What a beautiful photo!

January 12, 2020, Philippines: Lightning streak over Batangas as Taal Volcano continue its eruption on Sunday evening. Phivolcs reminded the public that the volcano’s main crater was ”strictly off limits” due to sudden steam explosions and the possible release of high concentrations of lethal volcanic gases. Residents of towns near Taal Volcano are being taken to safer ground following increasing volcanic activity, a disaster-mitigation official said. (Credit Image: © Domcar C. Lagto/Pacific Press via ZUMA Wire)

What a disaster! Nature is contemplating the consequences of a major volcanic eruption.

Geological evidence from volcanic deposits over the past 60,000 years suggests a 1-in-6 probability of a massive eruption occurring this century.

If that happened in the next 5 years, the costs would be colossal. In an extreme scenario, the economic impacts would cost more than US$3.6 trillion in the first year and $1.2 trillion more over subsequent years, owing to the effects of extreme weather, reduced crop yields and food instability, according to the insurance and reinsurance market Lloyd’s of London, which assessed these risks in May.

The article discusses the effect of global warming, and how climate change may worsen the effects of a major eruption. We seem to be doing exactly what would amplify the consequences.

Modelling of past eruptions can tell us a lot. But, in a hotter world, many physical and chemical processes in the atmosphere, in oceans and on land will also change. For example, global warming heats the lower atmosphere and cools the stratosphere. Alteration of atmospheric layers will affect how volcanic plumes spread and how high they reach.

Changes in circulation patterns will also affect how aerosols spread and grow. For example, faster air flows from the tropics to higher latitudes, which are already observed as a consequence of warming, hamper the coagulation of aerosols from eruptions in the tropics. Smaller aerosols scatter sunlight more efficiently and cool Earth’s surface more.

The oceans will also be affected. Global warming increases ocean stratification that then acts as a barrier to mixing of deep and shallow waters. Volcanic eruptions might thus disproportionately cool the upper layers of water and the air masses above the ocean.

Are we prepared for the consequences? No, we are not prepared. I welcome the appearance of volcano-deniers joining the climate-change-deniers to make everything a little bit worse.

As well as happening in a warmer climate, the next Tambora-like eruption will occur in a more interconnected world that supports eight times the population of 1815. Agricultural systems would suddenly face lower levels of sunlight, cooler weather and altered moisture patterns — all in close succession. Outsized societal impacts might follow.

For example, the 1991 Pinatubo eruption resulted in a 9% reduction in global maize (corn) yields and a 5% reduction in wheat, rice and soya-bean production. Crop failures from a more massive eruption would hit global breadbasket regions simultaneously — China, the United States, India, Russia and Brazil, which together produce most of the world’s wheat, maize, rice and soya beans. Loss of harvests would disrupt global food security and supply chains, potentially triggering unrest, conflict and migration.

One bit of optimistic news: I immediately thought of the Yellowstone supervolcano.

Currently, the annual probability of a volcanic eruption at Yellowstone is estimated to be around 0.001 percent, which Stelten said is “probably an overestimate for the short term.”

There are no signs of an impending eruption, as the magmatic system beneath Yellowstone is mostly solid.

Whew. Nice to know one catastrophe is unlikely, we’ve had enough of them lately.