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May 15, 2016

Makeover Monday: How warm is Earth becoming?


There was a lot of chatter on Twitter last week about this terrific visualisation by Ed Hawkins:

The beauty of this visualisation is in the animation. However, without the animation, it kind of fails to tell the story. Let’s dig a bit deeper.

What works well?

  • There is a clear title.
  • The background circles provide helpful context.
  • Including the month labels makes it easier to understand what you’re seeing.
  • The year in the middle helps tell the story.
  • The animation is compelling.
  • It has a nice color scheme that works well on a black background.

What could be improved?

  • While the title is clear, it could be more eye-catching, like a news headline.
  • If you see this as a static image, you lose the sense of change.
  • You can’t compare any time periods. All you know is 2016 is the warmest.
  • There’s no explanation about what the numbers represent. Though I do see in the Twitter post a link to additional information.
  • The color scale has nothing to do with the temperature change, which I assumed it did until I read hte additional information. The colors actually represent the years. That doesn’t add much value. I think coloring by the temperature change would be more impactful.

So, this data set is actually incredibly simple. All we have is one record per month, the temperature, and the confidence intervals.

The first thing I wanted to do was rebuild the radial chart. This wasn’t nearly as easy as I thought. This post by Jonathan Trajkovic was very helpful, but it wasn’t designed for months. I’ll record how I did made it for a future Tableau Tip Tuesday.

Click the image for the interactive version

This radial chart is basically the same as the original, however I can’t make it “play”on Tableau Public and I also changed the color to be the median temperature difference. Really, I only built this to see if I could. It’s not any more useful than the original.

Next, I took the radial chart and flattened it out.

Click the image for the interactive version

This doesn’t make the understanding all that much easier because I can’t tell which years are which. Maybe I should switch the color legend back to years?

Click the image for the interactive version

Oh wow! What a difference! Now I can easily see the distinction between the older and more recent years. I think this is much, much better than the original, especially in static format. I wanted to keep iterating though.

Whenever I’m working with time-based data, I like to build either calendar heatmaps or heatmaps by year and month. Here’s what this data set looks like as a heatmap:

Click the image for the interactive version

The heatmap makes the series of lines even easier to understand. It’s super easy to see the gradual temperature change over time. This is pretty compelling, yet I wanted to keep going. Was there a better way to tell the story?

Next I looked at the 10-year average, that is, a 120 month moving average of the median temperature change. I then overlaid the confidence intervals.

Click the image for the interactive version

Lastly, I took the 10-year moving average view and replaced the monthly confidence intervals for the monthly values while keeping the overall 10-year average. This is my submission for Makeover Monday. In this view, I like how I can see the drastic monthly fluctuations but still have the overall context. Including a reference line at zero helps emphasize the dramatic change since about 1984.

I also included a strip plot under the graph that shows the average median temperature difference for the entire year. This brings back a bit of the heatmap view above.

In the end, another fun week with a simple data set that provides lots and lots of options. Which one do you like best?

UPDATE: This week has been a fascinating exercise in iterating. That’s the beauty of Tableau. I can get another idea and build it quickly. After seeing some of the submission for this week, I thought a jitter plot might work well. Thoughts?

Click the image for the interactive version


  1. Hi Andy,
    Really enjoyed seeing all the different versions. I initially also started with a horizontal version here:
    which didn't get much attention, but the spiral did for some reason!

    1. Thanks for following along this week Ed and for inspiring so many of us. This was by far my favorite week so far. I hadn't seen this version but glad to see we think alike. I think the spiral got so much attention because of the animation of it. It tells a compelling story animated but if it were just static it wouldn't make as much sense. Congrats on your amazing work!!

  2. My entry to the same theme