Earth's five systems and how they affect each other
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
Read this first
Three loops (+ adds to the change, - reverses it)
Loop Links A warmer air + more evaporation + more water vapor + warmer air B warmer air + more weathering - less CO2 in the air + warmer air C warmer air + more thaw + more carbon gas + warmer air Bo counts the reversing links in each loop. Which loops amplify a change?
- B and C amplify, since each loop crosses three systems
- A, B and C amplify, since each loop returns to warmer air
- A just amplifies, since water vapor is the one gas that traps heat
- A and C amplify; B damps, since it has one reversing link
Card
Trees supply 30% of a region's rain by releasing water vapor (example data). Loop: less rain removes trees, fewer trees release less vapor, and less rain falls.
A drought removes 20% of the forest. Luz assumes vapor falls in step. By what percent does rain fall, and what sign is the loop?
- Rain falls 6%; the loop is negative, since fewer trees need less rain
- Rain falls 30%; the loop is positive, since less rain removes more trees
- Rain falls 20%; the loop is positive, since less rain removes more trees
- Rain falls 6%; the loop is positive, since less rain removes more trees
A bay over 30 years (example data)
Year Nitrate load (thousand tonnes) Lowest bottom oxygen (mg/L) 1990 20 4.0 2000 30 2.5 2010 45 1.2 2020 30 2.0 Kira judges claims about the table. Which claim does it support best?
- Oxygen fell as nitrate rose, then partly recovered: a link, not proof of one cause
- The table shows that nitrate alone caused the low oxygen in this bay over 30 years
- Low oxygen drove the nitrate load up, since the two moved together
- Cutting the load restored oxygen fully, back to its level in 1990
Global sea level rise since 1993 (example data shaped like satellite records)
Year Rise since 1993 (mm) 1993 0 2003 32 2013 66 2023 101 Pia grades claims about the table. Which reply fits it, and what can the table not tell?
- The rise sped up slightly (32, 34, then 35 mm a decade); ice melt cannot be split from warmer water
- Sea level is a hydrosphere change, so ice and air play no part in it
- The rise held steady at 32 mm a decade, and the table shows that ice melt alone caused it, with no other cause
- The rise slowed after 2003, since 66 mm is under twice the first decade
A pulse of methane halves every 8 years (example data) and mixes through the air within about a year. What remains after 24 years, and where, by Ren?
- One eighth remains, spread through the whole atmosphere
- One third remains, spread through the whole atmosphere
- One sixth remains, spread through the whole atmosphere
- One eighth remains, kept near the place it was released
Card
Nitrate travels 2,000 km down a river at 0.5 m/s to a bay. The bay forms warm, layered water in early June.
Fertilizer washes into the river on April 15. When does Tala expect the nitrate to reach the bay, and why does it matter?
- About July 2 of the next year, after the bay layers and mixes again
- About April 20, so the nitrate reaches the bay well before the bay layers
- About June 1, just as warm, layered water starts to trap low oxygen
- About June 1, but the nitrate stays on the farm and does not reach the bay
About 27.7 million tons of Saharan dust reach the Amazon each year, with 22,000 tons of phosphorus. What share is phosphorus, and does it matter, by Zee?
- About 8%, a large share that more than doubles the forest's phosphorus
- About 0.08%, too small to matter to living things in the forest
- About 0.8%, small but about what the forest loses to rain and floods each year
- About 0.08%, small but about what the forest loses to rain and floods each year
Feedback strengths (rounded textbook values)
Feedback Strength (W/m2 per degree C) More heat radiated to space -3.2 Water vapor 1.8 Sea ice and snow 0.4 Ari adds the strengths. Which feedbacks amplify warming, and what does the sum say?
- Heat radiated to space amplifies, since its number is the largest
- The three damp warming; the sum is -5.4 W/m2 per degree C, so Earth cools
- Water vapor and sea ice and snow amplify; the sum is +2.2, so warming runs away
- Water vapor and sea ice and snow amplify; the sum is -1.0, so Earth settles
A, farmland around it, 80, 45, 0.8; B, forest around it, 10, 4, 7.5. Milo compares the lakes. Which interaction explains lake A's low oxygen?
- Algae release oxygen, so lake A's 45 chlorophyll should raise its bottom oxygen
- Low bottom oxygen made the algae grow, so the algae came second
- Runoff phosphorus feeds algae, about 11 times the chlorophyll, and their decay uses up bottom oxygen
- Lake B has less algae because it is deeper, as the table shows
How fast each feedback responds (approximate)
Feedback Time to respond Sea ice and snow years to decades Permafrost carbon decades to centuries Rock weathering about 100,000 years Esme asks if rock weathering could cancel warming within 100 years. Which reply is best?
- No: weathering responds about 100 times slower than 100 years
- Yes: weathering is a negative loop, so it cancels warming at any speed
- No: weathering acts on rocks, so it cannot change the air
- No: weathering responds over about 100,000 years, about 1,000 times slower than 100 years
