Earth's five systems and how they affect each other
Grade 9 Science Worksheet
Circle the best answer.
Read this first
Absorbed sunlight (model values)
Surface Absorbed (W/m2) Sea ice 80 Open water 188 Ice cover shrinks from 60% to 40% of a region. Bo averages the absorbed sunlight. What changes, and what sign is the loop?
- About 108 W/m2 more is absorbed: a positive feedback, since less ice means more warming
- About 22 W/m2 more is absorbed: a positive feedback, since less ice means more warming
- About 22 W/m2 more is absorbed: a negative feedback, since less ice means more cooling
- About 22 W/m2 more is absorbed, but warm water (hydrosphere) first creates the ice
Permafrost site (example data)
Year Thawed layer (cm) Carbon released (g C per m2 per year) 2000 40 30 2020 75 60 Jun reads the table. Which description of the loop fits, and by what factor did carbon release change?
- Positive: carbon in the air first thaws the ground, and microbes then respond; release doubled
- Negative: warming deepens thaw and microbes release more carbon, which cools the air; release doubled
- Positive: warming deepens thaw and microbes release more carbon; release rose 30 times
- Positive: warming deepens thaw and microbes release more carbon, which adds warming; release doubled
Card
Rock weathering removes 240 million tonnes of CO2 a year. Each 1 degree C of warming speeds weathering by 5 percent (model).
The climate warms 2 degrees C. Luz finds the extra CO2 removed each year and the sign of the loop.
- About 25 million tonnes more, a negative loop: extra removal cools the climate
- About 12 million tonnes more, a negative loop: extra removal cools the climate
- About 265 million tonnes more, a negative loop: extra removal cools the climate
- About 25 million tonnes more, a positive loop: extra removal adds more warming
One river before and after logging (example data)
Period Sediment (tonnes per day) Rain (mm per year) 2013 to 2014 20 800 2016 to 2017 90 810 Kira reads the table. Which interaction explains the muddier river, and how much more sediment moves?
- The muddier river (hydrosphere) harmed the trees (biosphere), and it carries 4.5 times as much
- Logging (biosphere) loosened soil (geosphere), so the river (hydrosphere) carries 4.5 times as much
- Logging (biosphere) loosened soil (geosphere), so the river (hydrosphere) carries 70 times as much
- More rain (atmosphere) washed soil into the river (hydrosphere), which carries 4.5 times as much
Melting about 360 billion tonnes of land ice raises sea level by about 1 mm. A glacier system loses 540 billion tonnes of ice in a year. Milo converts it. What sea-level rise and which arrow fit?
- About 1.5 mm a year, from the cryosphere to the hydrosphere
- About 150 mm a year, from the cryosphere to the hydrosphere
- About 1.5 mm a year, from the hydrosphere to the cryosphere
- About 0.67 mm a year, from the cryosphere to the hydrosphere
Ice has a density of 917 kg per m3, and melting takes 334 kilojoules per kg. Extra absorbed sunlight is 22 W/m2. How long does Tala say it takes to melt 1 m of ice, and what flows?
- About 1,600 days, with energy flowing from sunlight into the ice
- About 160 days, with energy flowing from the ice into the sunlight
- About 16 days, with energy flowing from sunlight into the ice
- About 160 days, with energy flowing from sunlight into the ice
Card
Methane traps 28 times as much heat as CO2 over 100 years. A thawing area of 1 km2 (1,000,000 m2) releases 2 g of methane per m2 in a year.
Zee converts the release to CO2 equivalent. How many tonnes is it, and what moves?
- 56 tonnes of CO2 equivalent, matter moving from the atmosphere to frozen ground
- 56 tonnes of CO2 equivalent, matter moving from frozen ground to the atmosphere
- 2 tonnes of CO2 equivalent, matter moving from frozen ground to the atmosphere
- 56,000 tonnes of CO2 equivalent, matter moving from frozen ground to the atmosphere
A bay after fertilizer runoff (example data)
Measure Spring Summer Nitrate (mg/L) 0.5 3.0 Chlorophyll (micrograms per liter) 4 40 Bottom oxygen (mg/L) 8.0 1.5 Hypoxia is oxygen below 2 mg/L. Esme reads the table. Which chain fits, and is the bay hypoxic?
- Low oxygen starved the algae, which then released the nitrate; 1.5 mg/L is hypoxic
- Warm summer water alone raised the chlorophyll; nitrate played no part, and 1.5 mg/L is hypoxic
- Algae add oxygen to the bottom water, so 1.5 mg/L is healthy for fish
- Nitrate feeds algae, whose decay uses up bottom oxygen; 1.5 mg/L is hypoxic
Note: Sunlight on the snow is 250 W/m2. Wildfire smoke drops soot on snow. Ari compares absorbed sunlight. Which chain fits, and what happens to absorption?
- Fire (biosphere) puts soot in the air, which darkens snow (cryosphere); absorption doubles to 37.5 W/m2
- Smoke in the air darkens the snow; the fire is not part of the chain, and absorption rises 15%
- Soot darkens the snow (cryosphere), which lights the fire (biosphere); absorption doubles to 75 W/m2
- Fire (biosphere) puts soot in the air, which darkens snow (cryosphere); absorption doubles to 75 W/m2
A river delta (example data)
Measure Value Sediment reaching the delta before dams 100 million tonnes a year Sediment reaching the delta after dams 20 million tonnes a year Delta surface sinking 5 mm a year Sea level rising 3 mm a year People build dams on the river. Pia reads the table. How fast does the sea rise relative to the delta, and why?
- 3 mm a year, since dams trap sediment and the delta cannot build up
- 8 mm a year, since dams trap sediment and the delta cannot build up
- 2 mm a year, since dams trap sediment and the delta cannot build up
- 8 mm a year, since the rising sea alone is drowning the delta