Did you miss the scale at the bottom of the page?
We're already about 1 degree Celsius above the historical average, if you actually wanted to see what another half a degree will do, you could try reading the UN climate report explaining just what 1.5 degrees means for the world.
What years are used to determine the historical average? I noticed if you set the birth date to 1910, as low as it goes, it looks like it all evens out.
And there has been absolutely no advancement in science and our understanding of climate since the 1970's. The goal of science is further understand and explain reality. So with new technology and better data collection, the sum of knowledge becomes more intricate and complete.
For example, In the 70's the thought of a human retrovirus was considered an absurdity, about a decade later we had a more complete picture and understanding of HIV.
Retarded. When you make a nice-looking graph which seems alarming, how about maybe you mark it and show the scale so that we can see that the big, scary red bar of us all being cooked to death actually only means less than a half degree warmer. And you should also mention that you didn't travel to the future with a thermometer, you and your buddies just made up a number which was slightly higher than the number we already experienced, because global warming and shit.
edit:
Wow, that's a real scientific thing to say. The heat is "spreading."