What's the actual, tangible proof that man causes global warming?

Question

We all know the theory - we've increased the atmospheric CO2 levels by 30% of the immediately prior CO2 level (or, 1/11,000th of the atmosphere, though the AGW advocates don't put it in that context), CO2 traps heat, and starting about 80 years after we started to increase the CO2 level, the planet started warming, and has since warmed 1.1 degree F.

But it's also true that the present climate shift is similar in rate and extent to all the other ones, that the climate history is a sequence of intermittent multi-century warm and cool periods, and that we were coming out of a 400+ year cool period when the present warm period began. It's also true that during many warmer periods, CO2 levels were lower than today. CO2 is one of the weaker 'greenhouse' gases and its effects are dwarfed by water vapor, the level of which has almost nothing to do with us.

Stratospheric cooling is consistent with the CO2 blanket theory but has been going on for only about 20 years, not 120.

Answer 1

OK, first of all, in science, a hypothesis can never be proven to be correct. We only prove things in math. In science, we can do research and find data to DISPROVE an hypothesis, but you can't go the other way.

Does this lack of proof stop us from using the science to build paticle accelerators, electron microscopes and send people to mars and the moon? No. We go with what we've got.

The relatively constant average temperatures of the last 10000 years (http://en.wikipedia.org/wiki/Image:Holocene_Temperature_Variations.png ) has provided a stability that has allowed the human race to flourish. What we've experrienced in the last 40 years (http://www.co2science.org/scripts/Template/0_CO2ScienceB2C/images/subject/other/figures/mannetal_nh1000.jpg ), is NOT like anything seen in the last 10,000 years. The last 10000 years hit a sweet spot that I don't see on the graphs of the last 450,000 years, see for yourself: http://en.wikipedia.org/wiki/Image:Ice_Age_Temperature.png

I find the untruths, half-truths and misleading arguments I see here irritating in that a few minutes of unbiased reading shows them for what they are. It's like shooting down sitting ducks. The following is copied from http://www.care2.com/c2c/share/detail/15656 :

Fact vs. Fiction on Climate Change
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We've just had the coldest day in June -- so much for global warming!


Fiction: Just look at X: it's the coldest day/month/year on record ... or: Region X has cooled by Y°F over the past two years! There is no global warming!


Fact: Statements like the one above are deliberate attempts by climate contrarians to confuse and mislead the public. It's an attempt to disprove the reality of global warming with a cold weather anomaly. This is not only scientific bogus, comparing apples and oranges, but outright dishonesty. Weather is the state of the atmosphere at a given time and place, defined by variables such as temperature, moisture, wind, and barometric pressure. It is highly variable from day to day. By contrast, climate describes long-term weather patterns, with average temperatures and precipitation totals as well as typical occurrences of climatic extremes (such as normal dry periods or tropical storms) being used to characterize the climate for a particular region. This distinction is very important. Averages are always made up of numbers differing from the mean. Global warming is about the average going up. Over time this will make extreme colds become less likely.



Oh, what's a few degrees?


Fiction: A few degrees temperature increase won't matter much, and besides, warmer is better -- fewer cold-related deaths, longer growing seasons, lower heating bills. How many people actually notice the difference between 86 and 88.5°F?


Fact: Considering that in some regions people experience large daily temperature ranges (20-30°F), climate skeptics try to convince the public that global warming by a few degrees is nothing to worry about. This is another version of deliberately confusing weather and climate (see above). A small increase in the average temperature, however, obscures extremes and patterns of warming that are quite troubling: nighttime temperatures increase more than daily averages; there are already and will be more extreme heat but less extreme cold events; poleward latitudes warm more than other areas, etc. While the benefits of warming pointed out in the skeptics argument are certainly among the potential impacts of climate change, the potential negative impacts -- such as heat-related illnesses and deaths, increased heat stress for crops, greater energy needs for cooling etc. -- are strategically omitted. Moreover, it bears emphasis that the difference in global average temperature between the last ice age and the present day is about 9°F! This puts the IPCC's projected range of climate change-related global average temperature increases of 2.5-10.4°F in an entirely different light.



