How Tambora Stole Summer - Royal Meteorological Society

How Tambora Stole Summer:
Global consequences of the eruption
Dr. Nicholas Klingaman
Senior Research Fellow
NCAS-Climate, Univ. of Reading
Co-author of
”The Year Without Summer:
The Volcano That Darkened the
World and Changed History”
The eruption
• Initial eruption just before sunset on 5 April.
• Mistaken for cannonfire by lieutenant-governor of Java,
Thomas Stamford Raffles.
• Troops dispatched and rescue boats launched from bases
across Java.
• Light rain of ash
shortly after dawn
the following day.
• Explosions die away
in the following days,
but rain of ash
continues.
The eruption
• Main eruption began during the
evening of 10 April.
• Pyroclastic flows running down
the mountain heat the air above.
• Whirlwinds caused by pressure
vacuum destroy all vegetation.
• Village of Tambora vanishes in a
flood of pumice stone.
• Within 24 hours, ash cloud
expands to the size of Australia.
Satellite image of caldera formed
by 1815 eruption of Tambora.
Source: NASA
The eruption
• Tsunamis 15 feet high caused by
collison of pyroclastic flows with
sea around Tambora.
• Tsunami reaches Java about six
hours after the eruption began.
• Fields of pumice stone several
miles wide, driven west by
prevailing winds and currents.
• Some found by ships in the open
Indian Ocean up to three years
later, believed to be from
underwater volcanoes.
Pumice stone formed by an underwater volcano
Source: Sunnyskyz.com
The eruption
• Eruption lasts about 48 hours, but ash continues to fall for a week.
• Ash depths of 40 inches reported 20 miles away
• Ash depths of 10 inches reported 100 miles away
• Nearly all of the native population in the vicinity (~12,000) killed
by eruption.
• Tens of thousands more killed due to poisoned crops.
• Deadliest eruption in recorded history.
Devastation caused by
the eruption of Pamandayan
in Indonesia. Source: demisindonesia.blogspot.com
The eruption
• One of the four strongest eruptions of the past 10,000 years.
• Volcanic Explosivity Index – similar to the Richter scale for
earthquakes, in that each point on the scale is a factor of 10 in
terms of intensity.
Stratospheric aerosol veil
• Eruption ejected approximately 55
million tons of sulfur dioxide to a
height of 32 km (20 miles).
• Sulfur dioxide combined with
hydroxide gas to form more than
100 million tons of sulfuric acid.
SO2 + H2O2 = H2SO4
• Height of the eruption is critical
for climate consequences.
• Strong stratospheric winds
dispersed the sulfuric acid veil,
circumnavigating the equator in
about two weeks.
Satellite image of eruption plume
from Eyjafjallajokull.
Source: volcano.oregonstate.edu
Stratospheric aerosol veil
• Stratospheric winds are primarily zonal, so veil took 2-3 months
to reach the poles and completely cover the globe.
• Reflected approximately 0.5% of the incoming solar radiation.
• Imperceptible to the human eye.
• Likely caused dramatic
sunsets in the autumn of
1815 and 1815-16.
Impact on artists?
• Reports of coloured snow
in the winter of 1815-16.
Chichester Canal by J. M. Turner (1827)
Stratospheric aerosol veil
• Latitude of a volcanic eruption
determines the region directly
affected by the aerosol veil.
• Volcanoes directly influence
the climate only poleward of
their latitude.
• Lower stratospheric
circulation extends from the
equator to the pole in each
hemisphere.
• The return circulation is in the
troposphere.
Schematic of the general circulation in the
troposphere and stratosphere from the
summer hemisphere (left) to winter
hemisphere (right).
Source: World Meteorological Organization
Climate consequences
• Global cooling from Tambora of approximately 1ºC. Reduction in
global precipitation of approximately 3.4%.
• 1816 second coldest year since 1400 (only 1601 was colder).
• Land cools much more than oceans, as well as more quickly.
• Cooling does not necessarily scale with amount of sulfuric acid.
Temperature anomalies
from HadGEM2-ES
model simulations forced
with Tambora-like
volcanic aerosols.
Source: Kandlbauer et al.
(2013, JGR Atmospheres)
Climate consequences
• Volcanic eruptions often
induce a positive phase of the
Arctic Oscillation in winter.
• Strong polar vortex and
highly zonal flow
• Aerosol veil heats lower
stratosphere in the tropics,
but cannot do so in the
perpetually dark wintertime
polar latitudes.
• Increased equator to pole
temperature difference.
Model simulated sea‐level pressure anomalies in November 1815 – April 1816.
Source: Shindell et al. (2003, J. Climate)
Climate consequences
• Warm winter of 1815-16 in
New England as jet stream
confined to the north.
”Our own Winters are
…Comfortably Moderated
since the Land has been Peopled
... Our Snows are not so Deep,
and Long ... And our Winds blow
not such Rasours, as in the Days
of our Fathers when the Hands
of Good Men would Freeze
unto the Bread upon their
Tables.” -- Cotton Mather
• Sequence of snow and
rainstorms in continental
Europe, including some with
colored snow.
Model simulated sea‐level pressure anomalies in November 1815 – April 1816.
