D2.Geo.9.9-12: Climate Variability, Migration and Land Use from Mesa Verde to the Sahel
In plain English: D2.Geo.9.9-12 is the C3 Framework geography indicator for grades 9-12 that asks students to evaluate how long-term climate variability influences migration, settlement patterns, resource use and land use at local-to-global scales. Students test climate explanations against data and other causes, such as population growth and cultural traditions.
Evaluate the influence of long-term climate variability on human migration and settlement patterns, resource use, and land uses at local-to-global scales.
C3 Framework for Social Studies (NCSS) · Dimension 2: Applying Disciplinary Concepts and Tools · Discipline: Geography · Human Population: Spatial Patterns and Movements · Official standard
D2.Geo.9.9-12 asks students to evaluate how long-term climate variability (natural swings between wetter and drier, or warmer and cooler, periods that last decades or centuries) influences four things: migration, settlement patterns, resource use and land use, at local-to-global scales. Evaluating means more than linking a drought to a move. Students test a climate explanation against the timing in the data and against other causes, and they ask whether the same explanation holds at a different scale.
The lesson pairs two cases on two continents. At the local and regional scale, students read National Park Service pages on Mesa Verde, where Ancestral Pueblo people moved their homes into cliff alcoves near springs and then, by about 1300, migrated south, and they analyze a 1,300-year tree-ring reconstruction of moisture from NOAA's paleoclimate archive. At the national-to-global scale, they read an SVHS summary of a U.S. Geological Survey analysis of rainfall, farmland and population in Niger, where Atlantic Ocean temperatures help drive the rains. A scale matrix pulls the evidence together for a final judgment.
Learning Objectives
By the end of this lesson, students will be able to:
Distinguish long-term climate variability from weather events and from one-directional climate trends.
Analyze a tree-ring reconstruction to identify dry and wet periods and compare their timing with migration and settlement changes.
Explain how climate variability influenced migration, settlement patterns, resource use and land use at Mesa Verde and in Niger.
Compare the influence of climate variability at local, regional and national-to-global scales.
Evaluate a climate explanation against other causes named in the sources, such as population growth and cultural traditions.
Prior Knowledge Required
Students should already be comfortable with:
Linking long-term environmental change to spatial patterns D2.Geo.9.6-8
Explaining reciprocal influences between human and physical systems D2.Geo.4.9-12
Integrating data from charts with written sources RH.9-10.7
"A family farms the same land for three generations. One generation has twenty good years, the next has twenty dry years, and the third has twenty good years again. Would you expect the family to move away during the dry years? What else would you need to know before deciding?"
Collect answers and sort the "what else" list into three groups: climate (how dry, how long), resources and land (water sources, soil, stored food) and people (population, family ties, traditions, conflict). Tell students that geographers who study climate and migration make the same list, and that the hardest part is weighing the groups against each other.
Direct Instruction20 minutes
Part 1: Key terms.Weather is the condition of the air on a given day. Climate is the long-run pattern of weather. Climate variability is the way climate swings above and below its long-run average over years, decades or centuries; a one-directional change, such as steady warming, is a trend. A settlement pattern is where people put their homes and how those homes are grouped. Resource use is how people obtain and use water, soil, plants and animals. Land use is what the land is used for: fields, terraces, grazing, villages. Scale is the size of the area studied, from local (one mesa) to regional (the Four Corners) to national or global (a country, a continent, an ocean).
Part 2: Reading tree rings. In dry years trees grow thin rings. Scientists measured Douglas-fir trees and old logs near Mesa Verde and used them to reconstruct the moisture balance, precipitation minus potential evapotranspiration (P - PE), for September to May each year from 722 to 2011 (Stahle and others, 2015, archived by NOAA). Potential evapotranspiration is the amount of water the air and plants would draw from the ground if it were available. A negative value means the season's precipitation fell short of that demand. The data file does not give units, so compare values with each other and with the average of all years, 0.16.
Table 1. Mesa Verde moisture balance (P - PE, September-May), 25-year averages, 1100-1349, reconstructed from tree rings (real data: Stahle and others 2015, NOAA NCEI Paleoclimatology). Average of all years 722-2011: 0.16.