Human CO2 emissions are small compared to natural CO2 exchange.


Fiction: The 4.5% of the world's greenhouse gases that humans generate is insignificant when compared to the 95.5% generated by nature.


Fact: It is indeed true that human emissions of CO2 are a small percentage of the total carbon cycled through the different components of the Earth system: plants, soils, rocks, the oceans, and the air. But these human emissions are by no means insignificant. For the last 420,000 years, until the beginning of the industrial revolution (~1750), this cycle of carbon exchange was in a quasi-stable equilibrium, i.e., the continual release and uptake of carbon kept CO2 concentration in the Earth's atmosphere fluctuating between 180 ppm (parts per million) and 280 ppm. Since 1750, the atmospheric concentration of carbon dioxide has increased by 31%, to a present level of 367 ppm. This increase in the CO2 concentration of the atmosphere is mainly due to the burning of fossil fuels and large-scale deforestation and land-use change. These human activities have forced the carbon cycle out of the state of equilibrium and out of the known range of variation.



Satellite temperature records don't show any global warming.


Fiction: Satellite temperature records do not show a warming trend over the past 20 years, and ground-level data are incorrect and exaggerate the warming.


Fact: It is true that temperature records derived from satellites show either less warming than surface temperature data or even a cooling trend. Recent studies (most notably a study by the National Academy of Sciences published in 2000) found, however, that satellite data needed to be adjusted for some measurement and calibration problems. These adjustments bring surface and satellite records into better agreement, both showing a warming trend. It is important to note that many surface temperature records date back to 1860, while satellite records only date back to 1979. With such a short data record, observed trends can be strongly affected by extreme conditions -- such as the 1991 eruption of Mt. Pinatubo which decreased atmospheric temperatures for several years. In addition, satellite and surface data differ in what they record: surface thermometers measure the air temperature at the Earth's surface, while satellite data take temperatures of different slices of the atmosphere. Including records for the upper atmosphere -- where the depletion of the ozone layer has had a cooling effect -- will lower the overall temperature trends observed from satellites.



The observed warming is all due to solar variation, not human activities.


Fiction: An increase in solar irradiance is the main cause of the Earth's current warming trend. Therefore, reducing fossil fuel emissions would not impact the Earth's temperature.



Fact: Current scientific understanding leaves little doubt that the sun's radiant output impacts the Earth's climate on both decadal and centennial time scales. However, it is only one of many components affecting terrestrial climate. According to the findings of the Intergovermental Panel on Climate Change, the warming effect due to increases of greenhouse gases in the atmosphere is estimated to be more than 8 times greater than the effect of solar irradiance.



What about the 19,000 scientists who claim we should not worry about global warming?


Fiction: There is no scientific consensus on climate change. Just look at the 19,000 scientists who signed on to the Global Warming Petition Project.


Fact: In the spring of 1998, mailboxes of US scientists flooded with packet from the "Global Warming Petition Project," including a reprint of a Wall Street Journal op-ed "Science has spoken: Global Warming Is a Myth," a copy of a faux scientific article claiming that "increased levels of atmospheric carbon dioxide have no deleterious effects upon global climate," a short letter signed by past-president National Academy of Sciences, Frederick Seitz, and a short petition calling for the rejection of the Kyoto Protocol on the grounds that a reduction in carbon dioxide "would harm the environment, hinder the advance of science and technology, and damage the health and welfare of mankind."


The sponsor, little-known Oregon Institute of Science and Medicine, tried to beguile unsuspecting scientists into believing that this packet had originated from the National Academy of the Sciences, both by referencing Seitz's past involvement with the NAS and with an article formatted to look as if it was a published article in the Academy's Proceedings, which it was not. The NAS quickly distanced itself from the petition project, issuing a statement saying, "the petition does not reflect the conclusions of expert reports of the Academy."


