Case Study: The 2023-24 Panama Canal Drought

The Canal That Depends on Weather

The Panama Canal is a freshwater lock system, not a sea-level channel. Ships are raised 85 feet from the ocean to the surface of Gatun Lake, an artificial reservoir created in 1914 by damming the Chagres River, then lowered back to sea level on the other side. Each transit through the original Panamax locks consumes approximately 52 million gallons of fresh water. Each transit through the newer Neopanamax locks -- opened in 2016 to accommodate larger vessels -- uses water-saving basins that recapture about 60% of the lockage water, but still draws a net 20 million gallons from the lake.

The water is not recycled. It flows by gravity from the lake into the ocean and is gone. The lake is replenished by rainfall over a 1,290-square-mile watershed of tropical forest that channels runoff into the Chagres River and its tributaries. In a normal year, the wet season (May through December) deposits enough rain to sustain 36 to 38 daily transits year-round, with the lake hovering near its optimal operating level of about 87.5 feet above sea level.

The system's vulnerability is obvious once you state it plainly: the throughput capacity of a canal that handles 5% of global seaborne trade is determined by how much it rains in a specific patch of Central American jungle. When the rain fails, the canal closes -- not with a dramatic blockage like the Ever Given in Suez, but through a slow, grinding reduction in daily transits that squeezes global shipping capacity over months rather than days.

The 2023 El Nino and the Rainfall Collapse

El Nino -- the periodic warming of the central and eastern Pacific Ocean -- suppresses rainfall across Central America by shifting atmospheric convection patterns westward. This is well-established climate science, documented over decades of observation. The Panama Canal Authority (ACP) has known since at least the 1990s that strong El Nino years produce below-average rainfall in the canal watershed, and it has historical data linking El Nino intensity to Gatun Lake levels.

The 2023 El Nino was officially declared by NOAA in June 2023. By that point, the warning signs were already visible. The 2023 wet season, which should have begun replenishing Gatun Lake in May, arrived late and delivered well below normal precipitation. By July, the ACP reported that Gatun Lake was at its lowest level for that time of year since systematic records began in 1965. The lake stood at approximately 82 feet -- five and a half feet below the seasonal average and already below the level at which draft restrictions become necessary.

The ACP began imposing restrictions in stages. In late July 2023, it reduced the maximum allowable draft for vessels transiting the Neopanamax locks from 50 feet to 44 feet, forcing large container ships and LNG carriers to lighten their loads or wait for deeper slots. In August, it cut daily transits from 36 to 32. In September, to 31. By November, the number was down to 24 -- a one-third reduction from normal capacity.

Gatun Lake kept falling. In October 2023, it dropped below 80 feet for the first time since the 2016 Neopanamax expansion. By late January 2024, it reached a record low of approximately 78.5 feet above sea level, nine feet below optimal and dangerously close to the minimum level required for any lock operations at all. The ACP reduced daily transits to 22 -- less than two-thirds of normal throughput -- and restricted the maximum draft to 44 feet across all locks.

The Auction Market: $4 Million to Skip the Line

The Panama Canal operates a booking system that assigns transit slots to vessels in advance. Under normal conditions, booking is routine and slots are readily available. When the ACP cuts daily transits, the number of available slots drops but demand does not, creating a scarcity that the canal manages through an auction mechanism.

In the auction, shippers bid for the right to transit on a specific date, on top of the standard canal toll (which itself ranges from roughly $200,000 to $800,000 depending on vessel size). During the 2023-24 drought, auction premiums reached extraordinary levels. In November 2023, a single auction slot sold for approximately $3.975 million -- nearly $4 million above the normal toll -- to an LNG tanker whose cargo had contractual delivery deadlines that made the premium economically rational compared to the cost of rerouting around Cape Horn.

