Looking at ice core data allows us to understand how the Earth's temperature has varied throughout history. Open the Climate Trends learning tool, which displays historical data from ice cores and other temperature proxies.

Question: To what extent has Earth's surface temperature varied throughout history?

After opening the learning tool, click on the bottom option called "Temperature." Note that the temperature records you see are not surface temperature values themselves; they are anomalies from the average surface temperature between 1960 and 1990.

Notice that the on the scale the range goes from -10°C and 3°C. Several of the peaks and drops cover greater than a 10°C span. Earth's average surface temperature has ranged widely throughout history.