Can you convince me AGW is incorrect/Correct ?

Question

So, what I want is well reasoned arguments with sources. I see lots of talk in this section but not often a really good discussion.

I see lots of claims and would love to know their origins, so if you have links to websites which you believe back up your arguments I'd really like to read them.

From this question I hope to gain better understanding of both sides of the debate. Although at the moment I would be classed as a "believer", I do not have all the information. Maybe you can confirm my "belief" or " convert " me.

Thank you for your time.

P.S any argument based upon Al Gore , be it negative or positive about him, its 120% meaningless. Please refrain from using him.

Dr Jello you didn't answer the question at all. I used "believer" in quotation marks, since it is a ridiculous term, but its how I have seen it classed on here. I do not use it because I think of AGW as a religion. Your answer also appears to be implying that I am pushing my "faith" on others. Which, given the content and layout of this question is possibly the most ridiculous claim you could have meant.The fact you are classed as top contributor to this section makes a mockery of the entire system.

@ everyone else thanks for a great set of answers so far, I hope for many more.

Answer 1

First for the basic scientific observations.

The planet has warmed nearly 1 deg C over the past 100 years and more than 0.5 deg C over the past 30 years.

http://profend.com/gtr/graphs/meangraphave.html

Comparing this to when the planet naturally came out of the last ice age, warming 8 deg C over 8,000 years, the current warming is happening at a rate 20 times faster.

http://globalwarmingart.com/wiki/Image:Ice_Age_Temperature_Rev_png

Atmospheric CO2 levels have increased 38% since 1750 to 384 ppm, a level they have not reached in millions of years. I don't think that anyone disputes this increase is due to human fossil fuel burning emissions.

http://globalwarmingart.com/wiki/Image:Carbon_Dioxide_400kyr_Rev_png

We know CO2 is a greenhouse gas, so it's not a question of whether this increase will cause global warming. It's just a question of how much warming it will cause.

So it's established that we're seeing rapid warming, and that atmospheric greenhouse gas levels are increasing. The possible explanations for the current warming are:

1) Increased solar output
2) A natural cycle
3) Anthropogenic
4) Decreased galactic cosmic ray (GCR) flux due to increased solar magnetic field, seeding fewer clouds on Earth, reducing the cloud cooling effect and thus causing overall warming.

An analysis of the likelihoods of these theories:

1) Solar output has decreased slightly over the past 30 years as global warming has accelerated rapidly.

http://news.bbc.co.uk/2/hi/uk_news/6290228.stm

While nobody disputes the Sun has played a major role in past climate change, it's simply not causing the current warming. As they put it at RealClimate:

"That's a coffin with so many nails in it already that the hard part is finding a place to hammer in a new one."

http://www.realclimate.org/index.php/archives/2007/07/friday-roundup/

2) We're in the middle of a long-term very gradual cooling portion of the Milankovitch cycles.

http://en.wikipedia.org/wiki/Milankovitch_cycles#The_future

3) If the warming is caused by an increased greenhouse effect, we expect to see various events.

a) Cooling in the upper atmosphere. Because more radiation is being trapped in the troposphere, less is radiated upward to the stratosphere and higher levels. Thus they radiate more heat than they absorb, and overall they cool.

This is indeed what we're seeing. I don't have a plot for the mesosphere or ionosphere (but they are cooling), but here is one for the stratosphere showing a clear long-term cooling trend.

http://www.metoffice.gov.uk/research/hadleycentre/obsdata/HadAT.html

If the warming were due to the Sun, all levels of the atmosphere would be warming.

b) More warming at night than during the day. This is because greenhouse gases continue to trap heat at night. During the day clouds can reflect some incoming solar radiation to cause slightly more warming during the night. This result was predicted by Svante Arrhenius in 1894.

http://en.wikipedia.org/wiki/Svante_Arrhenius
http://answers.yahoo.com/question/index;_ylt=ApVrJTwr2fowQ9c1oYDbztvty6IX;_ylv=3?qid=20071228085145AAjfnlr

If warming is due to the Sun, we expect to see greater warming during the day when solar radiation is striking the surface. What we're seeing is greater warming at night, indicated by a decreased diurnal temperature range (DTR - difference between max and min daily temperature).

