Notes
Climate basics
- Weather is short-term; climate is the long-term average (30 years or more).
- Climate depends on latitude, elevation (about -6.5°C per 1,000 m), nearness to water, ocean currents and mountains (rain shadow).
- Zones: tropical, dry, temperate, continental and polar.
Causes of change
- Natural: Milankovitch cycles, solar changes, volcanoes, plate tectonics.
- The greenhouse effect warms Earth. Burning fossil fuels and deforestation raise CO₂ (280 ppm to over 420 ppm).
Evidence and responses
- Evidence: thermometers, satellites, ice cores, melting ice, rising seas and ocean acidification.
- Mitigation reduces emissions; adaptation copes with effects.
Topics in this unit
Each topic has its own short notes and practice.
Practice
Climate describes typical long-term conditions.
$1.5 \times 6.5 = 9.75$ cooler; $22 - 9.75 = 12.25$, about 12.3°C.
Rain falls on the windward side, leaving dry sinking air.
Trapped air bubbles record past CO₂.
CO₂ and CH₄ absorb heat.
They reduce or absorb greenhouse gases.
Free response
Write your answer first, then open the scoring guide.
Free-response question
A city on the coast is at sea level with an average yearly temperature of 18°C. A town 2,000 m higher at the same latitude lies inland behind a mountain range. Atmospheric CO₂ has increased from 280 ppm to 420 ppm.
(a) Estimate the town's average temperature using a drop of 6.5°C per 1,000 m.
Show the answer and scoring guide
$2 \times 6.5 = 13$°C cooler, so $18 - 13 = 5$°C.
Check off the points you earned:
(b) Calculate the percent increase in CO₂ and name one human activity that caused it.
Show the answer and scoring guide
$\displaystyle \frac{420 - 280}{280} \times 100\% = 50\%$. Burning fossil fuels (or deforestation).
Check off the points you earned:
(c) Explain why the mountain range may make the town drier than the coast.
Show the answer and scoring guide
Moist air rises on the windward side, cools and drops rain; the leeward side gets dry, sinking air (a rain shadow).
Check off the points you earned: