Submission in Support of Petitioners Case No. CHR-NI-2016-0001 2. Precipitation and Water Resources The effect of climate change on precipitation patterns and water resources will be varied depending on location and time of year. It is likely that climate change will increase the frequency of heavy precipitation during wet months in many areas, leading to a greater incidence of floods, landslides, erosion, and sedimentation.14 Future increases in precipitation extremes related to the monsoon are very likely according to the latest IPCC assessment.15 Climate change will also increase the frequency and severity of droughts and water shortages in presently dry areas. The IPCC predicts that there will be significant reductions in surface water and groundwater resources in most dry subtropical regions, thus intensifying competition for water among agriculture, ecosystems, settlements, industry, and energy production, and affecting regional water, energy, and food security.16 The primary drivers of these projected water shortages and droughts include: (i) reduced rainfall, (ii) reduced snowpack, resulting in less snowmelt supplying rivers and streams; and (iii) higher temperatures, which increase evaporation from surface water and soils. Sea level rise will also threaten freshwater supply in coastal areas by causing saltwater inundation of surface and ground water. There is evidence that climate change has already contributed to increased incidence of extreme precipitation events and drought in certain regions. In the Philippines, there has been an observed increase in the number of heavy rainfall days as well as in the number of “no rain” days, which has likely contributed to severe floods and landslides as well as droughts.17 In the future, PAGASA predicts that most areas in the Philippines will experience a reduction in rainfall during the summer season, making the unusually dry season drier and increasing the risk of drought.18 Some areas are also projected to experience an increase in rainfall 14 IPCC WGII (2014), supra note 8, at 187. Id. at 1334. 16 Id. at 232. 17 F.T. Cruz et al., A Climatological Analysis of the Southwest Monsoon Rainfall in the Philippines, 122 ATMOSPHERIC RESEARCH 609 (2013); James Warren, Climate Change on the Impact of Drought on Human Affairs and Human History in the Philippines, 1582 – 2009 (Asia Research Centre 2013); IPCC, Climate Change 2007: Observed Changes in Extreme Climatic Events, https://www.ipcc.ch/publications_and_data/ar4/wg2/en/ch10s10-2-3.html (noting that increased occurrence of extreme rains likely caused landslides and floods in 1990 and 2004 in the Philippines, as well as droughts in 1997-98 which caused massive crop failures and water shortages and forest fires in various parts of the Philippines). 18 PAGASA (2011), supra note 10, at 25. 15 Sabin Center for Climate Change Law, Columbia Law School 6