limate change is a red-hot
topic nowadays. Earth's
climate is warming up, and
scientists say humans are
mostly to blame. But natural
disasters can throw climate for
some big loops too.
In 1452, a volcano in the South
Pacific called Kuwae appears to
have kicked off two bitterly cold
years in Europe. In 1815, Tambora,
an Indonesian volcano, caused
another big chill. The following
year became known as the "Year
Without a Summer," and snow
fell on New Hampshire four
times in August. Then, in 1883,
Krakatau, in Indonesia, blew its
top and altered weather and sunsets
around the world.
Now scientists have identified
yet another climate-changing
volcano. This one put the Northern
Hemisphere on icefrom1601
to 1604. Called Huaynaputina
(way-na-puh-TEE-nah), it might
have even changed the course of
a distant country's history.
PERUVIAN
POWERHOUSE
Huaynaputina, which is in southern
Peru, erupted violently in February
1600. The explosion was so loud, it
echoed throughout the city of Lima,
1,000 kilometers (620 miles) to the
northwest. The volcano blasted tons
of ash (fine bits of rock and volcanic glass) and rocks into the air.
A volcanic
eruption
might have
changed
a far-off
country's
history.
Shield volcano
All volcanoes have an underground vent through which magma (motten rock) rises to Earth's surface. The magma that erupts onto
the surface is called lava. There it cools and hardens, often forming a mountain around the vent. Huaynaputina is a stratovolcano.
It has a cone shape and sticky, sitica-rich magma and tends to erupt violently. Not all volcanoes rock the world. Some, like those
in Hawaii, have nonexplosive eruptions. Called shield volcanoes, they spevtf runny, iron-rich lava and have relatively flat slopes.
Villages and farms were flattened
for 20 kilometers (12 miles)
around. So much ash fell that palm
trees 125 kilometers (78 miles) away
collapsed, says volcanologist Shan
de Silva of the University of Oregon.
Huaynaputina had only begun
to make itself felt, however. The
eruption also shot a plume of sulfurrich aemsols (liquid or solid particles suspended in the air) into the
stratosphere. Once there, the plume
slowly moved north. Sulfur can
affect climate more than anything
else a volcano dishes out. "It's all
about the sulfur," says de Silva.
Once an aerosol plume is aloft,
it spirals around the globe, says
Steve Self, a volcanologist with the
National Research Council. In the
cold stratosphere, sulfur aerosols
convert to sulfuric acid (H2SO4)
within about a month. The sulfuric
acid droplets absorb incoming radiation from the sun and scatter it before
it can reach Earth's surface. That
leads to a temporary climate change,
'it's quite effective," says Self.
By 1600, the world was already in
the grip of the Little Ice Age, a long
cold snap that lasted from the mid1300s to the mid-1800s. But 1601,
say historians, was even worse than
usual. In France, people were able
to drive their carriages across the
fTOzen Rhône River. In Germany,
the wine industry collapsed. "The
Baltic Sea was covered 94 percent
with ice," says oceanographer
Daniel Hansson of Gothenburg
Tieier' Shultersiock; Vol can oi Gary Braasch/CorUs
University in Sweden. "That implies
a severe winter."
The evidence collected from tree
rings backs up the historical record.
When trees are under stress, their
development is stunted. The growth
rings added to their trunks each
year are thinner The rings of old
trees clearly show that 1601 was one
of northern Europe's coldest years.
OK. So Europe had a couple of
colder-than-normal years. Why
finger Huaynaputina. thousands
of kilometers away? The evidence
contained in Arctic ice cores points
right to the volcano. An ice core is
a long cylinder of ice extracted
from a glacier or an ice sheet. It is
a frozen record of the snow that fell
and was compacted into a layer of
ice every year. Trapped within each
layer are atmospheric particles that
indicate what the climate was like
that year. Nothing says "volcano"
like sulfur. And sure enough, ice
cores extracted from Greenland's
ice cap show that sulfur wafted over
the Northern Hemisphere in 1601
and 1602.
DOUBLE WHAMMy
In Russia, conditions slid downhill
quickly. "The year 1601 is when
things got really bad," says Chester
Dunning of Texas A&M University.
"In 1602, the crops failed at the
end of the year. In 1603, the crops
failed again." By the end of 1604,
one-third of Russia's population
had starved to death. As famine
and death spread, civil war erupted.
By 1605, Dunning told Current
Science, new rulers had taken over.
New laws soon followed.
Dunning, an expert on 17thcentury Russian history, hadn't
heard of Huaynaputina until he
happened to meet Ken Verosub, a
volcanologist from the University
of California, Davis, on an airplane.
"This guy tells me about this
volcano in South America," recalls
Dunning. "I was excited to have
an explanation of why those years
were so severe." With Russia
already chilled by the Little Ice
Age, was Huaynaputina the final,
frozen straw? "I see the [Little Ice
Age and the] volcano as the double
whammy," says Dunning.
Could another big eruption
affect history in a similar way? Yes.
The 1991 eruption of Pinatubo,
a volcano in the Philippines, was
a chilling preview. After that eruption. Earth's climate temporarily
cooled by about 0.5 degrees Celsius
(I degree Fahrenheit).
That may not seem like much,
says Self "But it was enough to
knock back global warming for a
year or two." CS
CURRENT SCIENCE December 12, 2008 9