well a tsunami has hit the island nation
of tonga take a look at this satellite
video breaking news a tsunami advisory
is now in effect for the entire u.s west
coast and alaska it's a very large
explosive part of this
eruption saturday january 15th at 5 15
pm local time a volcano on the island of
hungatunga erupted sending a five
kilometer wide cloud of ash 20
kilometers into the atmosphere now tunga
is pretty much never included on maps
but if it was it would be a few hundred
miles northeast of new zealand
loud explosions could be heard on
islands up to 65 kilometers away from
space the erupting column of smoke and
even atmospheric shock waves were
captured propagating across the pacific
ocean the eruption started a magnitude
5.8 earthquake and a tsunami they
reached as far as the united states
although by the time it got there waves
were limited to only about four feet but
the tonga explosion will have far more
reaching consequences than what's
happened in the immediate aftermath
preliminary observations showed the
eruption ejected a large amount of
volcanic material into the stratosphere
enough to cool the earth and at least
temporarily reverse man-made climate
change get ready for some extreme ice
storms over the next few years and if
you live in florida you might want to
buy your snow park as now when an
eruption happens hundreds of millions of
tons of ash can be flung high into the
stratosphere
these particles reflect sunlight and
cause temporary cooling larger particles
of ash have little effect because they
fall out of the air almost instantly
standing near a volcano they can make it
feel like you're being pelleted by
raining pebbles medium-sized ash
particles of about two millimeters the
thickness of two credit cards stacked on
top of each other form a dark cloud in
the sky that shades and cools the areas
directly beneath it
this is what makes up the majority of
the great volcanic plume you can see
here
most of these particles are pushed out
of the atmosphere by rain within a few
days of an eruption but the smallest
particles of dust those the size of
human hairs get into the stratosphere
and are able to travel vast distances
often worldwide
these tiny particles are so light that
they can stain the stratosphere for
years reflecting sunlight back into the
air and causing cooling over large areas
of the earth
at the same time erupting volcanoes
emits sulfur dioxide sulfur dioxide is
much more effective than ash at cooling
the climate the sulfur dioxide combines
with water to form sulfuric acid which
makes a haze of tiny droplets in the
stratosphere that reflect incoming solar
radiation these droplets can stay in the
stratosphere for years spread around the
globe by wind and causing significant
cooling worldwide if you're interested
in learning more about this we made an
entire video about how some scientists
want to fight climate change by
injecting sulfur dioxide high into the
earth's atmosphere give that video a
watch after this one the tongue
explosion has been estimated to have a
vei of 5.
vei or volcanic explosivity index is a
scale for measuring the explosivity of
an eruption in the same way the richter
scale measures the severity of
earthquakes vei works on the logarithmic
scale every one point increase in vei is
a 10 times more powerful explosion so
the difference between a vei of a 4 and
a 5 is a 10 times more powerful eruption
and the difference between a 4 and a 6
is a 100 fold increase to help put this
number in context let's look back at
some eruptions from history the largest
volcanic eruption in recorded human
history was the 1815 eruption of mount
tambora the eruption pumped 150 cubic
kilometers roughly 36 cubic miles of ash
and some 55 million tons of sulfur
dioxide gas more than 20 miles into the
sky
today humans worldwide emit 26 million
tons of so2 from burning coal fossil
fuels engine exhaust and other sources
annually so this was about two years
worth of modern day so2 emissions put
into the atmosphere in the course of
only a few days
the eruption led to global cooling and
worldwide harvest failures and would
come to be known as the year without
summer while the explosion only and
we're using the word only very loosely
killed a hundred thousand people
directly the mass famines it caused
would indirectly lead to millions more
deaths around the world
only a few hundred miles away in the
same archipelago the 1887 eruption of
krukatoa had vei of 6 and caused global
temperatures to fall by 1.2 degrees
celsius on average while that might not
sound like a lot remember the global
goal on climate change is to prevent
only 2 degrees celsius of warming so an
eruption on this scale would accomplish
more than half our goal today
