User:MissPiggysBoyfriend/sandbox

I see the terms "denial" and "scientific consensus" used in relation to climate change quite a lot on this page, so I thought I'd provide some context. If you look at basic scientific constants such as the mass of a proton, the elementary charge, the Avagadro constant, and so forth, you typically see a relative uncertainty on the order of 10^-8. Anything that depends on knowing the Newtonian Gravitational Constant has a larger uncertainty, on the order of 10^-4. That's what a scientific consensus looks like. With that as background, let's look at climate change:

Arguably the most important constant in the field is equilibrium climate sensitivity. Per the IPCC, equilibrium climate sensitivity has a "most probable value" of 1.5-4.5 degrees Celsius (p. 45). Obviously, there is no scientific consensus on this vital question; if there were, presumably the IPCC would state it.

Another vital question: how long does CO2 remain in the atmosphere? The IPCC said this in AR4:

"About half of a CO2 pulse to the atmosphere is removed over a time scale of 30 years; a further 30% is removed within a few centuries; and the remaining 20% will typically stay in the atmosphere for many thousands of years."

In AR5, the picture changed rather dramatically; see p. 96 here, with the removal rate depending on the amount of carbon, an effect not claimed in AR4.

Similarly, for both temperature and sea level, the IPCC's expected increases have lower and upper bounds that differ by almost a factor of 2 for their "business as usual" emissions scenario., p. 11.

The point is that asserting there is a "consensus" on basic questions that WUWT is "denying" simply does not comport with what the IPCC itself says. To the extent that there is a consensus, WUWT frequently agrees with it -- temperatures are rising, sea level is rising, and increased CO2 leads to higher temperatures.MissPiggysBoyfriend (talk) 22:38, 12 June 2015 (UTC)