Krakatoa? Pinitubo? Santorini? Tamboura and "The Year Without A Summer"? Toba?
The eruption lasted perhaps two weeks, but the ensuing "volcanic winter" resulted in a decrease in average global temperatures by 3 to 3.5 degrees Celsius for several years. Greenland ice cores record a pulse of starkly reduced levels of organic carbon sequestration. Very few plants or animals in southeast Asia would have survived, and it is possible that the eruption caused a planet-wide die-off.
Lake Toba - Wikipedia, the free encyclopedia
The Toba eruprion is the one that pushed humans to the brink of extinction (some estimate as few as 14,000 humans were left before things got back to normal).
I would say those are pretty major.
So tell me, can you give some documentation of a volcano warming the Earth? Because you agree with something I said in sarcasm, and I have never seen anything to show that warming occurs after a volcano eruption.
No one is discounting volcanoes potential for changes to the climate. And I already provided documentation that volcanoes can cause global heating:
"Today we’re speaking with
climate scientist Peter Huybers of Harvard. Dr. Huybers received a 2009 genius grant from the MacArthur Foundation. He spoke with EarthSky about why the last ice age ended 12,000 years ago.
Peter Huybers: I think ice ages are really the outstanding mystery in Earth sciences presently.
Scientists have scrutinized the evidence for ice ages in Earth’s past. Dr. Huyber’s recent research focused on one possible factor triggering the end of an ice age – volcanic activity.
Peter Huybers:
The major finding was that there was a dramatic uptick in volcanic activity during the last deglaciation.
Volcanoes can cause carbon dioxide, or CO2 – a greenhouse gas – to increase in Earth’s atmosphere.
Twelve thousand years ago, volcanoes might have caused warming and melting ice. In some places on Earth, melting ice sheets might have taken a load off rock below. That might have increased volcanic activity even more – which means more CO2 – and more warming.
Peter Huybers:
In so much as volcanoes played an important role in providing a feedback in past climate, we can then contrast that with the even much stronger control of CO2, which humans are exerting.
In other words,
volcanoes at the end of the last ice age were releasing about three-tenths of a gigaton of CO2 each year. Today, humans are releasing about a hundred times more."
Peter Huybers: 'Ice ages are the outstanding mystery in Earth sciences' | EarthSky
Here is another excellent discussion of this very issue:
"
According to the U.S. Geological Survey (USGS), the world’s volcanoes, both on land and undersea, generate about 200 million tons of carbon dioxide (CO2) annually, while our automotive and industrial activities cause some 24 billion tons of CO2 emissions every year worldwide. Despite the arguments to the contrary,
the facts speak for themselves: Greenhouse gas emissions from volcanoes comprise less than one percent of those generated by today’s human endeavors.
Human Emissions Also Dwarf Volcanoes in Carbon Dioxide Production
A
nother indication that human emissions dwarf those of volcanoes is the fact that atmospheric CO2 levels, as measured by sampling stations around the world set up by the federally funded Carbon Dioxide Information Analysis Center, have gone up consistently year after year regardless of whether or not there have been major volcanic eruptions in specific years. “If it were true that individual volcanic eruptions dominated human emissions and were causing the rise in carbon dioxide concentrations, then these carbon dioxide records would be full of spikes—one for each eruption,” says Coby Beck, a journalist writing for online environmental news portal Grist.org. “Instead, such records show a smooth and regular trend.”
Do Volcano Eruptions Cause Global Cooling?
Furthermore, some scientists believe that spectacular volcanic eruptions, like that of Mt. St. Helens in 1980 and Mt. Pinatubo in 1991, actually lead to
short-term global cooling, not warming, as sulfur dioxide (SO2), ash and other particles in the air and stratosphere reflect some solar energy instead of letting it into Earth’s atmosphere. SO2, which converts to sulfuric acid aerosol when it hits the stratosphere,
can linger there for as long as seven years and can exercise a cooling effect long after a volcanic eruption has taken place.
Scientists tracking the effects of the major 1991 eruption of the Philippines’ Mt. Pinatubo found that the overall effect of the blast was to cool the surface of the Earth globally by some 0.5 degrees Celsius a year later, even though rising human greenhouse gas emissions and an El Nino event (a warm water current which periodically flows along the coast of Ecuador and Peru in South America) caused some surface warming during the 1991-1993 study period.
Volcanoes May Melt Antarctic Ice Caps from Below
In an interesting twist on the issue, British researchers last year published an article in the peer reviewed scientific journal Nature showing how volcanic activity may be contributing to the melting of ice caps in Antarctica—but not because of any emissions, natural or man-made, per se. Instead, scientists Hugh Corr and David Vaughan of the British Antarctic Survey believe that volcanoes underneath Antarctica may be melting the continent’s ice sheets from below, just as warming air temperatures from human-induced emissions erode them from above."
Volcanoes and Greenhouse Gases - Do Volcanoes Generate More Greenhouse Gas Than Humans?