Volcanoes are an important part of the Earth's geological and climatic processes. Volcanoes release CO2, SO2, H2S and many other ejecta after an eruption. Volcanic eruptions of VEI 5 ​​and above release large amounts of ash and CO2. Ash contains particulate matter and sulfuric aerosols that reduce the amount of light received from the sun (Burke, 1985). These smaller-scale eruptions cause a net cooling effect due to the volume of ejected materials and the light-scattering properties of particulate matter released after an eruption. There is also evidence that volcanoes have caused a global warming effect in Earth's history. This was true during the Cretaceous period, when CO2 production dwarfed today's CO2 levels (refer to Figure 4). Large amounts of atmospheric CO2 can cause an increase in the greenhouse effect. The Deccan traps in India are evidence of how large-scale volcanic activity can release enough carbon dioxide to cause global warming (Rycroft, 1993). Therefore, depending on the scale of volcanic activity, volcanic activity can contribute to both global warming and global cooling scenarios. Volcanic eruptions can cause negative environmental effects. This includes the destruction of plant and animal life, the production of greenhouse gases that can contribute to global warming, and the production of ash and numerous harmful particles in the air that can cause large-scale climate cooling. Volcanic eruptions release volcanic plumes that contain SO2 and fine ash. Through photolysis, SO2 gas is converted into the aerosol H2SO4 (Bernard, 1990). Sulfur aerosols produce a light-reflecting or solar-irradiation effect that reflects incoming solar radiation thus causing a net cooling effect. This can be seen du...... middle of paper ......CO2 is the result of increased widespread volcanic activity. These volcanic effects are opposite to the climatic effects caused by small-scale eruptions. While both events release CO2 into the atmosphere, the amount released by smaller eruptions is negligible. According to the US Geological Survey, the annual CO2 emitted by volcanoes is 0.26 billion tons per year, which when compared to volcanic eruptions such as those that formed the Deccan Traps of Indian and many other volcanic sites during the Cretaceous is insignificant . The composition of tephra and the production of sulfuric acid aerosols play a larger role in the climate effects caused by smaller volcanoes and not in the amount of CO2 released (nd). Therefore, both scenarios of volcanoes causing global warming and global cooling are possible as they both operate on different scales.