For context, the alternative to paying the auction premium was a detour around the southern tip of South America, adding roughly 8,000 nautical miles and 14 to 18 days of sailing time to an Asia-to-US-East-Coast voyage. At a daily operating cost of $30,000 to $80,000 for a large container ship or LNG carrier, the rerouting cost alone -- fuel, crew, charter time, schedule disruption -- could reach $1 million to $1.5 million. The auction premium was expensive, but it was not irrational. For time-sensitive cargoes, particularly LNG with delivery windows tied to winter heating demand, paying to skip the queue was the lesser of two costs.

LNG Rerouting and the Energy Market Impact

The Panama Canal is a critical conduit for liquefied natural gas shipments from the US Gulf Coast to Asia. The United States became the world's largest LNG exporter in 2023, and a substantial share of that volume transits the canal en route to buyers in Japan, South Korea, and China. When the canal restricted drafts and cut transits, LNG carriers faced a choice: wait in queue (burning money and potentially missing delivery windows), pay the auction premium, or reroute.

Many carriers rerouted. Some went east through the Suez Canal, adding roughly 10 days. Others went south around Cape Horn, adding 14 to 18 days. Both alternatives increased ton-mile demand on the global LNG fleet -- the same cargo required more ship-days to deliver -- which tightened the market for LNG carriers and pushed spot charter rates higher.

The rate impact was measurable. LNG spot charter rates in Asia rose from roughly $50,000 per day in the summer of 2023 to over $100,000 per day by December 2023, driven partly by the canal constraint and partly by seasonal winter heating demand. European natural gas spot prices, while primarily influenced by other supply-demand factors, incorporated a transport premium that reflected the longer delivery times from US Gulf terminals.

The LNG rerouting effect demonstrated a principle that applies to all canal disruptions: when a shortcut becomes unavailable, the additional voyage distance absorbs fleet capacity. The ships do not disappear -- they just take longer to complete each round trip, which reduces the effective supply of vessels available for new cargoes, which raises freight rates even if the total fleet size has not changed.

Container Rate Impacts

The container shipping market felt the drought through two channels: reduced slot availability for vessels transiting the canal, and cascading schedule disruptions across the transpacific and Asia-to-US-East-Coast trades.

Container rates from Asia to the US East Coast -- the trade lane most dependent on the Panama Canal -- rose through the second half of 2023. The Freightos Baltic Index (FBX) for the China-to-USEC route increased from approximately $2,200 per forty-foot equivalent unit (FEU) in July 2023 to over $3,800 per FEU by January 2024, roughly a 70% increase. Not all of this was attributable to the canal drought -- the simultaneous Red Sea disruption, which began in November 2023, compounded the pressure by removing the Suez Canal as a viable alternative for Asia-to-USEC cargo -- but the Panama restrictions were a significant contributing factor.

The rate impact on US consumer prices was modest but measurable. Container shipping costs account for a small fraction of the final retail price of most goods -- typically 1% to 3% for manufactured products -- so even a 70% increase in container rates translated to a price impact of roughly 1 to 2 percentage points on affected goods. The BLS Import Price Index for the first quarter of 2024 showed a slight uptick in transport-related import cost components, consistent with the rate increase but difficult to isolate from other factors.

The Dual Chokepoint Problem

The timing of the Panama drought was particularly damaging because it coincided with the Houthi attacks on Red Sea shipping. By December 2023, both the Panama Canal and the Suez Canal were functionally constrained -- Panama by water levels, Suez by security risk in its Red Sea approach. The two chokepoints that together handle roughly 20% of global container trade were simultaneously impaired.

This dual failure eliminated the standard rerouting options. A container ship blocked from the Panama Canal would normally divert to Suez. A ship diverted from Suez would normally consider Panama. When both were compromised, the only alternative was the long route around the Cape of Good Hope (for Asia-USEC traffic) or Cape Horn (for Asia-USWC traffic), both of which added substantial voyage time and fuel cost. The global fleet was stretched thinner than at any point since the COVID-era supply chain crisis of 2021.

