You say that 1880 was one of the coldest years in history. The data series used in the article indicate that the entire decade 1903-1913 was significantly colde

You say that 1880 was one of the coldest years in history. The data series used in the article indicate that the entire decade 1903-1913 was significantly colder. If you then look at the contribution to climate from volcanic activity (CO2 and sulphates, in both directions), the fourth graph in the article ("Is It Volcanoes?"), the data show that 1880 did not have a significant negative temperature contribution from volcanic activity, and although 1884-5 did, so too did 1964-66, 1983, and 1992. There is no consensus on the cause of the Little Ice Age; although volcanism is one possible cause, there are other possible causes both external (solar activity, orbital cycles) and anthrogenic (reafforestation following pandemic-induced population collapse in Europe and the Americas). If that last cause is indeed a contributing factor, it supports the anthrogenic climate change theory. Even if it is excluded, the removal or reversal of external factors is totally insufficient to explain observed warming in the last century.