It's all so confusing: Volcanic greenhouse gas emissions are allegedly too small to ever significantly affect climate; but volcanic greenhouse gas emissions were also allegedly large enough in the past to heat the oceans to "hot tub" temperatures

Do volcanoes emit more CO2 than humans?

The fossil fuels emissions numbers are about 100 times bigger than even the maximum estimated volcanic CO2 fluxes. Our understanding of volcanic discharges would have to be shown to be very mistaken before volcanic CO2 discharges could be considered anything but a bit player in contributing to the recent changes observed in the concentration of CO2 in the Earth's atmosphere.

After long-ago mass extinction, global warming hindered species' recovery | Science Codex

Up to 90 percent of marine species and 70 percent of land vertebrates had just been killed by massive volcanic eruptions from the region now called the Siberian Traps, which covers much of northern Asia.
...
The consequences are certain, however: the volcanoes spewed enough molten rock to cover millions of square miles, and enough greenhouse gases to dramatically increase Earth's temperature.
...
The Austrian researchers measured the amount of carbon in the rock, and confirmed that Earth's natural carbon cycle and climate were unstable for 5 million years after the Great Dying.
...
The researchers point to a recent study published in the journal Science, which found that ocean temperatures at the time were around 104 degrees Fahrenheit – close to the maximum recommended temperature for a short dip in a hot tub, but not a comfortable temperature to live in 24 hours a day.

What Is the Temperature of a Hot Tub? | eHow.com

The CPSC and other experts recommend hot tub temperatures should never exceed 104 degrees Fahrenheit, and many recommend lower temperatures.