6.1 & 6.2

Question 1

atmosphere:

Answer 1

dynamic system (w/ inputs outputs flows storage) that has undergone changes through geological time

Question 2

greenhouse effect:

Answer 2

• natural + necessary phenomenon that maintains suitable temps for living systems.
• gases trap heat energy that is reflected from the earths surface and reradiate it
• 51% is absorbed (for photosynthesis, heating ground & seas, evaporation) & 4% is reflected back
• GHG: water vapour, CO2, methane

Question 3

stratosphere ozone:

Answer 3

is good. some UV radiation from sun is absorbed, causing break up of ozone molecule. under normal conditions, the ozone molecule will reform ] process of ozone destruction & reformation which is an example of dynamic equilibrium

Question 4

effect of UV radiation:

Answer 4

• genetic mutations + subsequent health effects (skin cancer higher rates NZ & Australia)
• cataract formation in eyes
• damage to photosynthetic organisms & consumers of these
• in animals stimulates vitamin D production
• can be used to treat vitiligo & other skin diseases
• industrial uses: lasers, lighting, forensic analysis

Question 5

ODS:

Answer 5

eg. CFC’s from refrigerants and AC units ] releases chlorine atoms

HCFC’s replacement for CFC’s ] releases chlorine atoms. (same effect as CFC’s but better coz shorter lifetime in atmosphere)

halons from fire extinguishers ] releases bromine atoms.

Question 6

how is ozone destructed?

Answer 6

UV releases chlorine atoms from CFC’s which react with ozone which results in ozone destruction. also reacts w oxygen atoms to prevent ozone formation. in both processes -> chlorine atoms formed back & can react with ozone or oxygen atoms. reaction: positive feedback

Question 7

management strategies for ODS’s

Answer 7

• replace CFC’s w CO2, propane, air
• add ozone & remove chlorine from stratosphere
• legislate for fridges to be returned to manufacturers and coolants removed & stored
• recover, recycle CFCS from AC’s & fridges

Question 8

the albedo effect and its role in regulating the Earth’s global temperature -

Answer 8

albedo is a measure of the reflectiveness of a surface / is greater from lighter coloured/smoother surfaces.

high albedo means that solar radiation is reflected away from a surface, therefore reducing temperature while low albedo means that solar radiation is absorbed by a surface, therefore increasing temperature.

oceans/ice/clouds contribute significantly to Earth’s albedo.

Question 9

albedo effect & how it involves feedback loops -

Answer 9

the balance between the albedo of the Earth’s surfaces involves feedback loops:

negative feedback loops reduce change and maintain the global temperature, e.g. rise of global temperature -> increased evaporation -> increased cloud cover -> increased albedo and reflection of solar radiation -> decrease in global temperature

a change in the balance can result in a positive feedback loop which amplifies changes and results in a rise in the Earth’s global temperature, e.g. rise in global temperature -> increase melting in ice caps -> decrease in albedo -> increase in solar radiation absorption -> rise in global temperature.