Roger A. Pielke -- has had -- enough -- of lukewarmers

Roger A. Pielke, senior,  has rather blithely dismissed the lukewarmers' raison de arte. Skeptical Science has the story:

We believe Dr. Pielke framed the prudent path forward with regards to addressing the risks posed by climate change very well (emphasis added):

"The emission of CO2 into the atmosphere, and its continued accumulation in the atmosphere is changing the climate. We do not need to agree on the magnitude of its global average radiative forcing to see a need to limit this accumulation. The biogeochemical effect of added CO2 by itself is a concern as we do not know its consequences. At the very least, ecosystem function will change resulting in biodiversity changes as different species react differently to higher CO2. The prudent path, therefore, is to limit how much we change our atmosphere."

Dr. Pielke further clarified his position in a later comment:

"I am very much in favor of energy sources which minimize the input [of] gases and aerosols into the atmosphere. Much of my career has been involved with reducing air pollution (both in research and in policy). What we should move towards is an economy with as small a footprint on the natural environment as possible."

We strongly agree with Dr. Pielke on this issue, as we have previously written, and we hope climate "skeptics" heed his sage words.

Dr. Piekle, without mentioning lukewarmers by name, gets to the heart of why their position -- climate sensitivity may be lower than estimated (which Piekle believes to be true) -- therefore we should not act to reduce emissions -- makes no logical sense. We've been there before:

Most estimates of climate sensitivity, regardless of how they are derived (and there are several lines of evidence including comparisons with paleoclimate, response to modern forcings like the Mount Pinatubo eruption, and climate modeling) include in their 95% confidence interval sensitivities between 1-2C. In some cases, the central estimate is between 1.2-1.5C for a doubling of CO2. So favoring a low number for climate sensitivity is not, by itself, enough to put you at odds with the "consensus." You need the other piece – the it's-not-a-big-deal piece. And that's where the trouble starts. . . .

Scientists estimate a warming of 2C as the upper limit of what our civilization can adapt to, and not suffer disaster on a planetary scale. This is probably an optimistic number . . .

The hard lower limit of climate sensitivity -- the lowest it can possibly be and account for our direct observations – is about 1.1C (the real number is very likely to be in that range of 2.6C-4.1C – but we are following the "lukewarmist" argument to see where it leads). The change in forcings expected from a "business as usual" 21st century are +8.5W/m^2 – about 2 1/3 doublings of CO2.

Hence with the lowball number – the number Steven Fuller attributes not to lukewarmers but to out-and-out deniers – put us on course for 2.5C of warming this century. In other words, the lukewarmers' own numbers belie their causal attitude to reducing greenhouse emissions.

Perhaps I could insert a joke here about how maybe Pielke reads the blog, but this misses the point. This isn't my idea: it's just the iron grip of logic and common sense. Could climate sensitivity be lower than we think? Sure. Would that mean it was safe to radically alter the Earth's climate? No. In fact -- and Pielke echoes this part of my argument, as well -- the very fact that we can't predict the consequences with certainty implies the need for greater caution and "as small a footprint on the natural environment as possible."

"[A]s small a footprint on the natural environment as possible." What warmist-alarmist leftist-secular-socialist ecomarxist rent-seeking climate scientist could say it better?