Period
Average P - PE
Years with a negative balance
1100-1124
0.40
2 of 25
1125-1149
0.04
9 of 25
1150-1174
-0.14
14 of 25
1175-1199
0.15
7 of 25
1200-1224
0.16
11 of 25
1225-1249
0.32
6 of 25
1250-1274
0.27
8 of 25
1275-1299
-0.04
14 of 25
1300-1324
0.19
8 of 25
1325-1349
0.37
4 of 25
Finding the dry periods
Use Table 1. Which 25-year periods had a negative average balance, and how far below the 722-2011 average was the later one?
Result: 1150-1174 (-0.14) and 1275-1299 (-0.04). Each had 14 dry years out of 25. The later period was -0.036 - 0.162 = -0.198, about 0.20 below the long-run average.
Testing timing against settlement
Source 1 says most cliff dwellings were built from 1180 to 1300. Which dry period came just before that building began, and what does the timing suggest?
Result: The 1150-1174 period, the driest 25 years in the table. Building homes near seep springs right after it fits Source 1's argument that shrinking water supplies changed the settlement pattern. But people stayed on the mesa after that drought; they moved within it instead of leaving.
Measuring a regional migration
Use Diagram 2. How much farther from Mesa Verde is Taos Pueblo than First Mesa, in a straight line?
Result: 170.1 - 137.4 = 32.7, about 33 miles farther. Both moves crossed well over 100 miles, so the migration Source 2 describes is a regional pattern, not a local one.
Comparing land use and population at the national scale
Source 3 says that between the 1980s and the 1990s, farmland in Niger grew by 51 percent and the population by 37 percent. Did farmland per person rise or fall?
Result: 1.51 / 1.37 = 1.102, so farmland per person rose by about 10 percent. Wetter decades made new fields possible, but the change in land use also tracks the number of people who needed food.
Guided Practice20 minutes
Read Sources 1 and 2 with Diagram 1. Both sources are National Park Service pages for Mesa Verde National Park in Colorado. Words to know: seep spring (water that trickles out of a cliff where a rock layer stops it from sinking), alcove (a large arched hollow in a cliff wall), reservoir (a basin built to store water), terrace (a flat step built into a slope to hold soil and water).
1Mesa Verde National Park has some of the largest and best preserved cliff dwellings in North America. The ancestors of Pueblo people built most of the cliff dwellings from 1180 CE to 1300 CE. This identifies them as some of the last structures built in the Mesa Verde Region, and the people living in them were among the last to migrate south.
[...]
2"Why would they build here?" is a common question many visitors have about the cliff dwellings of Mesa Verde. This has also been a question that archeologists worked to solve for many, many years. The conclusion for most scholars points towards one thing that no person can live without - water.
3Cliff dwellings seem inhospitable, but most were built near seep springs, some of the only permanent water sources in Mesa Verde. These cliffside springs were increasingly important to Ancestral Pueblo people during the time period the cliff dwellings were built. Wood samples show evidence of extended droughts, and mesa top reservoirs were likely becoming less reliable. Faced with shrinking water supplies, people chose to move their homes to places with easier access.
National Park Service, Mesa Verde National Park, Cliff Dwellings: “Room with a View” and “Water is Life” (Source 1) (2026). US government work (17 U.S.C. 105). Source text.
1Farming was central to the livelihoods of every Ancestral Pueblo person. Between the 500s and the 1200s, people chose to transition from a life where farming, hunting, and gathering held equal weight, to one where the crops of corn, beans, and squash made up 90% of people's diet. Farming fields were supported by infrastructure like dams, terraces, and reservoirs. Most of a building's indoor space was dedicated to food storage for the long winter. Animals such as dogs and turkeys assisted with work and provided valuable resources as well as companionship.
[...]
2Migration and movement of people were common at Mesa Verde, just as people today move from house to house, state to state, and country to country. People frequently moved between communities for better opportunities, to be closer to family, and to escape drought. Even with this ebb and flow of population, life in the Mesa Verde area continued until the mid 1200s, when people started to move south.
3Over the course of several decades, the Ancestral Pueblo people left Mesa Verde entirely. The reasons for moving likely varied from individual to individual. Evidence shows that the 1200s were a period of persistent drought, limited resources, and social change. For Pueblo people, migration is an important cultural activity, and people may have decided it was simply time to move on and continue their people's journey.
[...]
