Includes statistics on the physical, biological and chemical characteristics of the environment and their changes over time. These fundamental background conditions are strongly interrelated and determine the types, extent, condition and health of ecosystems. Many of these natural conditions change very slowly as a result of natural processes or human influence. Others may show immediate and dramatic effects. Importantly, changes in environmental conditions and quality are the result of the combined and cumulative impacts of natural and human processes. Connecting the changes to individual activities or events is therefore not a simple process.