Climate change: a creeping catastrophe.

Q: People often blame unseasonal weather on climate change. Could you please explain the difference between weather and climate? A: Weather is what we see hourto-hour and day-to-day, and weather forecasts can tell us if it will rain, say, tomorrow afternoon, but because the weather is innately chaotic, forecasts for longer than 10 days are extremely poor. Climate is different. It is an average of the weather, usually taken over periods of 10 to 30 years, and it can tell us things like what the average dayand night-time temperatures are likely to be for any month and the average precipitation for that month. That is because there are elements of the climate system that are not chaotic; indeed we all know that winter follows summer (which means we are making a climate forecast). But climate forecasts cannot tell us if it will rain tomorrow, only what the monthly probabilities of this are.