The petition project was a deliberate attempt to mislead scientists and to rally them in an attempt to undermine support for the Kyoto Protocol. The petition was not based on a review of the science of global climate change, nor were its signers experts in the field of climate science. In fact, the only criterion for signing the petition was a bachelor's degree in science. The petition resurfaced in early 2001 in an renewed attempt to undermine international climate treaty negotiations.

Answer 2

Is global warming real? Yes. There is tons of proof that it is happening right now, and has been for the thousands of years. What is causing it is up for debate. For all the proof that some scientists have that humans are causing it, there are other scientists that have proof that it is occurring naturally. Personally, I tend to believe the second group. The planet has been a lot warmer than it is now, and there were no humans around to cause it. It will cool off and warm up again in the future, long after humans have become extinct. Does this mean we don't need to restrict pollution output from factories and cars and such? No. I like breathing clean air. It's good for my health and my kids health. Also, everything in my first paragraph is based on theories. One these theories is wrong. I believe in one of them, but I could be wrong. But I don't think we need to get everybody in a big panic until there is definitive proof that humans are causing it. Remember, just 30 years ago, the big scare was that humans were causing the planet to go into another ice age. We needed to stop "global cooling". I guess we humans are so good that we stopped the planet from cooling off into the next ice age in less than 30 years.

Answer 3

Close objective scientific scrutiny done with complete understanding of the factors others omit casts dispersions on the suggestion that man has a significant impact on global warming. The listed site and many others and books have excellent information about this and other phenomena. Because we burn fossil fuels in which CO2 was trapped milenia ago we are indeed releasing some CO2 back into the atmosphere. What we do not know is if this will cause plants, including ocean algae to improve their synthesis of CO2 or to simply increase their populations as a balance. This may well happen but we may not observe it in a single human lifetime. What is laughfable about being overconcerned and hyperreactive about the human effect on global warming is that if one large volcano erupts then its contribution to global cooling would offset the minimal effects of mankind many times over. ( OMG, let's drop a nuke into one and genrate an eruption!!-- lol) Other natural events such as solar storms may also contribute more while the lack of them causes cooling so we must factor in where we are in that cycle. There are many other factors conveniently not discussed by those trying to prove that man is causing global warming. I'm amazed that so many thinking people believe in the disastrous consequences some are forecasting. Warming and cooling cycles are a natural part of the Earth's lifetime and would continue if man did not exist or never existed. In fact the evidence found shows these periods occurred long before mankind began using fossil fuels. Sorry to inform the believers but the assumption that mere man is causing significant global warming
is bunk.

Answer 4

First, it is not a theory, it is an hypothesis. Gravity, electricity, and evolution are theories.

Second, the “rate” is not similar to anything over the past 10,000 years. Over the past half-century the trend and rate are with out precedent.

Third, ‘warming’ is somewhat misleading. The hypothesis does not claim that the temperature will respond uniformly over the whole earth at the same rate &/or time.

An important part of the hypothesis is that there will be increased variability and higher frequencies of extreme events (such as more [and more severe] hurricanes, drought, etc.).

Regarding temperature, a graph showing the infamous ‘hockey stick’ curve can be seen here:

http://en.wikipedia.org/wiki/Hockey_stick_controversy


And, while my real name is neither Bradley, Mann, nor Hughes, my data were used in their analysis and, thus, the article that gave the graph its stupid name.

An alternative view by Exxon hired thugs can be found here:

http://www.climateaudit.org/ , and here

http://www.multi-science.co.uk/mcintyre-mckitrick.pdf

where, McIntyre and McKitrick attack me by name several times.


Increased tree-ring growth at high-elevation (first detected by LeMarche et al [a ‘Science’ article sometime in the mid 1980s]) has been referred to as the ‘CO2 Fertilization effect’, and is coincident with the onset of the Industrial Revolution.

I would love to continue this further, but I do have to go to work.

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C D -

You really do not know anything about this at all, do you?

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sam -

Cool, another expert on long-term global climate change.

What specific spectral frequency responses are driving the cycles you reference? Personally, I'm skeptical of many such claims because I think you need some a priori reason to think that the response might be there - and might actually mean something.

I'm sure you are aware of the mathematical limitations of such analyses, given that they are, quite literally, forced to find solutions whether they are meaningful or not.

