Climate change is an existential threat, so are civil disobedience and direct action the only way to save the planet? And is a global carbon tax the best tool to do the job?

Justin Rowlatt speaks to protestors from the new and militant environmentalist movement Extinction Rebellion as they occupy the UK's Department of Energy building in protest at their government's alleged failure to tackle global warming. He also speaks to Ben Stewart of the 49-year-old campaign group Greenpeace, who have themselves been targeted by their new rivals for not being radical enough.

But what policy change should they be calling for? Professor Bill Nordhaus of Yale University received this year's Nobel Prize for Economics for his work on economic models for how government's might go about taxing carbon dioxide emissions. But why does he think that so few governments are implementing it?

Producer: Laurence Knight

(Picture: Extinction Rebellion activists occupying the UK Department of Energy in London; Credit: Roger Harrabin/BBC)

Does increasing the number of women on a company's board boost its financial performance? It's a popular narrative, but Manuela Saragosa speaks to Professor Renee B Adams of Said Business School at Oxford University, who claims there is no evidence to support it. And she asks Gay Collins of campaigning group the 30% Club whether it even matters.

Plus, how do you tell a male colleague that he's wrong without hurting his feelings? Or interact with a male employee without threatening his ego? Comedian Sarah Cooper has some tongue-in-cheek tips for the aspiring female executive.

(Picture: Young businessman being disciplined by female boss; Credit: LukaTDB/Getty Images)

As university tuition fees rise and rise, young female students are flocking onto online sugar dating platforms to find wealthy older men who can foot the bill. But where is the line between sugar babies and escorts - or indeed prostitution?

Manuela Saragosa speaks to the founder of one such dating platform. Brandon Wade is founder and chief executive of seeking.com, which claims 10 million members worldwide. And she asks Kavita Nayar, who is researching computer-mediated intimacy and erotic labour at the University of Massachusetts-Amherst, whether these young women are being exploited, or liberated.

Producer: Laurence Knight

(Picture: Young woman with an older man bearing a gift; Credit: Stockbyte/Getty Images)

Engineers showcase new technologies to help women return to work after maternity leave - but why is the engineering profession itself so male-dominated? Jane Wakefield attends a breast pump hackathon at MIT, speaking to businesses venture capitalists and campaigners such as Catherine D'Ignazio from Make The Breast Pump Not Suck. Jane also hears from engineers Emma Booth of Black & Veatch and Isobel Byrne Hill of ARUP about their experiences of returning to a very male-dominated industry after the birth of their own children, and the importance of networks such as The Women's Engineering Society. This programme was first broadcast on 19 July 2018.

(Picture: Woman holds up smart breast pumps; Credit: Frederic J. Brown/AFP/Getty Images)

Half of the world's population don't access the internet, and they're missing out on economic and social benefits says Dhanaraj Thakur, research director at the Web Foundation. Satellites might provide the solution to reaching people in remote areas according to Jason Knapp from the company Viasat and Larry Smarr from the University of Southern California. Dudu Mkhwanazi, CEO of Project Isizwe, describes the benefits of access for poor townships in South Africa.

(Photo: Internet users in the Ivory Coast, Credit: Getty Images)

The US unleashed what it calls its "toughest ever" sanctions against Iran. The Trump administration reinstated all sanctions removed under the 2015 nuclear deal, targeting both Iran and states that trade with it. They will hit oil exports, shipping and banks - all core parts of the economy.

But what difference will they actually make? Ed Butler hears from Professor Jeffrey Sachs of Columbia University, an outspoken policy advocate who thinks Trump's America First policies are endangering the very status of the dollar as the world's chosen reserve currency.

And to explain how a reserve currency works, Ed hears from Barry Eichengreen, a well-known currency expert and professor of economics at Berkeley in California. And the programme considers whether China's renminbi, or the euro, could ever take over from the mighty dollar.

Producer: Laurence Knight

(Picture: An Iranian protester burns a dollar banknote; Credit: Majid Saeedi/Getty Images)

How is America's industrial heartland faring two years into the Trump presidency? Fergus Nicoll visits the port of Duluth in the state of Minnesota and asks farmers, shippers and miners how the US-China trade spat has affected them.

Programme features interviews with Deborah DeLuca, executive director of the Duluth Seaway Port Authority; Kelsey Johnson, president of the Iron Mining Association of Minnesota; Randy Abernathy, owner of Industrial Weldors & Machinists Inc; and farmers Matt and Sara Weik, and Brad Hovel.

(Picture: Ship being loaded with iron ore at dock in Minnesota; Credit: PhilAugustavo/Getty Images)

As US health insurers ask customers to wear fitness trackers, are they opening a Pandora's Box of ethical dilemmas and business threats?

Ed Butler speaks to Brooks Tingle, chief executive of insurer John Hancock, which has been pioneering the controversial policy of rewarding customers willing to demonstrate that they exercise more. But Dr Michael Kurisu, director of the UCSD Center for Integrative Medicine in San Diego, asks what happens to those customers who refuse to participate? Plus the Financial Times' Undercover Economist, Tim Harford, talks us through the hazards and adversities of the insurance business, and why more information could obviate the purpose of insurance altogether.

(Picture: Young man checking his fitness tracker; Credit: kali9/Getty Images)

A caravan of migrants heading to the US-Mexico border has sparked more debate around immigration. Manuela Saragosa speaks to Reihan Salam, executive editor of the conservative magazine National Review, who argues that America's immigration policy has to move with the times. Aviva Chomsky, professor of history at Salem State University in Massachusetts, says the narrative of the American Dream has never been quite what it seems.

(Photo: Honduran migrants heading to the US border, Credit: Getty Images)

Brazil's new president Jair Bolsonaro says he doesn't know anything about the economy, so he's delegated economic reforms to a man called Paulo Guedes. Who is he? We ask the BBC's Daniel Gallas in Sao Paulo and speak to Gabriel Ulyssea, Brazilian economist and associate professor in development economics at Oxford University. And Chilean journalist Carola Fuentes tells us the story of the "Chicago Boys" - the free market economists who transformed Chile's economy under military dictatorship.

(Photo: Supporters of Jair Bolsonaro celebrate in Brasilia, Credit: Getty Images)

More than $4bn has already been raised by candidates running in the midterm elections in the United States. Ed Butler speaks to Shelia Krumholz, executive director of the Center for Responsive Politics and Charles Myers, chairman of Signum Global Advisors, on how Wall Street is giving more money to the Democrats this year. Michael Whitney from The Intercept describes Beto O'Rourke's record-breaking fundraising in Texas. And Mike Franz, co-director of the Wesleyan Media Project, discusses whether spending big on your campaign really matters.

(Photo: Stickers made available to voters in Iowa, Credit; Getty Images)

Thousands of paintings and antiques stolen by the Nazis and others remain in circulation on the art market, but just occasionally one gets returned to its rightful owner.

Manuela Saragosa speaks to two grateful beneficiaries. Penny Ritchie Calder is a warden at St Olave's church in London, which recently regained the 17th century statue of noted botanist and congregant Dr Peter Turner, while Sylvie Sulitzer got back a Renoir painting that belonged to her art dealer grandfather, in both cases some 70 years after they were stolen.

Professional art detective Chris Marinello of Art Recovery International guides us through the murky world of stolen artwork, while Lucian Simmons of the global auction house Sotheby's explains what the restitution department he heads is doing to identify and recover these items.

Producer: Laurence Knight

(Picture: Sylvie Sulitzer poses with the recovered Renoir painting "Two Women in a Garden" in New York; Credit: Spencer Platt/Getty Images)