Warming oceans, rising seas and melting ice

Grade 9 Science Worksheet

Circle the best answer.

1. Read this first

   Sea-level rise rates (IPCC AR6)

   Period	Average rate
   1901–1971	1.3 mm a year
   1971–2006	1.9 mm a year
   2006–2018	3.7 mm a year

   Note: Total 1901–2018, about 0.20 m.

2. 1.

   At IPCC's 2006–2018 rate of 3.7 mm a year, how much would sea level rise in 10 years, by Bo's math?

   • About 37 mm
   • About 13.7 mm
   • About 0.37 mm
   • About 370 mm
3. 2.

   IPCC AR6: sea level rose about 0.20 m (200 mm) from 1901 to 2018, which is 117 years. What is the average rate, by Esme's math?

   • About 23,400 mm a year
   • About 0.17 mm a year
   • About 1.7 mm a year
   • About 17 mm a year
4. 3.

   Which melting ice adds new water to the ocean, by Luz's reading (NOAA, NSIDC)?

   • Pack ice floating on the Arctic Ocean
   • Ice on a frozen pond far inland
   • Glaciers and ice sheets on land
   • Sea ice, which froze from seawater
5. 4.

   A climate chart with ocean heat content and sea level both rising. Model data: a column of seawater warms and expands a tiny amount. What happens to sea level above it, by Milo's reading (NOAA)?

   • It falls, since warm water shrinks
   • It rises a little, since the warm water takes more room
   • It rises because new ice forms on top
   • It stays the same, since no water was added
7. 5.

   IPCC AR6: Arctic sea-ice area fell about 10% in March and about 40% in September (1979–1988 to 2010–2019). How many times bigger is September's loss, by Noah's math?

   • 50 times
   • 0.25 times
   • 30 times
   • 4 times
8. 6.

   Model data: a September sea-ice area of 7 million km² shrinks by 40% (the IPCC AR6 Arctic figure). What area is left, by Pia's math?

   Use the picture in question 5.

   • About 4.2 million km²
   • About 6.6 million km²
   • About 47 million km²
   • About 2.8 million km²
9. 7.

   NSIDC: open ocean reflects about 6% of sunlight, and sea ice 50 to 70%. What happens as Arctic sea ice shrinks, by Ren's reading?

   Use the picture in question 5.

   • More sunlight is absorbed, adding warmth
   • The warmer water shrinks, so sea level drops
   • Nothing changes, since ice and water reflect equally
   • Sea level jumps, since floating ice adds new water

10. Use this

    A pH scale with a small step down from about 8.2 to about 8.1.

11. 8.

    NOAA: the ocean absorbs about 30% of the CO₂ released into the air. Of 40 billion tons released (model data), about how much is that, by Tala's math?

    • About 12 billion tons
    • About 1.2 billion tons
    • About 28 billion tons
    • About 70 billion tons
12. 9.

    NOAA: average surface pH is now about 8.1, after a fall of about 0.1. About what was it before the industrial revolution, by Zee's math?

    • About 9.1
    • About 7.1
    • About 8.2
    • About 8.0
13. 10.

    Why does more acidic seawater make it harder for oysters and corals to build shells, by Ari's reading (NOAA)?

    • A higher pH dissolves the shells faster
    • More carbonate ions crowd out the shells
    • Acidity makes the seawater far too cold
    • Fewer carbonate ions are free to build shells