Global Climate Change: Research Explorer

Climate Records from the Vostok Ice Core Covering the Last 420,000 Years

This graph presents a view of the relationships between greenhouse gases and, temperature in Antarctica over a 420,000-year period. Although these measurements cannot prove what factors caused climate changes, these data do strongly suggest that atmospheric gas concentration and temperature are related.

The red line (at top) and the green line (second from top) show the concentration of the greenhouse gases carbon dioxide and methane over the last 420,000 years. The dark blue line (at the bottom) shows the average temperature at the same times, plotted as differences from today’s average temperature (represented by the 0^oC line). Deviations above the line represent periods when the average temperature was warmer than today’s temperature; deviations below the line are periods when the average temperature was colder than today’s. It’s immediately apparent that decreases in temperature are associated with decreases in the concentration of these two gases.

glossary terms

Click for definitions of words used on this page:

correlation
ice core
proxy data

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Climate Records from the Vostok Ice Core Covering the Last 420,000 Years - This graph shows the relationship between the greenhouse gases carbon dioxide (CO2) and methane (CH4) and the average Antarctic temperature over the past 420,000 years. These measurements were made from atmospheric samples taken from east Antarctica’s Vostok ice core. Source: National Ice Core Laboratory

questions about the data

Using ice cores to understand climate change requires that we know the age of different sections of the ice—but how accurately can the age of ice cores be measured?

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research connection

One of the most difficult problems with measuring long-term phenomena such as climate is that climate researchers have only been taking careful measurements for a period of decades, but a complete understanding of climate requires much longer-term records. Ice sheets and glaciers preserve samples of the atmosphere trapped in bubbles from the time when they formed. Drilling and removing sections of ancient ice allows those atmospheric samples to be measured. That’s why coring of ice is among the most valuable sources of prehistoric climate data.

related sites

• Ice Core Contributions to Global Change Research - Past successes and future directions.