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The Climate Change Thread

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Gagger

Nick Farr-Jones (63)
Staff member
My favourite

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Bruwheresmycar

Nicholas Shehadie (39)
I like what you've done here Karl, you've set up a situation where absolutely any claim you make for the rest of this entire thread can be backed up with "I've already posted the supporting evidence", and label anyone who doesn't believe you as a victim of alzheimers. That tactic might also work well over at: http://www.theflatearthsociety.org/forum/

Seriously though, if you are going to be making claims that you think you've backed up months ago. Maybe it's worth going over the posts again just to check what you are saying does in fact support the main claims being made. And if you do, write down the post number so you can reference it in your posts. (or is that too alarmist of me to ask?)

This is not a topic that I don't have a strong view on either way. I haven't done the research to have a strong opinion.

So to those who have; What percentage of the warming we have seen in the world is attributed to people and our emissions and what percentage is part of a natural warming process? How do they work this out?

Back to this. First, I found the IPCC have a part of their report dedicated to this question, here is some of what they say: http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-2-1.html , http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-7-1.html


How do Human Activities Contribute to Climate Change and How do They Compare with Natural Influences?
Human activities contribute to climate change by causing changes in Earth’s atmosphere in the amounts of greenhouse gases, aerosols (small particles), and cloudiness. The largest known contribution comes from the burning of fossil fuels, which releases carbon dioxide gas to the atmosphere. Greenhouse gases and aerosols affect climate by altering incoming solar radiation and out- going infrared (thermal) radiation that are part of Earth’s energy balance. Changing the atmospheric abundance or properties of these gases and particles can lead to a warming or cooling of the climate system. Since the start of the industrial era (about 1750), the overall effect of human activities on climate has been a warming influence. The human impact on climate during this era greatly exceeds that due to known changes in natural processes, such as solar changes and volcanic eruptions.



Are the Increases in Atmospheric Carbon Dioxide and Other Greenhouse Gases During the Industrial Era Caused by Human Activities?

Yes, the increases in atmospheric carbon dioxide (CO2) and other greenhouse gases during the industrial era are caused by human activities. In fact, the observed increase in atmospheric CO2 concentrations does not reveal the full extent of human emissions in that it accounts for only 55% of the CO2 released by human activity since 1959. The rest has been taken up by plants on land and by the oceans.
...
Emissions of CO2 (Figure 1a) from fossil fuel combustion, with contributions from cement manufacture, are responsible for more than 75% of the increase in atmospheric CO2 concentration since pre-industrial times. The remainder of the increase comes from land use changes dominated by deforestation (and associated biomass burning) with contributions from changing agricultural practices. All these increases are caused by human activity. The natural carbon cycle cannot explain the observed atmospheric increase of 3.2 to 4.1 GtC yr–1 in the form of CO2 over the last 25 years. (One GtC equals 1015 grams of carbon, i.e., one billion tonnes.)

So they basically say the warming is due to an increase in the greenhouse effect, and that humans are the ones causing an increase in atmospheric greenhouse gas content. (there is no natural force that has been dramatically increasing greenhouse gas output in the last 200 years).

How do they work this out? A few ways (that i've seen).

- They compare the pre-industrial co2 cycle to the present one. What they find is the natural co2 cycle balanced itself out for thousands of years before hand (ie: the oceans release about the same co2 as they absorb). Humans have come along and started adding to the carbon cycle, even though they only pollute a relatively small amount, they cause an imbalance in the system. Very simplified, but this is kind of the picture:

Carbon_Cycle.gif





We can cause an imbalance and drive up atmospheric co2 levels, that will cause changes to the greenhouse effect (like we observe).

- They can measure chemical ratio's in the atmosphere to determine where the extra co2 originates from.


The increase in atmospheric CO2 concentration is known to be caused by human activities because the character of CO2 in the atmosphere, in particular the ratio of its heavy to light carbon atoms, has changed in a way that can be attributed to addition of fossil fuel carbon. In addition, the ratio of oxygen to nitrogen in the atmosphere has declined as CO2 has increased; this is as expected because oxygen is depleted when fossil fuels are burned. A heavy form of carbon, the carbon-13 isotope, is less abundant in vegetation and in fossil fuels that were formed from past vegetation, and is more abundant in carbon in the oceans and in volcanic or geothermal emissions. The relative amount of the carbon-13 isotope in the atmosphere has been declining, showing that the added carbon comes from fossil fuels and vegetation. Carbon also has a rare radioactive isotope, carbon-14, which is present in atmospheric CO2 but absent in fossil fuels. Prior to atmospheric testing of nuclear weapons, decreases in the relative amount of carbon-14 showed that fossil fuel carbon was being added to the atmosphere.

