Comment by voice_of_reason | Hacker News Reader

Comment by voice_of_reason | Hacker News Reader

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voice_of_reason

Convincing part stops at cloud feedback for me.

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.

ACC doesn't build upon the hypothesis that CO2 reduces the energy emission. The underpinning is the greenhouse effect whereby gasses, particularly CO2 prevent heat absorbed by the Earth's surface from radiating back out into space. Only about 26% of the Sun's energy is reflected by clouds or the atmosphere. CO2 concentration increases heat retention but not cloud albedo(reflectiveness) nor atmospheric reflectiveness.

Cloud formation is not related to CO2. CO2 is the primary factor driving the greenhouse effect. In fact research is beginning to show that a warmer planet may have lower cloud cover [1][2]. There is no cloud controversy, you are literally making that up.

[1] https://content.time.com/time/health/article/0,8599,1912448,... [2]https://www.nsf.gov/news/special_reports/clouds/question.jsp

It does build on the fact that increased concentration of CO2 reduces EM waves emission (in the parts of frequency spectrum that can be absorbed by CO2) from Earth to space. Earth is presumed to maintain thermodynamic balance (i.e. energy received should be equal to energy lost). To compensate for reduced emission caused by CO2, Earth's surface warms up and restores the balance. This is global warming 101, I believe.

Have you read your links?

"One of the biggest questions in climate sensitivity has been the role of low-level cloud cover. Low-altitude clouds reflect some of the sun's radiation back into the atmosphere, cooling the earth. It's not yet known whether global warming will dissipate clouds, which would effectively speed up the process of climate change, or increase cloud cover, which would slow it down.

But a new study published in the July 24 issue of Science is clearing the haze. A group of researchers from the University of Miami and the Scripps Institute of Oceanography studied cloud data of the northeast Pacific Ocean — both from satellites and from the human eye — over the past 50 years and combined that with climate models. They found that low-level clouds tend to dissipate as the ocean warms — which means a warmer world could well have less cloud cover. "That would create positive feedback, a reinforcing cycle that continues to warm the climate," says Amy Clement, a climate scientist at the University of Miami and the lead author of the Science study."

That's one study that recorded the cloud data for subset of Earth.

Read about clouds feedback issue here, it's very pro-CO2-CAGW site: https://www.skepticalscience.com/clouds-negative-feedback.ht...

I did read the links, they both point to positive feedback cycles, and you cherry picked that quote to obfuscate that point.

Your first statement is proving my point, CO2 contributes to the greenhouse effect, causing warming on average. Human activity is the cause of historically high CO2 levels.

"Point to" is not confident enough. Even skepticalscience, the "alarmist"-side site, admits that "While clouds remain an uncertainty, the evidence is building that clouds will probably cause the planet to warm even further".

"A group of researchers from the University of Miami and the Scripps Institute of Oceanography studied cloud data of the northeast Pacific Ocean"

Study from your first link recorded cloud cover data over subset of Earth's atmosphere. It doesn't say anything about whether clouds feedback is positive, or negative. Local data is not very useful evidence, global data would be preferable.

Here is an explanation of what is cloud feedback: increase of temperature has effects on cloud formation. If feedback from changes in cloud formation is positive, it will lead to even more warming. Negative feedback would mean that changed cloud formation actually reduces warming.

  cloud data of the northeast Pacific Ocean — both from satellites and from the human eye

What methodology did they use to turn eyeballed guesstimates into data?

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