Possible explanations for these results include the
neglect of negative forcings in many of the CMIP - 3 simulations of forced climate change), omission of recent temporal changes in solar and volcanic forcing [Wigley, 2010; Kaufmann et al., 2011; Vernier et al., 2011; Solomon et al., 2011], forcing discontinuities at the «splice points» between CMIP - 3 simulations of 20th and 21st century climate change [Arblaster et al., 2011], model response
errors, residual
observational errors [Mears et al., 2011b], and an unusual manifestation of natural internal variability in the observations (see Figure 7A).