I am on the fence, but I tend towards skepticism.

borez · 3 months

It's interesting on r/skeptics that the tide goes against anyone being skeptical against AGW, for a group of so called "skeptics" I find it most amusing that the science is settled there.

FTR: I'm on the fence too. I won't go into why here though, it's just a pointless exercise.

AlyssaMoore · 3 months

Here is one of my favorites that explains most of the skeptics' side:

Understanding the Global Warming Debate:

http://www.forbes.com/sites/warrenmeyer/2012/02/09/understanding-the-global-warming-debate/

The global warming alarmists' side is here at the UN's website:

http://www.ipcc.ch/

blackbird_jellyfish · 3 months

I found this page to be informative and interesting.

One of the criterion of distinguishing science from pseudoscience is falsifiability, that is whether there is a test for the hypothesis which can disprove it. There is nothing, it seems, which can disprove AGW and yet everything seems to prove it. More snow? AGW. Less snow? AGW. Cooler temps in one area? AGW. Warmer temps in another? AGW. Rain? AGW. Drought? AGW.

A scientific theory which is proven by everything doesn't really inform us of anything.

Kim147 · 3 months

Firstly it's a question of percentages , of the percentage of CO2 in the atmosphere and the percentage of that due to man . Then it's a question of the properties of CO2 versus all the other gasses and other molecules including H2O - CO2 isn't some magical molecule that has vastly stronger effect than other molecules . This is application of basic commonsense .

Then it's looking at it on the basis of causality . The AGW crowd have never shown any experimental proof .

Then it's a matter of looking at all the factors including :-

the history of climate over the centuries - the Medieval Warm Period , the Mini Ice Age - not man related - other stronger natural forces at work .
the fact that the solubility of CO2 in water is inversely proportional to temperature and that CO2 concentrations in the atmosphere lags the temperature rise by around 800 years - it takes that long for the warming to penetrate deep down and release the CO2 from the depths .
the effect of the Sun , the galaxy and cosmic rays - well documented .
the effect of water vapour - anyone who has been in a hot country such as Australia knows about this .
the natural weather processes going on - El Nino etc. .

Basically anyone who has good scientific or engineering training can easily recognise poor science when they see it and AGW absolutely reeks of it .

On top of this :-

the lack of determining and specifying the error margin of the temperature measurements made .
the usage of thermometers in weather stations that were in rural areas that are now urbanised - now in heat islands .
the use of unproven computer models .
the fact that predicted temperature rises have not occurred over the last 12+ years . In fact non of the predictions have proved correct .
the cherry picking of data . The adjustment of results . The lack of releasing of all data and methods and the associated lack of full peer review .
the lack of usage of the scientific method . The highly politicised and personalised and very religious approach of the AGW proponents .

The Sun has been going through a very different phase than it normally does . It normally has an 11 year sunspot cycle . It is currently going through a high activity to no activity change . This could produce another Maunder Minimum - cold weather . IE. there is a lot more going on than the AGW proponents are considering .

One of the very basic mistakes the AGW proponents make is that they narrow their focus so much that they miss a lot of the science - they miss a lot of what is happening and why it is happening .

It's basic theory of knowledge - basic set theory - if you narrow the focus - ie. narrow the locus of validity - you don't make things more valid but instead less valid . Just because the facts match up more closely that doesn't mean that their application - their locus - is more valid . Quite the opposite .

butch123 · 3 months

The basic issue here is not that climate changes...we all know it does. The issue is whether or not CO2 is the main driver of climate change in our time. Those who propose this position seem to denigrate all other causes and present the sky is falling arguments. Those who see other drivers of climate at work, are not accepting of the CO2 causes all warming. Some of the issues are cyclic warming /cooling, natural variation, warming trend for close to 400 years without large increases of CO2. CO2 increases following temperature historically rather than leading it. Denial by AGW proponents that Sun output influences climate. A host of other false alarmist statements that have been made over the years to scare people about climate change

lowlevelguy · 3 months

OMG this is awesome, I'm gonna start digesting. Reddit is a great place to have these convos

ascylon · 3 months

It seems I came late to the party, but let me offer my reasons

First of all a list of the things I agree on with the AGW side:

