Obviously, temperature in the Arctic has not risen to the balmy 12°C of the PETM. We can, however, use the general circulation models (GCMs), which you learned about at the beginning of the lesson, to estimate how much temperature will increase over the next century. Open the Climate Model learning tool and enter the last two topics to learn about where GCMs obtain their data. Then answer the following questions:

• What is the relationship between scenarios and pathways?
• How do the RCPs compare to each other?

Question: If anthropogenic greenhouse gas emissions continue on their current trajectory, what change in Arctic temperature is suggested by models?

Open the Visualizing Global Climate Change learning tool. This tool is a model that allows us to visualize the effects of GHG emissions upon the climate of the future. Choose RCP8.5 from the 'IPCC Scenario' drop down box. Now choose Temperature Anomaly from the 'Scene' drop down box to display the difference from the average temperature simulated in the next century. Locate Greenland on the map in the upper right corner. Note the temperature legend under the map. Hit play and watch the change in temperature difference as time progresses.

What does the model suggest Greenland's temperature will be in the year 2099?

By how much does the model suggest the temperature of Greenland will increase from 2006 to 2099?

Question: The temperature increases of the PETM were greatest at the poles. Open the Visualizing Global Climate Change learning tool again, hit play and compare the temperature change projected for an area somewhere in the tropics with that of Greenland. Why does temperature increase more quickly at the poles than at other places around the globe?