Because there is so much detail in a contour map, it is best to look at a large image. I think that I am limited to a small image in this article, so I will put a link after the small image, which will take you to a large image that I put on the Photobucket website. I hope that this works, it is the first time that I have tried this. If you can’t get to the large image, then you could try magnifying the small image using your browser. I know that Chrome has a Zoom control, and I assume that other browsers will have something similar.
For a large image of this contour map, from the Photobucket website, click this link:
http://i1042.photobucket.com/albums/b424/mta-graphs/Contour%201880%20to%202015%20-%20big%20with%20copyright_zps6tvnym4k.pngThe legend for global warming contour maps is here:Now that you have looked at a contour map, and looked at the legend, we can discuss what is on the map.
Along the bottom of the contour map, there is a line of what appear to be small red flames. These are not real flames, but they do represent a source of heat. These are the natural warming events, like El Nino and the Blob. If you count them, then you will find that there are about 46 of them between 1880 and 2015. Some of them merge together, so an exact count is difficult. That is about one natural warming event every 3 years, and I believe that El Nino’s occur about once every 2 to 5 years, so the number seems about right.
There are often small black regions between the natural warming events. I use black to show cooling, so these small black regions are either the cooling phase of an El Nino, or possibly a La Nina.
Now look at the big black area near the middle of the graph, As I said before, I use black to show cooling, so this appears to be a large cooling event. When I first found this, I thought that it might be an error in the graph. I checked it carefully, and found that it was an approximately 40 year cooling trend, that started about 1935, and finished in about 1975. As soon as I saw the year 1975, I knew what this was. I remembered that in 1976 there was a scare about a possible ice age happening. Time magazine ran 2 cover stories, one about “The coming Ice Age”, and the other about “How to survive the coming Ice Age”. I don’t believe that Time magazine would invent these stories with no evidence. It would make sense if some scientist noticed the 40 year cooling trend, and said something to somebody.