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Climate Change Deni

topic posted Fri, February 4, 2005 - 5:15 PM by  B
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The debate about the anthropogenic (human-caused) climate change is largely over.

A recent survey of peer-reviewed studies published in Science magazine found no respected research debunking pollution as a major cause of climate change.

"Some corporations whose revenues might be adversely affected by controls on carbon dioxide emissions have also alleged major uncertainties in the science. Such statements suggest that there might be substantive disagreement in the scientific community about the reality of anthropogenic climate change. This is not the case."

- “The Scientific Consensus on Climate Change” Science Magazine (Vol 306, Issue 5702, 1686 , 3 December 2004)

Even the Bush administration’s 2002 report on global warming made this point clear.

“Greenhouse gasses are accumulating in the Earth’s atmosphere as a result of human activities, causing global mean surface air temperature and subsurface ocean temperature to rise”

- US Climate Action Report (U.S. Department of State, May 2002)

Yet in the American public mind, there is still a debate about whether climate change is really a problem, what is causing it, and what, if anything, should be done about it.

Denial: A Lucrative Cottage Industry

The confusion in the public’s mind comes largely from a privately financed public relations campaign sponsored, at least in part, by petroleum interests.

The funding and intentions of this campaign became clear on May 28, 2003, when The New York Times broke the story. The paper discovered the following:

"...the company [Exxon Mobil], the world's largest oil and gas concern, has increased donations to Washington-based policy groups that, like Exxon itself, question the human role in global warming and argue that proposed government policies to limit carbon dioxide emissions associated with global warming are too heavy handed.

"Exxon now gives more than $1 million a year to such organizations, which include the Competitive Enterprise Institute, Frontiers of Freedom, the George C. Marshall Institute, the American Council for Capital Formation Center for Policy Research and the American Legislative Exchange Council.

"The organizations are modest in size but have been outspoken in the global warming debate. Exxon has become the single-largest corporate donor to some of the groups, accounting for more than 10 percent of their annual budgets. While a few of the groups say they also receive some money from other oil companies, it is only a small fraction of what they receive from Exxon Mobil…

"Exxon's publicly disclosed documents reveal that donations to many of these organizations increased by more than 50 percent from 2000 to 2002."


- “Exxon Backs Groups That Question Global Warming” Jennifer Lee, New York Times, May 28, 2003

Much like the “scientists” hired by the tobacco industry to find that cigarette smoke had no connection with lung cancer, these groups represent a well-funded effort to confuse the public about the science, risks, and severity of climate change.

What About Balance?

Journalists seek balance in all their work. But when such a large scientific concensus exists about climate change, "he said/she said" reporting has allowed a small group of skeptics to have their views artificially amplified. Read an analysis of the problem here.

Resources:

For the latest and best information on global warming we recommend Real Climate.org, a new blog edited by working climate scientists, not corporate lobbyists.
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B
offline B
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  • Unsu...
     
    big oil will be heavily hit by legislation geared toward lowering hazardous gas emissions. it's no surprise that they're investing big bucks to dispel the notion that global warming is a real problem.

    Climate change is inevitable if we maintain our use of oil and coal in electricity generation. Further, one cannot discount the obvious urban implications of combustion -- smog (NOx, SOx). This is a major problem. The health effects HAVE been proven and it is clear that individuals living in urban and industrial settings suffer from decreased respiratory intake.
    • Look folks, I do not disagree that humans play a role in global warming. I do not think any reasonable person can deny the obvious effects.

      I just think that when there is data suggesting other planets are also experiencing a warming trend and measurements of the suns radiant heat show a warming thrend there is the possability of something else having a large role.

      Here in So. Cal. it is perfectly obvious, to anyone who cares to see, that the air quality has been consistently improving. We also know that Mt. St. Helens put more C02 into the atmosphere than man has since our early recorded history. Bison emit more Methane than autombiles and industry combined. More Oil is spilled into the ocean from underwater vents than from all of mankinds transport of petrolium errors.

      Sure, we need to try hard to do better, but lets not get too carried away here. It is not in the long term best interests of any big business to kill the environment in which all of it's customer base lives. Earth was here before mankind and will be here long after us too.
      • Unsu...
         
        The issue isn't whether humans cause global warming, but what can be done by humans to preserve the climate for habitable life sustenance.

