Evidence for Man Made Climate Change

[Grandad.Malky]

No I don't, although it was from an IPCC report.

 

 

Accuracy of IPCC climate projections is questionable

 

Individuals in this section conclude that it is not possible to project global climate accurately enough to justify the ranges projected for temperature and sea-level rise over the next century. They do not conclude specifically that the current IPCC projections are either too high or too low, but that the projections are likely to be inaccurate due to inadequacies of current global climate modeling.

 

Richard Lindzen, Alfred P. Sloan Professor of Atmospheric Science at the Massachusetts Institute of Technology and member of the National Academy of Sciences: "We are quite confident (1) that global mean temperature is about 0.5 °C higher than it was a century ago; (2) that atmospheric levels of CO2 have risen over the past two centuries; and (3) that CO2 is a greenhouse gas whose increase is likely to warm the earth (one of many, the most important being water vapor and clouds). But – and I cannot stress this enough – we are not in a position to confidently attribute past climate change to CO2 or to forecast what the climate will be in the future.There has been no question whatsoever that CO2 is an infrared absorber (i.e., a greenhouse gas – albeit a minor one), and its increase should theoretically contribute to warming. Indeed, if all else were kept equal, the increase in CO2 should have led to somewhat more warming than has been observed."

 

Garth Paltridge, Visiting Fellow ANU and retired Chief Research Scientist, CSIRO Division of Atmospheric Research and retired Director of the Institute of the Antarctic Cooperative Research Centre."There are good and straightforward scientific reasons to believe that the burning of fossil fuel and consequent increase in atmospheric carbon dioxide will lead to an increase in the average temperature of the world above that which would otherwise be the case. Whether the increase will be large enough to be noticeable is still an unanswered question."

 

Hendrik Tennekes, retired Director of Research, Royal Netherlands Meteorological Institute: "The blind adherence to the harebrained idea that climate models can generate 'realistic' simulations of climate is the principal reason why I remain a climate skeptic. From my background in turbulence I look forward with grim anticipation to the day that climate models will run with a horizontal resolution of less than a kilometer. The horrible predictability problems of turbulent flows then will descend on climate science with a vengeance."

 

Antonino Zichichi, emeritus professor of nuclear physics at the University of Bologna and president of the World Federation of Scientists : "models used by the Intergovernmental Panel on Climate Change (IPCC) are incoherent and invalid from a scientific point of view". He has also said, "It is not possible to exclude that the observed phenomena may have natural causes. It may be that man has little or nothing to do with it"

[Cavegirl]

You will find an explanation here:

 

http://en.wikipedia.org/wiki/Younger_Dryas#Causes_of_the_Younger_Dryas

 

Unfortunately there is no other explanation than the huge rise in greenhouses gases for current warming. The sun is getting cooler, ground and ocean temperatures are increasing whilst the troposphere is cooling. The only explanation that accounts for both the warming and cooling at different levels of the atmosphere is the greenhouse effect.

 

The past climate has been divided into different phases- prolonged cold stages are 'glacials' and prolonged warm stages are 'interglacials'. Within our interglacial, known as the Holocene, there has so far been 1 stadial (short cold stage) known as the Little Ice Age (1300-1850AD) and 1 interstadial known as the Medieval Warm Period (950-1100AD).

 

During the Devensian stage- the previous glacial, we can recognise other stadial and interstadial events such as the Loch Lomond stadial (aka Younger Dryas in Europe) and the Windermere Interstadial.

 

This is what causes the problems with interpreting the data regarding anthropogenic climate change. The climate does and has changed naturally in cycles throughout the earth's history. We can't prove that modern climate change isn't also due to natural causes. The data set we tend to use most to recognise past climate change are ice core proxy records from the Arctic, but these depend upon the snow fall being compacted into layers so we cannot directly compare past climate records with modern climate records.

 

Modern data consists of temperature records, tree ring analysis (dendro records), analysis of CO2 levels and ocean pH values. It is very problematic to try to correlate these data sets with past ice core data sets and computer modelling is very unreliable because small changes in the programming of variables can lead to large distortions and exaggerated results.

