Tearfund on: Global impact

I received a letter this week from Tearfund (who I used to work for) and it began with the launch of a new initiative My Global Impact complete with its own carbon calculator (for the perils of those, see this post over at Make Wealth History). Anyway I was struck by this comment in the opening paragraph from Matthew Frost the chief exec of Tearfund.

"Love does no harm to its neighbour, says Paul in the book of Romans, yet accidental damage from our high consumption lifestyles is harming our poorer neighbours who are facing unpredictable rains and increased droughts and floods."

Here's a question for you, if I accept the link that Tearfund and others make, that our lifestyles in the west are unsustainable and are contributing to climate change that affects the poor the most, then if I know all that and do not change, can I still call that an accident? Even if it is an accident ('I didn't mean to run them over Officer') we do still remain liable. Doing nothing will soon become unacceptable...