A time series consists of a set of data (almost always for a single variable — like temperature) at a set of times. The word “series” implies more than one — if we have taken many measurements, or computed many averages or transformations or whatever, and we know the times at which each applies, then we have a time series.
Temperature isn’t the only thing about the Earth that’s changing, right before our eyes, so of course we’ll look at lots of graphs of lots of data about Earth’s changes. But because we want to get scientific about it, we’ll do more than just look at graphs. We’ll take the data and pick it apart, try to understand what it’s made of and what it’s telling us. We’ll pick up a scalpel and slice into it, dissect it, looking for the information that’s there in the most succinct and compact possible form.
We’ll start with Carbon Dioxide. CO2.
In the last post we talked about trend and noise, how trend reflects climate change while noise doesn’t, and the need to separate the two in order to figure out how global temperature has warmed, not just fluctuated. Now, let’s talk about the patterns of global temperature change since 1880, and what might have been the causes. I say “causes” rather than “cause” because there are many things that can affect global temperature.
Global average temperature, at Earth’s surface, has been changing for some time. I’d like to discuss how it has changed over time, since 1880 when we’ve had enough data from enough places to get a reasonable estimate of what the global average temperature is.
But first we need to learn about what trend means and how we estimate it. That’s what part 1 is about. In the next post (part 2) I’ll discuss the actual trend history.
I’ve mentioned trend and fluctuation, signal and noise. They are crucial concepts in understanding what data tell us — and data is “my bag” (to use a phrase from my youth, long long ago).
In the last post we saw that the planet earth, globally averaged, has been heating up. But a very important thing to know, something a lot of people aren’t aware of, is that not all places are warming at the same rate.
Global warming is the “hottest” environmental issue of the day, quite possibly of all time. Yet it’s increasingly clear that most people, even those who are passionate about the issue (on both sides), aren’t very well-informed about what earth’s temperature is doing, what it has done in the past, and what it’s likely to do in the future. There’s quite a gap between what most people know about the subject, and what people need to know.
I’d like to discuss the history of earth’s temperature according to thermometers.
You, the young, are the hope of the world.
You can do so much more than we, the old. You will face so much more danger than we will. We were warned, decades ago, but we haven’t done enough, and today we are the biggest obstacle to making things better. You, the young, will pay a heavy price for the faults of us, the old.