        Scientists disagree as to whether the cycles of global warming and cooling are in natural progression, but as a block they agree that human activity has been a contributing factor in the rate of climate change:

        <snip>
        In a 268-page report submitted to the United Nations, the US Environmental Protection Agency (EPA) endorsed what many scientists have long argued - that human activities such as oil refining, power generation and car emissions are significant causes of global warming.
        <snip>

        news.bbc.co.uk/1/hi/world...2023835.stm

        So, rather than pointing fingers and denying repeatedly. We should move beyond that, agree that scientists who don't make weapons systems may ALSO be competent at their jobs, and instead discuss what role Human Beings should play in modifying the rate of climate change through HUMAN action.
        • I just think we need to be aware and temper the revenue generating hype used by some scientist to help fund their efforts to find where the truth is.

          Shutting off the engine that supplies the research dollars (the economy) is not the "best" solution. Working WITH industry to continually reduce emmisions and increase efficiency is.
          • B
            B
            offline 124
            <I just think we need to be aware and temper the revenue generating hype used by some scientist to help fund their efforts to find where the truth is. >

            Interesting statement. What experience do you have in writing grant proposals> What experience do you have in the per review process. It is far easier to get a grant form a company to find evidence that supports their claims without a per review process. Again Frank from So. Cal. What is your background?
      • <<I just think that when there is data suggesting other planets are also experiencing a warming trend and measurements of the suns radiant heat show a warming thrend there is the possability of something else having a large role. >>

        Possibly true, there is some evidence that a solar cycle is adding to the problem. But that only makes it more urgent that we don't lend the sun a hand by adding more carbon to the atmosphere.

        Think of it as the radiator on your car, which gets rid of heat from your engine. The sun is warming up and it's the middle of summer and it's really getting hot out. Are you really going to drive up a steep hill in the blazing heat towing a heavy trailer with the air conditioner on? Of course not, because it would just add to your radiator's problems caused by the extra heat from the hotter sun.

        Same with the earth. If (theoretically) the sun is already warming up the planet more than it usually does, then the only logical thing to do is to burn less carbon so we don't heat up the earth even more. Why risk pushing the planet over the edge?
  • M
    M
    offline 384
    Frank, while I appreciate your contention that working with industry to reduce emissions would be the best and most contructive solution, please consider the following:

    --"Industry" contributes most of its campaign funding to politicians who belong to the Republican Party

    --"Industry" also continues to do little or nothing on its own to control emissions...witness the ongoing strenuous efforts by the power industry to keep its old coal-fired power plants on-line, or by the auto industry to continually and shamelessly oppose improved mileage standards and exagerrate their effects on the potential costs of vehicles to consumers.

    --The Republican politicians supported by campaign financing from said industries have taken virtually NO actions to truly reduce emissions of carbon monoxide or anything else (there are one or two exceptions to this, such as proposals to reduce emissions from diesel engines), and are in fact attempting to weaken standards that were in place before they came into office.

    --The Republican officeholders funded by industry also now nominally control all three branches of the U.S. government, making it difficult if not impossible for there to be real disclosure of which actions are being taken on behalf of their campaign contributors.

    Summary: we are beyond the point where industry can be trusted enough to simply "work with" it. Industry has demonstrated time and again that it is more interested in stacking the political process in its favor to enhance short-term profits at all cost, than honestly arriving at mutually beneficial, constructive solutions; this is evinced by the strategy of delay, deny, delay, deny that its governmental representatives have adopted.

    Let's get real.
      • interesting that it's gone up every year to the repubs and down to the dems...maybe because they know that democratic policies will be a hindrance to them polluting the earth and less costefficient for them.
      • www.opensecrets.org/industries/indus.asp
        ---
        Election Cycle
        Total Contributions
        Contributions from Individuals
        Contributions from PACs
        Soft Money Contributions
        Donations to Democrats
        Donations to Republicans
        % to Dems
        % to Repubs

        2004*
        $48,081,812
        $27,014,321
        $21,067,491
        N/A
        $11,875,988
        $36,171,457
        25%
        75%

        2002
        $57,877,455
        $14,378,834
        $20,480,882
        $23,017,739
        $15,547,245
        $42,299,096
        27%
        73%

        2000
        $67,244,033
        $18,533,611
        $18,820,728
        $29,889,694
        $16,630,278
        $50,060,396
        25%
        74%

        1998
        $41,729,772
        $9,994,041
        $16,273,817
        $15,461,914
        $11,740,513
        $29,920,351
        28%
        72%

        1996
        $46,581,076
        $14,151,871
        $15,015,788
        $17,413,417
        $12,682,188
        $33,488,220
        27%
        72%

