Weather, Climate and Climate Change
What this domain tests
Weather, climate and climate change questions test your ability to distinguish short-term atmospheric conditions from long-term patterns, interpret climate graphs and synoptic charts, and explain natural and human causes of climate change. You must use correct units and link atmospheric processes to weather outcomes.
Core rules and concepts
- The environmental lapse rate is the fall in temperature with height, averaging about 6.5 °C per 1,000 m in the troposphere.
- Low pressure occurs where air rises; high pressure where air subsides. Air moves from high to low pressure, deflected to the right in the Northern Hemisphere by the Coriolis effect.
- Frontal rainfall occurs when warm air rises over cooler air; relief rainfall occurs when air is forced over high ground; convectional rainfall occurs when surface heating causes rapid uplift.
- The enhanced greenhouse effect is the additional warming from human emissions of carbon dioxide, methane and nitrous oxide.
Worked example
Surface air is 20 °C and rises 1,500 m. Using 6.5 °C per 1,000 m, cooling = 1.5 × 6.5 = 9.75 °C. Temperature at 1,500 m = 20 − 9.75 = 10.25 °C. If the air then descends on the leeward side, it warms at the dry adiabatic rate, often producing a rain shadow. The reasoning is to calculate cooling per metre, apply it to the actual ascent, then subtract.
Traps that cost marks
Do not confuse weather with climate. Do not say the greenhouse effect is entirely human-made: the natural greenhouse effect keeps Earth habitable. In lapse-rate calculations, mixing metres and kilometres is a common error. Do not describe mitigation and adaptation as the same thing.