Of all known planets, only ours has the ingredients essential for fire: oxygen, plants to grow fuel, and lightning to ignite the two into flames.

Lightning is Nature's fire starter. Worldwide as many as 100 lightning discharges may occur per second, totalling more than eight million every day.

Forests need fire for renewal: to remove clutter and promote growth, to trigger reproduction, to destroy pests, and to help recycle nutrients.

Some species are dependent upon fire. There are beetles, for instance, that can only reproduce under the bark of burned trees, which built-in infrared sensors help them find.

Human beings are the fire species, the only creatures that can create and harness fires.

In recorded history, there have never been people who did not have fire.

In the cave paintings of Lascaux, paleolithic painters re-created the landscapes they knew by torchlight, with red ocher and black manganese dioxide prepared over flame.

Some scientists estimate that, before the arrival of Europeans, 100 million acres of the North American continent burned annually. The fires were set by lightning or by Native Americans to trap animals, help grow crops, or drive out enemies.

Enormous fires still occur today. In 1987, over 25 million acres of forest burned near Russia's border with China, but the Soviet government refused to acknowledge the event. Officially, the world's largest wildfire in five decades did not exist.

A year later, nearly half of Yellowstone National Park went up in flames. The government spent $130 million to control the fires—in vain. Only autumn snows finally ended the fire danger, after 1.4 million acres had burned.

Human-caused fires can also be enormous. In 1991, the retreating Iraqi army set over 700 Kuwaiti oil wells on fire, sending smoke plumes 10,000 feet into the air. A war fought for control of fossil fuels thus saw the fuels themselves become the ultimate weapon.

At the peak of the 2000 U.S. wildfire season, one of the most destructive in memory, 500 new fires were reported on some days.

On the peak day, August 29th, 28,462 firefighters, 1,249 fire engines, 226 helicopters, and 42 air tankers battled blazes covering 1.6 million acres.

Those fires featured 84 "large" fires, each over 100 acres in size, including several in the tens of thousands of acres.

By the end of the season, 18,417 lightning-caused fires and 104,410 human-caused fires had scorched a total of 8.4 million acres around the country.

All told, wildfires that year claimed 861 structures.

Wildfire, which can reach speeds of up to 15 mph, also kills people that it outpaces.

A simple, terrifying fact accounts for many firefighter fatalities: Going uphill, fires move faster, people move slower.

Today, we are more dependent on fire than ever. Every time we switch on a light, we harness fire's power, and fossil-fuel fire enables us to run our cars, our computers, our modern world.

Scientists are now wrestling with new questions raised by fossil fuel burning: What is the relation between fire and global warming? Are the greenhouse gases emitted by industrial fires around the globe different from those released by major wildfires like the Indonesian rainforest burn of 1997, which blanketed Southeast Asia with dense smoke?