A-Level Environmental Science: Topic 2 Atmosphere

Practice flashcards covering the structure of the atmosphere, the global energy budget, greenhouse gases, climate change impacts, feedback mechanisms, and ozone depletion.

What is the chemical composition of the Earth's atmosphere by percentage?

Nitrogen $78\%$, Oxygen $21\%$, Carbon dioxide $0.04\%$, Rare gases $1\%$, and Ozone $0.000007\%$.

How is dynamic equilibrium defined in the context of atmospheric gases?

Two processes in a state of balance that cancel each other out so there are no major increases or decreases.

What are the four main layers of the atmosphere in order from closest to Earth to furthest?

Troposphere, Stratosphere, Mesosphere, and Thermosphere.

Why does atmospheric pressure decrease as altitude increases?

The affect of gravity is reduced and there are fewer particles on top of them compressing them.

What is the reason for the temperature increase in the stratosphere?

The ozone layer absorbs UV radiation, which causes increased temperatures.

According to the Earth's global energy budget, what percentage of incoming solar radiation is absorbed by land and oceans?

$$51\%$$

Define the term 'albedo'.

The reflectivity of a surface.

Describe the natural greenhouse effect.

A process where naturally occurring gases like $CO_2$ absorb infrared radiation (heat) emitted from the ground, preventing it from escaping and keeping temperatures suitable for life.

Which industrial process uses nitrogen and hydrogen from the atmosphere to create artificial fertilizers?

The Haber process.

List the anthropogenic sources of methane ($CH_4$).

Livestock cultivation, landfill site decomposition (anaerobic), rice padi fields, and the enhanced greenhouse effect melting permafrost.

What is the difference between primary and secondary pollutants?

A primary pollutant is released directly by human activity (e.g., mining), while a secondary pollutant forms when pollutants react with other substances (e.g., tropospheric ozone formed from $NOx$ and sunlight).

Why does melting land ice contribute to sea level rise while melting sea ice does not?

Sea ice is already in the water and has displaced its mass; land ice is not in the ocean, so its meltwater flows in as additional volume.

What is the Gaia hypothesis proposed by James Lovelock?

The theory that the Earth is one living system that regulates its abiotic factors to maintain a dynamic equilibrium.

Explain a negative feedback mechanism related to temperature and clouds.

A temperature increase causes more evaporation, leading to increased cloud cover, which reflects more solar radiation and causes the temperature to decrease.

Define a 'tipping point' in environmental science.

The point of no return where environmental impacts continue and cannot be reversed even if the human activities that caused them are stopped.

What are the four main components of the Montreal Protocol regarding CFCs?

1. Banned CFC production; 2. Encouraged alternative materials (e.g., butane); 3. Encouraged alternative processes (e.g., roll-on deodorants); 4. Ensured proper disposal (incineration) of CFC-containing materials.

How is ozone ($O_3$) formed in the stratosphere?

$UV$ light photolyses (splits) a diatomic oxygen ($O_2$) molecule into two oxygen atoms ($O$), which then bind with other $O_2$ molecules.

What is the Rowland-Molina hypothesis?

The hypothesis that CFCs cause ozone depletion because they are persistent, reach the stratosphere, and react with $UV$ to release reactive chlorine radicals.

In what units is the total thickness of the ozone layer measured?

Dobson units (where $100\,Dobson\,units$ equals $1\,mm$ thickness at sea level).

What are ARGO floats used for in climate monitoring?

They are devices that sink to programmed depths in the ocean to collect data on temperature, $pH$, and salinity before transmitting it via satellite.