- They use measurements of the earth's ingoing/outgoing radiation to determine changes in the earth's energy balance. I can't say I understand any of this, but there are some basic explanations out there if you look. http://en.wikipedia.org/wiki/Radiative_forcing

IPCC:
The contributions to radiative forcing from some of the factors influenced by human activities are shown in Figure 2. The values reflect the total forcing relative to the start of the industrial era (about 1750). The forcings for all greenhouse gas increases, which are the best understood of those due to human activities, are positive because each gas absorbs outgoing infrared radiation in the atmosphere. Among the greenhouse gases, CO2 increases have caused the largest forcing over this period. Tropospheric ozone increases have also contributed to warming, while stratospheric ozone decreases have contributed to cooling.


There is a page here with in depth answers to all questions like this: http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faqs.html
Or the actual report: http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch7s7-3.html
 

Joe Mac

Arch Winning (36)
Thanks Bru, great response.

From my extremely limited knowledge, I also recall people saying that the world goes through different cycles of warming and cooling. Prior to 1700 or so, we were in a cooling phase and we have since been in a warming phase. The argument here is that the world at time has been much hotter naturally and much colder naturally and that comparing the last 300 years to the previous is bogus for this reason.

From someone that spends a significant amount of time (albeit in finance) making predictions and forecasts, this sticks out to me as data mining or fitting the figures around an outcome that the scientists desire. Obviously this could only be the case if the world does go through warming and cooling cycles like I have heard... Does it and do those periods of warming and cooling fit roughly with those time frames?
 

Karl

Bill McLean (32)
I'll go back and dig them up if I have to but I have posted a few times with information about current temperature trends correlating to total solar irradiance data as well, actually a better correlation than to co2 where on IPCC predictions we should have seen significant warming in the last 10 years in line with increased atmospheric co2, but we haven't.
 

Bruwheresmycar

Nicholas Shehadie (39)
From my extremely limited knowledge, I also recall people saying that the world goes through different cycles of warming and cooling.

This sounds a little weird, the climate and the factors that determine it are well understood. I don't think you can separate the climate into exclusively short term/long term and "cooling/warming" phases. Generally a scientist would say "an increase in co2/solar input/milankovitch cycle, caused a drop/rise in temperature". Not "the earth was in a cooling phase for 300 years".

A video on the subject:


Prior to 1700 or so, we were in a cooling phase and we have since been in a warming phase. The argument here is that the world at time has been much hotter naturally and much colder naturally and that comparing the last 300 years to the previous is bogus for this reason.

The global temperature has been 'relatively' stable for the last few thousand years, but there have been a few drops/rises if you look at the records. Wiki is a good start: http://en.wikipedia.org/wiki/Temperature_record

You might be referring to the "little ice age" as the "cooling phase". But quite simply, scientists have a good idea of what factors caused that to happen, and whether much of that is still relevant to today's climate. http://en.wikipedia.org/wiki/Little_Ice_Age#Causes They outline orbital cycles, solar activity and volcanic activity as the main contributors to the changes in climate at the time.

People who think it's "bogas" to look at the last 200 years of our climate record because of something that happened in the past are just simplifying the issue too much (and are flat out wrong). Scientists are aware of the main drivers of climate and have a good idea of how they relate to both today, and 300 years ago.

Scientists do the maths and conclude increasing the greenhouse effect can change the climate significantly in a few hundred years. Just because "the climate changed before" doesn't disprove anything, it's a poorly thought out response to scientists.

From someone that spends a significant amount of time (albeit in finance) making predictions and forecasts, this sticks out to me as data mining or fitting the figures around an outcome that the scientists desire.

The only way you could come to that conclusion is with a lack of understanding of how scientists study/determine the climate. The video I posted above is pretty good covering the basics, even if you don't agree with his overall conclusion (which isn't an opinion, he's just explaining what scientists conclude).

