Have you noticed how all those Fox talkers like Sean Hannity and Neil Cavuto who like to make global-warming jokes when heavy snowfalls arrive in the winter are utterly silent on the subject right about now, when the nation is enduring what could prove to be a historic heat wave?

Shauna Theel at Media Matters noticed too:

Over the past week, Fox News has not mentioned human-induced climate change or global warming while reporting on or discussing the current heat wave, according to a search of Snapstream video and Nexis transcripts.

The Washington Post reported that this "long duration, widespread heat wave continues to bake virtually the entire central U.S" and "969 daily high temperature records were either tied or broken in the country" through July 16. The Post further reported:

Climate change research indicates that manmade emissions of greenhouse gases may already be increasing the likelihood of extreme heat events like this one, including the 2003 European heat wave that killed tens of thousands. Also, recent studies have projected much hotter summers beginning as soon as just a few decades from now as the climate continues to warm. However, it will take months if not years for scientists to determine whether climate change has played a role in turning up the heat so far this summer, and in this heat wave specifically.

NASA climatologist Gavin Schmidt told Media Matters it's "very probable that any particular heat wave happening now will be shown to have become more likely because of global warming," adding: "Of all the different extreme events that can happen, the partial attribution of heat waves to ongoing climate change is one of the easier connections."

Schmidt explained that there are a number of questions to ask when considering whether global warming may be contributing to extreme weather events:

1) A sniff test - does it make any sense that this effect might be linked? (this doesn't mean that non-obvious things can't happen, but the burden of proof is higher). 2) Are there analyses in the scientific literature that indicate that models do in fact show a change in this extreme as a function of increasing global temperatures? Are these analyses credible? (this will depend on the scale involved, etc.), do all models show the same thing? 3) Have we seen increases in the data already? (this can be hard since the data on extremes is not very extensive). 4) Are the expected changes in the statistics commensurate with what has been seen? (i.e. if models predict a 10% increase but the increase has been 100%, then it's not clear we have understood what is going on).

In the case of heat waves, the answer to each of these questions is yes, Schmidt said.

The National Research Council explained in a recent report that heat waves are expected to become "more intense, more frequent, and longer-lasting" in the United States and around the globe as a result of human-induced climate change.