I suppose that by now most people will understand – well, most people outside the White House – that one of the most serious problems that climate change will bring is unpredictability. How do you grow crops, if you don’t know when to plant them? Though of course this only a worry for those of us who actually eat food.

A few days back I was talking to someone who grew up on the banks of the Winterbourne. If you don’t know it, it’s the stream that runs (occasionally) between the town of Lewes, and its extramural suburb, Southover. As the name suggests, it is one of those streams – they are common, in chalk country – that is dry during the summer months. Rain falls on the Downs, percolates through the soft rock, and, when the water table rises to a sufficient height, the dry stream bed becomes a rushing torrent, carrying a season’s worth of litter and dead weeds before it, until the trash screens are jammed, and neighbouring houses are threatened with flooding. ” We’d go out when the water started to rise, “said my friend, “and carve a channel in the dry earth for it to trickle along….Look! Look! The stream is flowing! Every year, that was, November to March, regular as clockwork. ” But not last year. Dry all autumn; started running in late February. The South East of England suffers from serious water stress, and it’s getting worse.

Silly, isn’t it? Transition Town Lewes is looking at potential sites to create a rain garden in central Lewes, to show people how we can redesign our urban landscape to mitigate the effects of flash flooding, and here’s me worrying about a drought. Two sides of the same coin, though. That’s unpredictability for you.  Now, none of us can prevent climate change by ourselves. However, we can take responsibility for the small patch of ground we live on, and make sure the rain falling on it stays there, helping us grow fruit and veg to reduce our food miles, and doesn’t run straight off to flood someone else’s home. Buy a water butt, and use it to store rain from the roof. The overflow can go into a raised bed. Garden with conservation of water in mind – use plenty of mulch, don’t water in the heat of the day, choose the right varieties for your soil type, and don’t let weeds steal water from useful plants. (And then plant weeds elsewhere, because we need wildlife, too ).  Above all, learn to eat food in season. If you are eating asparagus in January, you are exploiting a landscape thousands of miles away, where the water scarcity is a damn sight worse than it is here.

None of this is urgent, of course. Still plenty of food in the shops, and we can fly in lettuce from North America if we run short. Might be as well to get the thing in hand, though, while it is merely advisable. And before it becomes necessary.

Jon Gunson, Transition Town Lewes.