J.C. Moore Online
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Posts Tagged ‘NASA’

The Link between Global Warming and Extreme Weather

Wed ,22/08/2012

A large body of scientific evidence, going back to the middle of the 19th century, links the concentration of atmospheric carbon dioxide,  the temperature of the Earth, and the Earth’s climate. Those who study the Earth and its ecosystems have found ample evidence that the climate is changing. The USDA recently acknowledge that fact by shifting the plant hardiness zones for gardeners northward, acknowledging that frosts occur later in the fall and the last freeze in spring occurs earlier. However many people still doubt climate change and point to weather events as evidence.

Theory: Climate scientists would like to clearly establish the link between climate change and extreme weather events, but that is difficult because of the natural variability of the weather.  The link between global warming, heat waves and droughts would seem unquestionable, but it is difficult to prove. Global warming has increased the energy and moisture in the atmosphere, making conditions for severe storms and floods more likely.  In the last century, the Earth’s average temperature has increased by about 0.8°C, increasing the amount of water the air can hold by about 7%.  It is a reasonable conclusion that when it rains, it will rain more and when it snows, it will snow more. So strangely enough, global warming could actually lead to greater snowfall.  (1) However, it has been very difficult to prove, and certainly even more difficult to convince skeptics that that might be the case.

Climate Models: Another approach to linking extreme weather events to global warming has been through the use of climate models. The models take into account the factors that influence climate and weather, and are often used by meteorologists for “future casting” the weather for 10 day forecasts, which is about as long as normal weather patterns last. However, the models may also be used to examine the effect of global warming on the weather events. The models are used to compare the prediction for a weather event assuming that there is no global warming with a prediction of the weather event that includes global warming. In many cases, it can be shown that the weather and rainfall will be more extreme under the global warming conditions. The results are often challenged by climate Skeptics, who claim that the models do not accurately represent the data, or that the models are “falling apart”. The models were developed to fit a century’s worth of the weather and climate data, and there is little evidence to support the Skeptics claims. However climate scientists would like to show a definite link between global warming and weather events to silence those criticisms.

Statistical Evidence: A recent NOAA report, edited by Petersen, et al. (2) , examined 6 extreme weather events that occurred in 2011 and found that there was a link between climate change and the extreme weather event. One of the most interesting reports (3) ,  found that the 2011 heat wave and drought in Texas were 20 times more likely to happen than they would have been in the 1950’s. How did they arrive at that conclusion? A recent paper by Hansen et al.  (4), shows that extreme temperatures are much more likely to occur worldwide than in the 1950’s, and over 10 times as likely to occur as in 1980. As Hansen puts it, the extreme temperatures “which covered much less than 1% of Earth in 1950, now typically covers about 10% of the land area. It follows that we can state, with a high degree of confidence, that extreme anomalies such as those in Texas and Oklahoma in 2011 and Moscow in 2010 were a consequence of global warming because their likelihood in the absence of global warming was exceedingly small.”

Those two papers are important as they have been able to establish a quantitative link between the probabilities of weather events and global warming. More importantly, the link does not depend on theory or on climate models, and relies only on a straight forward statistical analysis of the data. The method depends on computing the normal distribution of the Earth’s temperature anomalies for each decade and then comparing how the distribution of extreme weather events change with time.

Normal distributions:  Before examining how the method works for weather events, it might be useful to examine how it works with something more familiar, like the height of American men. How could we show whether the number of extremely tall men was increasing as time went by?  This could be done by taking a representative sample of men and examining a graph of the normal distribution. We could find the average, μ , and then repeat the process every 10 years to see how the average changed with time. An increase in the average height might indicate that there would be more extremely tall men, but that is not the full story.

Another piece of information that needs to be considered is the variance, or how widely the height of men vary about the mean. The variance is usually measured by the standard deviation , σ, which can be easily calculated from the measurements done to compute the mean. A  graph of the normal distribution  is shown at the right.  “Normal” means that the data has been divided by the total number of men in sample, so that the area under the entire curve represents 100%. That feature is very useful for comparing heights, and it also allows us to associate an area under the curve with  probabilities.

The average height, μ on the graph, is 5’10”, and the standard deviation, σ, is 3 inches. About 95% of the sample falls within 2 standard deviations of the mean, which also says that the probability is 95% that a man selected at random would fall between 5’4″ and 6’4″. Those over 2σ  from the mean, or 6’4″, make up about 2% of the sample and are considered very tall. Finally, those over 3σ  from the mean , over 6’7″, are considered extremely tall and make up only 0.15 %. Michael Jordan and a host of other National Basketball Association players fall into that 3σ category.

