The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite detected 148,946 fires in this image on August 23, 2010. The fires are outlined in red. Most of the fires are concentrated in Bolivia, where the governments of two states had declared a state of emergency because of widespread fires three days earlier. Scores of fires also burn in Brazil, Paraguay, and Argentina.
The fires cloak the heart of South America in gray-white smoke. Spreading north and south along the east side of the Andes Mountains, the smoke extends over the entire 2,500-kilometer length of the image. The smoke closed 28 of Bolivia’s 39 airports, reported CNN on August 19.
While some fires do occur naturally in Bolivia, most of these fires were probably set deliberately to clear land for crops or pasture. August is the height of the dry fire season in the region. In 2010, however, unusually dry weather and winds allowed many land management fires to expand into dangerous large wildfires.
In Bolivia, the dry season comes in winter, and coincides with cold temperatures. The winter of 2010 has been exceptionally cold. Water temperatures in rivers that normally average 15°C (59° F) during the day fell to as low as 4° C (39° F). The cold waters have been linked to massive die-offs of many fresh-water species. On August 27, 2010, the journal Nature reported the loss of about six million fish and thousands of alligators, turtles and river dolphins.
Cold can kill fish by reducing the oxygen content of water, as well as by direct effects on the physiology of fish, especially tropical species. Experts caution, however, that multiple causes, not just cold, likely play a role in die-offs as large and widespread as this one. Smoke can be a significant source of river pollution, and some scientists believe that the extreme fire season plays a role in this ecological disaster. Nature reports that studies are planned in this region to discover the multiple causes of the die-off.