The temperature by the thermometers is higher. Why have an indirect indicator, when you have a direct one?
The Arctic ice cap doesn't lie -- water melting an freezing points are absolute. The volume of ice is a small fraction of what it was just a few years ago. If it is getting cooler, then why is the Arctic ice melting to lower and lower minimums?
And before you ask, the reason the Antarctic is gaining a *little* ice is because of the increased amount of moisture in the atmosphere, which falls as snow when it is below freezing. After we gain a little more heat, the Antarctic will then start losing ice volume.
We have great data on what the carbon dioxide levels were when the polar ice caps froze.
Sure in the past, carbon dioxide was as high as 1,000 PPM, and there was no ice at all anywhere, and sea level was a LOT higher. Volcanoes can change the carbon dixoide by
~100 PPM / Million Years -- which is about 1/10,000th PPM / Year. Humans are changing it by ~2 PPM / Year.