4The Pueblo and Hopi people are the direct descendants of those who built and lived in the communities at Mesa Verde and surrounding sites. When their ancestors left Mesa Verde, they created new villages or joined pre-existing ones along the Rio Grande River Valley, Little Colorado River drainages, and the Hopi Mesas. When they arrived in their new homes, they brought both physical reminders of their past, such as architecture, artistic motifs, and farming practices, but also traditions like ways of looking at the world, religion, and oral histories. All of these connect them to their ancestors, and Mesa Verde remains an important pilgrimmage site for Pueblo and Hopi people to learn and pay their respects to their past.
National Park Service, Mesa Verde National Park, People: “People of the Corn,” “A Time to Leave” and “The Pueblo and Hopi People” (Source 2) (2026). US government work (17 U.S.C. 105). Source text.
Code the sources. Mark each sentence that shows migration (M), settlement pattern (S), resource use (R) or land use (L). Some sentences get two codes.
Match words to data. Source 1 says "Wood samples show evidence of extended droughts." Ask: which bars in Diagram 1 could be that evidence, and which period in Source 1 do they overlap?
Read the reasons carefully. Ask: how many reasons for leaving does Source 2, paragraph 3, give, and which of them are not about climate?
Check the scale. Ask: which sentences describe one place (local), and which describe the whole Four Corners or the moves south (regional)? Mark the regional destinations on Diagram 2.
Teacher note. Source 2 presents Pueblo views of migration as a cultural practice as well as archeological evidence. Treat both as evidence and avoid framing the departure as a "collapse" or a "disappearance"; the descendants live today in the communities on Diagram 2.
Independent Practice15 minutes
Read Source 3 and complete the scale matrix. Source 3 moves to a different continent and scale: the country of Niger in the Sahel of West Africa, where the rains depend partly on the temperature of the Atlantic Ocean. Words to know: arable (able to be farmed), marginal areas (land that is barely good enough for farming, often because rain is unreliable), yield (the amount of crop grown on each unit of land).
1This is an SVHS-written summary of a 2012 U.S. Geological Survey fact sheet, A Climate Trend Analysis of Niger, prepared with the Famine Early Warning Systems Network (FEWS NET) of the U.S. Agency for International Development. Words in quotation marks are the fact sheet's own.
2Niger is a landlocked country in the Sahel, the dry belt of Africa south of the Sahara. Most of its rain falls from June to September. The fact sheet explains that “rainfall totals of more than 500 millimeters (mm) during this season typically provide enough water for crops and livestock,” but only about 3.3 percent of the country receives that much. “Fifteen percent of Niger’s land is arable and located in a region mainly along its southern border with Nigeria.”
3The rains vary from decade to decade. “Rainfall in Niger declined rapidly between 1950 and the mid-1980s and partially recovered during the 1990s and 2000s.” Even so, rainfall in the crop-growing districts in 2000-2009 averaged about 8 percent below the 1920-1969 mean. The fact sheet links the recovery to the ocean: “as the northern tropical Atlantic has increased in temperature over this period, this has drawn the summer rains further north, increasing rainfall in the Sahel.” As the rains returned, the area receiving more than 500 mm grew by about 25 percent. The authors warn that “In the past, Niger has experienced large, natural variations in mean rainfall on decadal time scales.”
4Its main crops are rain-fed millet, sorghum and cowpea, and in dry years the country “must rely on grain purchases and food aid.” The fact sheet finds that “Niger has offset very rapid population growth with a large expansion of cultivated land.” Between the 1980s and the 1990s, farmland grew by 51 percent while the population grew by 37 percent. Between the 1990s and the 2000s, farmland grew by 20 percent while the population grew by 42 percent. The authors suggest that “raising yields in wetter areas may be a more viable option than extending agriculture into more marginal areas.”
SVHS (summary of Funk and others, U.S. Geological Survey Fact Sheet 2012-3080), Rainfall, Farmland and People in Niger: an SVHS summary of a USGS fact sheet (Source 3) (2026). Original passage written for this page. Source text.
Scale matrix. Students draw a grid with three rows (local: Mesa Verde; regional: the Four Corners and the moves south; national-to-global: Niger and the Atlantic) and four columns (migration, settlement pattern, resource use, land use). In each cell they write one piece of evidence and rate the influence of climate variability as strong, partial, weak or no evidence, with a reason. Empty cells are allowed when the sources say nothing.
