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What's Really Warming the World?

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Re: What's Really Warming the World?

#61

Post by nom »

patricklorio wrote: post #13

That was really cool but it bothers me that they don't show the y axis for the effecting factors. Does anyone know if it's normalized or completely arbitrary?

They share the same Y axis, the values are taken from simulations. From the article:

"The colored temperature lines are the modeled estimates that each climate factor contributes to the overall temperature. Each factor was simulated five times, with different initial conditions; each slide here shows the average of five runs. GISS researchers laid out their historical simulations in detail last year in this [0] article."

[0] http://pubs.giss.nasa.gov/abs/mi08910y.html

Re: What's Really Warming the World?

#62

Post by sanderjd »

corradio wrote: post #18
karl11 wrote: post #11

Earlier quoted context omitted.

That doesn't make sense. What if the reference is 5 minutes ago?

Take the reference that is 5min ago, call it T0. You will still observe that temperatures (i.e the sequence of measured temperatures minus T0) are increasing. Changing the reference changes the y-scale of a graph, but does not change the derivative (the speed at which it changes, i.e. increases or decreases).

What? Just because it's daytime (in the US) right now? In a few hours when it's dark, the temperature will definitely be going down when compared with a baseline of 5 minutes in the past. I don't think you've thought this through...

Re: What's Really Warming the World?

#63

Post by stale2002 »

bsbechtel wrote: post #15
corradio wrote: post #6

Earlier quoted context omitted.

You shouldn't care about what reference is taken. The point is that compared to any reference, the curve is increasing .

That's ridiculous, of course you need a baseline for any sort of evaluation. Your comment implies any sort of warming, regardless of absolute levels, is bad.

Ok, then, how about this. The baseline is 0 degrees, because that is the lowest that temperature can be.

Would that be a fair baseline?

Re: What's Really Warming the World?

#64

Post by euyyn »

lrenaud wrote: post #38
euyyn wrote: post #12

Earlier quoted context omitted.

> proponents of global warming aren't engaging with the facts in an honest and forthright way. You want to read about global warming from climate scientists, as your questions are easily answered. Peer reviewers are as vicious as in any other science: the concerns you raise here would be the least of their ammunition.

That gives me even less faith in the quality of findings. Having seen the pathetic state of literature review in the various engineering fields, I cannot expect it to be better in meteorological fields. No doubt there is a certain subset of effective and critical reviewers, but I expect dogma, exciting findings, and name recognition still rule the day. The most the volume of politics in engineering where our work is…

We're talking about a pile of papers that have been accepted at Nature and Science over a span of decades, not a paper about how Agile is the best programming methodology.

Re: What's Really Warming the World?

#65

Post by kuldeepk »

Correct me if i'm wrong but this data seem to put deforestation as benign. Wouldn't continued trend of deforestation make effect of GHS emissions worse? More that temperature changes shouldn't we worried about oxygen health of the planet?

Re: What's Really Warming the World?

#66

Post by Homunculiheaded »

For a more rigorous, scientific and yet still thoroughly digestible talk I strongly recommend watching Dr. Richard Alley's talk "The Biggest Control Knob: Carbon Dioxide in Earth's Climate History" [0]

As a Bayesian I particularly enjoy Alley's running theme that: while there certainly could be alternative explanations for what is happening, we simply cannot find anything that explains the data better than CO2.

I see many skeptics pointing out tiny holes in the main AGW hypotheses, but the real Bayesian test is "how much better does one hypothesis explain the observed data than then other?". When you put all the pieces of the atmospheric CO2 argument together it seem to explain what we're observing dramatically better than a thousand "...but what about?" that don't fit together into a coherent counter hypothesis.

As an example: Suppose I come home and see my front window broken, my door open and my laptop missing. I assume I have been robbed based on this evidence. You could say "but couldn't the window have been broken by some kid throwing rocks?", "maybe you left the door unlocked and the wind blew it open", "are you absolutely sure you didn't leave your laptop at work?"

While individually each of these counter hypotheses may explain a single event just as well, together they don't work:

P(window broke, door open, laptop missing | robbed) x P(robbed) >> P(window broke, door open, laptop missing | neighbor threw rock, left door unlocked and left laptop at work) x P(neighbor threw rock & left door unlocked & left laptop at work).