        1994
        $29,929,373
        $9,505,805
        $13,738,504
        $6,685,064
        $12,959,158
        $17,208,584
        43%
        57%

        1992
        $34,345,180
        $12,528,982
        $14,492,744
        $7,323,454
        $13,759,879
        $20,801,887
        40%
        61%

        1990
        $18,504,718
        $6,147,845
        $12,356,873
        N/A
        $8,099,606
        $10,606,220
        44%
        57%

        Total
        $344,293,419
        $112,255,310
        $132,246,827
        $99,791,282
        $103,294,855
        $240,556,211
        30%
        70%

        *2004 figures do not include donations of "Levin" funds to state and local party committees. Levin funds are contributions of up $10,000 from sources that are allowed to give to parties under the applicable state's laws, including corporations and labor organizations in some states. Levin funds may be used for certain types of voter registration, voter identification and get-out-the-vote activity.

        METHODOLOGY: The numbers on this page are based on contributions of $200 or more from PACs and individuals to federal candidates and from PAC, soft money and individual donors to political parties, as reported to the Federal Election Commission. While election cycles are shown in charts as 1996, 1998, 2000 etc. they actually represent two-year periods. For example, the 2002 election cycle runs from January 1, 2001 to December 31, 2002. Data for the current election cycle were released by the Federal Election Commission on Monday, December 13, 2004.

        Feel free to distribute or cite this material, but please credit the Center for Responsive Politics.

        NOTE: Soft money contributions to the national parties were not publicly disclosed until the 1991-92 election cycle, and were banned by the Bipartisan Campaign Finance Reform Act following the 2002 elections.
  • "The debate about the anthropogenic (human-caused) climate change is largely over."

    If the debate is over then that's just sad considering that we still don't have much of a clue about all the various aspects of the environment.

    “Greenhouse gasses are accumulating in the Earth ’s atmosphere as a result of human activities, causing global mean surface air temperature and subsurface ocean temperature to rise ”

    Water vapor makes up 99% of greenhouse gases and CO2 makes up about .04%. Which do you think plays the more important part regarding global warming? Which do you think gets more coverage?

    "Denial: A Lucrative Cottage Industry"

    LMAO. Support is an even more lucrative industry.

    "For the latest and best information on global warming we recommend Real Climate.org, a new blog edited by working climate scientists, not corporate lobbyists."

    It's interesting that a couple of the scientists who actually created the Real Climate.org site debunk the possibility of the 11 degree Celcius increase proposed by a climateprediction report(which was the basis for all these recent headlines about climate catastrophe in ten years):

    "Uncertainty in climate sensitivity is not going to disappear any time soon, and should therefore be built into assessments of future climate. However, it is not a completely free variable, and the extremely high end values that have been discussed in media reports over the last couple of weeks are not scientifically credible."
    • Unsu...
       
      "If the debate is over then that's just sad considering that we still don't have much of a clue about all the various aspects of the environment. "

      the chemistry/physics is extremely complex. ask your president to dump more money into atmospheric research and less into building more nukes.

      "Water vapor makes up 99% of greenhouse gases and CO2 makes up about .04%. Which do you think plays the more important part regarding global warming? Which do you think gets more coverage? "
      what leads you to assert that co2's reactivity is directly proportional to its concentration? also, there's more up there than just co2 and water, like methane, cfcs...
    • <<Water vapor makes up 99% of greenhouse gases and CO2 makes up about .04%. Which do you think plays the more important part regarding global warming? Which do you think gets more coverage?>>

      You have no credibility on this CO2 issue until you address the information I have posted for you over and over and over.
    • We had this discussion before Zeppo and you vanished as soon as I started laying some facts on you. I will repost everything you ignored. (This is the fourth time I have posted it for you)

      <<However, what they won't tell you is that these glaciers have been naturally melting for thousands of years and they aren't melting any faster now.>>

      You are wrong, glaciers *are* melting faster. Yes, there are natural cycles, but the claciers melting this quickly is not part of the natural cycle.
      www.commondreams.org/headlin.../0922-02.htm
      www.cnn.com/2003/TECH/sc.....lacier.melt.ap/
      news.bbc.co.uk/1/hi/sci/tech/2137205.stm

      <<It's designed to reduce greenhouse gases(mainly CO2), not air pollution.>>

      What you are missing when evaluating CO2 as not being air pollution is that it creates what is called the Greenhouse effect. If the natural balance of C02 is out of whack then the earth warms up.

