5 Baseline Wet Season (Jun-Nov) CC Wet Season (Jun-Nov) Baseline Dry Season (Dec - May) CC Dry Season (Dec - May) 9
1-Jan 11-Jan 21-Jan 31-Jan 10-Feb 20-Feb 2-Mar 12-Mar 22-Mar 1-Apr 11-Apr 21-Apr 1-May 11-May 21-May 31-May 10-Jun 20-Jun 30-Jun 10-Jul 20-Jul 30-Jul 9-Aug 19-Aug 29-Aug 8-Sep 18-Sep 28-Sep 8-Oct 18-Oct 28-Oct 7-Nov 17-Nov 27-Nov 7-Dec 17-Dec 27-Dec Minimum temperature (Deg C) 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Figure 3 Minimum temperature typical year time series in lowland area BL BL min BL max GCM average GCM min GCM max Wet season Typical year 10
Daily minimum temperature (Deg C) Figure 4 Minimum temperature seasonal ranges in lowland area 35 Figure 11 30 25 20 C.Z. 15 C.Z. 10 5 0 Baseline Wet Season (Jun-Nov) CC Wet Season (Jun-Nov) Baseline Dry Season (Dec - May) CC Dry Season (Dec - May) 11
Daily temperature (Deg C) 50 45 Figure 5 Temperature seasonal ranges in lowland area Figure 13 Wet season (Jun-Nov) Dry season (Dec - May) 40 35 30 C.Z. C.Z. 25 20 15 10 5 0 Baseline Max Temp Baseline Min Temp CC Max Temp CC Min Temp Baseline Max Temp Baseline Min Temp CC Max Temp CC Min Temp 12
Map 4 Annual average precipitation 13
Map 5 Dry season average precipitation 14
Map 6 Wet season average precipitation 15
12 10 20 15 11 16 29 34 Total monthly precipitation (mm) 53 62 92 113 103 116 210 216 203 224 252 288 302 284 325 346 400 350 Figure 6 Monthly precipitation for a typical year in lowland area Figure 14 Baseline GCM average Wet season 300 250 200 150 100 50 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month - typical year 16
Percentage change in monthly precipitation Figure 7 Percentage change in monthly precipitation for a typical year in lowland area 60% 50% Figure 15 % change in precipitation Wet season 40% 30% 20% 10% 0% -10% Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec -20% -30% Month - typical year 17
Total precipitation (mm) Figure 8 Precipitation seasonal ranges in lowland area 1,800 Figure 18 1,600 1,400 C.Z. 1,200 1,000 800 600 400 C.Z. 200 0 Basline Wet Season (Jun-Nov) CC Wet Season (Jun-Nov) Baseline Dry Season (Dec - May) CC Dry Season (Dec - May) 18
Map 7 Historical storm tracks 25% 15% 41% 19% 19
Maximum daily precipitation in a year (mm) Figure 9 Ranking of annual maximum rainfall events 140 Figure 20 BL CC 120 100 80 60 40 20 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Rank 20
Gia Lai Province CC Threat overview AAS1109 Mekong ARCC This threat overview relies on projections of future climate change in the Mekong Basin for the period 2045-2069 compared to a baseline of 1980-2005. Statistical downscaling for 166 temperature and precipitation stations was used to develop these projections using IPCC scenario A1B and six GCMs. The results of the downscaling were incorporated into a basinwide hydrological model which computed changes in precipitation, evapotranspiration, PET, soil moisture, river discharge and runoff for every 5x5km grid cell in the Mekong Basin. THREAT OVERVIEW The 3S river basins are projected to experience some of the largest increases in temperature within the Mekong Basin with annual maximum temperatures rising by 12-16%. Annual precipitation increases in the 3S are moderate for the Mekong ranging between 5-8%, however the changes in seasons are more pronounced increasing by 11 % during the wet season and decreasing by 3-10 % during the dry. Gia Lai comprises upland areas of the Sesan Catchment and is projected to experience large increases in temperature with annual maximum temperatures rising by 8-11%. Annual precipitation increases in the province are moderate for the Mekong ranging between 5-8%. Daily maximum temperatures (Map 1-3 and Figure 1-2): Under baseline conditions maximum temperatures vary on average between 24 to 32 Deg C during the year, with temperatures peaking in April, averaging 31.9 Deg C and dropping to