We’ll start with the latest graph in which the El Nino is now at it’s peak. If you look at the warming from 1980 to 2015, you can draw a straight line and the 5 year average would curl closely to it. Looking at the added black line you could say that warming lately has been pretty linear .
Next we’re going to extend the graph. As this years El Nino was a bit like the one of 1998, we can copy the area between the peaks a couple of times to see what would happen if the same scenario would occur again and again and again.
I’ve drawn the same black line, but extended it all the way to 2100. As you can see it doesn’t match with the 1998/2016 scenario. You’d therefore could draw the conclusion that the speed of warming has increased a bit!
This warming still doesn’t seem to go beyond 3°C. Models however project that warming will end up between 3°C and 4°C. The most obvious explanation for this difference is that although declining rapidly, there’s still a lot of summer ice in the Arctic. Sadly this won’t last long and eventually there will be little summer ice left. The loss of Arctic summer ice is regarded as a major tipping point. With the sun shining 24 hours a day, the extra heat accumulated is just enormous. Keeping that in mind, we need to draw another line to what the models expect.
The new line we made now seems to be on course with the current warming we have in 2016. Notice that the new line dissects the 5 year average line of 2016 exactly. So with all of this in mind it seems that a 3.5°C scenario is still very much possible.