The final part of our interview with Dr. Rapp picks up mid-answer as he is dealing with the premise used by the climate community.

DR: The second point is that when you deal with the increased water vapor, the models just assume there’s a global average increase in absolute humidity. The relative humidity might stay the same, but as the temperature goes up the absolute humidity goes up. So, they assume a generalized absolute humidity increase for all regions of the earth uniformly.

The problem with that is that in the tropical areas near the equator, you’re already heavily saturated with water vapor; you have high humidity. Adding more water vapor to the atmosphere doesn’t increase the absorption of infrared heat very much. In the desert areas, quite the contrary occurs. If you increase the humidity in the desert areas, then you will get a lot more deposition of heat into the atmosphere. However, there’s some evidence that when you have a global-warming period, the deserts get hotter and drier, not wetter. This is because they become high-pressure areas that drive the moisture away from them.

Finally, as you have more water vapor in the atmosphere, you have more clouds, and they tend to reflect sunlight and produce a cooling effect. Everyone’s predicting all sorts of things, and nobody knows how to treat the clouds. And so you really have to understand how increased water vapor distributes itself globally, area by area, region by region. They haven’t done that, and I’m not sure they can do it.

IH: Readers may not be aware that a second edition of your book is now available online from various booksellers. Can you let us know some of the key changes between the 2007 edition of your book and the 2010 edition?

DR: First, where possible, I updated all the graphs with data through 2009 so the information is more complete and current. Second, I added a lot of references that had been missed before.

I also included new material on several topics that were not covered or covered too lightly in the first edition. For example, I include more analysis of the effect on atmospheric CO2 of different governmental energy-reduction and carbon-emission scenarios. I also have a discussion of the theory that human-generated particulate matter finds its way to the arctic and deposits on snow and ice, reducing its reflectivity and increasing melting. There is more coverage of climate-related catastrophes hypothesized by the IPCC, such as pestilence, starvation and really big hurricanes. I also have more data showing that global temperatures have not risen since 1998, and the biggest prior changes occurred in the upper latitudes of the Northern Hemisphere.

IH: What new climate research, if any, are you following with interest?

DR: There is considerable work being done on ocean currents, in particular the El Nino Southern Oscillation (ENSO), which correlates strongly with Northern Hemisphere temperatures. Prior to the 1980s, El Ninos and La Ninas were more or less balanced, but since then we have had more dominant El Ninos. This raises the question of whether ocean currents might be warming higher latitudes and causing more icecap melting.

Another group has an interesting theory about solar cycles. It revolves around magnetic fields and ionized particles in the earth’s upper atmosphere that vary with the sunspot cycles. When more particles are present as nucleation sites, water vapor condenses more effectively to form droplets and crystals, and clouds are formed more readily. This leads to greater reflection of sunlight and atmospheric cooling. Some researchers claim a direct correlation between very recent declining earth temperatures and reduced sunspot activity over the same period.

IH: Finally, in light of recent snowfall extremes in the eastern U.S. and elsewhere around the world, is there even a small kernel of legitimacy in any of the self-contradictory comments from news pundits like this quote from MSNBC’s Rachel Maddow: “I think global warming probably means extreme weather of all kinds.”

DR: Nonsense. Everything in weather is very spiky, and the recent snowfall says nothing. It doesn’t even support the doubters. IH