The Economist USA - 21.09.2019

38 TheEconomistSeptember 21st 2019

1

T

ake in theview from atop Gatun dam

and fathom what is missing. Container

ships float idly on Lake Gatun, near the

midpoint of the Panama Canal, awaiting

passage to the Caribbean sea, their gateway

to the Atlantic Ocean. What look like is-

lands are hilltops poking up from a valley

that American engineers flooded a century

ago, creating what was then the world’s

largest artificial lake. All seems well. But a

security guard from the Panama Canal Au-

thority (acp) points down to a problem: the

water lapping against the dam is 1.8 metres

(six feet) lower than it should be.

That water is Panama’s lifeblood. Lake

Gatun stores rain during the wet season,

which usually runs from mid-April

through to mid-December, for use in the

dry one. It supplies drinking water to Pana-

ma city, the capital, as does man-made

Lake Alajuela nearby. It is also two-fifths of

the canal, a shortcut between oceans for 3%

of the world’s maritime trade, as well as for

cruise ships and an occasional nuclear sub-

marine. The acpprovides an eighth of the

national government’s revenue. “Water is

money here,” says Oscar McKay, an engi-

neer at the dam site.

A normal rainy season fills Lake Gatun

to 26.5 metres above sea level. By the end of

the dry season that usually falls to 25.9 me-

tres. Prolonged dry seasons have big conse-

quences. If the water level falls below 24.4

metres, the acpmust limit the weight of big

“neopanamax” container ships lest their

hulls scrape on the lake bed. Below 24 me-

tres smaller “panamax” ships would risk

bumping on the bottom of the locks re-

served for them as they enter and leave the

lake. This June, after Panama’s most in-

tense drought since independence in 1903,

Lake Gatun fell nearly to that level. In 2016,

during a longer (but less severe) dry spell, it

fell below that for the first time.

Panama city’s rising population and the

canal’s growing traffic make such low wa-

ter levels more likely. Each time a ship

passes through the canal’s locks, Lake Ga-

tun releases 200m litres (52m American

gallons) of water. In a dry month, outflows

through the canal can reduce the lake’s lev-

el by 80cm.

This year many ships had to transit the

canal with less than their maximum load of

cargo. That cost the acpa few million dol-

lars in revenue. The canal came “this close”

to losing much more, says an executive,

holding his thumb and forefinger together.

It narrowly avoided having to impose

draught restrictions on panamaxships.

Rain since July has raised the water level

to 24.7 metres but has not lowered appre-

hensions. Several severe droughts since

2014 may indicate that dry seasons are be-

coming longer. That would threaten not

only Panama’s water supply and govern-

ment revenues but the canal’s role as a hub

of trade. “The whole global supply chain

depends on consistency,” says Onésimo

Sánchez, a former manager at the acp. If

the canal falters, shipping firms will turn to

competing routes, even if they cost more.

Precipitation, meet precipice

There is little doubt that climate change

threatens Panama. Rising seas will sub-

merge the low-lying Caribbean islands of

San Blas, a tourist attraction and home to

several thousand Guna, an indigenous

group. Warmer temperatures will speed

The Panama Canal

Beyond seasonable drought

PANAMA CITY

Changing rainfall patterns threaten an artery of global trade

The Americas

39 ElAltoandEvoMorales

40 Bello: The reds and the black stuff

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