TELLURIDE – The total number of people on the planet is expected to cross the 7 billion mark on Monday, October 31 according to the United Nations, and with that milestone, Telluride Mountainfilm’s Moving Mountains Symposium will focus on the key issue of population in 2012.

“We think this is the right theme for our next symposium, because it synthesizes so much of what the festival has covered the last several years with energy, water, food and extinction,” said Festival Director David Holbrooke. “The simple numbers are staggering – especially when you realize we were at 4 billion in 1974, and the U.N. believes that by 2050, the population will most likely double to 9 billion with some estimates as high as 11 billion. That’s a huge jump in 75 years, and we want to understand what this will mean for this planet, its people and other living creatures.”

In 1999, global population crossed the 6 billion mark, ending a century marked by falling prices (for oil, especially), an expanded food supply, and rising standards of living worldwide.

At the time, there was real concern that the population could fall below the replacement rate. As The Atlantic wrote, “Fifty years from now, the population will be declining with no end in sight.”

A dozen years later, according to a recent report from the Population Institute, “As we approach the 7 billion mark, world population is still growing, with no end in sight.”

We are also faced with rising food prices, peak oil, setbacks in reducing hunger and world poverty, and the increasingly ominous specter of global warming, which is causing rivers, lakes and glaciers to shrink, intensifying a dearth of arable land and water for a growing population.

There are potential solutions, and experts believe that one of the keys to stabilizing population is allowing women more control over their bodies and their pregnancies, particularly in the developing world. Increased availability of contraception will help, but there also needs to be a fundamental shift in the way women are educated and empowered in much of the world.

The most renowned expert on this subject is Stanford University professor Paul Ehrlich, author of The Population Bomb, who will attend the festival. Mountainfilm Program Director Emily Long said, “As we researched the subject of population, the name that came up time and again was Paul Ehrlich. I reached out to him and was thrilled he was available to come to Mountainfilm this year, as he is really the preeminent voice on this subject.”

Another guest will be groundbreaking environmentalist Dave Forman, founder of Earth First, who now runs the Rewilding Institute. Forman will talk about how 50,000 years ago, there were more tigers (not to mention blue whales, white rhinos and gorillas) than there were humans. One hundred years ago, there were more than 100,000 wild tigers in India alone – today, there is one tiger for every two million people, and that number isn’t likely to grow.

While population in some parts of the world is growing, other areas – like Europe – are not reaching replacement levels. If they keep their same birth rate, countries such as Spain, Italy and Germany will lose approximately 85 percent of their current population – unless those numbers are supplemented in their immigrant communities. Immigration, a controversial issue, will be examined in the symposium as well, since it is such an important component of population.

More than 200 million people live outside the country of their birth, a number that has doubled in the last 20 years. In the U.S. alone, some 36 million people legally immigrated to this country in the 20th century (add in the illegal immigrants, and you get 50 million).

Other issues relevant to this subject, including migration, refugees (climate refugees, in particular), economic growth and consumption will be on the agenda, as will films and art.