El Niño and Indonesia's Rupiah: How Drought, Haze, and Commodity Export Disruption Threaten the Fragile Recovery

Rupiah Stability Watch · 2026-07-06

The premise

Indonesia's rupiah has steadied around 17,979 per dollar after a volatile June, and the May 2026 trade deficit of $1.61 billion — the first monthly shortfall in 72 months — was initially framed as an oil-driven anomaly. But the next major pressure point is not geopolitical. It is climatic.

A strong El Niño is forecast to extend dry conditions across the archipelago through late 2026 and into early 2027. Indonesia's Meteorology, Climatology, and Geophysical Agency (BMKG) expects the dry season to peak between July and September, with below-normal rainfall across more than 80 percent of the country. The ASEAN Specialised Meteorological Centre has raised its transboundary haze alert to "Red" for southern Sumatra and Kalimantan — the same regions that produce the bulk of Indonesia's palm oil, coal, and rubber exports.

This analysis traces the transmission chain: from rainfall deficits to crop yields and mine operations; from haze-shrouded ports to delayed shipments; from reduced export receipts to a wider trade deficit; and from there, to the rupiah and Bank Indonesia's narrowing room to maneuver. We do not predict a specific rupiah level. We map the channels through which climate risk becomes currency risk.

What the evidence supports

1. El Niño severity for Indonesia, 2026–2027

This is not a generic El Niño warning. BMKG's seasonal outlook, updated in June 2026, projects the current episode to be among the stronger events since 2015–16. Sea surface temperature anomalies in the Niño 3.4 region have exceeded +1.5°C, a threshold historically associated with significant Indonesian rainfall suppression. The agency expects the dry season to be prolonged by 30–60 days in parts of Sumatra, Kalimantan, Java, and Sulawesi. Fire-hotspot counts in June 2026 were already running 40 percent above the five-year average for the same period.

The 2015 El Niño — the last strong event — cut Indonesian palm oil output by an estimated 8–10 percent, reduced coal production at several major Kalimantan mines due to water shortages for dust suppression and equipment cooling, and grounded barge traffic on the Mahakam and Barito rivers for weeks. The World Bank estimated the total economic cost to Indonesia at $16 billion (1.6 percent of GDP). The 2019 moderate El Niño cost $5.2 billion.

2. Commodity export exposure: the numbers

Indonesia's top three commodity exports — palm oil, coal, and ferroalloys — earned a combined $65–69 billion in 2025, depending on the source. The EBC Financial Group, citing President Prabowo's May 2026 parliamentary address, puts the figure at $30 billion (palm oil), $23 billion (coal), and $16 billion (ferroalloys). TradeInt data for January–October 2025 records palm oil at $20.2 billion and coal at $20.1 billion.

Palm oil alone accounts for roughly 10–12 percent of total merchandise export value. Coal contributes another 7–8 percent. Together with rubber, cocoa, coffee, and other agricultural exports, the commodity complex represents approximately 30–35 percent of Indonesia's foreign exchange earnings from goods exports.

This concentration matters. A 10 percent drop in palm oil export volumes — within the range observed in 2015 — would shave $2–3.5 billion off annual FX receipts. A similar proportional hit to coal exports would remove another $2 billion. Combined, a moderate El Niño disruption could widen the trade deficit by $4–5.5 billion on an annualized basis relative to the pre-El Niño baseline.

3. Haze and logistics: the underappreciated channel

Production losses are only half the story. Transboundary haze disrupts the movement of what is produced:

• Port operations: The Port of Dumai (Riau), a major palm oil export terminal, recorded 12 days of restricted visibility operations during the 2019 haze episode. Loading delays of 2–4 days per vessel were common. In 2015, average vessel waiting times at South Sumatran ports tripled.
• River barge traffic: Kalimantan's coal supply chain relies heavily on the Mahakam and Barito rivers. Low water levels during drought — compounded by haze-related navigation restrictions — can cut barge capacity by 30–50 percent. Several miners declared force majeure on coal deliveries in 2015.
• Air freight and land transport: Reduced visibility affects air cargo (high-value perishables, cocoa) and trunk road haulage. The 2015 haze episode added an estimated 15–20 percent to inland logistics costs for plantation companies in Sumatra.

These logistics frictions are not captured in simple production forecasts. They extend the impact window: even if rains return in late 2026, the export backlog can persist into Q1 2027.

4. Transmission to the rupiah: four reinforcing channels

Channel 1: Trade balance deterioration

The May 2026 deficit of $1.61 billion ended a six-year surplus streak. The oil and gas deficit ($3.76 billion) was the proximate driver, but non-oil and gas exports also contracted 4.2 percent year-on-year. A commodity export shock from El Niño would hit the non-oil surplus — the very cushion that had kept the overall balance positive. With imports likely to remain sticky (energy, food, capital goods), each $1 billion of lost commodity receipts translates nearly one-for-one into a wider deficit.

Channel 2: FX reserve depletion

Bank Indonesia's foreign exchange reserves stood at $144.9 billion at end-May 2026, the lowest since May 2024. Reserves have declined in four of the last five months, falling $1.3 billion in May alone — partly due to intervention and external debt payments. At the current level, reserves cover approximately 6.2 months of imports and external debt service, above the IMF's 3-month adequacy metric but well below the 8+ months seen in 2021–22. A sustained intervention pace of $2–3 billion per month — plausible if the rupiah comes under concerted pressure — would draw reserves toward the $135–138 billion range within a quarter.