 

We do know that CO2 emissions have increased quite dramatically over the past 50 years. This is potentially problematic for 2 reasons-

 

1. It could lead to increased CO2 uptake of the oceans, which are the main natural method of absorbing CO2 from the atmosphere. Increased uptake would lead to acidification of the oceans and this could be very detrimental to marine wildlife and to the balance of CO2 absorption.

 

2. The increase of gases in the upper atmosphere could trap more of the Sun's radiation beneath it thus gradually heating the surface of the planet.

 

However, the science is far from conclusive on this (anyone who says otherwise is lying). The computer modelling just isn't advanced enough to predict these things accurately and the variables involved are far too complex to fully integrate into the models. The data sets you choose can also provide totally different scenarios.

 

The fact is however, that if humans are changing the natural balances of the earth through industrial processes in any shape or form, we are taking incredibly serious risks. You don't need a science degree to figure that out.

[dell12]

I think you make several good points Cavegirl. My general thinking is that even if there is a 10% or even 0.1% chance that humans are partially or totally responsible for causing the climate to change we must do all we can to stop it, and mitigate our impact upon the earth.

[Cavegirl]

I think you make several good points Cavegirl. My general thinking is that even if there is a 10% or even 0.1% chance that humans are partially or totally responsible for causing the climate to change we must do all we can to stop it, and mitigate our impact upon the earth.

 

I couldn't agree more

 

But I think people are absolutely right to question whether a carbon tax is the best way to proceed with this. It does sound greedy and pretty ineffectual to me with carbon trading offering a 'get out of jail free' option and, as somebody else pointed out, a potential derivatives bubble for Goldman Sachs to earn a few more billions from in the near future.

 

It doesn't seem like a real commitment to reducing carbon in our atmosphere to me, but perhaps someone can put me right on this because I haven't looked into the economic situation as much as I have the environmental effects.

[Wildcat]

The past climate has been divided into different phases- prolonged cold stages are 'glacials' and prolonged warm stages are 'interglacials'. Within our interglacial, known as the Holocene, there has so far been 1 stadial (short cold stage) known as the Little Ice Age (1300-1850AD) and 1 interstadial known as the Medieval Warm Period (950-1100AD).

 

During the Devensian stage- the previous glacial, we can recognise other stadial and interstadial events such as the Loch Lomond stadial (aka Younger Dryas in Europe) and the Windermere Interstadial.

 

This is what causes the problems with interpreting the data regarding anthropogenic climate change. The climate does and has changed naturally in cycles throughout the earth's history. We can't prove that modern climate change isn't also due to natural causes. The data set we tend to use most to recognise past climate change are ice core proxy records from the Arctic, but these depend upon the snow fall being compacted into layers so we cannot directly compare past climate records with modern climate records.

 

Modern data consists of temperature records, tree ring analysis (dendro records), analysis of CO2 levels and ocean pH values. It is very problematic to try to correlate these data sets with past ice core data sets and computer modelling is very unreliable because small changes in the programming of variables can lead to large distortions and exaggerated results.

 

We do know that CO2 emissions have increased quite dramatically over the past 50 years. This is potentially problematic for 2 reasons-

 

1. It could lead to increased CO2 uptake of the oceans, which are the main natural method of absorbing CO2 from the atmosphere. Increased uptake would lead to acidification of the oceans and this could be very detrimental to marine wildlife and to the balance of CO2 absorption.

 

2. The increase of gases in the upper atmosphere could trap more of the Sun's radiation beneath it thus gradually heating the surface of the planet.

 

However, the science is far from conclusive on this (anyone who says otherwise is lying). The computer modelling just isn't advanced enough to predict these things accurately and the variables involved are far too complex to fully integrate into the models. The data sets you choose can also provide totally different scenarios.

 

The fact is however, that if humans are changing the natural balances of the earth through industrial processes in any shape or form, we are taking incredibly serious risks. You don't need a science degree to figure that out.

 

1. and 2. are happening and there is plenty of evidence for them.

