Topic 4.4 - Climate change

Question 1

enhanced /greenhouse effect

Answer 1

The greenhouse effect is caused by greenhouse gases reemitting radiation back into the Earth which causes heat to be retained in the Earth. The enhanced greenhouse effect is caused when too much heat is retained.

Question 2

CO2 (g) and H2O (g) and their roles in the atmosphere

Answer 2

Most significant greenhouse gases.
CO2 (g) released by respiration and combustion and removed by photosynthesis and dissolving on oceans.
H2O (g) evaporated from oceans and also transpiration in plants and removed by rainfall and snow.

Question 3

CH4 and nitrogen oxides and their roles in the atmosphere

Answer 3

Methane -> third and is emitted by methanogenesis and during the extraction of fossil fuels and melting ice in polar regions.
Nitrous oxides -> emitted by bacteria naturally and by agriculture and vehicle exhausts.

Question 4

Impact of greenhouse gases

Answer 4

Impact depends on two factors:
• how readily the gas absorbs long-wave radiation
• concentration of gas in the atmosphere

Question 5

Wavelength emissions involved with Earth

Answer 5

Earth absorbs short-wave energy from the sun and emits long-wave radiation.

Question 6

Global temperatures and greenhouse gas concentrations

Answer 6

Higher concentrations of greenhouse gases cause higher global temperatures.
Higher CO2 concentrations have been warming up the Earth because of the emissions of CO2 from the industrial revolution.

Question 7

Recent increases in atmospheric CO2 concentrations

Answer 7

Due to combustion of fossilised organic matter.