BBC: Climate change: Are there too many people?

We're talking about the environment in this programme, specifically climate change. Now, Sam, what do you think is the biggest cause of climate change?

An obvious answer would be that climate change is the result of carbon emmissions caused by humans. It's about people's carbon footprint- the measurement of how much carbon dioxide is produced by someone's everyday activities. 

That makes sense. But certainly some scientists, especially in the west, have been focusing on another issue: the increasing number of people in the world, something known as overpopulation. In this programme, we'll be discussing the controversial link between overpopulation and climate change. And as usual we'll be learning some new vocabulary, as well. 

Sounds good, Neil, but first I have a question for you. Over the last 100 years, within one lifetime, the world's population has soared. At the start of the 20th century, it was around one-and-a-half billion, but now many people are there in the world today? Is it: a)  seven billion   b)eight billion or c) nien billion?

I'll say around 8 billion people live on the planet today. 

OK, Neil, I'll reveal the answer later in the programme. Since climate change is caused by human activities, it seems common sense that fewer people would mean lower carbon emissions. But in fact the connection isn't so simple. Not everyone emits carbon equally, and people in the western world produce far more thant people in sub-Saharan Africa or Asia. 

Arvind Ravikumar is professor of climate policy at the University of Texas. He's made the surprising calculation that an extra two billion people born in low-consuming countries, would actually and very little to global carbon emissions. Here, Kate Lamble and Neal Razzell, presenters of BBC World Service programme, The Climat Qestion, discuss Professor Ravikumar's findings.

What he's saying is kind of astronishing, right? Two billion people is, to say the least, a lot. It's the combined population of Europe and Africa. 

He's crunched the numbers and found that an extra two billion low-income people as defined by the World Bank, these are people without cars, without electricity often, would see global emissions rise by just 1.6%.

Add two billion high-income earners- that's people with cars and power and all the mod cons, and Arvind reckons emissions would rise by more than 60%.(mod cons= modern conveniences)

So when it comes to climate change and population, where you were born matters. 

Professor Ravikumar made his discovery after crunching the numbers, an idiom meaning performing many mathematical calculations involving large amounts of data. 

He concluded that whereas two billion low-income people would increase carbon levels very little, two billion high-income people would increase it a lot That's becaue high-income populations have mod cons, which is short for 'modern conveniences': technology and machines like cars, fridges and air-conditioning that make life easier and more pleasant.