It is now generally thought that the aberrations occurred because of the 5–15 April 1815 volcanic eruptions of Mount Tambora on the island of Sumbawa in the Dutch East Indies (in today's Indonesia) which ejected over a million and a half metric tons of dust into the upper atmosphere. As is common following a massive volcanic eruption, temperatures fell worldwide due to reduced sunlight.

The unusual climate aberrations of 1816 had the greatest effect on the American northeast and northern Europe. Typically, the late spring and summer of the American Northeast are relatively stable: temperatures average about 68–77 °F (20–25 °C), and rarely fall below 41 °F (5 °C). Summer snow is an extreme rarity, though May flurries sometimes occur.
In May of 1816, however, frost killed off most of the crops that had been planted, and in June two large snowstorms resulted in many human deaths as well. In July and August, lake and river ice were observed as far south as Pennsylvania. Rapid, dramatic temperature swings were common, with temperatures sometimes reverting from normal or above-normal summer temperatures as high as 95 °F (35 °C) to near-freezing within hours.

Europe, still recuperating from the Napoleonic Wars, suffered from food shortages. Food riots broke out in Britain and France and grain warehouses were looted. The violence was worst in landlocked Switzerland, where famine caused the government to declare a national emergency.

# Jan. 8–12, Europe: wild storms battered many European countries, leaving 19 dead. High winds and flooding left people without power and shut down ferries, trains, and highways.

# Jan. 22–23, eastern United States: strong snow storms swept across the Midwest to the Atlantic coast, killing 20 people. A blizzard blanketed parts of the Northeast with snow depths up to 38 in north and south of Boston and the entire island of Nantucket lost power. By the end of January, Boston had the snowiest month on record with a total of 43.1 inches of snow.

Feb. 6–13, Pakistan: heavy flooding from snows and rain killed more than 1460 people and left thousands more missing. The Shadi Kor dam in Baluchistan province broke on Feb. 10, leaving thousands homeless.

# Feb. 17–23, Calif.: a series of storms caused flooding, landslides, and avalanches, killing at least 9 people, damaging many roads, and forcing the evacuation of many homes. More than 9 in of rain fell in downtown Los Angeles.

# Feb., South East Asia: extreme winter weather including cold, snowfall, avalanches, and flooding in Afghanistan, India, and Pakistan killed more than 1,400 people in the last month. Due to the lack of communications actual numbers were hard to confirm.

Mar. 18–22, Afghanistan: heavy rains and melting snows killed more than 200 and left thousands homeless. This followed what was already the worst winter in years that had killed several hundred people.

June, Southern China: widespread flooding for the month of June, particularly in southern China, killed 536 people. In addition the floods damaged dikes, reservoirs, roads, rail lines, and millions of acres of crops.

June 12, Northwest China: a flash flood, triggered by torrential rains, swept through an elementary school in Ning'an, in northeast Heilongjiang province, killing at least 117 of which 105 were children.

# June 18–19, Calgary, Alberta, Canada: flooding of the Elbow and Bow rivers, from a week of rain, impacted hundreds of homes, forcing the evacuation of more than 1,500.

# Europe: days of heavy rains in Austria, Bulgaria, Germany, Romania, and Switzerland inundated rivers and lakes, flooded cities and towns, damaged roads and railways, and killed at least 42 people, 31 of them in Romania.

Oct. 1–5, In El Salvador more than 130,000 people were evacuated and 80% of the roads were affected. In Guatemala, continuous torrential rains brought floods and mudslides that killed more than 2,000 and buried the whole village of Panabáj.

Oct. 7–Oct. 14, Northeast U.S.: Torrential rains caused flooded in several states in the Northeast, especially New Jersey and New Hampshire, killing 10.

You can't look at these events in isolation. You have to look at the pattern over a number of years (decades, centuries) etc.

Curiously, aerosol pollution of the northern hemisphere reduces global warming by reflecting sunlight back to space. This "global dimming" is transient and could disappear in a few days like the smoke that it is, leaving us fully exposed to the heat of the global greenhouse. We are in a fool's climate, accidentally kept cool by smoke, and before this century is over billions of us will die and the few breeding pairs of people that survive will be in the Arctic where the climate remains tolerable.

That's not to say we should do nothing about about it, however if the government were REALLY serious about it, they should have cats (or suchlike ) fitted to aircraft. These pollute far more than cars.