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Sean Penn -

No wonder Madonna dumped you.

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ruth -

Have you won a Nobel Prize? Really, you scientific knowledge is awe inspiring. You can probably multiply and divide stuff too, huh?

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Rick N -

You skipped every single one of those science classes, didn't you. It shows.

Answer 5

1. The present climate shift is more rapid than any observed in history, and coinicides with the most rapid shift in CO2 concentrations in history. Whether this is as fast, or faster, than prehistoric climate changes is completely unknown.

2. The two primary natural causes of climate change are orbital forcing (Milankovitch cycles) and solar activity. Orbital forcing, which is calculable, puts the peak temperature from the current interglacial period at 6000 years ago, with a slow cooling trend since. Recent solar activity shows no convincing trend. Since natural causes can be ruled out, it is clear that the cause of the current warming trend is human activity.
http://www.sciencemag.org/cgi/content/abstract/207/4434/943
http://ieg.or.kr:8080/abstractII/G0102523037.PDF

3. Water vapor in the air varies according to temperature, with warm air holding more water and cool air holding less. Thus water vapor acts as a feedback for the greenhouse effect, not a forcing agent. http://www.realclimate.org/index.php?p=142

4. Stratospheric cooling has been observed as far back as records go, which is now more than 40 years. http://www.grida.no/climate/ipcc_tar/wg1/fig2-12.htm

By contrast, effectively all of the CO2 increase since the industrial revolution is anthropogenic, and the surface temperature trend mirrors the CO2 increase with high correlation.

http://www.columbusnavigation.com/images/CO2-Temp.gif

Looking at this graph, you have to ask: what will put a brake on this trend? Any ideas?

Answer 6

Let's see. Went to a Weather briefing couple days ago to fly to West Coast. 5 hour flight. Perhaps the briefer had a little to much CO2.

WX on West coast was not what he called for upon arrival. Only 5 hours and you're telling me these dudes know what's gonna happen in 10 years,20 years,30 years.

Follow the money for the correct answer.

Answer 7

There is no proof, just common hysteria from environmental fear-mongering types. This from the same people who warned of a coming ice age, and those who want to silence anyone who disagrees with them. They compare anyone who poses legitimate questions to holocaust deniers. It's like the weather channel representative who wants to punish any meteorologists who don't toe the party line of CO2 man-caused global warming.

It has not been proven, only agreed upon by liberals. From the people who brought us the Bay of Pigs, the Desert One Iran hostage rescue debacle, numerous UN scandals, and countless other international incidents, we're now expected to buy into a shared guilt trip for natural climatic cycles.

Personally, I do not know what is happening to the Earth and its climates around the globe, but I think it should be investigated by responsible unbiased people without a vested interest. People who start out by saying the US and evil corporations are to blame for destroying the Earth cannot be considered responsible, unbiased, or without a vested interest.

Answer 8

The earth was made to replenish itself. Years ago they predicted that we would burn up the oil of the earth. Not so. Same thing here. The earth goes through cycles just as all things do. It warms up some then cools down. It is all part of a plan that we have no control over. If you read some of the reasons they give, they state, at this rate we will be --- in such and such time. There are no proofs one way or the other. Most of the time the predicted result won't happen for hundreds of years.

Answer 9

How about a few links, and I'll let you do the research.

The key, though, is that carbon levels are higher now than they've ever been in the last 800,000 years, and the start of the sudden rapid increase coincides with the industrial revolution.

Now--if you want proof, you have to learn a little science:

Answer 10

There IS no proof, nor could there be, as Man has diddly-squat to do with "global warming". I guess the environmental whackos deny the fact that there have been many Ice Ages. That's what happens when a planet undergoes cyclical temperature fluctuations. Then again, I suppose the Left would blame the Geico cavemen for causing the last Ice Age.

Answer 11

Wait until this cold spell leaves before you ask any global warming questions (please).

Proof? Since when is that required of liberal theories.

And between Jimmy Carter, and Al Gore, how many trees did it take for those books?