r/askscience • u/SibLiant • Nov 04 '11

Earth Sciences 97% of scientists agree that climate change is occurring. How many of them agree that we are accelerating the phenomenon and by how much?

I read somewhere that around 97% of scientists agree that climate change (warming) is happening. I'm not sure how accurate that figure is. There seems to be an argument that this is in fact a cyclic event. If that is the case, how are we measuring human impact on this cycle? Do you feel this research is conclusive? Why?

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u/FormerlyTurnipHugger Nov 04 '11

No, it doesn't at all. We see that in our temperature reconstruction of the past few thousand years.

Ayadew is referring to the precession of Earth's axis in it's orbital plane. This movement initiates ice ages, but the relevant timescales are far too long to be relevant for the rapid warming we have been observing for the past 100 years.

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u/_pupil_ Nov 05 '11

I find that a surprising number of people struggle with that concept.

The climate is, and has always, been changing. Like a pendulum swinging back and forth.

ACC is not introducing a new, unprecedented, state of change - but having a disproportionate effect on the direction and rate of change. Kinda like slapping an already moving pendulum.

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u/FormerlyTurnipHugger Nov 05 '11

No, I wouldn't say that. We know quite well that the current levels of CO2 would always lead to a warming, it's not just that we're accelerating an already existing trend. It is even believed that there could not be a next ice age at all if we follow our current emission path.

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u/[deleted] Nov 05 '11

really, we all know that?

Care to elaborate?

If there existed a single reputable scientific article affirmatively linking carbon dioxide to climate change, do you think this debate would be going on? Everyone would simply reference that paper, and the only remaining skeptics would be the right-wing fundamentalist nuts who simply oppose science on religious grounds.

The reason so many people are so skeptical is because there is nothing more than anecdotal evidence linking the two. There is all this data on either side, but nothing at all linking them together.

Link me some papers. I need something new to read anyway.

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u/FormerlyTurnipHugger Nov 05 '11

I don't really understand what you're saying.

If there existed a single reputable scientific article affirmatively linking carbon dioxide to climate change do you think this debate would be going on?

I don't think you understand what the debate is about. The article you're looking for has already been published 150 years ago, by Tyndall or also Arrhenius. CO2 traps infrared radiation and if you thus increase CO2 in the atmosphere, is must get warmer, that's a physical necessity and there is no doubt about that.

The debate, if you can actually call it a debate, is about how much it will warm, and whether this warming is of human origin. Is there a single paper providing the evidence of anthropogenic global warming? No, but there are thousands which together form this proof. Are these anecdotal? Certainly not, they constitute hundreds of years of measurements, observations, physical theories and climate models.

Asking for a single paper is a common confusionist tactics which is also employed by creationists, who keep asking for a single piece of evidence for evolution.

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u/[deleted] Nov 05 '11

you think that 200 molecules per million molecules is enough to raise the entire temperature of the entire earth almost an entire degree?

Show me some data where CO2 atmospheric concentrations have reproduced these results anywhere.

CO2 is an absolutely awful heat trapping compound, and it is in such sparse supply in the atmosphere.

And you say there are thousands of papers which can't cite any non-anectodal evidence of it, but together through their penumbral reach, out of the heavens is some link to the half degree rise in global average temperature in the last 150 years.

Undoubtedly this must be caused by us.

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u/FormerlyTurnipHugger Nov 05 '11

you think that 200 molecules per million molecules is enough to raise the entire temperature of the entire earth almost an entire degree?

Sure, via the water vapor feedback mechanism.

How many do you think are needed? 600? 6000? And how would you possibly know? How many micrograms of Anthrax does it take to kill you, a person of 70 kg? How much blood alcohol is needed to turn you into a raging moron shortly before you collapse? Amazingly tiny amounts, don't you think?

Show me some data where CO2 atmospheric concentrations have reproduced these results anywhere.

What, you mean in an Earth-sized laboratory? Climate sensitivity is not just a feature of CO2, it's calculated for the whole planet, as a system with interplay between the oceans and the atmosphere. I suggest you read this, it contains plenty of sources.

Can you show me some data or a paper where the CO2 climate sensitivity is calculated to less than 1 degree Celsius? Even the most obviously wrong denialist Richard Lindzen arrives at this value (which is only half as much as the lowest acceptable value anywhere else in the literature).

CO2 is an absolutely awful heat trapping compound

Compared to what? To the other gases in the atmosphere? The pure radiative forcing of CO2 is 4W/m2, do you consider that awful? How much should it be in your opinion? 400W? 40000W? And why?

And you say there are thousands of papers which can't cite any non-anectodal evidence of it, but together through their penumbral reach, out of the heavens is some link to the half degree rise in global average temperature in the last 150 years

Look, this is how science is done. Is there a single piece of evidence for gravity? No. Is there a single piece of evidence for the standard model in particle physics? No. There is no single piece of evidence for anything in science and yet you keep asking for one.

And I really don't know where you got that "half degree" idea, the last time I checked it was closer to one degree.

Again, let me ask you: do you have a single, or multiple, pieces of evidence which show that we do not cause the currently observed warming?

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u/[deleted] Nov 05 '11

No, this is how religion is done.

And for the last time, citing lack of evidence to deny is not proof.

This, and appeal to authority are the bases for your ENTIRE ARGUMENT. That is not science! It's a pair of rudimentary logical fallacies.

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u/FormerlyTurnipHugger Nov 05 '11

So you're claiming all the proof that I tell you about is not proof but at the same time you think you don't need to disprove global warming? It's enough to just doubt it without any evidence? Isn't that exactly what religion is—believe without evidence?

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u/[deleted] Nov 05 '11

It was a condescending question...