This document discusses criticisms of claims that the 1990s were the warmest decade and 1998 the warmest year of the millennium based on temperature reconstructions. It notes that minor variations in data versions and proxies can yield opposite results. It also discusses criticisms of the "hockey stick" temperature graph that was featured prominently in IPCC reports and disputes that multiple independent studies all found late 20th century warming, noting many used common proxies. The document questions whether key proxies like bristlecones have been robustly updated and whether simple statistical models apply to complex trees.