How would it be possible to tell whether the incidence of extremely tall men is increasing? One way would be to take height data collected every 10 years, plot the normal distribution, and see how the area of the graphs out past 3σ change. We could not only tell whether there were more extremely tall men, but we could calculate how the probability of finding an extremely tall man changed, just by comparing areas on the graph.

Weather events. Enough data and computing power is now available to calculate normal distributions of temperature data every 10 years for many decades. Having the normal distribution of the temperature data by decade can be used to find whether the probability of extreme temperatures is increasing or decreasing. The Earth’s temperature was fairly stable from about 1950 to 1980, making it a convenient standard for comparing changes. Rather than using temperatures, the graph uses temperature anomalies, which measure how far a temperature reading was above or below average. 

The procedure is similar to the one described for examining the height of men. Hansen, et al. used the Earth’s temperature data to graph normal distributions of the Earth’s temperature anomalies by decade, from 1950 to the present. They found that the distribution of temperature anomalies approximate a normal distribution. 

The results of their work for the summer months show that beginning in about 1970, the mean begins to move to the right toward higher temperatures. It can also be seen that the variance of the data increased and shifted to the right, showing that the probability of extreme temperatures increase greatly from 1950 to 2011.  It can be seen that the number of extreme temperatures, those out past 3 ( meaning 3σ), almost nonexistent in the 1950s, have grown significantly larger in each decade after 1980. A similar graph, using  σ for the last 30 year period (not shown), found the probability of temperatures past 3 sigma is 10 times as great as for the 198o2 to 2010 years.

It should also be noted that the left side of the graph flattens, but that the probability of extremely cool temperatures is not zero. Though  hot temperatures became more probable, that there was still a significant likelihood of cooler temperatures.

Climate Skeptics often argue that an extremely cold weather event disproves global warming. The normal distributions by decade for the winter months is given at the right.  The graph shows the average winter temperatures have increased significantly during the last 30 years and the variance in the temperature has become greater as time progressed. However, the left side of the graph shows there is still a significant probability of extremely cold weather even though global warming is occurring. This means that the skeptics argument is baseless. It is also sometimes argued that extreme snowfalls disprove global warming, but that is also a baseless argument. Extremely cold air can hold little moisture, and it is warmer air, slightly below freezing, that produces the greatest amount of snow. The Inuit know that a warm spell brings a much greater chance of snow.

So there we have it. Climate physics predicts that global warming should cause higher incidences of extreme weather. Climate models find that global warming makes increased rainfall and storms more probable. A straightforward statistical analysis of temperature data not only shows that extreme temperatures are more likely, but has allow climate scientists to calculate how global warming affects the probability of extreme temperatures. A definite link between global warming and extreme weather has been established by the research.

 (1) http://jcmooreonline.com/2011/03/22/the-case-of-global-warming-and-extreme-weather/ 

(2) http://www1.ncdc.noaa.gov/pub/data/cmb/bams-sotc/2011-peterson-et-al.pdf 

(3) http://usnews.nbcnews.com/_news/2012/07/10/12665235-2011-texas-drought-was-20-times-more-likely-due-to-warming-study-says?

4) http://www.pnas.org/content/early/2012/07/30/1205276109.full.pdf+html

(C) 2012 J.C. Moore

The Skeptic’s Guide to the Medieval Warm Period

Sun ,01/04/2012

“How can science claim man is the cause of global warming when the temperature of the Earth was much warmer during the Medieval Warm Period (MWP)?”

The science Skeptics are quite adept at casting doubt on climate science by using clever arguments. One of their favorites is “How can science claim man is the cause of global warming when the temperature of the Earth was much warmer in the last millennium during the Medieval Warm Period (MWP)?”  You don’t really have to be a scientist to figure out that there were no accurate temperature records during the Medieval times and that much of the world was unknown.

The Skeptics usually point to historical records such as those by H.H. Lamb, which describe record heat waves in the known world during the MWP. Skeptics rather ignore the fact that H.H. Lamb was so concerned about the effect of global warming that he founded the Climate Research Unit (CRU) to study the Earth’s temperature records. The scientific questions comes down to  (1) whether the MWP was worldwide, (2) how warm the Earth actually was during the MWP, and (3) what caused the MWP?

