Using Graph Analysis to Document Climate Change

Using Graph Analysis to Document Climate Change

By Julianna Bellini

Social Studies teachers are expected to help students develop reading and analytical skills and promote written, oral, and numeric literacy. Including graphs like these in a lesson on the impact of climate change addresses both analytical skills and numeric literacy.

Graph #1: Global Average Surface Temperature (1885–2025)

Source: https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature

This graph shows changes in Earth’s global average surface temperature using temperature anomalies in °C. A temperature anomaly is how much the temperature is above or below a reference “normal” period (1850-1900), rather than the actual temperature. Temperatures stay fairly stable in the late 19th and early 20th centuries, then rise noticeably from the mid-1900s, with the fastest warming in recent decades. This trend reflects the rise in greenhouse gases from human activities, especially burning fossil fuels, which trap heat in the atmosphere.

Questions

1. What does the horizontal x-axis represent?

2. What does the vertical y-axis represent?

3. At what point on this graph did global average temperature start to change?

4. What is the direction of this change?

5. What is the cause of this change?

Graph #2: Global Sea Level Average (1885–2025)

Source: https://www.climate.gov/news-features/understanding-climate/climate-change-global-sea-level

This graph shows changes in global average sea level from 1885 to 2025. Sea level is measured in centimeters compared to a long term baseline, so positive values mean higher than average seas. Over this period, sea level remained relatively low and stable in the late 19th and early 20th centuries, then began a steady rise in the mid‐1900s. The rise accelerates in recent decades due to warming temperatures, which cause ocean water to expand and ice on land to melt. This long‐term increase in sea level is consistent with global warming driven by rising greenhouse gas concentrations.

Questions

1. What does the horizontal x-axis represent?

2. What does the vertical y-axis represent?

3. When did sea levels begin to rise?

4. When did sea level rise accelerate?

5. What is the cause of this change?

Graph #3: Ocean Heat Content (1955–2024)

Source: https://www.climate.gov/news-features/understanding-climate/climate-change-ocean-heat-content

This graph shows changes in the amount of heat stored in the world’s oceans from 1955 to 2024. Ocean heat content is measured in joules, which are units of energy; the same unit scientists use to compare energy in different parts of the climate system. When greenhouse gases trap heat in the atmosphere, more than 90% of that excess energy goes into the oceans instead of staying in the air. Because water can store large amounts of energy with only small temperature changes, increases in ocean heat content clearly show the long‐term warming of the climate system. The graph shows that ocean heat content has risen steadily, reflecting continued heat absorption by the oceans as the planet warms.

Questions

1. What does the horizontal x-axis represent?

2. What does the vertical y-axis represent?

3. When did ocean heat content start to change?

4. What is the direction of the change?

5. What is the cause of this change?

Graph #4: Natural Disasters Reported (1955–2024)

Source: https://ourworldindata.org/grapher/number-of-natural-disaster-events

This graph shows the number of natural disaster events reported globally from 1955 to 2024. The data include disasters such as floods, storms, droughts, and wildfires that have been recorded in international disaster databases. The graph shows a clear upward trend in reported events over time. Some of this increase reflects better reporting and communication systems, especially in earlier decades.

Questions

1. What does the horizontal x-axis represent?

2. What does the vertical y-axis represent?

3. What is the trend in this graph?

4. What is the cause of this change?

Graph #5: CO2 Emissions (1885–2024)

Source: https://ourworldindata.org/co2-emissions

This graph shows global carbon (CO₂) emissions from 1885 to 2024, measured in gigatons of CO₂ per year (GtCO2/yr). CO₂ is the most abundant greenhouse gas emitted by human activities, mainly from burning fossil fuels such as coal, oil, and natural gas. The graph remains low and somewhat stable in the late 19th and early 20th centuries, then rises sharply throughout the 20th century as industrialization spread. Emissions accelerate particularly after World War II with increased reliance on fossil energy and continue to grow into the 21st century.

Questions

1. What does the horizontal x-axis represent?

2. What does the vertical y-axis represent?

3. When did carbon dioxide emissions start to change?

4. What is the direction of the change?

5. What is the cause of this change?

Graph #6: Maximum Arctic Sea Ice Extent (1980–2024)

Source: https://ourworldindata.org/grapher/arctic-sea-ice

This graph shows the annual maximum extent of Arctic sea ice from 1980 to 2024, measured in million square kilometers. Maximum sea ice extent refers to the largest area covered by sea ice each year, usually occurring in late winter. The graph illustrates a long term decline in the size of the Arctic’s winter ice cover, even though there is variability. This downward trend is linked to rising global temperatures, since warmer air and ocean conditions reduce the formation and persistence of sea ice.

Questions

1. What does the horizontal x-axis represent?

2. What does the vertical y-axis represent?

3. What is the trend with the annual maximum extent of Arctic sea ice?

4. What is the cause of this change?

Graph #7: Global Atmospheric Methane Concentrations (1984–2024)

Source: https://ourworldindata.org/grapher/global-methane-concentrations?time=earliest..20 25-09-15

This graph shows changes in the concentration of methane (CH₄) in Earth’s atmosphere from 1984 to 2024, measured in parts per billion (ppb). Methane is a powerful greenhouse gas (much more effective at trapping heat than CO₂ over short time periods) and comes from both natural sources (wetlands) and human activities (agriculture, fossil fuel production). The graph reveals a steady rise in atmospheric methane over the time period, with especially notable increases in recent years. Rising methane contributes to enhanced greenhouse warming and amplifies climate change alongside carbon dioxide.

Questions

1. What does the horizontal x-axis represent?

2. What does the vertical y-axis represent?

3. When did the concentration of methane in the Earth’s atmosphere start to change?

4. What is the direction of the change?

5. What is the cause of this change?

Graph #8: Ice Sheet Mass Balance in Antarctica (2002–2020)

Source: https://ourworldindata.org/grapher/ice-sheet-mass-balance

This graph shows the change in the mass balance of Antarctica’s ice sheets from 2002 to 2020, measured in gigatons per year (Gt/yr). Ice sheet mass balance represents the net gain or loss of ice (positive values mean ice is being added, and negative values mean ice is being lost.) The graph demonstrates that Antarctica has been losing ice overall during this period, with increasingly negative values over time. This ice loss contributes to global sea level rise because ice previously stored on land flows into the ocean. The moving toward more negative mass balance is consistent with warming ocean and air temperatures affecting ice stability.

Questions

1. What does the horizontal x-axis represent?

2. What does the vertical y-axis represent?

3. What is the trend in the mass balance of Antarctica’s ice sheets?

4. What is the cause of this change?