Контекст:

1. Nick Gowing, the BBC presenter: Den Esty is the reality checker, the challenger. In your book you warn about business and what you called not “brainwashing” or “white washing” but “green washing”.

2. Dan Esty is what we call our challenger. And then, you’ll be direct to the Yale Centre for Environment Law and Policy.
You used to work at the US Environmental Protection Agency, you have produced a new book “Green to Gold”, between the highlights to dilemmas – for many in business so just a bestseller at the moment. We gonna keep coming back to you as a kind of reality checker. We want to push and prove, and challenge if necessary, though.

BBC World : “The World Debate” (Debate on climate change)

reality checker - someone, who perform “reality check” – an occasion when you consider the facts of a situation, as opposed to what you would like or what you have imagined