http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F1520-0450(1984)023%3C1489%3ADDTRIT%3E2.0.CO%3B2
http://lwf.ncdc.noaa.gov/img/climate/globalwarming/ipcc02.gif
http://lwf.ncdc.noaa.gov/oa/climate/globalwarming.html

c) The upper troposphere should also be warming at a slightly faster rate than the surface. There's a bit of a question about this, because most measurements show the opposite.

http://globalwarmingart.com/wiki/Image:Satellite_Temperatures_png

However, this is most likely due to instrumentation problems. The upper troposphere temperature has been measured since 1978 by both satellites and radiosondes on weather balloons. However, the satellites have to make daily corrections, and they base these corrections on the radiosonde measurements.

The radiosonde measurements used to be slightly biased to the high side, because the thermometers were exposed to sunlight. A thermometer only measures temperature accurately when it's in the shade, not being constantly bombarded by solar radiation. Eventually radiosonde thermometers were put under plastic covers to measure more accurately, but consequently the earlier measurements were biased to the high side while more recent measurements are more accurate. This has resulted in less apparent tropospheric warming than scientists believe has actually happened.

So at this point it's unclear whether the upper troposphere vs. surface temperature trends validate or undermine the AGW theory. However, some skeptics (i.e. a recent paper by Singer, Christy, Douglass et al which got much publicity in the AGW denial circles) claimed that the apparent lesser warming in the upper troposphere disproved the AGW theory. They basically ignored the large uncertainty in the data. They also ignored all the other observations which support the AGW theory.

4) The GCR theory is interesting, but has several fundamental flaws which I've discussed here:

http://answers.yahoo.com/question/index;_ylt=AkCY_7Ayj6CgmztQ4MB3.n0jzKIX;_ylv=3?qid=20071030112550AA7AXSu

The main flaw is that there is no long-term trend in GCR flux, so how could it be causing rapid warming? On top of that, the theory cannot explain the decreased DTR or upper atmosphere cooling. Plus it hasn't even been proven that GCR has any significant effect on cloudcover in the first place.

It's basically a theory with no evidence to support that it's currently happening. I would describe it as a "this theoretically could cause warming" theory. The deniers love it though, because unlike solar and natural causes, it hasn't been 100% disproven, even though there's no reason to believe GCRs are causing the current warming. It's basically their Hail Mary pass at the end of the game.

Well, that took me a long time to write. I hope it was sufficiently convincing! The bottom line is that something has to be causing the current warming, and the only explanation which fits the observations is AGW. Skeptics try to pick holes in the AGW theory, but they have been unable to come up with a plausible alternative theory.

Answer 2

I think what most people have a hard time understanding about global warming is the fact that CO2 and other greenhouse gasses can actually increase the temp. on the planet if the concentrations of these gasses increase in the atmosphere. I find it easier to understand and "believe" when you look at other planets in our solar system. Venus, for example, has a far greater concentration of CO2 that earth and any other planet.

http://hyperphysics.phy-astr.gsu.edu/hbase/solar/venusenv.html

It is therefore the hottest planet in our solar system.

http://www.bobthealien.co.uk/table.htm

Note that it is even hotter than Mecury, which is closer to the sun than Venus is. This is because Mecury has no atmosphere to trap in heat, so on the dark side of Mecury the temp can get down to -180C!!!

Earth has to have some CO2 in the atmosphere to keep the planet from turning into an ice ball, but the more greenhouse gasses that are in the atmosphere, the hotter the planet will become. This is a fact that no one can dispute.

Since the industrial revolution, and especially in the last 50 or so years, we've been burning a lot of fossil fuels, such as coal and oil, in order to create energy. Burning these fossil fuels releases CO2 into that atmosphere that was originally stored in the ground in the form of coal or oil. CO2 will also stay in the atmosphere for 100s of years, so it's not like other greenhouse elements like water vapor that come down in a matter of days in the form of rain. Now based on what we know about how having too much CO2 in the atmosphere can cause a planet to heat up, wouldn't it be in our best interest to limit the amount of heat trapping gasses that we pump into the atmosphere?