A doubling of CO2 causes a forcing change that equates to just over 1 degree of warming (no feedbacks). This is a tangential point and I have currently no reason to doubt it.
Water vapor feedback (not including clouds) is positive. This is logical, more warming increases the capacity of air to carry moisture, and more moisture means an enhanced greenhouse effect. I am skeptical about the claim that relative humidity stays constant with an increase in temperature because of the energy required to evaporate enough water to increase it, but I accept the IPCC estimate of 0.5-0.6 degrees of positive feedback from water vapor as the upper limit.
Most of the CO2 rise (80-100%) since the preindustrial era is due to human activity.
Changes in TSI or Total Solar Irradiance can explain very little of the warming since the early 1900s. Note that this only includes the direct effect in solar output, not indirect effects.

Then the points that I am skeptical about:

Positive cloud feedback is assumed implicitly in climate models. This means that for every 1 degree of warming, the models expect another 2-3 degrees from changes in cloud cover. This is simply a guess, however, because there is no empirical evidence that the cloud feedback is positive globally. Models are also incapable of modeling cloud cover and major climatic cycles. The climate models that present CO2 emissions as the main cause of warming absolutely require positive cloud feedback, without it there's no disaster or alarm.
Just as an example, the cloud feedback at the tropics is heavily negative. Basically as temperatures start warming in the morning, moist air starts rising and forming clouds. These clouds reflect some of the solar energy from reaching the surface, slowing down the warming. If temperatures keep increasing, even more water evaporates and at some point you get a thunderstorm that actually cools the temperature by both blocking nearly all solar radiation but also transporting heat up where it more easily radiates out to space. Considering tropics gets the most solar energy per unit of area, assuming a positive cloud feedback when it's negative at the tropics requires extraordinary evidence to the contrary, which is something that doesn't exist (yet).
Different natural cycles are all but ignored in the models. Let's take AMO for example (woodfortrees.org. There's a clear long-term correlation between temperature and the AMO and while correlation does not automatically imply causation, the two correlate far too well to be just a coincidence. Because the AMO and others (such as the PDO) are cycles, they can't explain all of the warming in the 20th century, but they can exaggerate it when they are moving from their cool to warm phases (1910-1940 and 1970-2000 for the AMO) and mask it when moving from the warm to cool phase (1880-1910 and 1940-1970). Since these periods coincide well with the periods of warming/cooling, I believe neglecting cycles as potential contributors to temperature trends is a mistake. PDO is another significant oceanic cycle.
Ocean acidification becoming a major issue. This is a seperate attempt at demonizing CO2, and basically assumes that a pH change of about 0,3 to 0,4 in the next century will have adverse effects on sea life. There are a few issues with the theory, though. First of all the oceans would not "acidify" but rather will become more neutral as oceanic pH is around 8 (lots of local variation, though). Secondly, local monthly variation can be as high as 1,5 pH units. Certainly some species can be affected, but there simply is no reason to assume that the effect will be significant or even noticeable.
The claim that the variation in solar activity has no effect on the climate. As I stated above, I agree that TSI changes are fairly insignificant, but indirect solar effect on clouds remains a real possibility. The problem is that this area is still undergoing research, like Svensmark's cosmic ray hypothesis, and as such there is strictly speaking no conclusive evidence of a solar-cloud link. One reason is the lack of cloud cover measurements. Observations and experiments have been made that support the hypothesis (such as looking at cloud cover changes in response to a Forbush decrease and the Cern CLOUD experiment), but nothing yet that shows whether the magnitude of the effect is large enough. The Svensmark hypothesis is not the only one, increased solar UV emissions have also been hypothetised to be a possible cause. Funnily enough, the 1910-1940 warming period is explained away with increased solar activity, but the 1970-2000 period absolutely must be caused mainly by CO2.

