I could spend a day debunking all this stuff.
But needless to say, this chart is just as full of lies as all the rest. We can't accurately record sea or land temperature with anything close to accuracy with current measurement equipment. It's so bogus it would pin Phil's bogosity meter to the limit. Even a mile apart you can have drastically different temperatures. If you live in the desert you realize this quickly. Random sampling and averaging just doesn't cut it. If this chart were a political poll it would have to say Within +/- 80 percent margin of error.
It's created just for effect - like all the rest.