Unit 06 · Climate & Climate Change
This unit separates the weather outside the window from the climate of a place over decades. It covers what sets a region's climate zone, how the greenhouse effect keeps the planet warm and what happens when its balance shifts, how scientists read past climate from proxies — ice cores, tree rings, sediment — and how carbon moves through ocean, air, rock, and life in the carbon cycle. Mastery means you can tell weather from climate and read a proxy record as evidence of change over time, not a single day's forecast.
Student learning: Separate observed CO2, temperature anomalies and proxy-based inference
Choose the level by readiness, not age alone, and record it before instruction. Foundation, core, and honors tasks are study pathways, not an AP course or a promise of college credit. The instructor retains practical assessment and the published science rubric; integration is reported separately.
Prerequisites: Foundation: means, signed differences and graph axes. Core: elapsed-year rates, baselines and linear calibration. Honors: least-squares slope, residuals and baseline shifts. Readiness check: an annual mean of 13.8 C minus a 14.0 C baseline is -0.2 C. Practice that subtraction before trend fitting.
Suggested sequence: read and discuss the explanation; attempt the worked model; analyze the data at your selected level; check the answers; then complete the source-linked response and a fresh transfer question. These activities supplement, not replace, supervised practical work and the full-year schedule.
Assigned reading and focus
- NOAA Global Monitoring Laboratory: Mauna Loa annual mean CO2 data. Read the file header and the 1960, 1980, 2000 and 2020 rows. Cite NOAA GML and the Scripps Institution of Oceanography record credited in the header. The frozen excerpt below comes from the file created 2026-09-05, accessed 2026-09-27.
- NOAA Climate.gov: Climate Change, Global Temperature. Read Why global surface temperature matters and the anomaly/baseline discussion. Use the independent synthetic temperatures below for arithmetic; do not label them as NOAA global observations.
- NOAA NCEI: What Are Proxy Data?. Read the introduction and Ice Cores section. Distinguish a measured proxy characteristic, a temperature reconstruction and gases trapped in bubbles; ice age and gas age can differ.
Learn the science
The CO2 values are observed annual dry-air mole fractions from one monitoring record, in micromol/mol (ppm), not a globally averaged temperature or an emissions inventory. Only four widely spaced years are supplied; these do not describe seasonal variation or all interannual behavior.
The reported 0.12 ppm uncertainty is the file's estimated annual-mean uncertainty based on differences between independently determined NOAA and Scripps annual means. It is not a confidence interval for a regression or a measure of spatial representativeness.
An anomaly subtracts a stated baseline. The separate temperature table is wholly synthetic and uses an invented 1961-1990 site baseline of 14.0 C. Changing that baseline shifts every anomaly by the same amount but does not change a slope.
For least-squares y = a + bx, b = sum((x - mean(x))(y - mean(y)))/sum((x - mean(x))^2), a = mean(y) - b mean(x). A residual is observed minus fitted y. Use x = years since 1960 to avoid a large intercept; convert C/year to C/decade by multiplying by 10.
A trend or correlation is not causal proof. Human-driven warming is supported by physical mechanisms and multiple lines of evidence described by NOAA, not established anew by fitting four CO2 points or pairing them with an invented temperature record. Do not infer climate sensitivity from these two tables.
For the synthetic ice example only, temperature anomaly = 2 x (isotope value + 35) C. This is an assigned local linear calibration, not a universal isotope thermometer. Age, moisture source, seasonality and calibration uncertainty can alter a reconstruction; gas in bubbles need not have the same age as the surrounding ice.