 

The evidence of the cooling stratosphere is the strongest evidence that global warming is caused by CO2 emissions.

http://www.atmosphere.mpg.de/enid/20c.html

 

http://skeptico.blogs.com/skeptico/2009/05/upper-stratosphere-cooling.html

 

It is true the fine details of the science are not yet agreed upon the same could be said of any area of science, we don't yet have a grand unification theory, but at least 97.5% of those that publish papers on the subject are agreed that global warming is caused by humans. What makes you think that this weaker but more important issue is not settled?

 

http://www.skepticalscience.com/global-warming-scientific-consensus.htm

[Wildcat]

I couldn't agree more

 

But I think people are absolutely right to question whether a carbon tax is the best way to proceed with this. It does sound greedy and pretty ineffectual to me with carbon trading offering a 'get out of jail free' option and, as somebody else pointed out, a potential derivatives bubble for Goldman Sachs to earn a few more billions from in the near future.

 

It doesn't seem like a real commitment to reducing carbon in our atmosphere to me, but perhaps someone can put me right on this because I haven't looked into the economic situation as much as I have the environmental effects.

 

In principle carbon trading makes some sense but in practice it is pretty ineffectual.

 

As for carbon taxes.... well at least by taxing things that cause the problems there is money to be made that can be used to offset the damage done.

[Cyclone]

It was a joke but never mind if it went over your head.

 

So was my response. But likewise, never mind.

[Cavegirl]

1. and 2. are happening and there is plenty of evidence for them.

 

The evidence of the cooling stratosphere is the strongest evidence that global warming is caused by CO2 emissions.

http://www.atmosphere.mpg.de/enid/20c.html

 

http://skeptico.blogs.com/skeptico/2009/05/upper-stratosphere-cooling.html

 

It is true the fine details of the science are not yet agreed upon the same could be said of any area of science, we don't yet have a grand unification theory, but at least 97.5% of those that publish papers on the subject are agreed that global warming is caused by humans. What makes you think that this weaker but more important issue is not settled?

 

http://www.skepticalscience.com/global-warming-scientific-consensus.htm

 

I guess it's statements like this from your first link-

 

"Most of these readings only go back two or three decades at most and there are large uncertainities associated with the data."

 

which you say is the strongest evidence that we have for global warming that always reminds me to be sceptical of interpretations of scientific data.

 

I actually think the strongest evidence we have are charts such as this-

 

http://www.google.co.uk/imgres?imgurl=http://www.personal.psu.edu/ebt5007/IMG/atmosphere.jpg&imgrefurl=http://www.personal.psu.edu/ebt5007/hmwk3.html&usg=__7ll2Bbv9fI1tybgHp4GttdAGWc8=&h=505&w=600&sz=37&hl=en&start=4&um=1&itbs=1&tbnid=sroxiADRv1o9uM:&tbnh=114&tbnw=135&prev=/images%3Fq%3DCO2%2Bclimate%2Bchange%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26sa%3DN%26rls%3Dorg.mozilla:en-GB:official%26channel%3Ds%26tbs%3Disch:1

 

which show a strong correlation between CO2 levels and global surface temperature and illustrate the diversion that has occurred in the past 50 years, but even this doesn't prove that the apparent correlation is actually real. It depends upon all sorts of variables, some known, some unknown. We'll only know for sure after the fact whether this correlation is real because it has never been tested in this way before.

 

One thing, as I say, I know for sure, is that if we have more CO2 in our atmosphere than can be attributed to natural processes then we need to reduce that level because the risk is too significant to ignore.

[Wildcat]

Accuracy of IPCC climate projections is questionable

 

Individuals in this section conclude that it is not possible to project global climate accurately enough to justify the ranges projected for temperature and sea-level rise over the next century. They do not conclude specifically that the current IPCC projections are either too high or too low, but that the projections are likely to be inaccurate due to inadequacies of current global climate modeling.

