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Originally Posted by Phaneufenstein
Is it really that simple though?
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That depends on what you mean by "it". I said:
It's a basic question of does CO2 trap infrared radiation.... More CO2, the equilibrium will shift and more heat is retained (all else being equal).
All else being equal, well then yes of course it is that simple. We're a ball in space (which is a good insulator) with a single source of incoming energy (the sun). So much energy comes in, so much energy goes out, that reaches an equilibrium where the two are balanced. Change one factor (how much comes in, how much goes out) and the point of equilibrium changes.
Now of course all else isn't equal, there are multiple things (forcings) that come into play. Eject the earth from the solar system, we could have Venus levels of CO2 and it won't help us keep warm. Double the output of the sun, getting rid of all the greenhouse gasses won't keep us from boiling alive.
That's what climate science does, is study all the various forcings and their impacts to determine what the cause is for the observed phenomenon.
Sometimes people post here that "climate has changed in the past", that's true, but that's like saying people die so no reason to look for a murderer when someone dies. Every change in climate has a cause, and they look for fingerprints of various causes to differentiate between one and the other.
Human generated CO2 is the dominant forcing at his time according to those fingerprints.
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Originally Posted by Phaneufenstein
Why has the temperature leveled off in the past 15 years?
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troutman posted some links that sum it up pretty well but the short answer is it hasn't, it's just easy to cherry pick short term spans in a noisy signal that will show a short term trend contrary to the actual trend.
A good parallel would be during the span where the Kings had only won 1 game in 10.. How could the Kings be a playoff team let alone a cup contender playing at a 1 win in 10 games pace?
The answer is because looking at short term trend, especially one that I specifically chose (just like people specifically choose 1989 for their "leveled off" claims because it was an El Nino high year), isn't meaningful when what I'm really looking for is long term trends (i.e. how the game is played over a season, or how climate is changing over the long term).
Picking just short term cherry picked ranges you get this:
And that's the reason I posted the graph I did, because while atmospheric temperature points may look like they're not moving up, the ocean still is.
Just like if the atmosphere was nudging up but the ocean levels were going down such that the net change was zero, then there wouldn't be global warming, just atmospheric warming.
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Originally Posted by Phaneufenstein
Is there overwhelming evidence that the climate change is human-caused?
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I think there is. At its simplest CO2 is increased, we know because of Carbon isotope ratios that the increase of CO2 is from the fossil fuels we're burning (plus we know we're digging millions of years of carbon locked into the earth and releasing it into the atmosphere, that's what burning gas/oil/coal IS by definition). We know CO2 changes the energy balance of the planet. If the earth wasn't warming then we'd have to figure out what else was changing to compensate.
troutman also posted lots of good links.
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Originally Posted by Phaneufenstein
What about the ice ages that the planet has seen?
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No one claims that humans are the
only thing that can impact climate, there are lots of other things that can and do. As I mentioned though the argument that "humans die of natural causes therefore this dead human died of natural causes" isn't valid. We have to figure out why a specific change occurred, and that cause may be different than what caused other changes. Things like atmospheric composition, moving continents (and the resulting uplifts and ocean current changes), orbital cycles, solar variation, and volcanic activity can all contribute.
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Originally Posted by Phaneufenstein
I don't try to pretend that I know anything for a fact.
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Well we don't know anything for a fact, really.. We don't know that gravity will work tomorrow for a fact, but we provisionally accept it based on the best observations and theories because ultimately we have to live our lives and do stuff.
Facts in science refer to observations. That the global average temperature has been increasing is a fact. The cause of facts, the framework that explains a group of facts or a phenomenon, is a scientific theory (different from the common language usage of theory), which has explanatory and predictive power.
So it's not a matter of pretending to know something for a fact, it's making provisional judgements based on the best available information and understanding. All the information points to humans being the dominant forcing at this time.
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Originally Posted by Phaneufenstein
The problem is there's way too much information and misinformation on both sides of the coin which makes it hard to know who to believe, and one is left to basically pick a side.
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One doesn't have to pick a side. There's lots of issues where I don't choose a side because I don't feel I know enough to make a reasoned judgement. People all too often pick a side based on ideology regardless of reason or information.
From the actual science there's not much in the way of misinformation, if it's wrong it's wrong honestly (and if you can show it to be wrong then you'll be famous). So to avoid misinformation the best way is to assume that the media is getting it wrong (they always get science wrong) and go to the source.
