Watch this short video from the “Cosmos” series for a visual representation of weather vs. climate.
OK, so if we scientists are so good at making these dire long-term predictions about the climate, how come we’re so lousy about predicting the weather? Besides, for this year we had a colder winter in my town. For all us scientists know, we could be in for global cooling. Here’s the difference between weather and climate. Weather is what the atmosphere does in the short-term – hour to hour, day to day. Weather is chaotic which means that even a microscopic disturbance can lead to large-scale changes. That’s why those 10-day weather forecasts are useless. A butterfly flaps its wings in Bali, and six weeks later your outdoor wedding in Maine is ruined. Climate is the long-term average of weather over a number of years. It’s shaped by global forces that alter the energy balance in the atmosphere such as changes in the Sun, tilt of the Earth’s axis, the amount of sunlight the Earth reflects back to space, and the concentration of greenhouse gases in the air. A change in any of them affects the climate in ways that are broadly predictable. My friend’s meandering represents the short-term fluctuations – that’s weather. It’s almost impossible to predict what will attract his interest next but not hard to know what the range of his meandering will be because I’m holding him on a leash. We can’t observe climate directly. All we see is the weather. The average weather over the course of years reveals a pattern. I represent that long-term trend which is climate. Keep you eye on the man, not the dog. Weather is hard to predict, like my friend here, but climate is predictable. Climate has changed many times in the long history of the Earth but always in response to a global force. The strongest force driving climate change right now is the increasing co2 from the burning of fossil fuels which is trapping more heat from the Sun. All that additional energy has to go somewhere. Some of it warms the air most of it ends up in the oceans. All over the world the oceans are getting warm.