[0] https://www.youtube.com/watch?v=RffPSrRpq_g

edit: forgot to add my priors in that last section

Re: What's Really Warming the World?

#67

Post by izend »

corradio wrote: post #10
vivekd wrote: post #4

What makes me mad about these kinds of data based climate change arguments is that they don't engage with the data in an honest way. The huge problem is 1880 was one of the coldest years in history. That cold period was caused by volcanism, several volcanos erupted causing a cold period that lasted from the 1600s to the late 1800s. This period is known as the little ice age. The worst of this period was in 1816 which…

You're right. However, it's hard to argue with the speed at which this warming occurs. It's never seen before if you look at all the records we have. That's what's worrying.

The end of the last ice age had much faster warming, see:

http://www.nature.com/scitable/knowledge/library/abrupt-clim...

Re: What's Really Warming the World?

#68

Post by stale2002 »

joatmon-snoo wrote: post #23
corradio wrote: post #18

Earlier quoted context omitted.

Take the reference that is 5min ago, call it T0. You will still observe that temperatures (i.e the sequence of measured temperatures minus T0) are increasing. Changing the reference changes the y-scale of a graph, but does not change the derivative (the speed at which it changes, i.e. increases or decreases).

Did you look at the graph? The local derivative is most definitely not indicative of a general trend. For comparison, I throw a ball down at the ground, and for the first 0.1 seconds it's moving down - can I conclude that the ball is going to keep moving down, even when it hits the ground? That's your logic.

I don't think you know what baseline means.

Baseline is just the starting point of the x-axis. It doesn't matter.

Personally I'd set the baseline to 0 degrees. Because thats how temperature works.

But you can pick whatever you want. It does not matter what you x-axis starts at. It doesn't change the data.

Or you could just have no baseline. Just remove the X-axis line from the graph.

Re: What's Really Warming the World?

#69

Post by imh »

vivekd wrote: post #4

What makes me mad about these kinds of data based climate change arguments is that they don't engage with the data in an honest way. The huge problem is 1880 was one of the coldest years in history. That cold period was caused by volcanism, several volcanos erupted causing a cold period that lasted from the 1600s to the late 1800s. This period is known as the little ice age. The worst of this period was in 1816 which…

At first, you might think it's just something like this (http://www.tylervigen.com/spurious-correlations), but as far as I can tell, the arguments come largely from first principles physics, validated through both experiments and historical observations including both human and natural records. I don't think this is a dishonest "look these line up!" argument.

I agree that it's frustrating when lay person proponents make arguments that don't hold up, and initially thought this article was doing that, but it's really just a snapshot into what's mentioned in the Methods section, which points to ModelE2 which is a physical simulation. It's being honest, just super brief.

Re: What's Really Warming the World?

#70

Post by makmanalp »

lrenaud wrote: post #38
euyyn wrote: post #12

Earlier quoted context omitted.

> proponents of global warming aren't engaging with the facts in an honest and forthright way. You want to read about global warming from climate scientists, as your questions are easily answered. Peer reviewers are as vicious as in any other science: the concerns you raise here would be the least of their ammunition.

That gives me even less faith in the quality of findings. Having seen the pathetic state of literature review in the various engineering fields, I cannot expect it to be better in meteorological fields. No doubt there is a certain subset of effective and critical reviewers, but I expect dogma, exciting findings, and name recognition still rule the day. The most the volume of politics in engineering where our work is…

I don't find this type of argument very useful because usually instead of making specific, falsifiable criticisms of the literature, this argument starts with "wow, scientists can be wrong or prone to human biases sometimes" which turns into a general "I have a touchy-feely sense that maybe some stuff is wrong with climate science", which quickly turns into "I guess most of the literature out there is completely wrong and thus we can do away with those conclusions regardless of the volume of evidence" to "I guess everyone and every viewpoint has an equal chance of being right".

Of course scientists make mistakes. Of course there is dogma and politics. Of course this has an effect, and of course we should take this seriously - and scientists can and do take it seriously. For example, look up the "reproducibility crisis" - some of the harshest criticism of existing science is yet again made by practicing scientists. But this is different than armchair handwringing.

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