TheEconomistSeptember 21st 2019 531T
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 speedThe Panama Canal
Beyond seasonable drought
PANAMA CITY
Changing rainfall patterns threaten an artery of global trade
The Americas
54 ElAltoandEvoMorales
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