Hello and welcome to the Intelligence on Economist Radio. I'm your host, Jason Palmer.

Every weekday we provide a fresh perspective on the events shaping your world.

The red line on Chicago's metro system traverses a demographic as well as a geographic distance.

The journey from one stop to another might represent a sharp drop in life expectancy.

Our correspondent rides the rails to learn more about the city's inequality.

And you can't go anywhere in Turkey without being offered a glass, not a cup of tea.

Now there's a government-sponsored push to go organic and it's not clear whether Turkish

tea drinkers are willing to pay up.

But first, in these early days of the new year, we take a step away from the news to look at a necessary

front in the fight against climate change. The science of what needs to be done to tackle climate

change is well known. Lower the amount of gases such as carbon dioxide in the environment that are

warming the planet. But the practice of it has proven to be a thornier problem.

As so many times before, at the UN's annual climate meeting last month in Madrid,

governments struggled to find solutions that were seen as equitable for all countries.

While the headlines remain on reducing emissions, that almost certainly won't be enough to keep

the world from some of the worst effects of climate change. So if merely reducing the slope of

the emissions curve won't suffice, engineers are going to have to figure out how to reverse it.

Negative carbon dioxide emissions means rather than putting CO2 or another greenhouse gas into the

atmosphere, you remove it from the atmosphere. Catrine break is the economist's environment editor.

It's almost certain at this point that we will not be able to cut emissions fast enough

to avoid 1.5 to 2 degrees of global warming. And as a result of that, we are going to,

in addition to cutting emissions, we are going to have to actually remove carbon dioxide from

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