How is consensus settled, when there are renowned scientists out there who object the CAGW hypothesis? Roy Spencer, Richard Lindzen, Judith Curry, Freeman Dyson - are they all bought and paid for by oil industry?
Roy Spencer is a satellite observation expert, who has reversed his opinion of satellite measurements, and now believes that warming is about as described by the traditional thermometer datasets.
Judith Curry doesn't disagree with AGW, she disagrees with the scale predicted. That would mean less immediate, strict action, but action nevertheless.
Freeman Dyson isn't a climatologist, he also says himself "[m]y objections to the global warming propaganda are not so much over the technical facts, about which I do not know much, but it’s rather against the way those people behave and the kind of intolerance to criticism that a lot of them have." He also believes in AGW.
It's good to have sceptics, and in particular being sceptical about the scale of AGW is very reasonable. The IPCC predictions actually have a wide variance for these reasons. These scientists don't really speak against the moderate action currently proposed, they aren't backing for Trump's position.
I don't mind AGW at all (it's obvious that human activity influences the climate, and probably the effects of deforestation are as severe as effects from CO2 emissions), but I find CO2-CAGW (i.e. anthropogenic warming caused by CO2 emissions and leading to catastrophic consequences) unconvincing, to a lesser degree due to personal knowledge (uncertainty in clouds feedback, under appreciation of positive effects of higher CO2 concentration etc), and to a higher degree, due to views of Lindzen, Curry, Spencer Dyson, and other scientists.
Yes, Dyson's rhetoric on climate moved a bit towards "alarmist" side, but he still doesn't believe in catastrophic consequences:
"The good news is that the main effect of carbon dioxide … is to make the planet greener, [by] feeding the growth of green plants of all kinds [and] increasing the fertility of farms and fields and forests."
Even by the late '90s there were renowned medical scientists who disagreed with the consensus around the "HIV causes AIDS" hypothesis, despite ample evidence.
You asked how there could be "consensus" on the existence of ACC when some scientists dispute its existence.
The parent post gave an example of a case where some credentialed scientists continued to dispute the HIV-AIDS link well after the balance of evidence was against them.
Many people would say there was a "consensus" on the HIV-AIDS link despite the continued skepticism of some scientists, and that this scenario has parallels with climate science.
Can you offer a counter example, where a holdout group of scientists who disagreed with consensus in their field were proved right?
Climate changes anyway, so why do anything about it? People die anyway, so who cares what causes AIDS?
Call it "climate science denialism" if you prefer. It's no different from AIDS denialism.
Thabo Mbeki, President of South Africa in 1999-2008, listened to the denialists' views about the AIDS outbreak. He had an AIDS advisory panel staffed with consensus critics -- just like Trump and Pruitt are doing. The estimated number of premature deaths due to Mbeki's counterproductive actions is around 300,000.
The article is about paradigm shifts in science. Obviously those happen, but not every minority opinion is such a shift. They are notable because they are so very rare.
What do you see as the paradigm shift that turns climate science on its head and proves the consensus wrong?
Suppose that new discovery in natural climate variability provides IPCC with better models, and these models show that CO2 has only minor influence on global warming and climate overall. "Paradigm shift" would be a good description for this development.
This 'consensus' approach is biased from the start, because it automatically gives a benefit to the so-called "scientists" as if they are somehow more wise or knowledgable about anything any more than a soothsayer or even pulling a few stones out of the ground and interpreting the residual dirt in their cracks while intoxicated on some brewed concoction of plants.
Nope. The IPCC consensus has been reached through a lot of hard, unpaid or very poorly paid, work by people passionate about helping others, that all the time know they could easily get bought to spread falsehoods and reap large rewards.
consensus as in general agreement, as in a majority. Pointing out that some minority group exists is hardly a refutation. Would you not say there is a consensus the Earth is round?
Why should one trust majority, and not minority, if "minority" people are also qualified and respected (Spencer, Curry)? There were episodes in the history of science, when the majority turned out to be wrong.
I won't object to the fact that majorities can be wrong. There are many examples, ancient and recent. But that is a different argument from your other comment.
I trust majority in science because it is rarely wrong. I'd need a bit more than "majorities have been wrong before!" to switch sides.
Which part of the science do you find unconvincing? We have great ice core data going back 1000's of years, the greenhouse effect itself is universally agreed upon and understood, we have a measurable rise in global average temperature over the last 2 centuries, and we see that people are spewing greenhouse gases into the atmosphere. Solar cycles, volcanoes, and other non-human sources have been refuted and disproved time and time again. only scientists paid to lobby on behalf of the source of warming disagree with the cause. What's missing that could ever convince you?
The CAGW builds upon following argument: increased concentration of CO2 reduces the EM radiation's emission in frequencies that CO2 absorbs, ergo the surface temperature should rise in order to keep Earth's thermodynamic balance.
Increased temperature clearly affects the formation of clouds which have both positive and negative effects: they deflect incoming solar radiation, but also deflect surface radiation. The net effect is unclear, unfortunately.
I'm also quite puzzled by apparent lag between CO2 and temperatures in Vostok ice core data. Contrary to CAGW, temperature rises first, and CO2 follows.
My layman understanding is quite limited, of course, that's why eventually I go to the scientists for their expertise. I don't believe that all opponents of CAGW theory are shills; some of them are very respected people: Lindzen, Spencer, etc. My only conclusion is that science is not settled and CAGW is still an unconfirmed hypothesis.
Freeman Dyson is not a climate scientist at all and never has been.
Roy Spencer isn't a "renowned scientist"; he's a paid oil-industry shill.
Lindzen used to be a scientist; now he's retired and gets paid to be a Cato Institute shill.
Judith Curry also used to be a scientist and quit her academic job; presumably being a shill pays WAY better.
So, basically, yes, they are all bought and paid for, or, they simply have no credentials or knowledge of the field in question.
Dyson is a renowned physicist interested in climate science. I believe that his physics/math skills and general intelligence allow him to be quite competent in climate issues.
Lindzen retired only in 2013. I don't see how this makes his opinion about CAGW less valuable, especially given the fact that he was skeptical about CAGW hypothesis for a long time.
"Judith Curry also used to be a scientist and quit her academic job; presumably being a shill pays WAY better." - where's the proof that she is a "shill"?
Roy Spencer is a renowned scientist in my book: "Roy Warren Spencer is a meteorologist, a principal research scientist at the University of Alabama in Huntsville, and the U.S. Science Team leader for the Advanced Microwave Scanning Radiometer (AMSR-E) on NASA's Aqua satellite. He has served as senior scientist for climate studies at NASA's Marshall Space Flight Center."
Again, where is the proof that he is oil industry's shill?
To my knowledge, Freeman Dyson has no peer reviewed research contributions in the climate literature. That should be the price of entry, otherwise there is nothing of substance to critique.
This is exactly what I meant by fallacies. Either their research is legitimate or it is not. And that legitimacy is not a factor of the employer - if their science sucks, it'll manifest in the data, analysis, or conclusions, regardless of who's paying for it.
Judith Curry doesn't disagree with AGW, she disagrees with the scale predicted. That would mean less immediate, strict action, but action nevertheless.
Freeman Dyson isn't a climatologist, he also says himself "[m]y objections to the global warming propaganda are not so much over the technical facts, about which I do not know much, but it’s rather against the way those people behave and the kind of intolerance to criticism that a lot of them have." He also believes in AGW.
It's good to have sceptics, and in particular being sceptical about the scale of AGW is very reasonable. The IPCC predictions actually have a wide variance for these reasons. These scientists don't really speak against the moderate action currently proposed, they aren't backing for Trump's position.