ican keeps displaying that chart because no-one seems to be reading it. Every time I look at it, I see what may be a volcanic anomaly around the mid 1800's (from memory). But the graph shows a temp swing downwards towards the end of its plot in both hemispere trending and the global averaging.
For my part, I have never denied Global Warming is possible. I have simply maintained that it can not be proven. The data is simply not there to show what is really going on. It may be warming naturally, because we still have the remnants of an Ice Age (the planet almost never has glaciers except in an Ice Age) or it may be warming due to man. But it is not provable. It might even be about to send glaciers back down towards the equator. By the time we have adequate data, if the Global Warming Thuggees are right, it will probably be too late. On the other hand, if they are wrong and we act as though they are right, we will be doing serious damage to ourselves.
Politicians have tried to get people to focus on real problems, but they have used the lie of Global Warming to do it. This is counterproductive, and like the boy who cried wolf, it could end very badly indeed.
It is not science to take data for 30 years and say what the Global Climate is doing. We do not have enough information to eliminate variables. We do not have enough data from past variations of climate and we do not have enough current linear data to predict a trend. The Global Climate is changed by long term factors such as the position of the continents, mountains and ocean currents, add to this the effect of short term solar cycles, and it is not clear what will happen.
Global Warming is a guess, and for various reasons it seems a lot of scientists are happy with that. There are also many who are not. At the moment, the press is only listening to supporters. Many who would like to voice an objection can not. This is also true for being published. Unfashionable viewpoints have a habit of not being published by the editors who decide these matters.
If you want to believe in Global Warming, fine, I respect your right and your opinion. Do not claim it is scientifically proven, because it can never be with current data. We know too little about the past, and if it happens it will be upon us before we can measure it but so too might the next Glacial Advance.
IT IS A GUESS.