One morning session of the conference was devoted to the study of ice cores from both polar ice caps and high altitude glaciers in tropical latitudes. Because isotopes are preserved in ice for virtually limitless time, studying the composition of isotopes in the layers of ice drilled from these locations can provide a wealth of information about past climate. Some of these isotopes will be naturally radioactive because of the effect of cosmic rays on the so-called cosmogenic nuclides.
Movement of these nuclides are dependent on the rate of precipitation and atmospheric conditions, such as solar activity and ozone. By comparing the composition of these nuclides, which have been deposited over time in the ice, scientists can determine past climate patterns. In fact, scientists have reconstructed the history of carbon dioxide and methane concentration in the last 160 000 years by analyzing air bubbles trapped in the ice along with the isotopic composition of the ice itself. But part of the importance of studying the past, is using the data derived to predict future climate changes.
Some telling observations were presented at the Conference:
- The relationship between solar changes and climate can be observed in studies of polar ice
- With respect to climate changes and the warming trend over the last 50 years, greenhouse gas is the biggest factor
- There is also a correlation between solar activity and glacier retreats and changes in sea levels
- Glaciers at high altitudes in tropical latitudes are responding more to changes in temperature than to changes in precipitation
- Glaciers in many parts of the world are shrinking, both in mass and depth. The reason for this is complex and still the subject of much study.