Why Have Major Conservative "Think Tanks" Stopped Doing Research On Climate Change?

Several of the major conservative think tanks have stopped doing research on climate change.  They issue the occasional op-ed but the research has stopped.  Several explanations are considered but none of them speaks well for the think tanks.  My guess is that the problems in the economy have shifted focus from the problem of climate change.  Conservatives are less worried today than they were before the crisis on the potential for serious efforts by governments to address climate change.  The think tanks are more interested in amplifying the problem of budget deficits, and using debt as the rationale for attacking entitlement programs.  They have also been more active in justifying the growth in income inequality.