/sci/ - Science & Math

Where did you find that trainwreck of an image? It claims to be global average temperature, doesn't provide an actual data source, and looks like Greenland ice-core data. Also, it says nothing about when the near cut-off date is. I bet it doesn't go to past 1950.

Here's an actual reconstruction, graphed with current surface records. The two data set's aren't completely comparable, but it gives a decent idea of the scale of changes over the last 10k years.

First of all the scale of these graphs are literally 0.1 degrees , which means the big changes that appear to be occurring are actually nothing.
Second of all it doesn’t even make sense to make a global temperature average, why would you take the average of a place where on Antartica the temperatures can reach -70° and in Australia temperatures can reach 70° ? It doesn’t make any sense
Third of all, it has been proven that CO2 has NOTHING to do with temperature, actually, CO2 is dependent on the temperature, it is seen through various graphs that when the temperature decreases, the CO2 decreases after and the same thing when it increases (this is due to the amount of consumption of CO2 on the oceans according to the temperature but let’s not get to deep into that)

man kill earth while science man cry. god return everything later.

>>9338867
The Republican Party folks!

>>9338867
>it has been proven that CO2 has NOTHING to do with temperature
Okay.

>>9337995
>>9338628
Climate scientists here, neither of these graphs are fair graph.

The first graph is from ice core borehole temperature reconstruction spline fit through heat equation models. What they didn't tell you is that in the proper citation, Alley et al. 2000 a +- 3C uncertainty was given and the denier didn't give uncertainty envelope on their graph, plus adding a bunch of meme notations about human periods that are incorrect. The actual source paper didn't talk about Holocene climate variability, but rather the abrupt warming in the last deglaciation.
www.pnas.org/content/97/4/1331.full

The second graph is not fair only because Shaun's T reconstruction because it has about 120 years of running smoothing average on it. Slapping a modern, sub annual temperature rise at the end there is not fair, the least they can do is to do the same 120 year smoothing. Don't take it from me, take it from the author himself
http://www.realclimate.org/index.php/archives/2013/03/response-by-marcott-et-al/

Q: What do paleotemperature reconstructions show about the temperature of the last 100 years?
>Our global paleotemperature reconstruction includes a so-called “uptick” in temperatures during the 20th-century. However, in the paper we make the point that this particular feature is of shorter duration than the inherent smoothing in our statistical averaging procedure, and that it is based on only a few available paleo-reconstructions of the type we used. Thus, the 20th century portion of our paleotemperature stack is not statistically robust, cannot be considered representative of global temperature changes

>>9337995 (OP)
>>9338628
Climate scientists here, both of this graphs are misleading

(1). The first graph is from ice core borehole temperature reconstruction spline fit through heat equation models. What they didn't tell you is that in the proper citation, Alley et al. 2000 a +- 3C uncertainty was given and the denier didn't give uncertainty envelope on their graph, plus adding a bunch of meme notations about human periods that are incorrect. The actual source paper didn't talk about Holocene climate variability, but rather the abrupt warming in the last deglaciation.
www.pnas.org/content/97/4/1331.full

(2) The second graph is not fair only because Shaun's T reconstruction has about 120 years of running smoothing average on it. Slapping a modern, sub annual temperature rise at the end there is not fair, the least they can do is to do the same 120 year smoothing. Don't take it from me, take it from the author himself
http://www.realclimate.org/index.php/archives/2013/03/response-by-marcott-et-al/
>Q: What do paleotemperature reconstructions show about the temperature of the last 100 years?
>Our global paleotemperature reconstruction includes a so-called “uptick” in temperatures during the 20th-century. However, in the paper we make the point that this particular feature is of shorter duration than the inherent smoothing in our statistical averaging procedure, and that it is based on only a few available paleo-reconstructions of the type we used. Thus, the 20th century portion of our paleotemperature stack is not statistically robust, cannot be considered representative of global temperature changes

>>9337995
How about retreat of sea ice?

>>9338972
Really appreciate the nuance. It's difficult to find non-propaganda when looking for information on this subject.

>>9337995

>>9337995
>Can you provide a good argument against or for climate change and human influence on it?

1. CO2 is a greenhouse gas. It absorbs and reemit infrared while allowing visible light to pass. This is a fact, and 19th century undeniable physics
2. CO2 in the atmosphere is rising due to fossil fuel burning since the end of 19th century. This is also a fact.
3. 1+2 =3. When you add CO2 into the atmosphere, it is only fundamental physics that the earth will warm

Many different kinds of proxy data all show a rapid warming trend in the past 100 years and a slight cooling trend prior to that. This matches with instrumental records for the past 100 years (the black line).

>>9339838

>>9339168
Not the anon you replied to but have you heard of the meme that CO2 radiation is saturated and that adding more CO2 will not change anything?

>>9340012
That's like claiming a blanket is saturated, so adding another one on top won't do anything. It's not how thermodynamics works.

>>9340012
>>9340935
There is actually a lot of truth to that statement, we climate scientist called it the band saturation effect. David Archer wrote an really good intro chapter into greenhouse gases and has a whole subsection on band saturation effect here if anyone is interested
http://forecast.uchicago.edu/chapter4.pdf.. Pic related is the figure that he had on the chapter. This is why climate sensitivity is defined as change in W/m2 energy per doubling of CO2 concentration.

While band saturation effect is true and well known, it is well accounted into all climate models. It is kind of dirty tactics by denier to point out the band saturation effect, without going into the nitty gritty math details of integrating the whole absorption spectra for a given column of atmosphere (which is a fairly complex math to do, not even I remember how to do it because these things are automated in the models).

The bottom line is that there is a reason why 350.org is a thing. Preindustrial CO2 was 280ppm, and if you assume that you don't want an equlibrium temperature increase of more than 2 degrees C beyond preindustrial climate then plugging into EQ4-1 you'll get 350 ppm as your maximum CO2 limit.

This is a pretty rough calculation given the complexity of a climate system, but it is rooted in fundamental physics, and the layman answer is that yes the effect of band saturation is well known and taken into account in all climate models and policymaking decision

>>9337995
>i guess
L0Lno fgt pls

Impressive, thanks for the info. Could you share some more oppinions on whether the current panic makes sense?

>>9338972
>Don't take it from me, take it from the author himself

And yet people like this know full well the graph is the only thing anyone will ever see or remember and his bullshit-baffles-brains explanation of it is beyond the comprehension of the average person.

If you know you shouldn't be concatenating temperature data sets obtained using different instruments/proxies, just don't fucking do it. It's not that hard.

>>9337995
This video sums it up nicely, in a language everyone should be able to understand.

>>9337995
https://www.youtube.com/watch?v=9mxZoUdYOWA
This video sums up this discussion, in a simple language everyone should be able to understand.

If global warming is real then how come we still have winter?

>>9340012
Adding more CO2 results in band broadening - absorbance at the sides of the absorbance wavelength. Absorbance increases as ln(CO2) rather than as (CO2) as it would if it were not saturated. Not all transitions are saturated.

>>9342801
define "winter"

>>9342801
How come when I wear a thick woolly jumper I'm still colder at night than during the day?