Source: Shindell et al. (2003, J. Climate)
Climate consequences
• After a mild winter and spring, the summer of 1816 was 2-3ºC
cooler across western Europe and eastern North America.
• Aerosol veil cooled surface temperatures in the tropics more
than the poles, reducing the temperature difference.
• May saw six inches of
snow in New York
and Quebec, with ice
in the St. Lawrence
River.
Model simulated surface temperature anomalies in June – August 1816.
Source: Shindell et al. (2003, J. Climate)
Climate consequences
Typical summer jet stream
Jet stream in “summer” of 1816
Most storms stay
north of Europe
Cold, dry
Arctic air
Conveyor belt
of storms to
Warm and humid
Europe
air for the East Coast
Effects in the United States
• Frosts in New England and Ohio
Valley in every month of 1816.
• Drought in the eastern US lasts
through autumn and into winter.
• Many farmers sold their land and
moved west to the Ohio Valley,
including the family of the young
Joseph Smith.
• Religious revivals intensify (“Second
Great Awakening”) as many were
convinced God was punishing them.
Effects in the United States
• Repeated incursions of Arctic cold fronts across Quebec, New
England and the mid-Atlantic states.
”The ground was covered with snow, and the temperature of the
weather during the day more like that of March than May. Rarely
has vegetation been more backward at this season of the year than
it is now in this city.” – Albany, New York, 14 May
“[Farmers are] ploughing up and replanting the corn. The
temperature of the weather with us is very fluctuating-–the
evenings and the mornings generally so cold as to render a fire
quite agreeable.” – Norfolk,Virginia, 16 May
”The season continues extremely unfavorable to Agriculture.
Masses of snow still lie in the fields, and very little wheat has yet
been sown in this district.” – Quebec, May
Effects in the United States
• In early June, a strong cold front swept across the US Midwest,
southern Canada and New England.
• Trailed by several Arctic high pressure systems.
• Ridge over the Atlantic, combined with an early-season
hurricane, provided warm air and moisture.
Synoptic charts for 5‐6 June, drawn based on station data shown.
Source: Chenoweth (2009)
Effects in the United States
• 5 June: Boston reaches 86ºF reports of ”hot and sultry
weather” in Montreal; Salem, Mass. hits 92ºF.
• Overnight minimum of 72ºF in Albany, NY; 15ºF above normal.
• Steady rain overnight throughout New England.
• Strong NW gales reported by Royal Navy ships on Lake Erie.
Synoptic charts for 5‐6 June, drawn based on station data shown.
Source: Chenoweth (2009)
Effects in the United States
• Front passes across New England on 6 June.
• Maximum of 30ºF in Quebec City on 6 June. Steady snow with
accumulations up to 10 inches.
• 7 June: Montreal reports a ”frost [of] sharp ice as thick as a
dollar [coin], which as injured tender as well as hardy plants.”
Synoptic charts for 7‐8 June, drawn based on station data shown.
Source: Chenoweth (2009)
Effects in the United States
• Shift from mild southeasterlies to gale-force northwesterlies
across New England.
• 6 June: Snow and occasional hail throughout New England;
accumulations of up to four inches.
• Temperatures drop from 90ºF on 5 June to 35ºF on 6 June.
Synoptic charts for 7‐8 June, drawn based on station data shown.
Source: Chenoweth (2009)
Contemporary explanations
• No contemporary connection between
Tambora and the disrupted climate. Very
few reports of the eruption itself!
• Benjamin Franklin postulated a link
between volcanoes and temperatures
after the eruption of Laki in 1783.
• Contemporary explanations included:
• God
• Deforestation
• Icebergs
• Sunspots
• Earthquakes
• Changes in the magnetic field
Source: space.com
Impacts elsewhere
• Model simulations show cooling
of mean temperatures across
the globe.
• Contemporary reports of heavy
rainfall and incidence of waterborne disease in southern China
and southern India.
• Southward shift in monsoons
due to land cooling more than
ocean?
• Disrupted jet in summer 1816
led to mild conditions in eastern
Europe and western US.
Average (top) temperature and (bottom) precipitation anomalies for 1816‐20, from model simulations. Source: Kandlbauer et al. (2013, J. Geophys. Res.)
Epilogue
• No connection between Tambora and the Year Without a
Summer for nearly 150 years.
The picture can't be display ed.
• Scientists disagreed over
whether volcanic aerosol
clouds produced net
warming or cooling.
• Few volcanoes to observe
and few observations taken.
• Disagreements finally
resolved after observations
of response to nuclear
tests in 1950s and 1960s.
Nuclear explosion. Source: Wikipedia
Conclusions
• The Year Without a Summer is a powerful example of natural
climate change.
• Our climate system is finely balanced: a 0.5% reduction in
incoming solar radiation was enough to cool global temperatures
by 1ºC and severely disrupt the trans-Atlantic jet stream.
• By 1818, most of the sulfuric acid veil had dissipated and
temperatures had returned to near normal.
• Human activity is adding more greenhouse gases to the
atmosphere every year – anthropogenic warming will soon be
greater than was Tambora’s cooling. Our influence on the
climate system will not fade as quickly as Tambora’s did!