      Greenhouse gases absorb this infrared radiation and trap the heat in the atmosphere. Over time, the amount of energy sent from the sun to the Earth ’s surface *should* be about the same as the amount of energy radiated back into space, leaving the temperature of the Earth ’s surface roughly constant.

      Concentrations of carbon dioxide in the atmosphere are naturally regulated by numerous processes collectively known as the “carbon cycle ”The movement ( “flux ”) of carbon between the atmosphere and the land and oceans is dominated by natural processes, such as plant photosynthesis. While these natural processes can absorb some of the net 6.1 billion metric tons of anthropogenic carbon dioxide emissions produced each year (measured in carbon equivalent terms), an estimated 3.2 billion metric tons is added to the atmosphere annually. The Earth ’s positive imbalance between emissions and absorption results in the continuing growth in greenhouse gases in the atmosphere.

      Currently there is 30% more CO2 in the atmosphere than there was at the start of the Industrial Revolution, and we are well on the way to doubling CO2 levels in the atmosphere during this century.

      P.S. Smog -- the same emissions that release CO2 also emit nitrogen oxide that causes smog.

      <<But all of these extreme things that the activists have been predicting have been debunked by the science.>>

      Such as?
      • Unsu...
         
        <<But all of these extreme things that the activists have been predicting have been debunked by the science.>>

        what, your bs pseudo-science backed by industrial/big-oil hacks?
      • "www.commondreams.org/headlin.../0922-02.htm"
        www.cnn.com/2003/TECH/sc.....lacier.melt.ap/

        Broken links.

        "Yes, there are natural cycles, but the claciers melting this quickly is not part of the natural cycle."

        Let's just say for argument's sake that the glaciers are melting at a much faster rate than they should be naturally. 90% of the world's ice is in Anarctica and sea ice there has been increasing over the last 28 years. That's fact. So when people say that the polar ice caps are melting and that sea levels are rising at a higher rate they don't know what they are talking about.

        Now maybe Anarctica getting colder and getting more ice isn't a good thing. Maybe it will get colder to balance the rest of the planet getting warmer. I don't know. The scientists don't really know why it's happening(possibly something to do with wind force and direction) But at least people should acknowledge what is really happening instead of jumping on the "global warming will destroy us all very soon" bandwagon. That's the kind of thing that drives me crazy.

        "What you are missing when evaluating CO2 as not being air pollution is that it creates what is called the Greenhouse effect. If the natural balance of C02 is out of whack then the earth warms up."

        All greenhouse gases add to that affect, not just CO2. They are what keeps our planet from being an icecube. And I don't believe there is a natural balance of CO2. This is an interesting article on CO2:

        www.realclimate.org/index.php

        "Over time, the amount of energy sent from the sun to the Earth ’s surface *should* be about the same as the amount of energy radiated back into space, leaving the temperature of the Earth ’s surface roughly constant."

        Except that surface temperature has never really been constant. Climate is always in fluctuation. England was warm enough about 800 years ago to have thriving vineyards. Land use also affects surface temps. There are alot of variables involved.

        "Currently there is 30% more CO2 in the atmosphere than there was at the start of the Industrial Revolution, and we are well on the way to doubling CO2 levels in the atmosphere during this century."

        But scientists don't know if there there a “point of no return” or a “critical threshold” for CO2 levels. That's where the political stuff comes into play.

        "Such as?"

        Well, the 11 degree Celcius increase(the high end number of the latest climatic computer model) that you posted a link to was debunked on that Real Climate.org site:

        "Uncertainty in climate sensitivity is not going to disappear any time soon, and should therefore be built into assessments of future climate. However, it is not a completely free variable, and the extremely high end values that have been discussed in media reports over the last couple of weeks are not scientifically credible."

        I've told you several times that I don't deny that humans have had some impact on the climate, but all the gloom and doom cataclysmic scenarios that have been thrown at us in recent years by activists have not been backed up by the scientists. They just are not in the habit of making those kinds of claims. They are more interested in collecting data and making sure that it is as accurate as it can be before they make any predictions about possible future scenarios.
        • M
          M
          offline 384
          < But scientists don't know if there there a “point of no return ”or a “critical threshold ”for CO2 levels. That's where the political stuff comes into play. >

          Incorrect. Many climate scientists believe an atmospheric level of CO2 of 400 ppm is the point at which a major warming trend will become inevitable. We are now in the high 300 ppm range.

          Politically, I think the point here is pretty obvious.

          Say for a moment you were a "conservative". I don't mean of the neo- variety, for those people aren't conservatives at all but actually barbaric political radicals who are using "conservatives" for political advantage.

          What would a true "conservative" do?

