Thirty four years ago, on this day, June 15th, 1991, Mount Pinatubo erupts. It is the second largest volcanic eruption of the 20th Century
As per Wikipedia –
“The 1991 eruption of Mount Pinatubo in the Philippines‘ Luzon Volcanic Arc was the second-largest volcanic eruption of the 20th century, behind only the 1912 eruption of Novarupta in Alaska. Eruptive activity began on April 2 as a series of phreatic explosions from a fissure that opened on the north side of Mount Pinatubo. Seismographs were set up and began monitoring the volcano for earthquakes. In late May, the number of seismic events under the volcano fluctuated from day-to-day. Beginning June 6, a swarm of progressively shallower earthquakes accompanied by inflationary tilt on the upper east flank of the mountain, culminated in the extrusion of a small lava dome.[4]
“On June 12, the volcano’s first spectacular eruption sent an ash column 19 km (12 mi) into the atmosphere. Additional explosions occurred overnight and the morning of June 13. Seismic activity during this period became intense. When even more highly gas-charged magma reached Pinatubo’s surface on June 15, the volcano exploded, sending an ash cloud 40 km (25 mi) into the atmosphere. Volcanic ash and pumice blanketed the countryside. Huge pyroclastic flows roared down the flanks of Pinatubo, filling once-deep valleys with fresh volcanic deposits as much as 200 m (660 ft) thick. The eruption removed so much magma and rock from beneath the volcano that the summit collapsed to form a small caldera 2.5 km (1.6 mi) across.
The amount of carbon dioxide in the air was roughly 358ppm. As of 2025 it is 430ppm, but check here for daily measures.
The broader context was volcanoes erupt! See also 1816, the year without a summer (and a fun book called A Single Summer with LB, by Derek Marlowe, but I digress).
The specific context was the masking effect of the increased albedo probably reduced global temperatures for a bit.
“Global mean air temperatures were reduced, by up to 0·5°C at the surface and 0·6°C in the troposphere, for some months in mid-1992, in approximate accord with model predictions.”
What I think we can learn from this – shit blows up. Also, lahars is a great word! (okay for scrabble but unfortunately laharic is not).
What happened next The denialists latched onto volcanoes to confuse people about the causes of climate change. Because shitheads and assholes.
What do you think? Does this pass the ‘so what?’ threshold? Have I got facts wrong? Interpretation wrong? Please do comment on this post, unless you are a denialist, obvs.
You can see the chronological list of All Our Yesterdays “on this day” posts here.
What do you think? Does this pass the ‘so what?’ threshold? Have I got facts wrong? Interpretation wrong? Please do comment on this post, unless you are a denialist, obvs.
If you want to get involved, let me know.
If you want to invite me on your podcast, that would boost my ego and probably improve the currently pitiful hit-rate on this site (the two are not-unrelated).
Also on this day:
June 15, 1994 – Canberra Times soils itself by publishing denialist claptrap – All Our Yesterdays