a minimum in December and January. With climate change temperatures will continue to follow a similar pattern; however there will be positive shift in the mean temperature of 3.4 Deg C. Daily maximum temperature will also become more variable with climate change with an average range of 9.3 Deg C compared to a range of 7.5 Deg C under the baseline. Under baseline conditions, average daily maximum temperatures do not exceed 35 Deg C, in the future with climate change average daily maximum temperatures will reach 38 Deg C. Daily Minimum Temperatures (Figure 3-4): Under baseline conditions average daily minimum temperatures range between 14-21 Deg C, peaking at the start of May. With climate change, 1
temperatures will continue to follow a similar pattern; however there will be a 3.7 Deg shift in the average of (18.6 to 22.3 Deg C) and a move of the peak in minimum temperature to occur in July. Under baseline conditions, average minimum temperatures do not exceed 24 Deg C, while with climate change they will reach 28.5 Deg C. Conversely, with climate change average minimum temperatures will no longer drop below 10 Deg C. Precipitation (Figure Map 4-6 and Figure 6-8): Gia Lai shows a strong seasonal pattern characterized by the monsoon rains from May to November. Peak rainfall occurs in August often due to the combination of monsoon rains and tropical storms arriving from the Pacific Ocean and accounting for about 20% of the total annual rainfall. With climate change, annual rainfall will increase from 1,945 mm/yr to 2,110mm/yr (+165mm/yr). Peak monthly rainfall in August will increase from 390to 430 mm/yr. The largest increases in rainfall will occur during October (14% increase in monthly rainfall), while the largest reduction in rainfall will occur in February (-9% reduction in monthly rainfall). Storms (Map 7 and Figure 9): Comparison of the ranked annual highest rainfall events for the 25 years of baseline and climate change shows that the large rainfall events will be increasing in size with the number of rainfall events each year greater than 100mm/day doubling. Droughts: Comparison of monthly rainfall and Potential Evaporation (PET) conditions gives an agricultural definition of drought. Under historic conditions drought is a typical occurrence between December and March. In April and May drought occurs in around half of the years for baseline and under climate change. With climate change there will no significant changes in drought trends. Soil water availability: Soil moisture is an important parameter for terrestrial plants as it measures the amount of water available in the shallow and deep soil layers. Soil moisture in Gia Lai will not see any significant changes with climate change. With climate change, soil moisture will decrease during the dry season, by a maximum decrease of 1.7% in May, and. Increase during the wet season, by a maximum increase of 1.1%. 2
CLIMATE CHANGE THREAT DETAIL List of maps and figures The following maps and figures are provided below to aid intrepation of climate threats in the province: Map 1 - Annual average maximum temperature Map 2 Dry season average maximum temperature Map 3 Wet season average maximum temperature Map 4 Annual average precipitation Map 5 Dry season average precipitation Map 6 Wet season average precipitation Map 7 Historical storm tracks Figure 1 Maximum temperature typical year time series in lowland area Figure 2 Maximum temperature seasonal ranges in lowland area Figure 3 Minimum temperature typical year time series in lowland area Figure 4 Minimum temperature seasonal ranges in lowland area Figure 5 Temperature seasonal ranges in lowland area Figure 6 Monthly precipitation for a typical year in lowland area Figure 7 Percentage change in monthly precipitation for a typical year in lowland area Figure 8 Precipitation seasonal ranges in lowland area Figure 9 Ranking of annual maximum rainfall events Definitions Typical year: The daily values (temp, rainfall etc) for a typical year is calculated as an average of that day over the 25 years of modelled data. Comfort zone: The range of precipitation or temperature that was experienced during 50% of the baseline around the mean. It can be assumed that the system is not stressed within this temperature and precipitation range. 3
