Environmental Engineering Reference
In-Depth Information
Source: NASA
Global Carbon Cycle
Oceans
Carbon dioxide reacts with water in a reversible reaction to form carbonic acid (H
2
CO
3
). As the carbon diox-
ide increases in the atmosphere, the ocean absorbs more carbon dioxide, and more carbonic acid is formed,
lowering the pH of seawater. This affects all the living organisms in the world's oceans, both plant and animal.
Temperature
Determining changes in the Earth's temperature is difficult because accurate temperature data only dates back
to about 1850. One way to measure historic air temperatures is to study ice cores. Ice core samples are often
collected on ice sheets in Antarctica, in Greenland, or on glaciers found in higher elevations. As ice forms, it
traps gases found in the atmosphere, allowing analysis of historic levels of atmospheric gases. Collected ice
core samples range from just a few years old, to as old as 800,000 years. Analysis of these samples shows that
historic increases in air temperature have averaged less than 2°C per 1,000 years. However, since the Industrial
Revolution, we've seen a dramatic increase in the concentration of greenhouse gases in the Earth's atmosphere.
