Massive Tonga Volcanic Eruption Also Has Meteorological, And Possibly Global Climate Effects

Satellite view of massive volcanic eruption in 
Tonga today. Depending on how much ash and
other material the eruption put in the stratosphere,
this could have some slight, temporary cooling 
effect on the global climate 

 If you hadn't heard, there's a lot of breaking news this morning about an incredible volcanic eruption in Tonga. 

Tonga is a chain of island in the southwestern Pacific Ocean. There, an underwater volcano has been erupting. There was a large eruption Friday, then Saturday, an immense one.  This is surely the most powerful explosion the world has seen in decades, possibly centuries. 

It immediately produced an immense cloud of ash, a shock wave that traveled thousands of miles and tsunamis that are in one form or another affecting the the entire Pacific Ocean basin, all the way to the United States and Canadian west coasts. 

That's impressive, given that Tonga is about 8,600 miles from Los Angeles. Any tsunami activity on the West Coast will be relatively minor. No big waves smashing into buildings, but it is too dangerous this morning to be hanging out on the water or right on the beach. Tsunami waves as high as 2.7 feet have already been reported in Hawaii. 

Relatively small tsunamis then hit the United States west coast, causing some damage in California mostly to boats and cars parked at marinas. 

More destructive tsunamis have hit islands in and near Tonga.

So far, I've discussed geology and oceanography, not meteorology and climate, which is the point of this blog. But the eruption has had or might have effect on both those sciences.

The explosion was so huge it sent shock waves through the atmosphere far and wide. People in New Zealand, about 1,500 miles from the eruption, heard booms and rumbles from atmospheric shock waves generated by the explosive volcano. Barometric pressure in New Zealand wiggled up and down. This morning, barometers registered tiny, but abrupt changes in air pressure that moved west to east across the nation.

Those barometric wiggles were noticed here in Vermont shortly before 11 a.m. today. 

To give you an idea of the scale of this, had the Tonga explosion occurred in Miami, we would have heard the boom and rumbles from it here in Vermont. 

There's a chance this eruption could cause a bit of global cooling.  We probably won't know for weeks what effect the eruption will have on the global climate, if any. 

We do know the explosion was big enough to loft ash, sulfur and other stuff into the stratosphere, which is the layer of the atmosphere above where most weather occurs.

From there, the gunk from Tonga would be swept across nearly the entirety of the stratosphere above Earth.  If there's enough stuff up there, it could cause temporary global cooling.  

A tsunami washes over a Tonga island after a massive
volcanic eruption in the southwestern Pacific Ocean today

A huge eruption of the volcano Pinatubo in the Philippines back in 1991 cooled the world by about 1 degree Fahrenheit for a year or two, and temporarily putting the brakes on global warming.

An even worse volcanic explosion in 1815 spewed so much stuff into the atmosphere that the Earth cooled dramatically.  It caused the infamous Year Without A Summer in 1816 in North America and Europe. (There were hard freezes every summer month in Vermont that year, and snow drifted up to 20 inches deep in Danville during early June).

So far, there's no indication that things will get this dire worldwide from the Tonga eruption. One thing that might have helped is the eruption was partly under the sea, which might have contained some of the ash and sulfur.

How much this eruption cools the world, if at all, will also be the amount and combination of ash and sulfur there is.  If it's mostly ash up there, that will rain out of the atmosphere pretty quickly and not have much of an effect. If there's a lot of sulfur, that would have at least a one to two year cooling effect.

Another question is if this volcano has a series of similar explosions like today's a whole bunch more gunk will end up in the stratosphere, which would have a more pronounced effect on the global climate.

Regardless of what happens, this doesn't cancel climate change. It's possible it could slow or even stall climate change temporarily. Then climate change would come roaring back and quickly rise to levels the atmospheric warming would have had without the volcano