What could be improved?

• Using dotted lines indicates there are breaks in the timeline, but there aren't. Therefore, a solid line should be used.
• The labels on the ends of the lines hide the data.
• It could use an impactful title and subtitle. Though I suppose this is just a report, not analysis.

What I did

I created a map to ensure that the country names were correct. When I did this, I then saw that there were lots of aggregations of countries.  For some reason, the income level categories captured my attention so I filtered down to just those items.

The years 2015-2018 were include and didn't have any values. I filtered those out. There were years when no data was captured for some countries. I filtered those out.

I plotted the data as a line chart and created a calculation to show the change vs. the first year for each country. I noticed that there was a spike in CO₂ per capita in 1973 for high income countries. This reminded me of the oil crisis of 1973, but that wouldn't have anything to do with carbon emissions I wouldn't think.

That got me thinking about climate change in general. I entered "when did people start paying attention to climate change" into Google and the first search result was an article from National Geographic titled "Climate Change First Became News 30 Years Ago. Why Haven’t We Fixed It?"

This particular line was what I was looking for: "The Intergovernmental Panel on Climate Change was established in late 1988..."

So, back to the data I went and I filtered the data to 1988-2014 and compared every subsequent year to 1988 in order to see how much things have changed since climate change started garnering some attention. I expected high income countries to have ever increasing CO₂ per capita. I was wrong.

It turns out that the middle income countries have had the largest change in CO₂ per capita. So that became the focus of this analysis.

I decided to create a map for each of these topics, as a scrolling story, with three actions you can take to help reduce the impact of cow manure pollution. We all want safe drinking water after all.

• Simple layout. It's easy to see you have days within months going left to right and years going down.
• Colors match the official EPA colors for the AQI categories
• Including the ranges we know what constitutes a good reading vs. a bad reading
• The title tells me what I'm looking. Including the date range is a nice touch too.
• Using a strip plot along with the colors helps reveal seasonal patterns
• Including the source in the footer

What could be improved?

• Make the colors color-blind friendly
• It's difficult to see how a month has changed across the years.
• I can't hover to see the values.
• It says each “tile” represents one day of the year and is color-coded based on the AQI level for that day, but I think it's actually showing the max measurement for each day. It should be more clear what they are representing.
• There's very little context. How does one county compare to others? How does one county compare to the national average? 

What were my goals?

• Last year I challenged The Data Duo to visualise an almost identical data set. Pooja created a pretty amazing viz (of course), so I wanted to pick some parts off of it. Particularly, the State selectors on each site and the dot plot.
• I wanted to understand how each month changed across the years, which is pretty much exactly what a cycle plot was created for. I used a trend line instead of an average though because that seemed to show the patterns better.
• I wanted to add context for comparisons to the national average and to the state average (which appears when you click on a state).
• I wanted to use color-blind friendly colors.
• I wanted a small sparkline-type chart to show how things have changed since 1990.