Obviously this could only be the case if the world does go through warming and cooling cycles like I have heard. Does it and do those periods of warming and cooling fit roughly with those time frames?

This "warming/cooling" phase sounds like nonsense (it's not how scientists describe the climate in any sense). The global climate is historically determined by a few key factors. You could probably list all the different combinations of solar input, greenhouse effect and orbital cycles - split them into 3 different groups "warming, cooling and stable" phases and look at it that way. But I doubt that's what you are talking about here, rather just someone trying to over-simplify the issue an in attempt to discredit simple facts about today's climate.

Karl might come along and try to tie solar irradience to account for all the recent changes in the climate. But as far as I'm aware of there is no credible journals or universities supporting this conclusion (probably because there isn't enough evidence supporting it). But that wont stop him. I'm not even sure what it would prove, the Greenhouse Effect is still a key factor in determining the climate, and for as long as it's increasing, the amount of energy in the system will increase, which will eventually push up the temperature (and already has). Here is a graph plotting sun activity against co2 and temps: http://en.wikipedia.org/wiki/File:Temp-sunspot-co2.svg


But don't take my word, or Karl's word for it. Contact your local experts on the matter (maybe a university or something), get them to explain the science to you (or ask where you could find information from experts). Unless you think the thousands of smart people studying the climate at universities around our country are all tieing themselves to work that's either a hoax, or not valid physics, in which case there isn't much anyone can do to help. All sorts of crackpots say that about financial/economic forecasters don't they? But it can all be put down to their ignorance at the end of the day. (ps, I doubt you are someone who thinks like that, but there have been a few people entering this thread who do seem think like that)
 

Joe Mac

Arch Winning (36)
Bru, thanks again for the info- I am getting a much better understanding of the science behind this topic.

I have a gripe with the video though, and its a pretty big one.

As mentioned before, I have no background in science but I do have it in statistics. In the video, he says that the two key drivers of global temperature are C02 and Solar Irradiation (I think that's how you spell it). He says that neither of them are correlated with global temperatures but once combined they have a strong correlation with global temperatures. That doesn't make sense.

Its like saying; A is not correlated with C. B is not correlated with C. But A/B combined is very strongly correlated with C.


I see this stuff all the time with traders and trading books claiming to have worked out a way to forecast the future direction of the market. You can fit any set of indicators to past results and make it look accurate but when you apply them to real life situations, you find that they don't work at all. This look eerily similar to that type of claim... Have you got any other explanations for me to look at that might shed a little more light on this?
 

matty_k

Peter Johnson (47)
Staff member
I think what he is saying is:
On their own they do nothing but combined they have an effect.
And if I have that right then it is like heat, fuel and oxygen. Separately they are pretty harmless but when combined they make fire.

I know this is simplified but that is how I understood what was said in the video.
 

Bruwheresmycar

Nicholas Shehadie (39)
Bru, thanks again for the info- I am getting a much better understanding of the science behind this topic.

No worries.

I have a gripe with the video though, and its a pretty big one.

As mentioned before, I have no background in science but I do have it in statistics. In the video, he says that the two key drivers of global temperature are C02 and Solar Irradiation (I think that's how you spell it). He says that neither of them are correlated with global temperatures but once combined they have a strong correlation with global temperatures. That doesn't make sense.

We know they (GHG's and Solar Activity) both have a big impact on the global climate because you can do the maths and messure it. What they say is, towards the early stages of the earth's existence, solar output was low and the greenhouse effect was very high. Without a high greenhouse effect the earth would freeze over.

Over time the solar activity has increased, while co2 levels have decreased. Which can account for a major part of the historic temperature recordings of the earth.

Knowing this, if you graphed co2 alone against temperature over the long term, why would you expect an exact correlation? It wouldn't make sense.

It would be like saying; "the import price index has a big effect on our terms of trade, but doesn't directly correlate with terms of trade". But that's because there is another major determining factor. (the export price index)

Its like saying; A is not correlated with C. B is not correlated with C. But A/B combined is very strongly correlated with C.

The example in the video covers this quite well. Lets say you start measuring the temperature (C) of your house while leaving both the fireplace and heater on overnight. Let's assume the fireplace (A) gets progressively colder overnight, and the heater (B) gets progressively warmer over the night.

