You think there is a conspiracy to supress detailed global temperature measurements that were taken before 1880? It's interesting that we have ways to estimate global temperature before 1880, but that marks the start of modern record keeping.
It also has the advantage of showing the blip of very high US temperatures in the 1930s. People also complain about bias if those extremes are left out.
It also has the advantage of showing the blip of very high US temperatures in the 1930s. People also complain about bias if those extremes are left out.