Fires are an important agent of change in ecosystems around the world. Natural fires, such as those set by lightning strikes, have historically been so frequent that many plants have evolved in response to regional fire regimes. Many fire-adapted plants have reproductive strategies that actually use fire to stimulate their seeds to drop and/or sprout on newly burnt soil. Fires release the nutrients bound up in living vegetation, thus fertilizing new growth. By removing standing vegetation, fires make space for new vegetation to grow. Humans have used fire for thousands of years to clear land and prepare soil for crops. By changing the frequency, intensity, and patterns of fire around the world, human activity has changed, and continues to change, the face of our planet.
Satellite observations that detect and map fires provide important insight into the widespread nature of fire activity around the world. This visualization, which shows global satellite observations of fires from January 2001 to May 2005, emphasizes two regions where fire plays a dominant role in the landscape: Southern California and sub-Saharan Africa. The wildfires that roared through Southern California in autumn 2003 were particularly fast-burning and destructive because people have actively suppressed fires in the region to protect lives and property. In contrast, throughout sub-Saharan Africa, humans have used fires for thousands of years to clear land. These fires, small enough to clear individual fields, are lit seasonally to prepare the fields for planting. Over a period of 4 to 10 years, most of this landscape is cleared by agricultural burning.
Global fire data, provided by NASA, were gathered by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard both the Terra and Aqua satellites. Higher resolution images were drawn from the Thematic Mapper aboard Landsat 5 and the Enhanced Thematic Mapper Plus aboard Landsat 7.
Data Sources:
- MODIS Rapid Response System Global Fire Maps
http://rapidfire.sci.gsfc.nasa.gov/firemaps/
- Web Fire Mapper
http://maps.geog.umd.edu/