Sandeep Bathala and Carmen BarrosoJoin a Grist live chat on population issues on Monday, Oct. 31, at 1:00 p.m. Eastern / 10:00 a.m. Pacific, marking the occasion of the world population hitting 7 billion. We’ll have two experts on hand to answer your questions: Sandeep Bathala of the Woodrow Wilson International Center for Scholars, formerly director of the Sierra Club’s population program; and Carmen Barroso, director of International Planned Parenthood Federation, Western Hemisphere Region. The chat will be moderated by Grist Senior Editor and Queen of Pop(ulation) Lisa Hymas. Ask questions in the box below, or tweet your questions to @grist.
Bone up on population by checking out our 7 billion comic, our population facts and figures, and the rest of our special series on the topic.

The numbers behind the numbers: Meet your 7 billion neighbors
What you don’t know about women, climate change, and population [VIDEO]
7 billion in 7 minutes: Science magazine explains it all [VIDEO]
I am the population problem
Will my baby be the 7 billionth?
Come and get your Endangered Species Condoms
Population math explained: Growth rate is down, total is up [VIDEO]
Women, population, and the age of the ‘Black Swan’
Women’s rights are key to slowing population growth
How environmental and women’s groups can work together
International family planning saves lives. So why is the GOP cutting it?
Where’s the contraceptive for overconsumption? [VIDEO]
Will more attention to climate change bring back ‘population control’?
7 billion? It's time to talk
We can feed 10 billion of us, study finds — but it won’t be easy
An indigenous take on family planning and population
Remember when Americans used to care about population? [VIDEO]
Talking to my son about sex and sustainability
Are Americans more worried about population than climate change?
What if population grows faster than the experts project?
Who you gonna call? GrowthBusters! [VIDEO]
7 billion, unpacked — a comic
Stop the ‘man swarm,’ save the wild world
Is the environmental crisis caused by the 7 billion or the 1%?
Three’s a crowd: Is it unethical to have more than two kids?
Live chat on population 7 billion — ask your questions and have your say-so
Climate change is our biggest challenge, says McKibben — but we need to keep working on population
How to feed 7 billion of us without ruining the planet