Natural Climate Change & Carbon Cycle
- Over the past 2.6 million years global climates have fluctuated between interglacial (warm) and glacial (cold) periods
- Data from Antarctic ice core samples, show temperatures and carbon dioxide levels roughly match
- Higher temperatures are associated with high concentrations of carbon dioxide in the atmosphere
- The last 2.6 million years are the Quaternary period when there have been 60 cold periods and warmer interglacial periods
- The last ice age ended approximately 25,000 years ago
Ice core data: changes in temperature over the last 11,000 years
Mean Antarctic temperatures and atmospheric CO2 concentration over the past 200,000 years
- An increase in carbon dioxide (CO2) in the atmosphere leads to enhanced global warming and temperature increase
- Lower levels of CO2 reduce the effectiveness of the natural greenhouse effect
- Increasing carbon dioxide levels increase global temperatures
- However, a change in temperature can also affect the levels of carbon dioxide in the atmosphere due to melting of the permafrost releasing methane (positive feedback loop)