Freeman Dyson's position is interesting. It reveals his lack of understanding of how data is collected and models work in the real world. He suggests just going out and measuring the actual temperature and not relying on models. Think about that for a bit, what would it mean? What is the temperature, right now, in your house? Hard to answer isn't it. It will depend on where you measure, how you measure, the time between measurements and so on. You will need a model to answer the question. You need models to answer any question. Dyson is out of touch with how science is actually done today.