in 1784 the smaller lackey volcano
eruption at a vei of 4 released enormous
amounts of sulfur dioxide killed a
quarter of the icelandic population and
caused northern hemisphere temperatures
to drop by about 1 degree celsius the
following year and this was for an
eruption about 10 percent the size of
the one we just saw
notice how we have to go back hundreds
of years to show equivalent eruptions
well that's because eruptions on this
scale are quite rare since 1800 there
have only been 20 volcanoes with a vei
of 5 or higher about 1 every decade on
average these eruptions lowered global
temperatures by about 0.4 degrees
celsius for an average of six years
until temperatures returned to normal
after being relatively inactive since
2014 the tonga volcano erupted on
december 20 2021 less than a month ago
over the next few weeks as activity on
the island decreased the volcano was
declared dormant on january 11 2022 just
four days before it would produce the
largest volcanic explosion of at least
the last 20 years no matter how much
you've screwed up at your job rest
assured you didn't tell the world
everything was safe days before half
your island was obliterated that's
pretty much on par with this tweet from
the world health organization
[Music]
it's important to know that not all
volcanoes of a given vei have the same
effect the three factors that have a big
impact on how much an eruption cools
global temperatures are the distance to
the equator the chemistry of the volcano
and how high the volcanic plume reaches
into the atmosphere the tonga eruption
is poised to go three for three in these
categories
the eruption in krakatoa we mentioned
earlier had a latitude just six degrees
south of the equator and cooled the
earth by 1.2 degrees celsius but the
novoraptor explosion in alaska at 60
degrees north of the equator had the
same vei rating of 6 but cooled the
earth by less than a fifth that amount
tonga at 21 degrees south of the equator
is a medium distance away but the
coriolis effect makes up for this
distance in the southern hemisphere
currents are deflected to the left as a
result air systems seem to rotate
clockwise on the day of the eruption and
immediately following it tonga was
pitched in the middle of three swirling
air pockets by far the largest of these
was to its south
this means warm air from tonga
containing millions of tons of ash in
so2 was pulled south where it spiraled
with colder air from antarctica since
warm air rises this quickly pushed all
the ash and so2 from the eruption high
into the atmosphere moving on to factor
two the effective eruptions on cooling
also depends on the chemistry of the
volcano
since so2 is much more effective at
cooling the earth compared to ash the
more so2 the volcano emits the more it
will cool the planet the tonga eruption
was underwater and since water is
incredibly good at absorbing so2 we
likely won't have estimates for how much
so2 was released for weeks if not months
but other volcanoes in this part of the
world are amongst the highest sulfur
dioxide emitters meaning it's a safe bet
that more than 10 million tons of so2
six months worth of human emissions were
just emitted into the atmosphere in a
matter of hours
finally subsupine cooling is also
dependent on how high the volcanic plume
reaches into the atmosphere the higher
it goes the more fine particles reach
stratospheric levels where they can
remain airborne for years
satellite imagery of the tonga eruption
shows the ash cloud reached an altitude
of 20 kilometers into the atmosphere
much higher than the kurkatoa eruption
which only reached an estimated six
kilometers and still caused 1.2 degrees
of cooling today the earth is about one
degree celsius warmer than
pre-industrial revolution averages or as
temperature rises by an average of 0.18
degrees celsius or 0.32 degrees
fahrenheit every decade based on prior
volcanic eruptions over the next five
years the tonga eruption will lead to at
least a half degree celsius reduction in
global temperatures in effect
temporarily turning back the global
clock two decades maybe we'll finally
have some good ski weather it's
important to realize this isn't a
long-term solution in fact it's not even
really a short-term solution over the
next few years as fine ash and so2 drop
back out of the upper atmosphere the
earth's warming will reset back on its
original path but perhaps the tonga
eruption can be a modern day trial of
how so2 released high into the
atmosphere affects global climate maybe
one day as temperatures continue to
climb humanity will begin purposely
injecting so2 high into the atmosphere
check out how we could do that in this
video here and remember there is always
more to learn