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