          While a conservative would certainly be reluctant to run off half-cocked with *radical* policy changes that might do more harm then good, neither would a conservative stick his/her head in the sand and in essence gamble that things--i.e., the *entire* global economy--were going to be A-okay if we can just "wait out" the issue. A conservative would want to "conserve" the natural environment that allows us to work, play and do business freely.

          A conservative would insist on taking some real action immediately to get emissions under control, WHILE further studying the problem to see if additional measures were warranted, because of the huge stakes involved. If sea levels were to rise 5-15 feet and global temperatures were to rise another 3-4 degrees Centigrade on average, the economic consequences would be long-term and catastrophic and it would no longer matter what brand of computer you owned or where your vacation cottage was located.

          Whereas nature can certainly do things to us on occasion and we can't stop it, in this instance evidence suggests our own activity is a major factor, and a conservative would certainly not want us to be the *cause* of our own demise. He/she would take immediate and prudent action to at least begin to address the problem.

          The problem is, right now a political cabal that controls the U.S. government and *calls* itself conservative--not the same thing--is doing everything it can to avoid taking any action at all, to avoid offending its campaign contributors in heavy industry. They talk a lot--"new technologies", "better science", "clean coal", but the results are invariably the same: NO REAL ACTION. This is, of course, their goal. One need look no father than the administration going through the gyrations of trying to undermine the credibility of its *own* studies to be convinced of that.

          This is shortsighted, foolish, and selfish. In a word: DENIAL.
        • Thanks for having this discussion with me, hopefully we can all learn something from this.

          <<90% of the world's ice is in Anarctica and sea ice there has been increasing over the last 28 years. That's fact.>>

          You are kind of right, but you are missing some key points.

          Reducing sea ice extent in some regions has been balanced by increasing extent in others. But the danger of rising sea levels does not come from sea ice since it already resides in the sea and it melting has no impact on sea level. It is the ice shelves residing on land sliding in to the water that instantly create rising sea levels. One region of Antarctica where detectable climatic change does seem to be occurring is the central and southern parts of the west coast of the Antarctic Peninsula. Climate records from this region extend back 50 years and, over this period, annual mean temperatures have risen by nearly 3°C. So, while sea ice may increase in one portion of the Antarctic, the melting of ice shelves over land in another portion can have a significant impact. The observed warming has already had a significant impact in the region and is believed to have caused the disintegration of both the Wordie Ice Shelf and the northern part of the Larsen Ice Shelf.
          “Large ice shelves in the Antarctic Peninsula disintegrated in 1995 and 2002 as a result of climate warming. But these floating ice shelves did not affect sea level as they melted. Glaciers, however, are another story. They rest on land and when they slide off into the water they instantly affect sea level.”
          www.commondreams.org/headlin...2-02.htm
          In addition, the danger is not from just rising sea levels, the food chain is also affected:
          “Disappearing sea ice and warmer temperatures in the Southern Ocean around Antarctica are causing an 80 percent drop in the numbers of Antarctic Krill. Krill, a small custacean which feeds on algae under ice sheets, is at the bottom of the food chain. Penguins, seals, fish, sea birds and whales are all dependent on Krill as a food source. This will also impact southern Fisheries.
          www.melbourne.indymedia.org/news...1.php
          <<All greenhouse gases add to that affect, not just CO2>>
          Sure they do, but other greenhouse gases have not increased so rapidly as CO2 has. Look at this NASA chart. www.giss.nasa.gov/research/...indell_02/
          This graph shows the distribution of Green House Gases in Earth's atmosphere. Carbon Dioxide is clearly the majority. www.umich.edu/~gs265/soci...eenhouse.htm

          Also, you indicated that CO2 levels were not as important as other greenhouse gases and that is incorrect: “CO2 is the MOST prominent green house gas in earths atmosphere.” “The World Energy Council reported that global carbon dioxide emissions from buring fossil fuels rose 12% between 1990 and 1995. (www.eb.com:180)”


          << And I don't believe there is a natural balance of CO2.>>

          There is a natural carbon cycle and it is very important.

          “Recently, scientists have studied both short- and long-term measurements of atmospheric CO2 levels. Charles Keeling, an oceanographer at the Scripps Institute of Oceanography, is responsible for creating the longest continuous record of atmospheric CO2 concentrations, taken at the Mauna Loa observatory in Hawaii. His data (now widely known as the “Keeling curve,” shown in Figure 2) revealed that human activities are significantly altering the natural carbon cycle. “

          “Burning oil and coal releases carbon into the atmosphere far more rapidly than it is being removed, and this imbalance causes atmospheric carbon dioxide concentrations to increase. In addition, by clearing forests, we reduce the ability of photosynthesis to remove CO2 from the atmosphere, also resulting in a net increase.”

