claim: The divergence of tree-ring proxies from temperatures after 1960 is openly discussed in the peer-reviewed literature and the last two IPCC assessment reports.
evidence: The Geological Society of America ( GSA ) concurs with assessments by the National Academies of Science ( 2005 ), the National Research Council ( 2006 ), and the Intergovernmental Panel on Climate Change ( IPCC, 2007 ) that global climate has warmed and that human activities ( mainly greenhouse‐gas emissions ) account for most of the warming since the middle 1900s.