Are you prepared to drive within the speed limit? Are you prepared to put on another layer instead of turning up your heating? If you answered "yes" and "yes" then please write to your MP and to Gordon Brown asking them to “up” the target for CO2 emissions from 60% to 80%.

A new report compiled by the Institute for Public Policy Research (ippr), WWF and the RSPB lays out the science showing that 80% cuts by 2050 will not cripple our economy, will not sacrifice wildlife or fragile environments but will stave off catastrophic climate change brought about by an otherwise likely 2 degree Celsius rise in temperatures.

If the UK Government is serious about leading the way on tackling climate change then we'll all have to play a part. It's a collective problem that requires a solution longer than a political party's term of office. Politicians are reluctant to commit to something they consider would make them unpopular because they'll lose support. Hearteningly, a BBC survey of 22,000 people worldwide found four out of five people are prepared to change their lifestyles because of climate change. Go on Gordon, up it to 80%.

Agatha Christie's play The Unexpected Guest was on at the Hackney Empire the other night and it ends leaving you guessing who the killer is. She wrote it in such a way that each theory you're presented with is as compelling as the next. It's where we amateur sleuths are given just enough evidence to convince us of a character's guilt before a second raft of evidence is produced to clearly show that another character is to blame. Of course, by the end of the performance, we all had our theories and stuck to them.

Perceptions are tricky things and Christie played on this brilliantly in her stories. Even when presented with scientific fact it can be difficult to shirk off assertions that become beliefs, which through repetition become common "facts".

And so it is with many birds. Some have been demonised but, unlike Christie's characters, they do not have ulterior motives. They do not act out of jealousy or anger; their actions are based on needs set by evolution.  I left the Theatre thinking of the many voices I've heard at recent events quick to condemn the magpie or the sparrowhawk for falling garden bird numbers.

Christie would have looked deeper and found layer upon layer of reason for the sad decline of our garden birds. Yes, maybe predation does play a part in the tale, but there are other suspects that need interrogation before we condemn. In-fill of back gardens for housing; loss of front gardens for car parking; loss of Brownfield land for development; the trend for decking and low-maintenance gardens; air pollution; climate change, oh, and my fondness for malted milk biscuits. The complexity of our lives is affecting the land we share with each other and with nature.

There are simple things you and I can do to limit this impact, but by far the best is to lead by example. So, I'm asking you to join me by signing-up for Homes for Wildlife. By registering, we'll show how individual actions can collectively make a huge impact on wildlife and improve your wellbeing and outdoor space at the same time.

Were she alive today, I'm sure Agatha would agree. As far as climate change is concerned the deed is done, so forget whodunnit, or even whydunnit, let's look at how we can un-dunnit.