WCC: Water, Carbon and Climate - The Role of Feedbacks in Cycles and their Link to Climate Change Flashcards
The roles of feedbacks within and between cycles and their link to climate change and implications for life on Earth.
What are the 3 major atmospheric positive feedback loops caused by global temperature rise that involve carbon and water?
Warming tundra emitting CO2 and CH4
Increased oceanic temps causing increased evaporation from ocean surface
Increased oceanic temps causing oceans to release dissolved CO2
How do the 3 major positive feedback loops caused by global temperature rise lead to further temperature rise?
They all result in more CO2, CH4 and water vapour in the atmosphere, leading to the enhanced greenhouse effect.
Give an example of a positive feedback loop in the water cycle that does not involve greenhouse gases.
Warming temperatures reduce ice coverage, replacing it with water which has a lower albedo. More heat is absorbed from the sun, further melting and reducing the ice coverage.
What 4 impacts will increased melting of ice have for life on Earth?
Changing precipitation patterns
Reduced availability of freshwater
Affected trade routes
Affected development of settlements
Give an example of a negative feedback loop in the water and carbon cycle.
More marine phytoplankton due to wamrer temperatures increase cloud formation through DMS production, lowering the temperature.
What negative feedback loop plays a major part in controlling global temperatures?
the Mountain Thermostat feedback loop
What is the mountain thermostat feedback loop?
A negative feedback loop that controls global temperatures by the impact of vegetation growth on rates of weathering
Explain how the mountain thermostat feedback loop maintains the global temperature balance.
In warmer climates tree roots are more likely to grow into the mineral layer of the soil, enabling acidic water to react with carbonates and increasing the rate of weathering. The trees sequester more CO2 into the atmosphere to facilitate the increased weathering, lowering global temperatures.
How significant has the mountain thermostat feedback loop been in maintaining global temperatures?
In the past, this natural process may have prevented the planet from reaching temperatures that are catastrophic for life.
Why might the mountain thermostat not be significant enough feedback loop to stabilise current global temperatures?
The responses take thousands to millions of years and cannot do much to slow the rate of global warming we are experiencing this century.’
