Ecology, Climate and Human Activities Conspire to Set the World on Fire

Beginning of article

Earth is a fire planet. Ever since the first plants appeared--and provided fuel--more than 420 million years ago, fire has flourished in Earth's oxygenated atmosphere. Some scientists even think that long before humans, fire carved out entire landscapes, clearing dense forests to make way for grasslands.

In recent years, the fingers of flame have extended their reach over more of the Earth's surface. Wildfires are occurring more often and becoming more severe, a perplexing change in fire patterns that threatens to transform ecosystems, reduce biodiversity and even alter climate. To stamp out the flames, researchers have to understand why fire is spreading and figure out how to fight fire with science.

[ILLUSTRATION OMITTED]

Fire has many faces. It helps some ecosystems thrive but destroys others. It helps people clear land but can also destroy homes and take lives. Sometimes useful, sometimes destructive, fire is always unpredictable--and that makes it a difficult subject. "Understanding fire is a science, and until now, the science of fire hasn't been properly recognized," says ecologist David Bowman of the University of Tasmania in Hobart, Australia.

But now, researchers from different disciplines are beginning to investigate the science of fire. Some ecologists monitor forest fires burning today, using satellite images to discern how much forest is aflame and how severe the fires are. Other scientists track how forests regenerate after fires. And geologists reach into the past, using remnants of long-cooled forest fires for clues about how fire shaped the ancient Earth.

"Everyone in their respective fields had some knowledge about fire. But now we've got to come together to map out the role of fire in the Earth system," Bowman says.

The "Earth system" is the sum of the planet's physical, chemical, biological and social parts, processes and interactions. Fire can shape landscapes, shift climate and even change processes such as the carbon cycle--blazes have impacted the planet for eons. But now, people could be shifting the balance in a new direction.

Bowman and other fire experts reviewed recent fire research in the April 24 Science. The latest work illuminates the complicated role that fire plays on Earth and highlights the …