 

Richard Lindzen, Alfred P. Sloan Professor of Atmospheric Science at the Massachusetts Institute of Technology and member of the National Academy of Sciences: "We are quite confident (1) that global mean temperature is about 0.5 °C higher than it was a century ago; (2) that atmospheric levels of CO2 have risen over the past two centuries; and (3) that CO2 is a greenhouse gas whose increase is likely to warm the earth (one of many, the most important being water vapor and clouds). But – and I cannot stress this enough – we are not in a position to confidently attribute past climate change to CO2 or to forecast what the climate will be in the future.There has been no question whatsoever that CO2 is an infrared absorber (i.e., a greenhouse gas – albeit a minor one), and its increase should theoretically contribute to warming. Indeed, if all else were kept equal, the increase in CO2 should have led to somewhat more warming than has been observed."

 

Garth Paltridge, Visiting Fellow ANU and retired Chief Research Scientist, CSIRO Division of Atmospheric Research and retired Director of the Institute of the Antarctic Cooperative Research Centre."There are good and straightforward scientific reasons to believe that the burning of fossil fuel and consequent increase in atmospheric carbon dioxide will lead to an increase in the average temperature of the world above that which would otherwise be the case. Whether the increase will be large enough to be noticeable is still an unanswered question."

 

Hendrik Tennekes, retired Director of Research, Royal Netherlands Meteorological Institute: "The blind adherence to the harebrained idea that climate models can generate 'realistic' simulations of climate is the principal reason why I remain a climate skeptic. From my background in turbulence I look forward with grim anticipation to the day that climate models will run with a horizontal resolution of less than a kilometer. The horrible predictability problems of turbulent flows then will descend on climate science with a vengeance."

 

Antonino Zichichi, emeritus professor of nuclear physics at the University of Bologna and president of the World Federation of Scientists : "models used by the Intergovernmental Panel on Climate Change (IPCC) are incoherent and invalid from a scientific point of view". He has also said, "It is not possible to exclude that the observed phenomena may have natural causes. It may be that man has little or nothing to do with it"

 

I like Richard Lindzen, he says tobacco smoking is only mildly linked with cancer..

 

if only we could chose what we believe to have the outcomes we want.

 

It is a shame the world doesn't work like that.

[Wildcat]

I guess it's statements like this from your first link-

 

"Most of these readings only go back two or three decades at most and there are large uncertainities associated with the data."

 

which you say is the strongest evidence that we have for global warming that always reminds me to be sceptical of interpretations of scientific data.

 

I actually think the strongest evidence we have are charts such as this-

 

http://www.google.co.uk/imgres?imgurl=http://www.personal.psu.edu/ebt5007/IMG/atmosphere.jpg&imgrefurl=http://www.personal.psu.edu/ebt5007/hmwk3.html&usg=__7ll2Bbv9fI1tybgHp4GttdAGWc8=&h=505&w=600&sz=37&hl=en&start=4&um=1&itbs=1&tbnid=sroxiADRv1o9uM:&tbnh=114&tbnw=135&prev=/images%3Fq%3DCO2%2Bclimate%2Bchange%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26sa%3DN%26rls%3Dorg.mozilla:en-GB:official%26channel%3Ds%26tbs%3Disch:1

 

which show a strong correlation between CO2 levels and global surface temperature and illustrate the diversion that has occurred in the past 50 years, but even this doesn't prove that the apparent correlation is actually real. It depends upon all sorts of variables, some known, some unknown. We'll only know for sure after the fact whether this correlation is real because it has never been tested in this way before.

 

One thing, as I say, I know for sure, is that if we have more CO2 in our atmosphere than can be attributed to natural processes then we need to reduce that level because the risk is too significant to ignore.

 

The article whilst admitting some uncertainty in the data is however sufficiently confident of it from a variety of sources to make the claims it does. All it has to show to is that there is cooling, whilst the troposhere warms, the precise extent of it is not so important, although it is sufficiently precise to show different levels of cooling at different heights, predictions made by the greenhouse effect theory that have been shown to be true and that are otherwise inexplicable.

 

Agreed on your last point. I just think however your scepticism about the consensus opinion misplaced.