BIOLOGY · Stage 8 · Chapter 8: Weather and Climate
Biology 8.5 Chapter 8 Review: Weather and Climate
5 min read 6 parts Lesson 5 of 6
Lesson summary
8.5 Chapter 8 Review: Weather and Climate — Alhussan International Academy — Biology (Stages 7–9) notes: Revise weather measurement, the greenhouse effect, natural and human causes of climate change and the evidence for past climates.Weather — the state of the atmosphere at a tim…
- Instruments
- Natural effect
- Enhanced effect
- Consequences
- Tree rings
- Bog pollen
Section 1 of 6Weather and climate
- Weather
- the state of the atmosphere at a time and place, described by temperature, precipitation, humidity, wind speed, wind direction, air pressure and cloud cover.
- Climate
- the average of weather over at least 30 years.
- Instruments
- thermometers, rain gauges, anemometers, wind vanes, barometers and sunshine recorders.
- A thermometer must be kept in the shade, and measurements should be repeated.
Section 2 of 6The greenhouse effect
- Natural effect
- greenhouse gases such as carbon dioxide, methane and water vapour absorb infrared radiation from the warm Earth and re-emit it, keeping the planet warm.
- This effect is essential for life.
- Enhanced effect
- burning fossil fuels, deforestation and farming raise greenhouse gas concentrations and increase global temperatures.
- Consequences
- rising sea levels, melting ice, more extreme weather and changes to habitats.
Section 3 of 6Natural climate change
- Causes
- changes in the Earth's orbit, in the Sun's activity, in atmospheric gases and volcanic eruptions, with feedback such as ice reflecting sunlight.
- Cycles
- ice ages and interglacials alternate over thousands of years.
- Rate
- natural changes took thousands of years, but present warming is faster and linked to the rise in carbon dioxide from human sources.
Section 4 of 6Evidence for past climates
- Ice cores
- layers of ice with trapped air bubbles show past gas concentrations and temperature.
- Tree rings
- wide rings show good growth in warm, wet years.
- Bog pollen
- pollen types in peat layers show which plants grew and so the climate.
- Fossils
- the type of fossil in an area shows the climate when the organisms lived.
- Reliability
- agreement between different sources makes conclusions more reliable, while single records may be local or have dating errors.
Section 5 of 6Peer review
- Peer review = independent experts checking scientific work before it is published in a journal.
- It increases trust in the evidence, which can then be combined with other studies.
- Flawed work is corrected before it can mislead anyone.
- Repeatability
- scientists record their methods in enough detail for others to repeat them.
- Importance
- climate science affects government decisions, so checked and repeated findings carry far more weight than unchecked claims.
Section 6 of 6Reducing climate change
- Replace coal with renewable energy to cut carbon dioxide emissions.
- Protect forests so that trees continue to absorb carbon dioxide.
- Improve insulation to reduce the energy burned for heating.
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