Most people quite rightly respond by simply getting on with the business of their day. Indeed the answer may well be to focus on the small - even mundane - things that we can do to make this planet a better place.
This thought came to mind on Wednesday morning when I was called by BBC Radio 5 Live's breakfast programme be interviewed about ... no, not the economic abyss ... no, not the political turmoil in the US ... but plastic shopping bags.
The story was Sainsbury's decision to start 'hiding' plastic bags from shoppers from 1 October, in the hope that they would use less of them.
'Is this a good PR move by Sainsbury's?' asked the presenter Shelagh Fogarty.
My argument was that, yes, any move to cut down on our use of plastic bags - billions of which end up clogging landfill sites - must be a good thing, but it was hardly the boldest initiative ever.
For a year now Marks & Spencer has stopped giving plastic bags away, making consumers buy them if they forget to bring their own food shopping bags.
My suggestion that retailers should take the lead and begin to make the use of disposable bags 'socially unacceptable' was greeted by Fogarty as 'controversial'.
But we should probably put this in perspective. It is only a couple of decades ago that our grandparents always took their own bags to the shops. Equally, in the US most shoppers use paper bags instead, which are often biodegradable.
The big retailers have serious reputation issues in the UK. Not least accusations of unfairly dominating the high street and screwing down suppliers. So surely the environment is one area where they could take the lead and actually be a force for good?
Meanwhile, the challenge for consumers is to stop fretting about toxic derivatives and to remember to take our own bag to the shops.