Here are a few good, politically unbaised web sites where you can learn more about global warming:

http://www.nationalgeographic.com/
http://www.npr.org/templates/topics/topic.php?topicId=1007

Good site with a map about changing surface temps:

http://ngm.nationalgeographic.com/ngm/2007-10/climate-map.html

Answer 3

Bush administration scientists coordinating across ten federal agencies are deeply involved in exploring the relationship between mankind's carbon emissions and current warming trends. The research includes mitigation recommendations. Here are some of the latest findings in both presentation and pdf brochure format, current as of October and November 2007:

http://co2conference.org/agenda.asp
http://www.climatescience.gov/Library/sa...
http://www.globalcarbonproject.org/activ...

It was eye-opening to me that the reality of the science behind carbon cycle science, even in the oil-friendly and publicly skeptical Bush administration, is quite a contrast to the public appearance of debate, which is apparently created and nurtured by the oil industry in the same way that tobacco companies denied intentionally adding addictive nicotine and denied any links between smoking and health issues (including cancer).

Here are some of the myths you'll be presented with:

Anti-global warming claims
http://scholarsandrogues.wordpress.com/2007/07/23/anti-global-heating-claims-a-reasonably-thorough-debunking/

Myth #1: All the CO2 in the air at present comes from the mantle.
Myth #2: Increasing CO2 in the air is due to gases coming out of solution as the ocean heats up.
Myth #3: Humans are not the source of the recent increase in atmospheric CO2 concentration.
Myth #4: CO2 is rising at 0.38% per year, not 1% per year as the IPCC Third Assessment Report claimed.
Myth #5: CO2 is such a weak greenhouse gas that it cannot be the cause of the observed warming.
Myth #6: CO2 concentrations are not correlated with global temperature due to periods in the geologic history when CO2 was higher and the planet was in an ice age.
Myth #7: Temperatures during the Medieval Warm Period were warmer than modern temperatures.
Myth #8: The existence of the Medieval Warm Period has been ignored in order to support anthropogenic global heating.
Myth #9: Modern temperature increases are a direct result of the Earth’s climate exiting the Little Ice Age.
Myth #10: Global cooling between 1940 and 1970 happened even though anthropogenic CO2 was rising at
Myth #11: Cosmic rays hitting the earth are behind global heating.
Myth #12: The Stefan-Boltzman law breaks the equations of global heating.
Myth #13: Computer models are too inaccurate to accurately predict a system as complex as the Earth’s climate.
Myth #14: The oceanic storage of heat is required to account for the differences between data and early models. But the updated models still require an unrealistically large oceanic depth of water to make them work right.
Myth #15: The oceans have already begun to cool in response to natural variations, so global heating is wrong.
Myth #16: Satellite measurements of tropical air don’t correspond to directly measured temperatures, so global heating isn’t actually happening.
Myth #17: Global heating will be good for the planet, not bad.
Myth #18: Water vapor is a more powerful greenhouse gas than CO2, and since humans have almost no direct impact on the amount of water vapor in the air, humans can’t be the cause of global heating.
Myth #19: We don’t have enough climate data to make valid predictions of any kind.
Myth #20: Volcanoes spew more CO2 into the air in a single eruption than humanity has emitted in its history.

Here's the full writeup on the actual science behind each:
http://scholarsandrogues.wordpress.com/2007/07/23/anti-global-heating-claims-a-reasonably-thorough-debunking/

Answer 4

1. Ice ages and inter-glacial periods are triggered by small changes in Earth's orbit called Milankovitch cycles, or "orbital forcing". Since we can compute Earth's orbit for thousands of years into the past and future, we know that orbital forcing peaked 6000 years ago, during the Holocene Maximum, and has been slowly cooling the planet since then. Here's the science:
http://www.sciencemag.org/cgi/content/abstract/207/4434/943

So the cause of the current warmth isn't related to us coming out of the last ice age; we're already out. Maybe it's the Sun then?

