Review of 2017, heat records, and recent warm years.

Yesterday I posted the December global anomaly (base 1961-90) results for TempLS mesh, and noted that it made 2017 the second warmest year, after 2016. I'd like to put that in a bit more context. For the last three years (eg here) I have posted a progressive plot showing in steps the advance of the hottest year to date. Since 2014, 2015 and 2016 were each the hottest years to date, there was something new to show each year, and the plot showed the rapidity of those rises. This year, with 2017 in second place, it doesn't add new information to that style of plot. So I tried a way of adding information. I superimposed on the steps plot a column plot of each year's temperature. This measn that you can follow the max outline, or focus on the columns, which also show how far the years following a record were cooler. It emphasises the warmth of 2017 relative to earlier years. Here is the plot:



The legend shows the color codes for the record years. I'll probably make an active plot of all the indices when they become available. But I was also curious about how 2017 came to be warmer than the near Niño year of 2015. So I drew a column plot by month of the last four years, shown by color
I've also marked each year's average in the appropriate colour. 2017 is almost a mirror image of 2015, and the main contribution to its warmth came from the first three months, a somewhat separate peak from the El Niño. But what is clear is that the apparent level of later 2016 and 2017 is a good deal higher than 2014, a record year in its day. Even the coolest month of 2016/7 (June 17) was at about the 2014 average.

In my previous post, I reported December 2017 as virtually unchanged from November. Further data has made it a little warmer. In other news, the Australia BoM 2017 climate statement is out, and here 2017 was the third warmest year, after 2013 and 2005.