Typically, volcanic eruptions have a cooling effect. One of the principle emissions is sulfur dioxide which reflects high frequency solar energy (green house gases absorb and convert that same radiation into longer wave energy which excites atmospheric gases).
Typically, volcanic eruptions have a cooling effect. One of the principle emissions is sulfur dioxide which reflects high frequency solar energy (green house gases absorb and convert that same radiation into longer wave energy which excites atmospheric gases).
You can read more at the University Corporation for Atmospheric Research.