Southeast Asia and the Pacific: Deficits persist in Maritime SE Asia

Southeast Asia and the Pacific: Deficits persist in Maritime SE Asia

28 May 2025

THE BIG PICTURE

The forecast for the 12-month period ending in January 2026 indicates that exceptional surpluses throughout Maritime Southeast Asia will mostly diminish, though pockets of severe to exceptional deficits will persist in portions of the Philippines, Indonesia, Papua, West Papua, and New Guinea. 

Severe to exceptional surpluses are anticipated in: 

  • Philippines, with the most intense anomalies occurring in northern areas of the island of Luzon. The islands of Panay and Negros can expect severe to extreme surpluses.  

  • Indonesia, with severe surpluses emerging in regions of West and East Nusa Tenggara, northern and eastern Sulawesi, North Maluku, and Borneo, within the state of Sabah. 

  • Papua, throughout the Mamberamo Raya and Merauke regencies. Papua New Guinea is also expected to observe exceptional surpluses, primarily near the Western Highlands Province.   

Severe to exceptional deficits are expected in:

  • Northern Laos, with the most intense anomalies occurring in the Thongsaly province, the Nam Ha National Bio-Diversity Conservation Area, and near the Nam Song River. 

  • Northern Vietnam, throughout much of the Northwest region of the country and the Cao Bang province.  

  • Indonesia, in western coastal and central regions of the island of Sumatra.

The 3-month maps (below) show the evolving conditions in more detail. 

FORECAST BREAKDOWN
The forecast through July 2025 indicates that exceptional surpluses will emerge in southern and northcentral Papua, as well as southern coastal regions of Papua New Guinea. Central islands of the Philippines will observe severe surpluses. Moderate to severe surpluses are expected in Sabah, as well as portions of East Kalimantan. 

From August through October 2025, severe to extreme deficits are anticipated in regions of northern Sumatra and southern Malaysia. Portions of southern Thailand and Myanmar will observe moderate to severe surpluses. Severe surpluses are expected throughout much of Java. Southern coastal regions of Papua and Papua New Guinea are expected to observe continued exceptional surpluses. 

The forecast for the final months – November through January 2026 – indicates that moderate to severe deficits will continue in Sumatra and spread throughout much of Singapore, Malaysia, and southern Thailand. Deficits are also expected to expand in northern Laos and northern Vietnam. Moderate to severe surpluses are expected in Indonesia, throughout the islands of Java, East and West Nusa Tenggara, western Sulawesi, and the southern coast of Kalimantan. 

Please note that WSIM forecast skill declines with longer lead times.

IMPACTS
On May 15th, 10 deaths occurred and 10 missing people were reported as flash floods and landslides hit Indonesia’s West Papua province. The flooding occurred after days of heavy rain struck the remote Gunung Arfak Regency 15, with difficult terrain and poor communication hindering early rescue efforts. Local authorities warned that continued rainfall could trigger more landslides and urged residents to stay vigilant.

Coffee prices rise as Vietnam, the world’s largest robusta producer, continues to experience drought. Severe drought conditions have decreased Vietnam's coffee crop by 20%, reducing it to 1.472 million metric tons, its smallest yield in four years. The Vietnam Coffee and Cocoa Association recently cut its production forecast for 2024-2025 from 28 million bags to 26.5 million bags. 

Vietnam’s Mekong Delta is facing worsening droughts and saltwater intrusion which jeopardize agriculture operations and threaten livelihoods. Local farmers have suffered crop losses and rising debts as expensive water systems implemented to promote climate adaptation malfunction or cause new issues. Experts argue that these engineering solutions lock communities into debt and environmental degradation, while failing to offer lasting resilience.

NOTE ON ADMINISTRATIVE BOUNDARIES
There are numerous regions around the world where country borders are contested. ISciences depicts country boundaries on these maps solely to provide some geographic context. The boundaries are nominal, not legal, descriptions of each entity. The use of these boundaries does not imply any judgement on the legal status of any territory, or any endorsement or acceptance of disputed boundaries on the part of ISciences or our data providers.

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Many analyses reported in ISciences-authored blog posts are based on data generated by the ISciences Water Security Indicator Model (WSIM). Other sources, if used, are referenced in footnotes accompanying individual posts. WSIM is a validated capability that produces monthly reports on current and forecast global freshwater surpluses and deficits with lead times of 1-9 months at 0.25°x0.25° resolution. This capability has been in continuous operation since April 2011 and has proven to provide reliable forecasts of emerging water security concerns in that time-frame. WSIM has the ability to assess the impacts of water anomalies on people, agriculture, and electricity generation. Detailed data, customized visualizations, and reports are available for purchase.

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