2. If the Sun is causing the current warmth, then we're getting more energy, and the whole atmosphere should be getting warmer. If it's greenhouse, then we're getting the same amount of energy, but it's being distributed differently: more heat is trapped at the surface, and less heat is escaping to the stratosphere. So if it's the Sun, the stratosphere should be warming, but if it's greenhouse, the stratosphere should be cooling.

In fact, the stratosphere has been on a long-term cooling trend ever since we've been keeping radiosonde balloon records in the 1950's. Here's the data:
http://hadobs.metoffice.com/hadat/images/update_images/global_upper_air.png
http://hadobs.metoffice.com/hadat/hadat2/hadat2_monthly_global_mean.txt
http://cdiac.ornl.gov/trends/temp/sterin/sterin.html

3. If it's the Sun, we're getting more energy during the day, and daytime temperatures should be rising fastest. But if it's greenhouse, we're losing less heat at night, and nighttime temperatures should be rising fastest. So if it's the sun, the difference between day and night temperatures should be increasing, but if it's greenhouse, the day-night difference should be decreasing.

In fact, the daily temperature range has been decreasing throughout the 20th century. Here's the science:
http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F1520-0450(1984)023%3C1489:DDTRIT%3E2.0.CO%3B2
http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F1520-0477(1993)074%3C1007%3AANPORG%3E2.0.CO%3B2
http://www.bom.gov.au/bmrc/clfor/cfstaff/jma/2004GL019998.pdf

4. Total solar irradiance has been measured by satellite since 1978, and during that time it has shown the normal 11-year cycle, but no long-term trend. Here's the data:
http://www.ngdc.noaa.gov/stp/SOLAR/solarda3.html

5. Scientists have looked closely at the solar hypothesis and have strongly refuted it. Here's the peer-reviewed science:
http://www.pubs.royalsoc.ac.uk/media/proceedings_a/rspa20071880.pdf
http://www.mpa-garching.mpg.de/mpa/publications/preprints/pp2006/MPA2001.pdf

6. CO2 levels in the air were stable for 10,000 years prior to the industrial revolution, at about 280 parts per million by volume (ppmv). Since 1800, CO2 levels have risen 38%, to 384 ppmv, with no end in sight. Here's the modern data...
http://www.esrl.noaa.gov/gmd/ccgg/trends/
... and the ice core data ...
http://www.ncdc.noaa.gov/paleo/icecore/antarctica/law/law.html
http://www.ncdc.noaa.gov/paleo/icecore/antarctica/domec/domec_epica_data.html
http://www.ncdc.noaa.gov/paleo/icecore/antarctica/vostok/vostok_data.html
... and a graph showing how it fits together:
http://www.columbusnavigation.com/co2.html

7. We know that the excess CO2 in the air is caused by burning of fossil fuels, for two reasons. First, because the sharp rise in atmospheric CO2 started exactly when humans began burning coal in large quantities (see the graph linked above); and second, because when we do isotopic analysis of the CO2 we find increasing amounts of "old" carbon combined with "young" oxygen. Here are the peer-reviewed papers:
http://adsabs.harvard.edu/abs/1984JGR....8911731S
http://www.ingentaconnect.com/content/mksg/teb/1999/00000051/00000002/art00005
http://www.sciencemag.org/cgi/content/abstract/256/5053/74

So what's left to prove?

Answer 5

we all know that CO2 is a greenhouse gas because it absorbs infra-red radiation at wavelengths of 4.26 µm and 14.99 µm.(1) since the industrial revolution the burning of fossil fuels and deforestation has caused levels of carbon dioxide to increase by a third from 284.3ppm in 1832(2) to 383ppm in 2006(3). most of this increase has been caused by the burning of fossil fuels because this is adding carbon to the cycle and where as natural CO2 emissions are balanced with sinks human emissions do not have the same checks and balances. (http://environment.newscientist.com/channel/earth/climate-change/dn11638 )

when oceans are heated carbon dioxide becomes less and less soluble and it is released back into the atmosphere increasing levels. this is why CO2 has followed temperatures but lagged behind by about 800years.(4) this is because CO2 normally only acts as a feedback mechanism increasing any warming caused, such as that by the Milankovitch cycles (5). this was until humans started unlocking all this fossil carbon and carbon dioxide begin to cause warming instead of just feedback.

