The Dec. 22nd, 2007 issue of the Economist had a good article about climate change (“The Summer of Acid Rain”). It told the story of the volcanic eruption in the summer of 1783 of the Laki volcano in Iceland. In the late 18th century, it was fashionable among the newly literate middle classes to keep diaries, so the effects of the eruption were well-documented. Scientific interest, too, was in a state of increased activity. So there were many observations of “dry fogs”, soot and falling ash, a “dull” sun, and reports of sulphurous odors from Denmark, to Sweden, to France.

The effects of the eruption were severe. The parish records of the English midlands reveal a spike in the number of deaths among the agricultural communities in the months following the eruption. By some estimates 5% of the French population died, mostly contained to the young men and women working in the fields, breathing the polluted air in the stifling heat. One of the gases emitted by the volcano was fluorine, which quickly fell back to earth in the form of hydrofuoric acid, with horrible results. “The horses lost all their flesh,” wrote one Lutheran priest in Iceland, “the skin began to rot off along the spines. The sheep were affected even more wretchedly. There was hardly a part on them free of swellings, especially their jaws, so large that they protruded through the skin… Both bones and gristle were as soft as if they had been chewed.” Half the horses and cattle and three-quarters of the sheep on the island died, leading to a massive famine which claimed a quarter of Iceland’s population over the following months.

The European summer of 1783 was the warmest before 1995, possibly the result of a short-term greenhouse-gas effect, but this was followed by a freakishly cold winter due to the light-scattering effects of the volcanic gases in the upper atmosphere. In the United States, George Washington complained of being “locked up” by snow and ice, and ice flows floated all the way to New Orleans and out into the Gulf of Mexico. Japan suffered one of the worst famines in its history in 1783-1786 — special crews had to be hired to clear the roads of the dead — and tree-ring evidence from the Urals, Siberia, and Alaska suggests that this was the coldest summer for 400 to 500 years.

Volcanic eruptions demonstrate the massive effects that atmospheric changes can have on our climate. Another example is the eruption of Krakatoa in 1883: it caused record snowfalls around the world. Of primary interest to this blog is whether or not human pollution can have similar effects.

A recent article in the Economist (December 22nd, 2007) had a brief article about how to reform Mexico’s oil industry.

Mexico is the world’s 6th largest oil producer, but it hit its peak in production in 2004. Between 1998 and 2006, the total number of barrels in reserve fell by approximately 50%. Cantarell, the largest oil-field in Mexico (and the world’s largest offshore field), is running out of oil after three decades of production. The question the article addresses is how to make Pemex financially viable.

There is a related article at The Oil Drum:
Potential Impact of Cantarell’s Decline on Mexico’s Oil Production”.