Experts in the science of global climate change often criticise their opponents by disparaging their expertise in climate science. But experts in climate science are not experts in economics. So when they campaign for particular measures to combat warming there is perhaps some ground for asking whether they are advocating the most cost-effective solution.
This is a big issue not made easier by the fact that questioning the suggested actions is seen as the same as questioning the existence of warming leaving many who accept the reality of warming labelled as "skeptics" or "deniers". An example of this would be Bjorn Lomberg, whose book, Cool It, led to him being likened to a Nazi by Rajendra Pachauri (see footnote 1046 in page 202 in the english edition).
Lomberg's book doesn't challenge the reality of warming (though he questions how evidence has been used to persuade the public). More relevant to this question, he argues that the solutions proposed by many campaigners are poor ways to avoid the expected downsides of warming. For example, if we think malaria will spread in a warmer world (see related question Will a warming world directly damage human health? for more) spending money to avoid warming will be an incredibly wasteful way to hold back malaria (in fact we could probably eliminate it entirely for a tiny fraction of the cost of lowering carbon dioxide emissions).
Several other authors have made a similar argument (though many are regarded as skeptics on the reality of warming). Nevertheless both Nigel Lawson in An appeal to Reason, and Christian Gerondeau in Climate: the Great Delusion, accept the forecasts of the IPCC and base their arguments on the economics of proposed solutions arguing that preventing climate change is both unrealistic and exceedingly expensive and that policy should focus on adapting to change or developing new technologies to sequester carbon dioxide rather than avoid emitting it.
So are their economic arguments credible? Is attempting to freeze greenhouse emissions ridiculously unrealistic? Might the world be better off is we devoted our energy to adapting to warming rather than attempting unrealistic and excessively expensive ways to avoid future greenhouse emissions? Might geoengineering CO₂ capture be better than avoiding emissions?
NB This question is about the economics of warming not the debate about the science or the history. So please stay on topic.