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 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
- About 22 W/m2 more is absorbed: a positive feedback, since less ice means more warming
- About 108 W/m2 more is absorbed: a positive feedback, since less ice means more warming
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?
- 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: carbon in the air first thaws the ground, and microbes then respond; release doubled
- 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 25 million tonnes more, a positive loop: extra removal adds more warming
- 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
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?
- Logging (biosphere) loosened soil (geosphere), so the river (hydrosphere) carries 4.5 times as much
- The muddier river (hydrosphere) harmed the trees (biosphere), and it carries 4.5 times as much
- More rain (atmosphere) washed soil into the river (hydrosphere), which carries 4.5 times as much
- Logging (biosphere) loosened soil (geosphere), so the river (hydrosphere) carries 70 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 hydrosphere to the cryosphere
- About 1.5 mm a year, from the cryosphere to the hydrosphere
- About 150 mm a year, from the cryosphere to the hydrosphere
- About 0.67 mm a year, from the cryosphere to the hydrosphere
Card
pH is logarithmic. A drop of 1.0 means 10 times the hydrogen ions, so a drop of 0.1 means 10 to the power 0.1 = 1.26 times.
Ocean surface pH falls from 8.2 to 8.1 as the air gains CO2. Noah finds the change in hydrogen ions and the arrow.
- About 26% more hydrogen ions, from the hydrosphere to the atmosphere
- About 10% more hydrogen ions, from the atmosphere to the hydrosphere
- About 26% more hydrogen ions, from the atmosphere to the hydrosphere
- About 100% more hydrogen ions, from the atmosphere to the hydrosphere
A forest's carbon in one year (example data)
Item Amount Carbon taken in by trees 6.0 t C per ha Carbon returned by soil and respiration 5.5 t C per ha Forest area 200 ha Ren finds the net CO2 removed from the air in a year. A carbon atom has mass 12 and CO2 has mass 44.
- About 367 tonnes of CO2, matter moving from the atmosphere to the biosphere
- About 100 tonnes of CO2, matter moving from the atmosphere to the biosphere
- About 4,400 tonnes of CO2, matter moving from the atmosphere to the biosphere
- About 367 tonnes of CO2, matter moving from the biosphere to the atmosphere
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
- 56,000 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 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?
- 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
- Low oxygen starved the algae, which then released the nitrate; 1.5 mg/L is hypoxic
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?
- 8 mm a year, since the rising sea alone is drowning the delta
- 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
- 3 mm a year, since dams trap sediment and the delta cannot build up
