While gardeners may worry about the effects of climate change on their flowers, shrubs, fruit and vegetables, Gordon Brown is more concerned about the wider implications to humanity.
The prime minister used the recent Major Economies Forum to speak of his fear that climate change could eventually have an effect greater than the two world wars and the Great Depression combined.
He said it is vital that world leaders work out a plan of action for reducing carbon emissions at the upcoming UN summit in Copenhagen this December.
The Labour leader has begun contributing to the UKs carbon emission reduction efforts by instructing Downing Street staff to grow a kitchen garden, but he hopes more widespread measures can be agreed in Denmark.
He explained there is no back-up plan for the planet and warned of potential catastrophe if something is not done soon.
"If we do not reach a deal at this time, let us be in no doubt – once the damage from unchecked emissions growth is done, no retrospective global agreement in some future period can undo that choice," Mr Brown said.