Closure10 minutes
Exit ticket. "Choose one row of your scale matrix. In three sentences, judge how strongly climate variability influenced that scale, and name the strongest other influence the sources give."
Share two or three exit tickets that reach different judgments from the same evidence, and point out what made each one well supported.
Differentiation Strategies
For Struggling Students
Provide a matrix with the evidence already entered for the local row, so students only add ratings and reasons.
Give the three-word cue for each code (M: moving away; S: where homes are; R: getting water or food; L: what the land is used for).
Pair Diagram 1 with a sentence frame: "In the period ___, the balance was ___, which is ___ than the average, so ___."
For Advanced Students
Download the full NOAA reconstruction and compare the September-May series with the June-July series for the 1200s.
Explain why Source 3's authors say rainfall gains are "much less certain" than temperature gains, and what that means for land-use planning (see the fact sheet).
Find a third case at a different scale, such as a city's water supply in a multiyear drought, and add a row to the matrix.
Assessment Guidance
What to Look For
Strong answers keep climate variability separate from a single weather event or a one-directional trend, quote the timing in the data accurately, and say which of the four influences (migration, settlement, resource use, land use) each piece of evidence shows. The best answers compare scales, notice where the climate explanation fits and where it does not, and weigh it against the other causes the sources name. Watch for answers that treat "drought" as the whole explanation.
02
Classroom Activities
3 Activities
1
Scale Ladder Card Sort
15 minGroups of 3
Groups sort 12 cards twice. First by scale (local, regional, national-to-global). Then by what the card shows: migration, settlement pattern, resource use, land use, or climate evidence or cause. Groups must justify any card they place in two categories.
The 12 Cards
A family carves a small basin to collect water dripping from a cliff.
Homes on one mesa are rebuilt inside cliff alcoves near springs.
Farmers build stone walls across small gullies to trap soil and water.
Thousands of people leave the Mesa Verde region over several decades.
Newcomers join existing villages more than 100 miles away.
Corn, beans and squash make up most of the diet across the region.
Warmer ocean water pulls summer rains farther north over a continent.
Farmland in a dry country spreads into land where rain often fails.
A country buys grain from abroad in a dry year.
Farm villages crowd into the one region of a country that gets enough rain.
A herder moves animals to another pasture for one dry season.
A 25-year dry period shows up in tree rings from one canyon.
Answer Key
Scale: local 1, 2, 3, 11, 12; regional 4, 5, 6; national-to-global 7, 8, 9, 10. What it shows: migration 4, 5 (and 11, but see below); settlement pattern 2, 10 (5 also fits); resource use 1, 6, 9; land use 3, 8; climate evidence or cause 7, 12. Card 11 is a trap: one season's move is a response to weather, not to long-term climate variability.
Discussion
Ask: which cards change meaning if you move them up or down the ladder? For example, card 2 is local, but if it happened on every mesa in the region it would become a regional settlement pattern. Groups name one card whose scale they argued about and explain the decision.
2
Reading the Tree-Ring Record Year by Year
20 minPairs
Pairs graph 30 years of the NOAA reconstruction behind Diagram 1 and decide whether the late 1200s look like one long drought or a mix of wet and dry years.
Draw a bar graph with a zero line and a dashed line at 0.16, the 722-2011 average.
Count the years with a negative balance.
Find the longest run of negative years in a row, and the average of that run.
Find the wettest year.
Write two sentences: does this record fit the phrase "a period of persistent drought" (Source 2, paragraph 3)? What would you need from other sources to decide whether it caused people to move?
Answer Key
2. 15 of the 30 years are negative. 3. The longest run is 1285-1289, five years in a row; its average is (-0.519 - 0.194 - 0.215 - 0.250 - 0.147) / 5 = -0.265. 4. 1271 (1.408). 5. Answers vary. Strong answers notice that wet years still came (1271, 1275, 1284, 1290) but that dry years grew more common after 1276, and that the data alone cannot show why people moved.
3
Structured Academic Controversy: Was Climate the Main Driver?
20 minGroups of 4 (two pairs)
Each group of four answers one question: "Was long-term climate variability the main reason Ancestral Pueblo people left Mesa Verde by about 1300?" One pair argues yes, the other pair argues no; then they switch sides; then the group writes a consensus statement.
Steps
Pair A presents the strongest case for "yes" in 3 minutes, using Sources 1-2 and Diagram 1. Pair B restates it accurately.