Answer 6

There's massive proof that it's real, and mostly caused by us. Don't trust my words, or anyone else's here, the proof is in the links below. I've put an asterisk by the ones I think are particularly relevant. A couple of good scientific papers are in the Source. References that use wikipedia are verifiable facts, not opinions.

This is science and what counts is the data.

"I wasn’t convinced by a person or any interest group—it was the data that got me. I was utterly convinced of this connection between the burning of fossil fuels and climate change. And I was convinced that if we didn’t do something about this, we would be in deep trouble.”

Vice Admiral Richard H. Truly, USN (Ret.)
Former NASA Administrator, Shuttle Astronaut and the first Commander of the Naval Space Command

Here are two summaries of the mountain of peer reviewed data that convinced Admiral Truly and the vast majority of the scientific community, short and long.

* http://www.globalwarmingart.com/wiki/Image:Climate_Change_Attribution.png
*** http://ipcc-wg1.ucar.edu/wg1/wg1-report.html
summarized at:
http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-spm.pdf

It's (mostly) not the sun:

* http://news.bbc.co.uk/1/hi/uk/6290228.stm
http://solar-center.stanford.edu/sun-on-earth/FAQ2.html

And the first graph above shows that the sun is responsible for about 10% of it. When someone says it's the sun they're saying that thousands of climatologists are stupid and don't look at the solar data. That's ridiculous.

Science is quite good about exposing bad science or hoaxes:

http://www.cs.cmu.edu/~dst/ATG/polywater.html

There's a large number of people who agree that it is real and mostly caused by us, who are not liberals, environmentalists, stupid, or conceivably part of a "conspiracy". Just three examples of many:

"Former Republican House Speaker Newt Gingrich challenged fellow conservatives to stop resisting scientific evidence of global warming"

"Our nation has both an obligation and self-interest in facing head-on the serious environmental, economic and national security threat posed by global warming."

Senator John McCain, Republican, Arizona

“DuPont believes that action is warranted, not further debate."

Charles O. Holliday, Jr., CEO, DuPont

There's a lot less controversy about this is the real world than there is on Yahoo answers:

http://www.worldpublicopinion.org/pipa/articles/home_page/412.php?lb=hmpg1&pnt=412&nid=&id=

And vastly less controversy in the scientific community than you might guess from the few skeptics talked about here:

* http://en.wikipedia.org/wiki/Scientific_opinion_on_climate_change
http://www.sciencemag.org/cgi/content/full/306/5702/1686

"There's a better scientific consensus on this [climate change] than on any issue I know... Global warming is almost a no-brainer at this point. You really can't find intelligent, quantitative arguments to make it go away."

Dr. Jerry Mahlman, NOAA

Good websites for more info:

* http://profend.com/global-warming/
* http://environment.newscientist.com/channel/earth/dn11462
http://www.ucsusa.org/global_warming/science/
http://www.realclimate.org
"climate science from climate scientists"

Answer 7

try this one even though some one used gore name in the title.
http://www.21stcenturysciencetech.com/Articles%202007/True_CO2_Record.pdf

Answer 8

Read Ann Coulters book 'Godless'. Global warming like darwins evolution can not be proved to be valid but the opposites can. The antartica has gotten colder over the past thirty years, specifics are in Coulter's book. The ice that is melting in the northern hemisphere is simply that we are at the end of a multi million year ice age. Global warming and evoltion are the big liberal lies, and I think the entire mess should be brought to litigation and when found that there is no scientific fact to prove their existance, then it should be criminal to teach that to our children.

Answer 9

Science isn't something you "believe". It just is.

No one have to "believe" what the speed of light is, or has to "believe" how far the Sun is from the Earth. These can be proved by anyone with the desire to do so.

Faith requires belief. You "believe" in global warming, you "believe" in UFO's, as these cannot be proved. These require the interpretation of a group rather than being able to stand on the facts. This is done by the "consensus" with global warming.

You are free to "believe" what ever you want. Just don't push your "faith" on others.

Answer 10

Al Gore said so so it must be true