In the same way that Rinehart tries to make the radiative properties of carbon dioxide go away by pointing out it's only a small fraction of the atmosphere, Palmer also tries to confuse the issue by saying, "97% of carbon dioxide is by natural sources".
This produced a temperature spike.Still, all the extra heat implied by higher radiative forcing has to go somewhere.
The best estimate for total man-made radiative forcing in 2011 is 43% above 2005 levels.Of course, more heat does not necessarily equal perceptible climate change.
But there is no sign that the rise in radiative forcing has slowed during the past 15 years of flat surface temperatures.
If so, some scientists argue, then perhaps it should not have increased its confidence that man is the main cause of global warming.In theory, a lower climate sensitivity means temperatures would rise more slowly for any given amount of extra radiative forcing.
A rise indicates that heat is building up in the system.Total radiative forcing from man-made sources since 1750 (ie, before industrialisation) has risen from 0.29-0.85W/m2 in 1950 to 0.64-1.86W/m2 in 1980 to 1.13-3.33W/m2 in 2011.
This radiation is inversely related to a particle's mass and, since protons weigh 1,836 times as much as electrons, radiative losses are far greater for electrons than protons.
The other is a limit on "radiative forcing"—the increase in energy delivered to the surface of the Earth over time, largely as a consequence of extra greenhouse gases of 1 watt per square metre above pre-industrial levels.
The leaked assessment from the IPCC (which is still subject to review and revision) suggested that aerosols' estimated radiative "forcing"—their warming or cooling effect had changed from minus 1.2 watts per square metre of the Earth's surface in the 2007 assessment to minus 0.7W/m ² now: ie, less cooling.One of the commonest and most important aerosols is soot (also known as black carbon).
But as the leaked IPCC assessment says, "the cloud feedback remains the most uncertain radiative feedback in climate models".
That link was deemed "likely" (which means probability of 66%) in 2001, and "very likely" (90%) in 2007.The latest iteration identifies radiative forcing, the difference between the amount of heat coming into the climate and the amount reflected back, as the immediate cause of warming.