To conclude, I believe that the cause of the warming has been both the solar effects and CO2 with cyclical components added from at least the AMO, possibly also from the PDO. I have no idea what the relative strengths are but as both the oceanic cycles are moving into their cool phase and solar activity is expected to decrease dramatically, the question should be answered in the next 5-10 years. About the only thing I worry wrt climate is the adoptation of ruinous economic policies based on the climate scare instead of using resources for problems that are real. I am willing to entertain the possibility that I will be proven wrong in 10 years if temperatures start climbing but considering all the uncertainty involved, the developing nations' increasing emissions (mainly China/India) and the costs involved in CO2 reductions that are meaningless as long as developing nations don't participate, I don't think wanting to wait another 10 years is unreasonable.

lowlevelguy · 3 months

This subreddit is probably the least informed place to ask. Try /r/climate

OortCloud · 2 months

You'll notice that this sub is trolled ruthlessly by AGW supporters. If you do a quick check you'll find that they are usually the first to comment regardless of the headline topic. You'll also observe that the skeptics are trying to talk to you and give answers while the supporters are trying to convert you. Welcome to the sub.

The only criticism I'll offer of your post is that you're a bit vague. Most people have at least some understanding of the topic so it's not a good use of time or space to go over stuff you already know. Here is a link to a recent article that gives a good overview of the skeptic case. While it's not exhaustive it's a great start. You could ask specific questions on any of those topics and most of the skeptics will be happy to answer as best they can. We, at least, know that we don't have all of the facts.

Kim147 · 3 months

Just one point on water vapour . A very simple set of tests :-

1) sit on a beach without clouds - hot sun bearing down . Sit on the same beach with clouds - cooler .

2) in the desert with no clouds , at night - cold . With clouds - at night - warm .

The water vapour will retain the heat but it won't trap the heat as a greenhouse gas does . It has a strong effect on temperature but much more as an insulator than as a greenhouse gas .

GWstalker · 3 months

Hey lowlevelguy. I'm really happy to see what appears to be a true skeptic. Most people who call themselves "skeptics" are anything but.

It's the sign of a true skeptic when someone admits to not knowing enough to come to a conclusion.

I was once in a position like yours, but I'm not going to start convincing you what's right or wrong. Instead I'll encourage you to investigate for yourself. You'll learn a lot more, and be much better equipped to dealing with questions about it in the future.

Like you, I tended towards skepticism. I had heard about all the nasty stuff going on at the IPCC, the fakery, the trickery, etc.

So I started asking questions about these things in debates between skeptics and AGW proponents.

I quickly found that one of the sides consistently misrepresented the science. In addition to that, they used dishonest tricks like cherry-picking, quote-mining, Gish Gallops, constantly changing the subject, frequently just posting lots of claims and never following up when someone asked critical/skeptical questions.

If you want to know what to think, look at the debate, and notice who are the most anti-science. The science is the key here.

I found that those who oppose the science are the ones that use dishonest tactics to win debates because they feel that the science threatens their world view.

Look at the science. If you are a true skeptic, you will get it right.

nuclear_is_good · 3 months

People that will try to sell you the idea that you can easily understand in 10 minutes the intricate details which are generally the result of researching for 20-30 years in very specific fields are most likely selling you snake oil. Only if you have a very strong scientific mind, with very good understanding of mathematics, physics and basic statistics and you are ready to take a few months to become familiar with the mountains of evidence that are very relevant to this field you might be able to reach a decent level of generic (non-expert) understanding which will not automatically give you the ultimate answers but at least will allow you to make informed decisions on which papers are relevant and which are debunked junk.

That being said - if you are curious about the overwhelming consensus among the actual climate scientists the best place to start is at:

http://www.ipcc.ch/

If you are not ready to enter very detailed and more general/complex aspects but instead you want some good and accessible answers to questions which seem to cast doubts on the position of actual climate scientists then a very interesting place to start will be

http://www.skepticalscience.com/argument.php

Some people might argue that some of the points scored on that very long list are not precisely reflecting their own position - but as we have seen just yesterday the debate on uncertainties is just a matter of the magnitude in probability between skepticism and denial :)

you'll need to login or register to do that

create a new account

login