Pair B presents the strongest case for "no" in 3 minutes. Pair A restates it.
The pairs switch sides and add one new piece of evidence each.
The group drops its assigned roles and writes a two-sentence consensus that says how strong the influence of climate was.
Scoring
Score the reasoning, not the side: accurate use of the data, at least one quotation from a source, a fair restatement of the other pair's case and a consensus that names a second cause. Both answers to the question can be well supported.
Variation: Change the Scale
Run the same protocol with Source 3: "Will rainfall or population growth matter more for how Niger uses its land in the next 20 years?"
03
Diagrams & Visual Aids
2 diagrams
Diagram 1: Mesa Verde Moisture Balance in 25-Year Periods, 1100-1349
Real data: tree-ring reconstruction of the September-May moisture balance (precipitation minus potential evapotranspiration) at Mesa Verde National Park headquarters, Stahle and others (2015), archived by NOAA NCEI Paleoclimatology (file mesaverde2015p-pe.txt). Each bar is the average of 25 yearly values; the dashed line is the average of all years, 722-2011. The shaded band marks the years when most cliff dwellings were built (Source 1).
Diagram 2: From Mesa Verde to the Hopi Mesas, Zuni and the Rio Grande
State outlines: U.S. Census Bureau 2023 cartographic boundary file (1:5,000,000). Mesa Verde: the official point for the mesa (summit) in the USGS Geographic Names Information System. Dots: 2023 Census Gazetteer points for present-day Hopi and Pueblo communities named as census places (First Mesa and Second Mesa CDPs, Zuni Pueblo CDP, Ohkay Owingeh CDP, Santo Domingo Pueblo CDP, Taos Pueblo CDP, Isleta CDP). Zuni Pueblo lies on the Zuni River, in the Little Colorado River drainage (USGS hydrologic unit 15020004, "Zuni," part of the Little Colorado River Basin). The blue arrows show only the general direction of the moves south in the late 1200s, not routes: the paths people actually took are not known from these sources. Distances are great-circle (straight-line) distances computed from those points.
04
Homework Assignment
~30 min
D2.Geo.9.9-12 Homework: The Ostrander Basin
Directions: The Ostrander Basin is an invented dry valley with a lake, a river and a market city named Tarvis; all data below are invented for this homework. Use them, and Sources 1-3 from class, to answer the problems.
Average yearly rainfall by decade (mm): 1950s, 420; 1960s, 410; 1970s, 330; 1980s, 300; 1990s, 360; 2000s, 390. Lake area (square kilometers): 1960, 85; 1985, 40; 2005, 60. Population: lakeside fishing villages, 1960: 12,000; 1985: 7,500; 2005: 9,800. Tarvis, 1960: 20,000; 1985: 41,000; 2005: 52,000. Other facts: In 1978 a dam was built upstream to store river water for Tarvis. In the 1980s many herders switched from cattle to goats, which need less water and forage. Irrigated fields along the river grew from 900 hectares in 1970 to 2,600 hectares in 2000.
Part 1: Analyze the Data (Problems 1-3)
Find the percent change in decade rainfall from the 1960s to the 1980s, and the percent change in lake area from 1960 to 1985. Which changed more, and give one reason, from the facts, why the lake might have shrunk faster than the rain fell.
Make a table that sorts the basin's changes into migration, settlement pattern, resource use and land use, and label each local or regional.
Find the percent change in the population of the lakeside villages and of Tarvis from 1960 to 1985. Describe the migration pattern these numbers suggest, and explain one way climate variability could help cause it.
Part 2: Evaluate (Problems 4-6)
Evaluate this claim: "The lake shrank between 1960 and 1985 because of the dry decades." Use at least two facts, including one that is not about climate.
Compare the Ostrander Basin with Mesa Verde (Sources 1-2) or Niger (Source 3). Name one way climate variability worked the same way and one way it worked differently, and say what scale each comparison is at.
Write a paragraph of 6-8 sentences: "How strongly did long-term climate variability influence migration, settlement, resource use and land use in the Ostrander Basin?" Rate the influence on at least two of the four and support each rating with data.