Channel 3: The state-controlled export chain (GR 24/2026)

Government Regulation 24/2026 mandates that designated commodity exports (palm oil, coal, minerals) flow through state-linked trading entities (BUMNs) and comply with Domestic Market Obligations (DMOs) before earning export permits. The regulation aims to secure domestic supply and capture more value domestically.

During a supply disruption, this structure introduces two new frictions:

• Coordination delays: Export approvals now require BUMN verification of DMO fulfillment. In 2015, ad-hoc export bans and permit confusion added weeks to shipment schedules. The new framework formalizes this bottleneck.
• Price disincentives: DMO reference prices (e.g., coal capped at $70/ton vs. $121.83/ton international benchmark in June 2026) reduce producer margins. During a drought-induced output drop, miners and planters face simultaneous volume and margin compression, potentially accelerating production cuts.

Whether GR 24/2026 stabilizes or amplifies the shock depends on implementation speed and BUMN capacity — both untested under El Niño conditions.

Channel 4: Capital flow sensitivity

Indonesia's policy rate (BI-Rate) was raised to 5.75 percent on June 18, 2026, maintaining a roughly 200 basis point premium over the Fed funds rate (5.25–5.50%). This premium has attracted portfolio inflows into government bonds (foreign holdings ~$255 trillion IDR as of May 2026). However, a widening trade deficit and reserve drawdown would signal external vulnerability, increasing the risk premium on Indonesian assets. Foreign investors have reduced bond holdings in three of the last five months. A reversal of the carry trade would compound the current account pressure.

What the evidence does not support

• A specific rupiah price target. The transmission from El Niño to exchange rate runs through too many conditional variables (global commodity prices, Fed policy, BI intervention intensity, export chain execution) for point forecasts to be meaningful.
• A 2015-magnitude repeat as the base case. The 2015 event coincided with a Fed tightening cycle, a Chinese growth scare, and a commodity supercycle bust. Today's global backdrop differs: commodity prices are firmer, China's demand is weaker but more stable, and the Fed is on hold. The structure of vulnerability is similar; the amplitude is uncertain.
• GR 24/2026 as a clear stabilizer or destabilizer. The regulation's export-chain centralization could, in theory, give the state better visibility and control over foreign exchange repatriation. In practice, the added administrative layer has not been stress-tested. We illuminate the mechanism; we do not prejudge the outcome.
• Regional contagion as a given. Malaysia and Thailand face the same El Niño, but their export structures differ. Malaysia's palm oil exposure is comparable (~5–6 percent of GDP), but its reserves ($115 billion) and current account surplus provide a larger buffer. Thailand's rice exports are affected, but tourism and manufacturing diversify its FX base. Indonesia's vulnerability is concentrated, not necessarily unique.

The least-harm path: scenarios, not forecasts

We model three scenarios for the July 2026 – March 2027 window. All assume the Fed holds rates steady and Brent crude averages $70–80/bbl.

Rupiah ranges are illustrative, derived from historical elasticity of IDR to trade balance shifts (~-0.8 to -1.2 percent per $1B deficit widening) and reserve adequacy metrics. They are not targets.

Key swing factors:

• Global palm oil prices: If drought is regional (Indonesia + Malaysia), prices rise and partially offset volume losses. If La Niña emerges in South America, soybean oil competition limits the price cushion.
• BI intervention tolerance: The central bank has signaled willingness to spend reserves to prevent "disorderly" moves. The definition of disorderly is the practical constraint.
• GR 24/2026 execution: If BUMNs streamline permits during disruption, the regulation helps. If they become a choke point, it hurts.

What I'm uncertain about

1. El Niño's peak intensity and duration. Climate models converge on a strong event but diverge on whether it persists into mid-2027. A "double-dip" (weakening then re-intensifying) would extend the export disruption window.
2. BUMN export-chain capacity under stress. No public stress-test data exists for the new state trading entities handling surge volumes with permit complexities.
3. Indonesian fiscal response. The 2026 budget assumed a trade surplus. A sustained deficit may trigger import compression measures (non-tariff barriers, licensing tightening) that distort the transmission mechanism further.
4. Global financial conditions. A surprise Fed hike or China growth scare would amplify capital outflow pressure independently of the trade channel.
5. Household pass-through. Our prior work ("How 22% Depreciation Reaches Indonesian Households") showed food and fuel prices transmit with a 2–3 month lag. A renewed depreciation wave would reach low-income households just as El Niño reduces domestic food supply — a double bind not captured in trade models.

Closing observation

The rupiah's recovery since mid-June rests on three pillars: lower oil prices, a stable Fed, and BI's rate premium. El Niño threatens the foundation of that recovery — the trade surplus that historically anchored confidence in Indonesia's external position. The May deficit was a warning. The dry season is the test.

What happens next depends less on the weather than on the plumbing: whether export permits flow, whether barges float, whether reserves hold, and whether the policy framework absorbs or amplifies the shock. The climate signal is clear. The policy response is the variable.

This analysis builds on Rupiah Stability Watch's prior work: Weekly Rupiah Monitor (July 4, 2026); "Indonesia's New State-Controlled Export Chain" (July 3, 2026); "Bank Indonesia's Defensive Stance" (June 10, 2026); "Indonesia's Rate-Hike Premium Over the Fed" (July 5, 2026); "Strait of Hormuz Reopening and the Rupiah" (July 4, 2026); and "How 22% Depreciation Reaches Indonesian Households" (June 10, 2026).