Since there were no thermometers and no worldwide network of weather stations during the MWP, scientists have used a variety of proxy data from ice cores, isotope ratios, sediments, geological records, and even tree rings to try to reconstruct the temperatures for the last thousand years. Though there are large uncertainties in proxy records and they require careful calibration, they do show a similar pattern as you can see in the figure below, which is made up of 10 different reconstructions. The black line is the instrumental temperature record.* (See end of article for references.)

 

Though there are wide uncertainties in the proxy temperature records, taken together they form an overall pattern which answers the scientific questions. The proxy records show that that (1) there was a warm period from  AD 1000 to 1200, followed by a cooler period from  AD 1550 to1850  NASA identifies as the Little Ice Age, though it was not a true Ice Age. The record also show that (2) temperatures during the  MWP were quantitatively lower than the temperatures during the latter 20th century. To discover the cause of the MWP, it is necessary to look at another reconstruction.

While studying the cause of the past Ice Ages, scientists have identified the three  main factors which affect the Earth’s temperature, solar irradiance, greenhouse gases (primarily H2O and CO2), and particulates from volcanic activity. Below is a reconstruction of the three main factors controlling the Earth’s temperature. There are many interesting things in the records, but they show (3) the Earth was likely warmer worldwide during the MWP because of the higher solar radiation. It also shows that the solar radiation has been relatively constant during the last century while the other factors, primarily greenhouse gases, have increased.

 

 While it is possible to dispute or argue about the meaning of any of the individual records, it is rather disingenuous to claim that scientists “ have no data” or to dispute the obvious causes of the current global warming. To emphasize that, below is data from the last century, which is based on scientific records. While H20 and clouds accounts for about 75% of the greenhouse warming, their effect has increased only slightly( about 4%) while the amount of carbon dioxide has increased by about 39% in the last century.

CO2: Man is now putting about 30 billion tons of carbon dioxide into the air each year. About half of it dissolves in the ocean and they have become 20% more acidic in the last century. Much of the rest stays in the air, and  CO2 is building up in air:

Temperature: CO2 is one of the greenhouse gases that warm the Earth, and NASA’s graph shows how its increase is changing the Earth’s temperature. Note:  The effect of particulates from the explosion of Pinaturbo can be seen in the temperature decline from 1991 to 1995.

 

NASA GISS 2010A

 

The Sun: The current global warming is often wrongly attributed to an increase in intensity of the sun. The sunspot activity does not show up above the noise in the temperature record above. The solar irradiance increased slightly until 1960 and has declined slightly since then.

 

There is the scientific story. Disputes in science are settled by the data. Though Skeptics may dispute the evidence showing the current global warming is caused by man, the question is ” Where is the evidence?”

* References for temperature reconstructions:  The original version of this figure was prepared by Robert A. Rohde from publicly available data from NOAA and the references therein. The article stated: “For the purposes of this comparison, the author is agnostic as to which, if any, of the reconstructions of global mean temperature is an accurate reflection of temperature fluctuations during the last 2000 years. “ The reconstructions used, in order from oldest to most recent publication are:

  • (dark blue 1000-1991): P.D. Jones, K.R. Briffa, T.P. Barnett, and S.F.B. Tett (1998). “High-resolution Palaeoclimatic Records for the last Millennium: Interpretation, Integration and Comparison with General Circulation Model Control-run Temperatures”. The Holocene 8: 455-471. doi:10.1191/095968398667194956
  • (blue 1000-1980): M.E. Mann, R.S. Bradley, and M.K. Hughes (1999). “Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations”. Geophysical Research Letters 26 (6): 759-762.
  • (light blue 1000-1965): Crowley and Lowery (2000). “Northern Hemisphere Temperature Reconstruction”. Ambio 29: 51-54. Modified as published in Crowley (2000). “Causes of Climate Change Over the Past 1000 Years”. Science 289: 270-277. doi:10.1126/science.289.5477.270
  • (lightest blue 1402-1960): K.R. Briffa, T.J. Osborn, F.H. Schweingruber, I.C. Harris, P.D. Jones, S.G. Shiyatov, S.G. and E.A. Vaganov (2001). “Low-frequency temperature variations from a northern tree-ring density network”. J. Geophys. Res. 106: 2929-2941.
  • (light turquoise 831-1992): J. Esper, E.R. Cook, and F.H. Schweingruber (2002). “Low-Frequency Signals in Long Tree-Ring Chronologies for Reconstructing Past Temperature Variability”. Science 295 (5563): 2250-2253. doi:10.1126/science.1066208.
  • (green 200-1980): M.E. Mann and P.D. Jones (2003). “Global Surface Temperatures over the Past Two Millennia”. Geophysical Research Letters 30 (15): 1820. doi:10.1029/2003GL017814.
  • (yellow 200-1995): P.D. Jones and M.E. Mann (2004). “Climate Over Past Millennia”. Reviews of Geophysics 42: RG2002. doi:10.1029/2003RG000143
  • (orange 1500-1980): S. Huang (2004). “Merging Information from Different Resources for New Insights into Climate Change in the Past and Future”. Geophys. Res Lett. 31: L13205. doi:10.1029/2004GL019781
  • (red 1-1979): A. Moberg, D.M. Sonechkin, K. Holmgren, N.M. Datsenko and W. Karlén (2005). “Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data”. nature 443: 613-617. doi:10.1038/nature03265
  • (dark red 1600-1990): J.H. Oerlemans (2005). “Extracting a Climate Signal from 169 Glacier Records”. Science 308: 675-677. doi:10.1126/science.1107046