Rubric
Criterion
Full Credit (3 pts)
Partial Credit (2 pts)
Minimal Credit (1 pt)
Accurate Data Analysis
All percent changes correct and correctly interpreted
Most calculations correct, or one misread
Calculations missing or mostly incorrect
Classifies and Scales
Each change placed in the right category and scale, with reasons
Most changes placed correctly
Categories confused or scale ignored
Evaluates Causes
Weighs climate against the dam, irrigation or city growth with specific evidence
Names another cause but does not weigh it
Treats climate as the only cause
Compares Cases
Accurate comparison with a class source at a stated scale
Comparison is general or the scale is unclear
No comparison
05
Quiz: 20 Questions
Interactive, with answers
Instructions
Questions 3, 4 and 15 use Source 1, and questions 5-8, 16 and 20 use Source 2 (both in Guided Practice). Questions 11-13 and 17-20 use Source 3 in Independent Practice. Questions 9, 10, 16 and 20 use Diagram 1, and question 14 uses Diagram 2. Choose the best answer, then check it.
Multiple choice: pick an option to check it. Short answer: write your answer, then reveal the model answer.
0 of 20 answered · 0 correct
Question 1 of 20 · Multiple Choice
Which of these is an example of long-term climate variability?
Answer: B
Variability is the swing above and below the long-run average over decades or longer, as in dry decades followed by wet ones. Choice A is weather. Choice C is a human change to a local surface. Choice D is a one-directional trend, not a swing.
Question 2 of 20 · Multiple Choice
A village digs storage pits so it can keep three years of corn. Which of the four influences in D2.Geo.9.9-12 does this mainly show?
Answer: D
Storing food changes how people use a resource. Choice C would apply if the fields themselves changed use, for example from crops to grazing. Choices A and B would need a change in where people live.
Question 3 of 20 · Multiple Choice
According to Source 1, paragraph 3, why were most cliff dwellings built near seep springs?
Answer: A
Source 1 says the springs were "some of the only permanent water sources in Mesa Verde." Choice D reflects the common comparison with forts that Source 1 mentions only in a left-out paragraph, and choices B and C are not in the source.
Question 4 of 20 · Multiple Choice
According to Source 1, what kind of evidence shows the extended droughts?
Answer: B
Source 1 says: "Wood samples show evidence of extended droughts." Tree rings in wood are also the basis of Diagram 1. Choices A, C and D are not the evidence Source 1 cites for drought.
Question 5 of 20 · Multiple Choice
Source 2, paragraph 3, gives several reasons for leaving Mesa Verde. Which list matches it?
Answer: A
Source 2 says "the 1200s were a period of persistent drought, limited resources, and social change." The other choices include events the source does not mention.
Question 6 of 20 · Multiple Choice
Which sentence from Source 2 most weakens the claim that climate alone explains the migration?
Answer: C
The cultural explanation offers a reason for moving that does not depend on climate. Choice D describes the move's timing but not its cause. Choices A and B describe resource and land use before the move.
Question 7 of 20 · Multiple Choice
According to Source 2, paragraph 4, where did people go when they left Mesa Verde?
Answer: C
Source 2 says they "created new villages or joined pre-existing ones along the Rio Grande River Valley, Little Colorado River drainages, and the Hopi Mesas." All three lie south of Mesa Verde (Diagram 2), which matches "people started to move south." The other choices are not in the source.
Question 8 of 20 · Multiple Choice
Which detail in Source 2, paragraph 1, describes land use rather than resource use?
Answer: D
Fields with dams, terraces and reservoirs describe what the land itself was used for and how it was shaped. Choices A, B and C describe how people used food, animals and stored resources.
Question 9 of 20 · Multiple Choice
Use Diagram 1. During the main cliff-dwelling era (the bars for 1200-1299), which 25-year period had the highest average moisture balance?
Answer: C
The 1225-1249 bar is the tallest in that span, at 0.32. Choice B (1250-1274, 0.27) is the second highest, and choice D (1275-1299) is the only negative bar in the span.
Question 10 of 20 · Multiple Choice
Use Diagram 1. By how much did the average balance fall from 1250-1274 to 1275-1299?
Answer: B
0.269 - (-0.036) = 0.305, about 0.31. Choice A (0.23) subtracts 0.036 instead of adding it. Choice C (0.20) compares 1275-1299 with the long-run average of 0.16 instead of the earlier period. Choice D is just the value of the later period without its sign.
Question 11 of 20 · Multiple Choice
According to Source 3, how has Niger kept up with very rapid population growth?