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You know that (A) and (B) are the determining factors of (C), but if you just graphed (A) and (C) alone you wouldn't get a correlation at all. You have left out key information, and all the video attempts to show is how some guy left out key information to promote his case against climate scientists.

Scientists apply this to today's climate as well. They measure all the determining factors and weigh them up against things like temperature. (I think) What they find is that there is a significant change in temperature that can only be accounted for by the rising greenhouse effect, the other key drivers of climate haven't changed significantly enough to account for all the changes we see.

I'm not great at drawing parallels, but as I said before. The terms of trade are dictated by 2 key drivers, but if you plotted only 1 against the terms of trade, it too would look weird. You'd be missing key information.


I see this stuff all the time with traders and trading books claiming to have worked out a way to forecast the future direction of the market. You can fit any set of indicators to past results and make it look accurate but when you apply them to real life situations, you find that they don't work at all. This look eerily similar to that type of claim. Have you got any other explanations for me to look at that might shed a little more light on this?

There are crock traders out there, but they aren't publishing for nature magazine :D I imagine the statistical training required to publish leading research about the climate/atmosphere is immense, they wouldn't make the basic errors you see in the crackpot parts of the finance industry. No leading science journal would systematically tie themselves to such basic errors.
 

Gnostic

Mark Ella (57)
As mentioned before, I have no background in science but I do have it in statistics. In the video, he says that the two key drivers of global temperature are C02 and Solar Irradiation (I think that's how you spell it). He says that neither of them are correlated with global temperatures but once combined they have a strong correlation with global temperatures. That doesn't make sense.

Its like saying; A is not correlated with C. B is not correlated with C. But A/B combined is very strongly correlated with C.


In natural systems two unrelated inactive or minimally active factors can combine to produce an effect in a system that is far in excess of the combined effect of the individual components. Indeed such factors can combine in such a way that the outcome is an effect/product that neither factor could produce individually.

The easiest way to think about this is by considering catalysts. In many catalytic systems the inputs are inactive until the catalyst is added to the system and a product is then produced that would not have happened otherwise. To go another step different catalysts in different concentrations can produce different results.

As I have posted earlier, this is a reason why no genuine Climate scientist will talk in absolute statements. The systems are too complex with far too many variables to make such statements. The idea that Solar Irradiation can have a significant effect on global temperature is valid. To dismiss it out of hand or assert it has minimal impact is as scientifically reckless as dismissing the theories surrounding atmospheric concentrations of CO2 and other greenhouse gases. The fact remains that in a global system ALL inputs will have an effect and those effects are cumulative. The question is what are the relative values of those inputs. In previous posts I brought up a few other inputs that also have to be considered in any wholistic review, Volcanic action, the Urban Heat Tank effect, changes to ocean currents due to infusion of fresh water from melting glaciers and ice caps and so forth.
 

Joe Mac

Arch Winning (36)
In natural systems two unrelated inactive or minimally active factors can combine to produce an effect in a system that is far in excess of the combined effect of the individual components. Indeed such factors can combine in such a way that the outcome is an effect/product that neither factor could produce individually.

The easiest way to think about this is by considering catalysts. In many catalytic systems the inputs are inactive until the catalyst is added to the system and a product is then produced that would not have happened otherwise. To go another step different catalysts in different concentrations can produce different results.

As I have posted earlier, this is a reason why no genuine Climate scientist will talk in absolute statements. The systems are too complex with far too many variables to make such statements. The idea that Solar Irradiation can have a significant effect on global temperature is valid. To dismiss it out of hand or assert it has minimal impact is as scientifically reckless as dismissing the theories surrounding atmospheric concentrations of CO2 and other greenhouse gases. The fact remains that in a global system ALL inputs will have an effect and those effects are cumulative. The question is what are the relative values of those inputs. In previous posts I brought up a few other inputs that also have to be considered in any wholistic review, Volcanic action, the Urban Heat Tank effect, changes to ocean currents due to infusion of fresh water from melting glaciers and ice caps and so forth.


I agree with what you guys are saying in terms of catalysts. That makes sense. But there isn't anything about these two things being combined which is a catalyst to increased temperature.

For example: They argue that a significant increase in C02 will increase temperatures on its own right? It doesn't say enough C02 will do nothing without an increase in solar irradiation...

