Why is the UN denying IPCC climate science?

From Benjamin Zycher of AEI.

"So let us examine what the Intergovernmental Panel on Climate Change (IPCC) says and does not say. In its fifth assessment report (The Physical Science Basis, 2013, chapter 9) IPCC notes the recent "pause" in the climate trajectory, despite an increase in atmospheric greenhouse gas (GHG) concentrations of about 13 percent (from 354 ppm to almost 400 ppm) since 1990, and despite the predictions of 73 mainstream climate models. The length of the pause depends heavily on the data used, but appears to be 19 years in the surface record and 16 to 26 years in the lower troposphere. As an aside, the pause — that is, the absence of a recent temperature trend — is an enormous problem for the climate industry, as efforts to explain it (there now are at least 52 explanations offered in the literature and the public discussion, none of which were predicted by the climate models) have the effect of reducing the impacts of anthropogenic emissions, that is, they reduce the effect of mankind's activities."

"In the fourth assessment report (The Physical Science Basis, 2007, Table SPM.3), the range of predicted temperature increases is 0.11 to 0.64 degrees Celsius per decade; in the fifth assessment report (2013, p. 11-52), the range is 0.10 to 0.23 degrees C per decade."

"With respect to the effects of greenhouse gas concentrations, the evidence suggests that increases in extreme weather events have not happened despite the predictions of many. The past two years have set a record for the fewest tornadoes ever in a similar period, and there has been no trend in the frequency of strong (F3 to F5) tornadoes in the United States since 1950. The number of wildfires is in a long-term decline. It has been eight years since a Category 3 or higher hurricane landed on a U.S. coast; that long a period devoid of an intense hurricane landfall has not been observed since 1900. The 2013 Atlantic hurricane season was the least active in 40 years, with zero major hurricanes. There has been no trend in the frequency or intensity of tropical cyclones, and global cyclone activity and energy are near their lowest levels since reliable measurements began by satellite in the 1970s."

"The worst of these potential extreme events is the possible disappearance of the summer Arctic ice, an outcome that IPCC now views only as "likely" with "medium confidence," only under an extreme scenario called "RCP8.5," and one inconsistent with the recent satellite evidence. "Extreme" may be in the eye of the beholder; but IPCC displays little confidence in the inevitability of such events."

"What would the effect of an enforced global emissions agreement be, using an IPCC climate model? One such model is the MAGICC/SCENGEN climate simulator developed at the National Center for Atmospheric Research. An obvious scenario, however unlikely, is adoption of policies similar to those of the Obama administration by the rest of the world, including China and India.

Let us adopt the IPCC temperature sensitivity assumption: a 3.0 degree warming by 2100 attendant upon a doubling of greenhouse gas concentrations from pre-industrial levels. If the entire world were to reduce greenhouse gas emissions by 17 percent below 2005 levels by 2020 — the Obama policy — the predicted temperature reduction would be about 0.04 degrees C by 2050, and 0.15 degrees C by 2100. (Note that the standard deviation of the surface temperature record is about 0.11 degrees C.) What costs would be justified in pursuit of such outcomes?"