When our earliest ancestors first learned to manipulate perhaps the most powerful of natural forces by creating and harnessing fire, it set the human species on a trajectory towards global domination from which we, for better or worse, have yet to veer. What began as humble campfire flames flickering in the otherwise pitch-black, prehistoric night, now propels our combustion engines and powers our cities, lighting our houses and drowning out stars. But in as much as the flames of our ambitions burn in relation to the benefits of fire, the impact it has on our planet bends to the inverse -- and, as a newly released NASA animation shows, it never stops burning.
This visualization leads viewers on a narrated global tour of fire detections beginning in July 2002 and ending July 2011. The visualization also includes vegetation and snow cover data to show how fires respond to seasonal changes. The tour begins in Australia in 2002 by showing a network of massive grassland fires spreading across interior Australia as well as the greener Eucalyptus forests in the northern and eastern part of the continent. The tour then shifts to Asia where large numbers of agricultural fires are visible first in China in June 2004, then across a huge swath of Europe and western Russia in August, and then across India and Southeast Asia through the early part of 2005. It moves next to Africa, the continent that has more abundant burning than any other. MODIS observations have shown that some 70 percent of the world's fires occur in Africa alone. In what's a fairly average burning season, the visualization shows a huge outbreak of savanna fires during the dry season in Central Africa in July, August, and September of 2006, driven mainly by agricultural activities but also by the fact that the region experiences more lightning than anywhere else in the world. The tour shifts next to South America where a steady flickering of fire is visible across much of the Amazon rainforest with peaks of activity in September and November of 2009. Almost all of the fires in the Amazon are the direct result of human activity, including slash-and-burn agriculture, because the high moisture levels in the region prevent inhibit natural fires from occurring. It concludes in North America, a region where fires are comparatively rare. North American fires make up just 2 percent of the world's burned area each year. The fires that receive the most attention in the United States, the uncontrolled forest fires in the West, are less visible than the wave of agricultural fires prominent in the Southeast and along the Mississippi River Valley, but some of the large wildfires that struck Texas earlier this spring are visible.
While much is made of the enormous amount of carbon emissions released into the atmosphere from the 'contained' fires of motor vehicles and coal burning power plants, the smoke pollution generated by free-burning fires is no small matter. According to the National Center for Atmospheric Research, CO2 emissions from fires just in the US are equivalent to roughly 4 to 6% of anthropogenic emissions produced there, but in many parts of the world the former actually exceeds the latter.
In hopes of better understanding the impact fires are having on the global climate, NASA has been monitoring burns with Moderate Resolution Imaging Spectroradiometer, or MODIS, currently in place on two orbiting satellites. From 2002 to the present, researcher have been able to track fires from around the world -- and when presented as an animation, a pattern seems to emerge.
"What you see here is a very good representation of the satellite data Scientists to use Understand the global distribution of fires and to determine where and how fire distribution is responding to climate change and population growth," says NASA scientist Chris Justice.
To make matters worse, scientists predict that wildfires will become more common and harder to stop due to the droughts and higher temperatures related to global climate change -- a phenomenon exacerbated by the very wildfires it causes.
For a visual tour of fires isolated by continent, check out more videos at NASA/Goddard Space Flight Center Scientific Visualization Studio
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