The debate over climate change seems to be extremely polarized with a
lot of money being thrown at it by vested interests. Witness the
recent polarized responses, with an all or nothing point of view.
There are some journal articles which are guarded optimistic. A
recent paper in AJP claims that most climate predictions ignore the
sun's influence. They claim that there is evidence for a significant
fraction of current change being due to natural cycles which have
resulted in increase solar output. They also claim that these cycles
will produce a countervailing dip in solar output which will in the
short term counteract some of the human influence.
This article does not claim, however, that the human influence is
negligible or that it should not be fixed in the long term. So we do
not know the exact percentage of human influence, but it appears to be
significant. We also do not know the exact probability of runaway
greenhouse, but it also appears to significant. If you knew there
were something which could kill your children at what probability leve
would you take action?