Page 2 of 23 Duncan Steel: Perihelion precession, polar ice and global
warming Introduction Record melting of Arctic sea ice over the past year (Schiermeier 2012) has been widely presumed to be a consequence of anthropogenic global warming (AGW), and yet a natural mechanism exists that may be responsible, at least in part.
In 2015 Bill Johnston warned that the
introduction of electronic sensors in the late 1990s was artificially
warming the
records and asked the Bureau for data from the two different kinds of instruments side by side.