The compound effect on freight rates was greater than either disruption would have caused in isolation. Carriers that could offer transit through either canal -- because they had secured slots or were willing to pay premiums -- gained pricing power. Carriers that could not were forced into the longest possible routings, absorbing capacity and creating a feedback loop of rising rates.

The Climate Science: Trend, Not Anomaly

The 2023-24 drought was triggered by El Nino, but the underlying vulnerability is structural and worsening. Climate models project declining mean annual rainfall over Central America through the remainder of the century under most emissions scenarios. The Intergovernmental Panel on Climate Change's Sixth Assessment Report identifies the Central American dry corridor -- which overlaps with the Panama Canal watershed -- as a region of particular concern for precipitation declines.

The historical record supports this trajectory. The five driest years in the canal watershed since 1950 have all occurred since 1997. The 2015-16 El Nino forced the ACP to impose draft restrictions for the first time since the Neopanamax expansion. The 2019 dry season required moderate restrictions. The 2023-24 event was the most severe on record. The trend is toward more frequent and more intense water shortages.

The ACP has responded with infrastructure investments. A $2 billion program to build a new reservoir on the Rio Indio, west of the existing canal watershed, was approved in 2024 and is expected to take roughly a decade to complete. The project would increase the canal's freshwater supply by approximately 25%, providing a buffer against moderate droughts. Whether it is sufficient for the most severe drought scenarios projected under high-emissions climate pathways is an open question.

Recovery Timeline

The drought began easing in May 2024 as the wet season arrived and La Nina conditions replaced El Nino in the tropical Pacific. Gatun Lake levels rose steadily through June, July, and August 2024, climbing from their January low of 78.5 feet back above 84 feet by August and approaching 87 feet by October. The ACP progressively loosened restrictions: daily transits rose from 22 in February to 27 in May, 31 in July, and back to 36 by September 2024.

Freight rates on the Asia-USEC route responded to the recovery with a lag. Container rates remained elevated through the spring of 2024, reflecting both residual canal constraints and ongoing Red Sea disruptions. By mid-2024, as Panama operations normalized, the canal-specific component of the rate premium dissipated, though overall transpacific rates remained higher than pre-crisis levels due to continuing Red Sea rerouting.

The full recovery -- from first restriction in July 2023 to full normal operations in September 2024 -- took approximately 14 months. During that period, the ACP estimates it lost approximately $700 million in toll revenue due to reduced transits. The indirect costs to global shipping -- rerouting expenses, auction premiums, schedule delays, cargo insurance adjustments, and consumer price pass-through -- are impossible to quantify precisely but certainly ran into the billions.

Lessons for Risk Assessment

Climate is a shipping variable, not a background condition. Before 2023, most shipping risk models treated Panama Canal capacity as constant. Geopolitical risks in the Strait of Hormuz and military threats in the Red Sea received analytical attention; rainfall patterns in Central America did not. The drought forced a recalibration. Any risk model that does not incorporate hydrological data for the canal watershed is incomplete.

Slow-onset risks are harder to hedge than sudden shocks. The Ever Given blocked the Suez Canal for six days. Markets reacted, adjusted, and normalized within weeks. The Panama drought unfolded over fourteen months. There was no single dramatic moment -- just a grinding, incremental tightening that made hedging and planning decisions harder because the duration and severity were uncertain throughout.

Dual chokepoint failures are not improbable. The 2023-24 period saw simultaneous constraints at Panama and the Red Sea. This was not a coincidence in the statistical sense -- there was no causal link between Central American rainfall and Houthi military strategy -- but it was not as improbable as it appears. There are only five major maritime chokepoints. If each has an independent annual disruption probability of even 10%, the probability that at least two are disrupted in the same year is roughly 1 in 4. Global shipping is concentrated through a small number of narrow passages, and multi-point failures should be expected, not treated as black swans.

Key Takeaways