They also don't say, a huge amount of solar irradiation will do nothing without a simultaneous increase in C02 do they?

A significant increase in either, on their own, should increase temperatures, on their own. Correct?

If that's the case then correlations should exist individually and if they don't then it seems to me that we are missing some inputs and the outcome of the analysis is questionable...
 

Gnostic

Mark Ella (57)
Its not that simple JM. Like I was saying the system as a whole has feedback loops (see previous post) as well as so many other inputs. Measuring one factor such as CO2 inputs from human sources will not prove or disprove anything other than we are a wasteful inneficient and poluting society. The increase in CO2 levels from human activities has profound impacts on so many regulatory systems that themsleves may impact global climate systems which can then lead to other changes in other systems and so on. Then add in the feedback loops changing still further systems to correct the balance and you will see why I say that no absolute statements can be made regarding any one or two such factors and that includes CO2 and Irradiation.

They will contribute in isolation and the effect together will be different and possibly magnified significantly but it is the overall effects that need to be looked at.

Let me just add another variable to the debate with regard to these two factors that hasn;t been addressed. What are the effects of increased electromagnetic irradiation on the polutants like Nitrous Oxides and Sulphur Oxides in the atmosphere? A quick answer is they change chemically into other compounds by the effects of this energy input and the system therefore can move in another direction again. What compounds are produced can be predicted accurately if you know the climatic conditions at the time of the exposure and the concentrations of the chemicals etc.

So in short can you see how highly variable the output of the systems are even when considering a vaery narrow range of inputs.
 

Cutter

Nicholas Shehadie (39)
On a more fundamental level, isn't Pythagoras' theorem an example of A and B alone not correlating with C but together they do?
 

Bruwheresmycar

Nicholas Shehadie (39)
I agree with what you guys are saying in terms of catalysts. That makes sense. But there isn't anything about these two things being combined which is a catalyst to increased temperature.

The "co2 vs solar activity" thing is probably something you should put to the side for now, that was mainly concerning the 500 million year graph in the video. When you are looking at short term changes to the system, (not long term correlation) it's a bit of a different picture. One that's not as simple.

For example: They argue that a significant increase in C02 will increase temperatures on its own right? It doesn't say enough C02 will do nothing without an increase in solar irradiation.

Altering the greenhouse effect can contribute to an increase the global temperature (through feedbacks as well) that is - If the other key factors that determine the global climate stay relatively stable over the same period (solar activity being one of them), so if co2 levels in the atmosphere dramatically rise, then you would expect changes to the climate such as rising temps.

They also don't say, a huge amount of solar irradiation will do nothing without a simultaneous increase in C02 do they?

These two factors don't rely on each other, what we were talking about before is how over extremely long periods of time - increasing solar activity is cancelled out by a decline in co2 levels. It doesn't have much relevance to the discussion about climate change we see today.

A significant increase in either, on their own, should increase temperatures, on their own. Correct?

Yes. (through a complicated process)

If that's the case then correlations should exist individually and if they don't then it seems to me that we are missing some inputs and the outcome of the analysis is questionable.

Think about it, to get an "individual correlation" over a period of time, you would need ALL factors that determine the climate staying exactly the same, while one dramatically rises. That just doesn't happen.

But you can calculate the influence of all known inputs/outputs, and determine whether there is a net loss/gain in energy to the system. That is something climate researchers do.

I don't have time at the moment to read up on the exact scientific position here. But I'm pretty sure the scientists conclude that the increase in the greenhouse effect we see today is not cancelled out by any other known factor, and that results in a (significant) net gain of energy into the earth's system. As a result we will see changes to the system.
 

Joe Mac

Arch Winning (36)
Thanks for your patience with me Bru. I am still dubious about the correlation thing. From those charts they look like it would be an extremely low correlation if any (maybe 0.2 or something) for each of the major drivers behind temperatures. In my mind, that seriously dicredits this idea.

BUT

You are right that I have effectively picked out one small thing and am not looking at the big picture. So moving right along.


A year or so ago I read Super Freakonomics and there was a great article on this topic. It talked about solutions that we could utilise to cool the earth in a short period if it became necessary. One was sending a tubs up with balloons into the stratosphere to put gas in there which would shield the earth from some of the rays and cool the earth... Do you know much about this idea?
 
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