Source: Proxy-Based Temperature Reconstructions (Mann et al., 2008)

Source: The HadCRUT4 Dataset (Morice et al., 2012)

The Little Ice Age in Europe (1300-1850)

Factors Causing Decadal Fluctuations in Earth's Mean Temperature

A graph displays the 5-year moving average of Northern Hemisphere temperature deviations from the 1961–1990 average, covering the years 1000 to 2019. The data shows relatively stable temperatures with several notable cold periods from approximately 1300 to 1850. After 1850, the trend shows a gradual increase, which becomes exceptionally steep and rapid in the 20th and 21st centuries. Based on an analysis of these described features, which of the following statements represents the most significant conclusion about the long-term temperature trend?

Analyzing Claims with Historical Data

A graph of Northern Hemisphere temperature deviations from the 1961–1990 average shows a 5-year moving average. The data indicates several exceptionally cold periods between 1300 and 1850. Based on this information, it is accurate to conclude that every single year within this 550-year span was colder than the 1961–1990 average.

An economic commentator states, 'As a country's average income grows significantly, its citizens will invariably choose to work fewer hours to enjoy more leisure time.' Based on the observed economic trends in developed countries during the latter half of the 20th century, which of the following best evaluates this statement?

Interpreting a Temperature Anomaly Graph

A graph shows Northern Hemisphere temperature deviations from the 1961–1990 average, from the year 1000 to 2019. Match each time period with the description that best characterizes the temperature trend during that era according to the graph.

Intertemporal Choice and Mutual Gains

Analyzing the Impact of a Baseline Shift

Evaluating the Impact of a Baseline Period on Data Interpretation

Official Caption for Figure 1.2b (Northern Hemisphere Temperatures)

A graph displaying long-term temperature data from the year 1000 to 2019 uses a 5-year moving average to represent the temperature deviations. What is the primary analytical purpose of using this statistical method instead of plotting the data for each individual year?

Factors Causing Short-Term Temperature Fluctuations

Source: Proxy-Based Temperature Reconstructions (Mann et al., 2008)

Source: The HadCRUT4 Dataset (Morice et al., 2012)

A graph displays two trends from 1750 to 2019. The first trend, representing the atmospheric concentration of carbon dioxide, is relatively stable until the mid-19th century, after which it begins to rise, with the rate of increase accelerating sharply in the 20th century. The second trend, representing the average temperature in the Northern Hemisphere, shows a similar pattern: relative stability for the first century, followed by a consistent and increasingly rapid upward trend. Based on the patterns described, which of the following statements provides the most accurate analysis of the relationship between the two variables?

Evaluating a Policy Conclusion on Climate Data

Consider a graph that plots two variables from 1750 to 2019: (1) the global atmospheric concentration of carbon dioxide and (2) the average temperature for the Northern Hemisphere. A policy analyst makes the following claim based solely on this graph: 'This graph provides definitive proof that the average global temperature has risen as a direct result of the increase in atmospheric carbon dioxide.' Is the analyst's claim a fully accurate and justified conclusion based only on the information described?

Analysis of Historical Climate and CO2 Data

Critiquing a Climate Change Argument

A graph displays two trends from 1750 to 2019: the global atmospheric concentration of carbon dioxide and the average temperature for the Northern Hemisphere. Both variables are relatively stable until the mid-19th century, after which they begin to rise at an accelerating rate. Match each analytical term below to its correct interpretation based on this graph.

Critiquing a Conclusion from Graphical Data

A graph from 1750-2019 shows that as the atmospheric concentration of carbon dioxide increased, so did the average temperature in the Northern Hemisphere, with both trends accelerating over time. Imagine a new global policy is enacted that successfully reduces the rate of increase of atmospheric CO2 to half of what it was in the final years of the graph. Based on the relationship shown, what is the most likely immediate impact on the total atmospheric concentration of CO2?

A graph shows that from 1750 to 2019, the total atmospheric concentration (stock) of carbon dioxide and average temperatures have risen together, with the rise accelerating over time. Based on the underlying principle that the stock determines temperature, if the annual addition (flow) of CO2 into the atmosphere were to suddenly drop to zero, the total atmospheric stock of CO2 would also immediately begin to fall, causing temperatures to quickly decline.

Evaluating a Local Climate Policy Proposal