The fifth Intergovernmental Panel on Climate Change (IPCC) report states with 95 percent confidence that humans are the main cause of the current global warming. Many media outlets have reported that this is an increase from the 90 percent certainty in the fourth IPCC report, but actually the change is much more significant than that. In fact, if you look closely, the IPCC says that humans have most likely caused all of the global warming over the past 60 years.
Why is the IPCC AR5 so much more confident in human-caused global warming?
I have to agree with the Nutter about this. Data tampering by government climate scientists is likely responsible for 100% of the warming shown in their graphs since 1940.
Temperatures were much hotter during the 1930s
Whatever happened to their 110% claim?
I don’t understand how the article claims that the IPCC is saying that that humans caused ALL warming, when it is clear from the quote that they only say “more than half”.
That could mean only 51%
Actually it’s the opposite of what the article implies, because previously the IPCC said that warming was entirely due to “anthropogenic greenhouse gas concentrations”, whereas now it says that it was “caused by the anthropogenic increase in greenhouse gas concentrations and other anthropogenic forcings together.”
So the contribution from “anthropogenic greenhouse gasses” appears to have diminished.
I never knew the US heat wave meant that global temps were higher than they were today. Oh wait, the US is only 2% of the earth’s surface…
And the Pacific covers more area than all land mass combined. The Pacific has not warmed since 1994. What is your point?
I can’t believe what I’m reading on the SS page.
Dana “I work for big oil but don’t tell anyone” Nuccitelli makes the above claim about humans causing all of the warming and then several paragraphs down quotes the IPCC paragraph that directly contradicts him.
Yet SS readers will somehow end up parroting “The IPCC sez all of the warming caused by humans, because science.”
I think the claim of humans causing 100% of the warming in the last 60 years is progress. If you look at the radiative forcing components in the AR4 report, positive anthropogenic forcings account for nearly 200% of the rise since 1750. Temperatures had been constrained by aerosols. Using aerosols pushes up the climate sensitivity of the CO2.
http://manicbeancounter.com/2012/04/10/aerosols-the-unipcc-ar4-adjustment-factor/
Yesterdays report reduces the amount contributed by aerosols, and admits the possibility that aerosols may be net positive on warming. The potency of CO2 is also reduced by 10% from 60ppm equivalent to 1 Wm-2 of warming to 66ppm.
The report doubles the uncertainty bands for CO2 and CH4 as well. Oddly, the scientists despite correcting past errors and being less certain of their results, are more confident of their figures. If I found my figures had been out, I would be less confident in my figures. But then I am not a climate scientist.
My analysis is here
http://manicbeancounter.com/2013/09/28/radiative-forcing-unipcc-ar5-undermines-ar4-but-scientists-have-unshaken-confidence-in-their-work/
And the funniest part is that the people at SS (a more descriptive acronym than the SkS they would rather you use) actually admit there’s been a pause in temperatures.
In the course of attempting to ridicule the “deniers”, someone thought of creating a animation they call “the escalator”, comparing the “steps” in the temperatures as opposed to a steady rise.
If you took that animation to it’s next LOGICAL step, you’d superimpose the two final images. There, you’d see that their “rise” has been running above the “top step” (the observations) since about ’96, and that the top step reflects the current “pause”.
Maybe someone should ask them how much longer they expect that top step of “the escalator” to get before someone sees a need to add a new one.