Lesson focus: How do we distinguish a cold day from a changing climateThe usual weather pattern in a place over many years.?
Distinguish weatherThe conditions in the air at one place and time, such as rain, sun or wind. from climate and interpret a long-term trendThe general direction that results move in, such as going up over time..
Build on earlier learning
Analysing dataDescribe a pattern while retaining information about variation.
You will be successful when you can…
- Distinguish weather and climate.
- Read temperature anomalies.
- Describe trend with variation.
- Evaluate measurement consistency.
Words that carry the science
- weather
- Atmospheric conditions at a particular place and time.
- climate
- Long-term pattern of weather, including averages and variability.
- temperature anomaly
- Difference from a stated reference average.
- baseline
- Reference period or value used for comparison.
- trend
- Overall direction of change across data.
Use long records to distinguish climate trends from weather variation
01Weather is a short-term state
A cold day or hot week is weatherThe conditions in the air at one place and time, such as rain, sun or wind.. It can sit above or below a longer-term average. weatherThe conditions in the air at one place and time, such as rain, sun or wind. is what the air is like over a few hours or days. climateThe usual weather pattern in a place over many years. is the average weather over many years (usually 30 or more).
02Climate needs long, broad evidence
climateThe usual weather pattern in a place over many years. is described using many years and locations. A trendThe general direction that results move in, such as going up over time. does not require every year or site to change in the same direction. One cold winter is just weather. Each year goes up and down a bit, but a warming trendThe general direction that results move in, such as going up over time. means that, on average over many years, temperatures are rising.
03Records need consistency
Instrument changes, station moves and urban development must be documented and analysed. Quality control improves a record; it does not justify dismissing all observations.
The greenhouse effect
Sunlight passes through the atmosphere and warms the ground. The warm ground gives off infrared, and greenhouse gases such as carbon dioxide absorb some of it and send it back down.
Sunlight Infrared Carbon dioxide
Controls
The model is illustrative: about 3 °C of warming for each doubling of carbon dioxide. Without any greenhouse gases the Earth would be about −18 °C.
Describe the illustrative trend
Decadal anomalies are −0.2, 0.0, +0.1, +0.3 and +0.5 °C.
- Identify the baseline-relative values.
- Compare first and last: rise of 0.7 °C.
- Describe the overall upward trend.
- State that decade averages do not make every day or location warmer.
How to make the reasoning visible: The illustrative series rises overall while retaining short-term and spatial variation not shown by the averages.
Climate evidence audit
Separate valid inferences from claims that exceed the data.
| Evidence | Valid inference | Not justified | Needed next |
|---|---|---|---|
| One cold day | Weather was cold | Climate is cooling | Long record |
| Five rising decades | Upward trend in series | Every year warmer | Annual variation |
| Station moved | Possible measurement shift | All warming false | Overlap/calibration |
| Many regions agree | Broader pattern | Every place identical | Spatial detail |
Why does one cold winter not disprove warming?
Why state the baseline?
Use the table. Why does one cold day not show that the climate is cooling?
Check your understanding
Answer from memory, then check against the suggested answer.
What is weather?
What is climate?
What is temperature anomaly?
What is the difference between weather and climate?
What is a trend?
A station moves from shade to paving. How could this affect its record?
Why do several independent datasets strengthen a climate conclusion?
Why is it stronger evidence when many regions show the same warming trend?
Exam Question Practice
Exam Question Practice
Mark points shown after marking
Someone says: “We had a really cold winter, so the climate is not warming.” Answer the parts to explain why they are wrong.
What do we call the conditions over just a few days, or one season such as a winter?
(1)What is climate?
(1)Is every year exactly the same?
(1)What evidence do you need to see a warming trend?
(1)Total for this question: 4 marks
Command word: Use the words weatherThe conditions in the air at one place and time, such as rain, sun or wind. and climateThe usual weather pattern in a place over many years. correctly.