Data, provenance, and assumptions
| Year | Annual mean CO2 (ppm) | Reported annual-mean uncertainty (ppm) |
|---|---|---|
| 1960 | 316.91 | 0.12 |
| 1980 | 338.76 | 0.12 |
| 2000 | 369.71 | 0.12 |
| 2020 | 414.21 | 0.12 |
| Year | Synthetic annual mean (C) | Synthetic baseline mean (C) |
|---|---|---|
| 1960 | 13.8 | 14 |
| 1980 | 14 | 14 |
| 2000 | 14.5 | 14 |
| 2020 | 14.7 | 14 |
| Ice age (years BP) | Isotope value (per mil) |
|---|---|
| 0 | -35 |
| 10000 | -38 |
| 20000 | -40 |
Worked model
Observed CO2 rises 414.21 - 316.91 = 97.30 ppm over 60 years: the endpoint-average rate is 1.6217 ppm/year. The separate synthetic anomalies are -0.2, 0, 0.5 and 0.7 C. Their endpoint rate is 0.9/60 x 10 = 0.15 C/decade. These are different variables with different provenance; equal calendar labels do not create a causal experiment.
Numerical calibration
- 1.6217 ppm/year, observed endpoint average
- 1.61425 ppm/year, four-point least-squares slope
- -0.2 C relative to the synthetic 14.0 C baseline
- 0.16 C/decade, synthetic four-point fit
- -10 C under the assigned proxy calibration only
Attempt the assigned level
Try the tasks before reading the calibration. These are practice answers, not a secure examination; use a new dataset or changed assumption for the assessed transfer.
Foundation: typically grades 7-8
- Calculate all four synthetic anomalies and draw labeled year/anomaly axes. State the baseline and why a negative anomaly does not mean a negative Celsius temperature.
- Calculate the observed CO2 change from 1960 to 2020 in ppm and percent of the 1960 value. Label this dataset observed and the temperature dataset synthetic.
Check after your attempt
- Anomalies are -0.2, 0, 0.5 and 0.7 C relative to the invented 14.0 C baseline; 13.8 C is positive even though its anomaly is negative.
- The observed increase is 97.30 ppm, about 30.7% of 316.91 ppm. A percentage increase in atmospheric mole fraction is not the percentage of Earth's warming caused by CO2.
High-school core: typically grades 9-10
- Calculate CO2 endpoint rates over 1960-1980 and 2000-2020. Compare them with the full-span rate without claiming a constant future rate.
- Apply the supplied ice calibration to all three rows and give the oldest row's temperature sensitivity to +/-0.2 per mil. Explain why this is a proxy reconstruction, not a thermometer record.
Check after your attempt
- Early rate: (338.76 - 316.91)/20 = 1.0925 ppm/year. Late rate: (414.21 - 369.71)/20 = 2.225 ppm/year. The full-span 1.6217 lies between them and is not a forecast.
- Model anomalies are 0, -6 and -10 C; the oldest row has +/-0.4 C sensitivity from isotope error alone. It remains a calibrated inference with unquantified dating and calibration errors, not a direct temperature measurement.
Honors extension: typically grades 11-12
- Fit lines to the four observed CO2 means and, separately, the four synthetic temperature anomalies using years since 1960. Report slopes, temperature residuals and the difference from endpoint slopes.
- Change the synthetic baseline from 14.0 to 14.2 C and recompute anomalies. Bound its 1960-2020 endpoint trend using +/-0.1 C at each endpoint. Explain why neither a fit nor this bound establishes causal attribution.
Check after your attempt
- CO2 least-squares slope = 1.61425 ppm/year with intercept 311.47 ppm at x = 0; synthetic temperature slope = 0.016 C/year = 0.16 C/decade, intercept -0.23 C. Temperature residuals are 0.03, -0.09, 0.09 and -0.03 C. Fits use all four points; endpoint rates are 1.6217 ppm/year and 0.15 C/decade.
- New anomalies: -0.4, -0.2, 0.3 and 0.5 C; slope remains 0.16 C/decade. Endpoint differences span 0.7-1.1 C over 60 years, or 0.1167-0.1833 C/decade. This is a sensitivity interval, not a fitted-slope confidence interval or causal proof.
History, reading, and writing connection
Using the NOAA file header and NCEI proxy explanation, write a provenance note comparing the modern monitoring record with ice-based reconstruction. Cite which numbers were observed, which were invented, which were inferred and what evidence beyond a trend would support a causal explanation.