Answer: B
Source 3 quotes the fact sheet: "Niger has offset very rapid population growth with a large expansion of cultivated land." Choice A exaggerates: grain purchases and food aid are needed "in dry years," not every year. Choice C is impossible because Niger is landlocked, and choice D contradicts the stagnant yields described in the fact sheet.
Question 12 of 20 · Multiple Choice
Source 3 says that between the 1990s and the 2000s, Niger's farmland grew by 20 percent and its population by 42 percent. What happened to farmland per person?
Answer: D
1.20 / 1.42 = 0.845, so farmland per person fell by about 15 percent. Choice A subtracts the percents (42 - 20) instead of dividing the growth factors. Choice B is the 1980s-to-1990s result. Choice C confuses this with the 8 percent rainfall figure.
Question 13 of 20 · Multiple Choice
According to Source 3, where is most of Niger's arable land?
Answer: C
Source 3 quotes the fact sheet: "Fifteen percent of Niger's land is arable and located in a region mainly along its southern border with Nigeria." Choice B is impossible because Niger is landlocked; choice A is the driest part of the country.
Question 14 of 20 · Multiple Choice
Use Diagram 2. About how much farther from Mesa Verde is Isleta than Zuni Pueblo, in a straight line?
Answer: A
185.5 - 145.0 = 40.5, about 41 miles. Choice B (19) is the gap between Santo Domingo Pueblo and Zuni Pueblo, choice C (48) the gap between Isleta and First Mesa, and choice D adds the two distances instead of subtracting.
Question 15 of 20 · Short Answer
Using Source 1, explain how climate variability influenced both resource use and the settlement pattern on Mesa Verde. Cite paragraph 3.
Model answer: Source 1, paragraph 3, says that during extended droughts "mesa top reservoirs were likely becoming less reliable" (resource use: a water source failing). In response, "people chose to move their homes to places with easier access," building cliff dwellings beside seep springs in the cliffs (settlement pattern: homes moved from mesa tops to cliff alcoves). The drought changed which water source people relied on, and that changed where they lived. Full credit: both influences named, linked and cited.
Question 16 of 20 · Short Answer
Source 2, paragraph 2, says people "started to move south" in the mid 1200s. Compare that timing with Diagram 1. How strong is the case that drought started the migration?
Model answer: The case is only partial. The mid 1200s fall in the 1250-1274 period, when the average balance (0.27) was above the long-run average (0.16), so the start of the move does not line up with a dry quarter century. The driest stretch came later, in 1275-1299 (-0.04), when the last people left. Drought may have pushed the final departures, but the other reasons Source 2 gives are needed to explain why the move began. Full credit: accurate use of the two bars and a reasoned judgment.
Question 17 of 20 · Short Answer
Compare the influence of climate variability on land use at Mesa Verde (local scale) and in Niger (national scale).
Model answer: At Mesa Verde, people shaped the land around water: fields built up with structures that held soil and water (Source 2), and homes moved toward springs in the dry era (Source 1). In Niger, wetter decades let farmland spread, and the area with more than 500 mm of rain grew by about 25 percent (Source 3), so climate variability helped change land use across a whole country. A difference: in Niger, land use also tracked rapid population growth, so the influence of climate is mixed with demand on a scale far larger than one mesa. Full credit: one accurate point for each scale and a clear comparison.
Question 18 of 20 · Short Answer
Source 3 says that "raising yields in wetter areas may be a more viable option than extending agriculture into more marginal areas." Explain this advice using the idea of climate variability.
Model answer: Marginal areas get enough rain only in wet decades. Because Niger's rainfall swings over decades ("large, natural variations in mean rainfall on decadal time scales"), farms pushed into marginal land during the wet years could fail when a dry decade returns. Raising yields in wetter areas uses land where rain is more reliable, so it is less exposed to the next swing. Full credit: links the advice to decade-scale swings and to where land is farmed.
Question 19 of 20 · Short Answer
Source 3 links Niger's rain to the temperature of the northern tropical Atlantic Ocean. Explain why this makes the Niger case a global-scale example, even though Source 3 is about one country.
Model answer: The rain that decides where Niger can farm depends on conditions in an ocean more than a thousand miles away. Source 3 quotes the fact sheet: warming of the northern tropical Atlantic "has drawn the summer rains further north, increasing rainfall in the Sahel." So land use in one country is tied to a climate system that spans an ocean and a continent, which is the global end of the local-to-global scale. Full credit: identifies the ocean link and explains the scale.