Daily maximum temperature (Deg C) 50 Maps and figures legend The box 45 and whisker graphs represent the following statistics: 40 Maximum 35 30 75 th percentile Median 25 th percentile 25 20 Minimum The following shading is used to mark the wet seasons and the comfort zone: 15 Wet season Baseline Wet Season (Jun-Nov) CC Wet Season (Jun-Nov) Comfort zone Baseline Dry Season (Dec - May) CC Dry Season (Dec - May) In the maps the green dot represents the location of the point time series data used to create the figures: 4
Map 1 - Annual average maximum temperature 5
Map 2 Dry season average maximum temperature 6
Map 3 Wet season average maximum temperature 7
1-Jan 11-Jan 21-Jan 31-Jan 10-Feb 20-Feb 2-Mar 12-Mar 22-Mar 1-Apr 11-Apr 21-Apr 1-May 11-May 21-May 31-May 10-Jun 20-Jun 30-Jun 10-Jul 20-Jul 30-Jul 9-Aug 19-Aug 29-Aug 8-Sep 18-Sep 28-Sep 8-Oct 18-Oct 28-Oct 7-Nov 17-Nov 27-Nov 7-Dec 17-Dec 27-Dec Maximum temperature (Deg C) 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 Figure 1 Maximum temperature typical year time series BL BL min BL max GCM average GCM min GCM max Wet season Typical year 8
Daily maximum temperature (Deg C) 45 Figure 2 Maximum temperature seasonal ranges Figure 5 40 35 30 C.Z. C.Z. 25 20 15 Baseline Wet Season (Jun-Nov) CC Wet Season (Jun-Nov) Baseline Dry Season (Dec - May) CC Dry Season (Dec - May) 9
1-Jan 11-Jan 21-Jan 31-Jan 10-Feb 20-Feb 2-Mar 12-Mar 22-Mar 1-Apr 11-Apr 21-Apr 1-May 11-May 21-May 31-May 10-Jun 20-Jun 30-Jun 10-Jul 20-Jul 30-Jul 9-Aug 19-Aug 29-Aug 8-Sep 18-Sep 28-Sep 8-Oct 18-Oct 28-Oct 7-Nov 17-Nov 27-Nov 7-Dec 17-Dec 27-Dec Minimum temperature (Deg C) 30 Figure 3 Minimum temperature typical year time series BL BL min BL max GCM average GCM min GCM max 25 20 15 10 5 0 Wet season Typical year 10
Daily minimum temperature (Deg C) 30 Figure 4 Minimum temperature seasonal ranges Figure 11 25 20 C.Z. C.Z. 15 10 5 0 Baseline Wet Season (Jun-Nov) CC Wet Season (Jun-Nov) Baseline Dry Season (Dec - May) CC Dry Season (Dec - May) 11
Daily temperature (Deg C) 45 40 Figure 5 Temperature seasonal ranges Figure 13 Wet season (Jun-Nov) Dry season (Dec - May) 35 30 C.Z. C.Z. 25 20 15 10 5 0 Baseline Max Temp Baseline Min Temp CC Max Temp CC Min Temp Baseline Max Temp Baseline Min Temp CC Max Temp CC Min Temp 12
Map 4 Annual average precipitation 13
Map 5 Dry season average precipitation 14
Map 6 Wet season average precipitation 15
1 1 8 7 11 11 27 26 Total monthly precipitation (mm) 70 73 87 95 197 226 241 224 296 320 323 310 327 356 387 429 Figure 6 Monthly precipitation for a typical year 500 450 Figure 14 Baseline GCM average Wet season 400 350 300 250 200 150 100 50 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month - typical year 16
Percentage change in monthly precipitation 20% Figure 7 Percentage change in monthly precipitation for a typical year Figure 15 % change in precipitation Wet season 15% 10% 5% 0% Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec -5% -10% Month - typical year 17
Total precipitation (mm) 2,500 Figure 18 Figure 8 Precipitation seasonal ranges 2,000 C.Z. 1,500 1,000 500 C.Z. 0 Basline Wet Season (Jun-Nov) CC Wet Season (Jun-Nov) Baseline Dry Season (Dec - May) CC Dry Season (Dec - May) 18
Map 7 Historical storm tracks 25% 15% 41% 19% 19
Maximum daily precipitation in a year (mm) Figure 9 Ranking of annual maximum rainfall events 160 Figure 20 BL CC 140 120 100 80 60 40 20 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Rank 20