Write in your own words or use an approved accessible equivalent. Cite a specific assigned section or figure, identify its evidence, and state one limitation or counterargument. Use the AI practice contract only for permitted coaching, never to invent observations or write the assessed response.
Transfer to a new case
A new fictional site has means 12.0 C in 1980 and 12.6 C in 2010, relative to an assigned 11.8 C baseline. Foundation: find anomalies. Core: find the endpoint trend. Honors: add 0.3 C to the baseline and test whether the slope changes. All levels: distinguish these synthetic quantities from causal evidence.
Calibration: Foundation: anomalies are 0.2 and 0.8 C. Core: the endpoint trend is 0.6/30 x 10 = 0.2 C/decade. Honors: a 12.1 C baseline gives -0.1 and 0.5 C, with the same slope. Neither baseline choice nor this two-point synthetic trend proves a cause.
Evidence to retain
At the agreed level retain the provenance-labeled graphs, baseline/interval work, selected fit or proxy calculation and new-site transfer. Assess the Climate quantities and Record and proxy reasoning science criteria; use historical/source writing for separately reported integration. No field data collection is assigned. Sources checked 2026-09-27.
Record units, calculations, source/date, uncertainty, and what is measured versus inferred. A simulation or supplied dataset must stay labeled as such. No field exposure or weather chasing; no water sampling, ingestion, or chemical tests; no solar viewing. Use supplied data and approved images or non-destructive indoor alternatives only. A worksheet does not demonstrate practical performance or authorize a real location or safety forecast.
Return to all eight learning pathways. Print this unit page for the student lessons; the linked five-page packet remains the separate assessment companion.
| Criterion | Developing | Proficient | Mastery |
|---|---|---|---|
| Climate quantities | Confuses an anomaly, baseline, rate or weather event. | Calculates with help but omits the time span or provenance. | At the agreed level, defends anomalies, endpoint rates or fitted slopes/residuals with baselines, units and limits. |
| Climate zones & what sets them | Cannot say why one place is a desert and another a rainforest. | Names climate zones but not the factors — latitude, altitude, currents — that set them. | Explains how latitude, elevation, ocean currents, and winds combine to set a region's climate zone. |
| Greenhouse effect & the carbon cycle | Thinks the greenhouse effect is only harmful, or confuses it with the ozone hole. | Describes the greenhouse effect but cannot trace carbon through its reservoirs. | Explains how greenhouse gases trap heat and traces carbon through ocean, atmosphere, rock, and life. |
| Record and proxy reasoning | Calls invented temperatures observations or trends causal proof. | Labels sources but needs help explaining a proxy calibration. | At the agreed level, distinguishes observed CO2, synthetic temperatures and proxy inference, with uncertainty and a causal limitation. |
| Climate-data method | Omits axes, source or baseline. | Labels the graph but cannot explain a changed baseline. | Defends the fresh site transfer and retains source/version, baseline and units; does not infer climate sensitivity from these tables. |
| Integration (cross-domain) | Makes no supported connection between the source and the science. | Uses the source but needs help connecting evidence, writing, or limitations to the science. | Independently connects History, Reading, and Writing using a cited source, appropriate evidence, a limitation, and a scientific explanation. |
Integration is reported separately and cannot lower the science grade or block a science demonstration pass. Science and practical criteria determine that pass. Use the integration guide's evidence checklist for the separately reported criterion.
“The observed CO2 endpoint rate is about 1.622 ppm/year. The separate, synthetic temperature fit is 0.16 C/decade; changing its baseline moves the intercept, not that slope. The ice exercise reconstructs a temperature using an assumed calibration. These calculations do not, by themselves, prove a cause of warming.”
“It snowed last week, so global warming can’t be real. Weather and climate are pretty much the same thing anyway.”
At the agreed level, submit source-labeled graphs, baseline/rate or fit/proxy work and the new-site transfer. Distinguish the observed NOAA record from synthetic exercises and trend evidence from causal attribution. These are science criteria; historical/source writing is separately reported integration. No field measurements are required.
A 5-page clipboard packet — unit overview, key terms, the mastery rubric, anchor examples, and a score sheet you can print and grade against.