Why Is the Ocean Warming? Questions From a Storm-Ready Town

0 / 11

Why Is the Ocean Warming? Questions From a Storm-Ready Town

Use ocean and emissions data to ask good questions about what is warming Earth.

The ocean, layer by layer

Read the passage and Tables 1 and 2. Then answer questions 1–4.

Questions for an Ocean Scientist

1Marsh Point is a small town on the coast of Georgia, with salt marshes on one side and the Atlantic Ocean on the other. The town, the people and the data here are made up, but the data follow patterns that scientists have measured. Each June, before hurricane season, the town holds a Storm Ready Week. This year, emergency manager Ms. Hyacinth Morrow told sixth graders Saoirse Delaney and Rashid Benali that the ocean off Marsh Point has been getting warmer, and warm water can give storms more energy. The students wanted to know why the ocean is warming, so their class set up a video call with ocean scientist Dr. Lukas Brandvold.

2To get ready, the class read about global warming. Earth's average surface temperature has risen about 1.2 °C since the late 1800s. Scientists estimate that more than 90% of the extra heat that Earth has gained has gone into the oceans. Today, thousands of robot floats drift through the oceans, sinking as deep as 2,000 m and rising again while they measure the water's temperature.

3The class listed factors that might change Earth's temperature. People add greenhouse gases to the air: carbon dioxide (CO₂) from burning coal, oil and gas and from making cement, and methane from farm animals, landfills and leaking gas wells. Clearing forests also adds CO₂. Natural factors include changes in the energy coming from the Sun, large volcanic eruptions, and heat flowing up from inside Earth, for example at undersea volcanoes on the seafloor.

4Dr. Brandvold sent two data sets ahead of the call: how much the ocean has warmed at different depths, and where the world's greenhouse gases come from. The town also shared its own sea temperature records.

Table 1. World Ocean Warming by Depth, 1960 to 2020 (global averages)
Depth	Warming (°C)
Surface	0.6
100 m	0.4
300 m	0.2
700 m	0.1
2,000 m	0.02

Table 2. Average August Sea Temperature off Marsh Point
Decade	Aug. sea temp (°C)
1980s	28.0
1990s	28.2
2000s	28.5
2010s	28.9

1.

Use Table 1. Do not round.

From 1960 to 2020, the ocean surface warmed °C more than the water at 700 m. The surface warming was times the warming at 2,000 m.

2.

Which statement best describes Table 1?

A. The deepest water warmed the most, and the surface warmed the least.B. The water near the surface warmed, but the layers below 100 m cooled.C. Each layer warmed by about the same amount, close to 0.3 °C.D. The water warmed most near the surface, and less and less with depth.

3.

Rashid wonders whether heat from undersea volcanoes is what has been warming the ocean. What do the data in Table 1 suggest?

A. Volcanoes are a likely cause, because the water got warmer at five different depths.B. Most of the heat came in from above, because the warming was greatest at the top.C. Volcanoes are a likely cause, because the deep water warmed by 0.02 °C.D. Most of the heat came from the seafloor, because warm water sinks below cold water.

4.

Use Table 2. From the 1980s to the 2010s, the average August sea temperature off Marsh Point rose by °C.

Where greenhouse gases come from

Use paragraph 3 and the graph to answer questions 5–7. In the graph, Industry includes making cement and steel.

5.

Together, power and heat and transportation make up about % of the world's greenhouse gas emissions.

6.

Match each source in the graph to an activity that belongs to it.

7.

Underline each question that the graph alone could help answer.

Questions for the call

Use the passage, the tables and the graph to choose and write questions for Dr. Brandvold.

8.

Saoirse wants to know whether the warming off Marsh Point is part of a worldwide change or something that happens only near her town. Which question would help her most?

A. Which beach in Marsh Point has the warmest water in the summer?B. How many hurricanes came within 100 km of Marsh Point in the 2010s?C. Have sea temperatures in other parts of the world also risen since the 1980s?D. How warm will the sea off Marsh Point be in August of next year?

9.

Rashid wants a follow-up question that would test his undersea volcano idea directly. Which question is best?

A. Has the heat flowing up through the seafloor increased since 1960?B. How many undersea volcanoes are there in the Atlantic Ocean?C. Which undersea volcano is the closest one to Marsh Point?D. How hot is the lava that comes out of an undersea volcano?

10.

The class wants to know how much the largest source in the graph has added to the warming over time. Which question should they ask?

A. How many power plants are there in the state of Georgia this year?B. How much CO₂ have the world's power plants released each year since 1960?C. Do power plants use more water than factories do each year?D. Which fuel makes the most electricity in Marsh Point today?

11.

Rashid's uncle says, "The ocean is warming because of heat leaking out of undersea volcanoes, not because of anything people do." Do you agree? Write a claim, use data from Table 1 and the graph, and explain your reasoning. Then write one new testable question you would ask Dr. Brandvold, and name the data that would answer it.