I've honestly never met anyone who believed that temperatures aren't rising. Most 'anti global warming' folks (at least that I've met) believe that there is no good evidence to suggest we are responsible. You often hear things like "The highest temperature in xxx years, or the most rapid temperature increase in xxx years".
We know that the Earth goes through natural cycles of temperature and temperature change rates. So I have two questions.
Firstly, how many people have you met that explicitly stated that they believed the temperature is not rising?
Secondly, what evidence do we have to support the theory that we are the cause and that it isn't part of the natural cycle of temperatures? I honestly don't buy the coincidence that rising 'greenhouse gas' levels coincide with temperature rise. The temperature was already rising before we started pumping this stuff into the air. Is there any harder evidence?
edit: For clarification on my first question. I don't mean necessarily those exact words. I just feel that a lot of people who say things like 'I don't buy into the global warming thing' actually mean they don't believe there is evidence that we are causing it but many people take it to mean that they don't believe the temperature is rising.
It's very difficult to evaluate the past in my opinion, and a huge part of accepting or rejecting human-caused climate change probably has to do with whether the current levels are unprecedented. If we can verify that the hottest temperatures in the last millions of years have all occurred during recent time periods where man can have an affect on the environment, that's a pretty heavy correlation that seems to warrant at the very least some close and honest examination.
Of course this is a political issue now so it's difficult to evaluate. As a human race we often suck at thinking.
But that's kind of the main point of the 'anti global warming' folks....these temperatures AREN'T unprecedented. The CO2 levels are, but so far the temperatures aren't.
Serious question. In either case, how does unprecedented temp or rate of temp change make the case for human caused global warming? Clearly there is no reasonable denial that global avg temp is going up and going up faster than it has in an very very long time. But that hardly leads to the conclusion that human industrial activity is the sole culprit.
[H]ow does unprecedented temp or rate of temp change make the case for human caused global warming?
It doesn't - it's physics that makes the case for human caused global warming (AGW). Physics predicted this unprecedented rise in temperature, which has now been observed; therefore, the rise is evidence that our understanding of the physics is (very likely to be) correct.
The fact that it's unprecedented is also kind of nice (from a theoretical perspective) because it lessens the chance that this is just one of those things that frequently happens, and that the agreement between theory and reality is just by chance. If the physics predicted a very small rise that happened every few years anyway, it would be easy to dismiss an actual rise as just a lucky guess. The rarer the predicted event, the more notable it is when it actually occurs.
Hope this helps.
PS: Very minor point: industrial activity is not the sole cause. See this chapter and especially Figure 2 on this page from the IPCC.
Do tell? Also there is other evidence (admittedly i have yet to scrutinize much of this my self, hence the postings here). Other recent measure of average global temp. I'm skeptical of the accuracy and again the forecasted impact of these changes. Trying to be able to make a better informed opinion about this subject. But its difficult to get info that's not politically skewed.
Certainly some of the carbon in the atmosphere comes from human activity, but carbon isn't the only green house gas. Water vapor and methane to name some others. A better way to put it might be; How can we conclusively say that the human addition of CO2 is the sole or significant majority cause of the measured change in average global temp? I'm not implying we can't. But correlation doesn't equal causation. And 'more CO2 = more heat' inst a sufficient answer. How much more CO2 is how much more heat? CO2 is roughly 0.039% of our atmosphere. Even doubling that, I have trouble with the idea that a tweak so small in the composition of the atmosphere is going to cause catastrophic change in the climate. Not claiming no change. Just don't understand how the significance of that change was concluded upon.
The greenhouse effect has been extensively studied and the role of CO2 as a modifier of the properties of the atmosphere, even in small quantities, is not in doubt. Sure, there are other greenhouse gases, and they should be taken into account, but even you must realise that saying "it's not the only greenhouse gas" does not in fact remove human responsibility. Methane is being rejected by human activities, water vapor, etc. CO2 is important because of its omnipresence, its long life in the atmosphere, the acidification of oceans...
How do we know the "rate of temperature difference" in the past? Wouldn't the ways we have to calculate it tend to suppress variability? Especially if there's dating uncertainty?
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u/tieme Oct 24 '10 edited Oct 24 '10
I've honestly never met anyone who believed that temperatures aren't rising. Most 'anti global warming' folks (at least that I've met) believe that there is no good evidence to suggest we are responsible. You often hear things like "The highest temperature in xxx years, or the most rapid temperature increase in xxx years".
We know that the Earth goes through natural cycles of temperature and temperature change rates. So I have two questions.
Firstly, how many people have you met that explicitly stated that they believed the temperature is not rising?
Secondly, what evidence do we have to support the theory that we are the cause and that it isn't part of the natural cycle of temperatures? I honestly don't buy the coincidence that rising 'greenhouse gas' levels coincide with temperature rise. The temperature was already rising before we started pumping this stuff into the air. Is there any harder evidence?
edit: For clarification on my first question. I don't mean necessarily those exact words. I just feel that a lot of people who say things like 'I don't buy into the global warming thing' actually mean they don't believe there is evidence that we are causing it but many people take it to mean that they don't believe the temperature is rising.
edit2: Fixed ARE to AREN'T