6.3 Atmospheric Carbon Flashcards
What is the greenhouse effect
co2 & methane -> most important greenhouse gases
-their increasing presence in atmosphere is upsetting earths natural temperature- control system -> greenhouse effect
Why is the carbon cycle so essential for the Earth
-regulates the Earth’s temperature by controlling amount of CO2 in atmosphere
-thi affects hydrological cycle
-Ecosystems, terrestrial and oceanic , also depend upon the carbon cycle
-carbon cycle provides the link between atmosphere, hydrosphere, lithosphere, biosphere
Explain the greenhouse effect
-incoming solar radiation 343 watt per m2
-solar radiation passes through clear atmosphere. net incoming solar radiation: 240 watt per m2
-solar energy is absorbed by the earth’s surface and warms it
-Some of the infrared radiation passes through the atmosphere and is lost in space
-Some of the infrared radiation is absorbed and re-emitted by the greenhouse had molecules. The direct effect is the warming of the Earth’s surface and the troposphere
-Surface gains more heat and infrared radiation is emitted again
-and is converted into heat causing the emissions of longwave (infrared) radiation back to the atmosphere.
The Earth’s climate is driven by incoming short-wave solar radiation:
31% is reflected back into space by clouds, GHGs and by the land surface
the remaining 69% is absorbed at the Earth’s surface, especially by the oceans
much of this radiation absorbed at the surface is re-radiated as long wave radiation
large amounts of this long-wave radiation are, however, prevented from returning into space by clouds and GHGs
the trapped long-wave radiation is then re-radiated back to the Earth’s surface
What 2 factors play an important role in regulating the composition of the atsmophere
-ocean photosynthesis
-terrestrial photosynthesis
How does photosynthesis regulate the earth’s temperature
-photosynthesis by terrestrial and oceanic organisms -> keeps co2 levels constant -> regulating Earth’s temperature
The amount of photosynthesis varies spatially, particularly with net primary productivity (NPP). (This is the amount of organic matter that is available for humans and other animals to harvest or consume). NPP is highest in the warm and wet parts of the world, particularly in the tropical rainforests and in shallow ocean waters. It is least in the tundra and boreal forests.
Why is soil health important in the functioning of the carbon cycle
Soil health is an important aspect of ecosystems and a key element in the normal functioning of the carbon cycle. Soil health depends on the amount of organic carbon stored in the soil. The storage amount is determined by the balance between the soil’s inputs (plant and animals remains, nutrients) and its outputs (decomposition, erosion and uptake by plant and animal growth.)
Carbon is the main component of soil organic matter and helps to give soil its moisture-retention capacity, its structure and fertility. Organic carbon is concentrated in the surface layer of the soil. A healthy soil has a large surface reservoir of available nutrients which, in their turn, condition the productivity of ecosystems. All this explains why even a small amount of surface soil erosion can have such a devastating impact on soil health and fertility.
Why is fossil fuel combustion bad for the carbon cycle
-it alters balance of carbon fluxes and stores
Describe the implications for climate as a result of fossil fuel combustion
-half the extra emissions of carbon dioxide since 1750 have remained in the atmosphere
-rest have been fluxed from the atmosphere into the stores provided by the oceans, ecosystems and soils
-additional co2 in atmosphere is responsible for:
-rise in global temperature
-more precipitation and evaporation
-sudden shifts in weather patterns
-more extreme weather events; floods, storm surges and droughts
Describe the implications for ecosystems as a result of fossil fuel combustion
increased co2 leading to changes in climate effect:
-sea level -> rising -> melting ice sheets & glaciers -> flooding
-ecosystems -> declining in the goods and services they provide -> decline in biodiversity; changes in the distributions of species; marine organisms threatened by lower oxygen levels & ocean acidification; the bleaching of corals etc.
Describe the implications for the hydrological cycle as a result of fossil fuel combustion
increased temperatures and evaporation rates cause more moisture to circulate around the cycle
Meaning of anthropegenic
impacts of change on carbon cycle as carbon stores are released