          “Because of these human activities, atmospheric carbon dioxide concentrations are higher today than they have been over the last half-million years or longer.”

          There are occilations that occur over 100s of thousands of years, but they have a huge impact on the species and environment. “During interglacial periods, atmospheric CO2 concentrations were relatively high, and during glacial periods, CO2 concentrations were relatively low. We are currently in an interglacial warm period, and human activities are pushing CO2 concentrations higher than they have been for hundreds of thousands of years (Figure 3).”

          www.visionlearning.com/librar...wer.php

          << But scientists don't know if there there a “point of no return ”or a “critical threshold ”for CO2 levels. That's where the political stuff comes into play.>>

          Scientists have discovered there may be a point of no return for CO2 levels and that is why you are seeing this influx of new artcles on the subject that speak more definitively on global warming. Yes, there is disagreement and we will get more accurate scientific data in the future.

          “The concentration of carbon dioxide in the atmosphere after which the two-degree rise will become inevitable, and says it will be 400 parts per million by volume (ppm) of CO2. The current level is 379ppm, and rising by more than 2ppm annually - so it is likely that the vital 400ppm threshold will be crossed in just 10 years’ time, or even less (although the two-degree temperature rise might take longer to come into effect).”
          www.tai.org.au/Publicatio...ge%20FV.pdf

          Whether CO2 levels can lower back down to current levels after rising is beside the point. The point is that humans and the animal species we share the earth with will STILL be affected negatively by this warming.

          <Well, the 11 degree Celcius increase(the high end number of the latest climatic computer model) that you posted a link to was debunked on that Real Climate.org site:>>

          Even 2 to 5 degrees will have a significant impact on humans and animal species, it is only the high end predictions that are not reliable. A 6 degree change in temp. due to volcanic emission of CO2 is thought to have caused the extinction of Dinosaurs.

          From your RealClimate web site: “Hence, we feel that the most important result of the study of Stainforth et al. is that by far most of the models had climate sensitivities between 2ºC and 4ºC, giving additional support to the widely accepted range.”




          << I've told you several times that I don't deny that humans have had some impact on the climate, but all the gloom and doom cataclysmic scenarios that have been thrown at us in recent years by activists have not been backed up by the scientists.>

          You are most likely right about the “upper end” temp. increase of 11 degrees and the doom associated with that scenario. But there is doom associated with a 3 degree shift as well. It would have a serious impact on agriculture, land species, and sea species of animals. A three degree shift would have serious consequences for our society.

          P.S. “The United States is currently responsible for approximately one quarter of global CO2 emissions.”

          P.P.S. The same emissions that release CO2 also emit nitrogen oxide that causes smog.
          • Zeppo, this information from your RealClimate.org web site clears up some things as well.

            independent groups, with different analysis methods, have arrived at similar results for the last millennium. The details differ (mostly within the uncertainty bounds given by Mann et al, so the difference is not significant), but all published reconstructions share the same basic features: they show relatively warm medieval times, a cooling by a few tenths of a degree Celsius after that, and a rapid warming since the 19th Century.

            The main reason for concern about anthropogenic climate change is not that we can already see it (although we can). The main reason is twofold.
            (1) Carbon dioxide and other greenhouse gases are increasing rapidly in the atmosphere due to human activity. This is a measured fact not even disputed by staunch “climate skeptics”.
            (2) Any increase in carbon dioxide and other greenhouse gases will change the radiation balance of the Earth and increase surface temperatures. This is basic and undisputed physics that has been known for over a hundred years.
            But how strong is this warming effect? That is the only fundamental doubt about anthropogenic climate change that can still be legitimately debated. We climatologists describe this in terms of the climate sensitivity, the warming that results in equilibrium from a doubling of CO2. The IPCC gives the uncertainty range as 1.5-4.5 ºC. Only if this is wrong, and the true value is lower, can we escape the fact that unabated emissions of greenhouse gases will lead to the warming projected by the IPCC.
            Chances for that are not good. A new large uncertainty analysis that appeared this week in Nature shows that it is very difficult to get a climate sensitivity below 2 ºC in a climate model, no matter how one changes the parameters. And climate history, with its Ice Ages and other large changes, also speaks strongly against low climate sensitivity.
            www.realclimate.org/index.php

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