…On Global Warming, Climate and Weather.

Climate change is a long-term change in the statistical distribution of weather patterns over periods of time that range from decades to millions of years. It may be a change in the average weather conditions or a change in the distribution of weather events with respect to an average, for example, greater or fewer extreme weather events.

“If there is Global Warming why have we got so much snow this year?”
“They can’t predict the weather for next week, how do they expect us to believe they can predict the climate for the next century?”

Typical comments heard across the country and around the globe regarding global warming, climate and weather.

And, alas, each of them demonstrates a fundamental lack of understanding about the terms.

It is that lack of understanding which I want to reflect upon today; for as long as people continue to make statements based upon complete misunderstanding of the topics, we can not possibly hope to have any form of meaningful debate or discussion about the whole thing.

So are Global Warming and the recent snowy weather incompatible? Hardly, any more than occasional rain in the Sahara is incompatible with it being a desert. We still have winter each year (for the planet as a whole to warm up sufficiently to eliminate snowfall would require a massive and potentially fatal global temperature rise), naturally. And we still get occasional “extreme” winters. However, these days they happen less frequently than in the past, which is completely consistent with Global Warming. Extreme winters which once happened on average every 5 years or so, nowadays only occur around once every 20 years or so. That certainly sounds consistent with Global Warming, doesn’t it.

So please,let’s stop with the uneducated and, frankly, ignorant “It’s snowing; that proves there’s no Global Warming” claims so beloved of our media in particular – such claims are ill-informed, uneducated, ignorant and outright wrong.

Which leads to the whole climate versus weather issue.

Weather is the study of atmospheric conditions (air pressure, temperature, precipitation etc) in the short term (hours, days or even a few weeks at a push), whilst climate is the study of those over the long term (years, decades, centuries, millennia or even longer). Weather forecasts can be very specific whereas climate forecasts will be more general, providing overall indications of atmospheric conditions but without specific individual detailed forecasts. Thus, for example, a weather forecast might specify specific amounts of rain, speed and direction of wind, and detailed temperatures for a particular location, whereas climate forecast would be more along the lines of overall general changes in weather patterns and overall temperatures without necessarily specific details per location.

Due to the highly chaotic nature of the atmosphere, specific weather forecasts are only accurate for a few hours (or a few days if they are generalised); climate forecasts, on the other hand, by their nature can be accurate for much longer time spans. Weather forecast might indicate 5cm of snow tomorrow in a specific town, whereas climate forecast would indicate more snow in general over the next 100 years (these are given here as illustrative examples only, not specific forecasts!)

What’s the difference between climate and weather, and why can climate forecasts be given when “they” can’t even accurately forecast the weather for next week?

To illustrate this, let’s take a simple example.

Take a pan, filled with water. Place this pan on the stove and turn up the heat. What will happen? The water will get hotter and hotter, right? Good, you have just forecast the climate for the pan of water. However, look closely – a it heats up, bubbles of air form on the submerged surfaces and bubble their way up through the water to the surface. Again, you might forecast that as the water gets hotter, so more and more bubbles will develop and the water will get choppier as a result. Very good, you have now made your climate forecast even more accurate.

But tell me this – where and when exactly will each individual air bubble form? What path will it take? As you see one start to form you can make some very short range predictions about it, but you can’t forecast with any accuracy where and when they will form. Oops, your weather forecast is highly short term. Does this mean that because you can’ forecast when and where these bubbles will form and how they will rise to the surface, that I should now disregard your prediction for increased bubble activity and hotter water? I mean, if you can’t forecast when even a single bubble will form, how can you forecast that lots will?

And further consider this – if a bubble doesn’t appear at a particular spot, does that mean there’ll be no bubbles anywhere?

And there, dear readers, is the difference between climate and weather.

So snow in winter is not proof against global warming, weather and climate are NOT the same thing, and it is perfectly possible to have accurate climatic forecasts even thought weather forecasts may not be accurate for more than a few hours.

Please bear these in mind next time you hear someone coming out with the comments we started with here. And next time you see one of our beloved newspapers or news programmes coming out with them, consider that if they are peddling untruths on this topic then where else are they peddling untruths?