Volcanoes and climate Flashcards
Why study volcanic eruptions and climate?
Helps improve climte models
Allows us to mkae seasonal and interannual forecasts following large volcanic eruptions
Large volcanic eruptions may result in crop failure, famine and epidemic diseases
Provides an analog for geoengineering the climate (global warming mitigation) using stratospheric aerosols
How did the 1815 Mount Tambora eruption affect the global temperature?
0.5c northern hemisphere summer temperature anomaly
What are the tropospheric and stratospheric effects of a volcanic eruption?
Sulfate columns can end up in the upper atmosphere 80% of volatile mass in stratosphere from the most explosive eruptions
Net heating in the upper atmopshere and net cooling in the lower atmosphere
Overall net effect is COOLING
How does the global hydrological cycle respond to large volcanic eruptions?
Precipitation reduced in tropics
Stratospheric aerosols reflect sunlight, reducing evaporation
Cooler temperatures stabilise the atmosphere and reduces its water holding capacitu (cooling)
Reduced stream flow for major tropical river systems
Increased stream flow in SE USA and parts of Europe
What are the (year long) effects of a large tropical eruption on weather and climate?
Enhance/reduce el Nino
Reduced tropical precipitation
Reduced Sahel precipitation
Global cooling
Strotospheric warming
Feasibility of solar radiation management
The doubling of co2 concentration causes a greenhouse warming of 4 W/m2
The cooling efficiency of sulfate is 0.75 W/m2 for every megaton in the stratopshere
So to combat effect of doubling, needs to be 2 Megatons of small sulfate particles added every year
