大象传媒

Have you ever presented your loved one with a lump of carbon? If so, I only hope it sparkled and was wrapped in gold rather than black and sooty. It greatly enhances your chances of marriage. It is our love or carbon in all it's forms - from diamond to coal - that we explore in this week's show.

And it's a deep and lasting relationship. Carbon generates much of our electricity; helps fuel our cars, and even puts the lead in our pencils (it never was lead, but graphite). Oh, and it also happens to be a key element in humans. We literally couldn't live without it.

James Smith, the boss of oil giant Shell UK tells us why he thinks the price of carbon is too low, and argues that oil production will soon hit it's peak. "I think we're going towards the point in the next 10 or 15 years were we will see plateau oil. At the moment, oil production around the world is 85 million barrels a day. I think it's unlikely we'll get oil production of over 100 million barrels a day because the easy oil has now been found." With global energy demand set to double, change is coming believes the oil boss.

We also investigate illegal diamond mining in Venezuela, and a Beijing taxi driver responds to the London cabbie we spoke to earlier in the series who suggested it was pointless tackling climate change while China was building new power stations every day.

Plus, a columnist from America rallies against what he sees as hypocritic environmentalists who surround him whenever he goes to dinner parties.

As ever, tune in (or download), have a listen and tell us what you agree or disagree with. Then let us know, contact Mike and the One Planet team at oneplanet@bbc.com. You can also find us on Facebook if you're a fan - the link's below.