Question 20 of 20 · Short Answer
Evaluate this claim: "In both cases, long-term climate variability was the main influence on where people lived and how they used the land." Agree, disagree or partly agree, using evidence from at least two sources and Diagram 1.
Model answer (more than one judgment can earn full credit): Partly agree. Climate variability clearly shaped resource use and settlement at Mesa Verde, where drought made reservoirs unreliable and homes moved to springs (Source 1), and wetter decades in Niger let farmland expand (Source 3). But it was not the only main influence. Diagram 1 shows people stayed through the very dry 1150-1174 period, Source 2 names reasons beyond drought, including a cultural tradition of migration, and Source 3 shows farmland tracking rapid population growth. Full credit: a clear position, evidence from two sources and the chart, and at least one other influence weighed.
0 of 20 answered · 0 correct
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Frequently Asked Questions
10 Questions
What does D2.Geo.9.9-12 mean?
D2.Geo.9.9-12 asks high school students to judge how much long-term swings in climate have shaped where people move and live and how they use resources and land. Students work at several scales, from one valley to a whole continent, and weigh climate against other causes such as population, economics and culture.
What is the difference between climate variability and climate change?
Climate variability is the natural rise and fall of climate around its average over years, decades or centuries, such as a run of dry decades followed by wet ones. Climate change usually refers to a lasting shift in the average itself. D2.Geo.9.9-12 names variability, so lessons often use long records, such as tree rings, that show the swings.
What does "local-to-global scales" mean in D2.Geo.9.9-12?
It means students compare the same question at different sizes of area. A local study looks at one mesa or town, a regional study at a group of states or a river basin, and a global study at links across continents or oceans. An explanation that works at one scale may not work at another.
How do tree rings show past climate?
Trees grow wider rings in wet years and narrower rings in dry years, so a long series of ring widths records past moisture. Scientists match living trees with old logs and timbers to extend the record back many centuries, then calibrate it against modern weather station data.
Is D2.Geo.9.9-12 about the current climate debate?
No. The indicator asks students to evaluate evidence about climate variability and human patterns, and it works well with historical and data-rich cases. Teachers can keep the focus on evidence and scale, and on how geographers weigh several causes, without asking students to take positions on current policy.
What is the difference between resource use and land use?
Resource use is how people obtain and use water, soil, plants and animals; land use is what the land itself is used for. Storing grain or switching to a different water source is resource use. Turning grassland into fields, building terraces or laying out a village is land use.
Which courses teach D2.Geo.9.9-12?
It is usually taught in high school human geography or world geography, and it also fits environmental science and world history units on migration. It pairs well with literacy standards on integrating data with written sources, such as RH.9-10.7.
How does D2.Geo.9.9-12 build on the middle school indicator?
In grades 6-8, D2.Geo.9.6-8 asks how long-term environmental change caused by people affects patterns of conflict and cooperation. The high school indicator shifts to climate variability and adds migration, settlement, resource use and land use across scales, so the evaluation becomes more complex.
What mistakes do students make with D2.Geo.9.9-12?
Many students treat climate as the only cause, or link a move to a drought without checking the timing. Others confuse a single season of bad weather with long-term variability. A good habit is to ask: does the timing fit, does it fit at every scale, and what else changed?
How should I assess D2.Geo.9.9-12?
Use tasks that make students weigh evidence: a data question on timing, a scale comparison and a written evaluation with a rubric that rewards accurate data use and attention to other causes. Score the reasoning rather than the final judgment, since several judgments can be well supported.
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Related Standards
5 standards
These standards connect to D2.Geo.9.9-12: prerequisites to review first, parallel standards at the same level, and next steps that build on it.
Before this lesson
D2.Geo.9.6-8Prerequisite
Evaluate how long-term human-induced environmental change affects conflict and cooperation
Evaluate how human-made and natural catastrophes affect trade, politics and migration
Lesson coming soon
Standard text: National Council for the Social Studies (NCSS), The College, Career, and Civic Life (C3) Framework for Social Studies State Standards: Guidance for Enhancing the Rigor of K-12 Civics, Economics, Geography, and History (Silver Spring, MD: NCSS, 2013). NCSS was not involved in the production of this lesson and does not endorse it.