(c) 2012 J.C. Moore

Note added on 07/09/2013 : In a new study by the PAGES 2k project, that was  published in Nature Geoscience , 78 researchers from 24 countries worked for seven years on the most extensive climate reconstruction to date of the past 2000 years.  It is based on 511 climate archives from around the world, from sediments, ice cores, tree rings, corals, stalagmites, historical documents and measurements.  Their  graph below confirms the basic “hockey stick” shape of the graph:Pages 2K

 

 

Gaming the Peer Review System: Part 2. Exploiting Loopholes

Fri ,03/02/2012

There is evidence that the authors of a recent paper may have gamed the peer review system to publish a biased climate science paper.

The Review Process: When a paper is submitted to a journal for publication, the editor removes the name of the author and sends the manuscript to several experts in the area, usually three, for review. The editor keeps the names of the reviewers confidential. If an error is found, the reviewer’s comments are returned to the author with suggestions for corrections. It is a good system for ensuring the quality of research publications, but even then papers are sometimes published that contains errors. The reviewers may miss an error, a biased editor may publish the paper in spite of flaws, or authors may exploit loopholes in a journal’s rules to get a paper published. Some journals allow the author to suggest names of reviewers and the editor often picks reviewers from the list. Most scientists submit names of reliable reviewers as it is an embarrassment to have errors found in their paper after publication. However, even if the papers are properly reviewed, the practice can bring accusations of “pal” review. Since reviewer’s names are kept confidential by the editor, it is difficult to know for sure whether that may have happened. However, there is evidence that the authors of a recent paper may have gamed the system by suggesting a set of reviewers that shared their bias. See what you think.

The paper: Last July 25th, Roy Spencer and Danny Braswell authored a paper in the rather specialized technical journal, Remote Sensing, titled “On the Misdiagnosis Of Surface Temperature Feedbacks From Variations In Earth’s Radiant Energy Balance“.  The paper claimed “The sensitivity of the climate system to an imposed radiative imbalance remains the largest source of uncertainty in projections of future anthropogenic climate change. Here we present further evidence that this uncertainty from an observational perspective is largely due to the masking of the radiative feedback signal by internal radiative forcing, probably due to natural cloud variations.”  It seems that only an expert in climatology would know what that means or what its implications were, but in three days a sensationalized version of the paper appeared on internet sites, in major business magazines, and in news articles in major newspapers. Millions of people likely read about the paper.

The Publicity: The renewed public interest in science should have made climate scientists pleased; however, they were not. Beneath the technical language is a claim that the climate sensitivity to CO2 has been misinterpreted by climate scientists because of natural cloud variations. Were it true, it would mean that natural forces, not man, were responsible for much of the observed global warming. That idea had been examined before and found to be inconsistent with the evidence, but the idea is one that some climate skeptics have been promoting. And, they are part of a well-funded pipeline that carries misinformation about climate science to major news outlets before all the facts can be known.

Forbes: One main branch of the misinformation pipeline runs through the Heartland Institute, where James Taylor is listed as a senior fellow. James Taylor once wrote articles for the tobacco industry suggesting that secondhand smoke was not harmful, and he has now turned his talents to denying the ties between rising CO2 levels and global warming. Inexplicably, James Taylor has been hired by Forbes magazine to write on energy and environmental topics. James Taylor picked up on Spencer’s paper and wrote an article for Forbes titled, New NASA Data Blows Gaping Hole In Global Warming Alarmism. Not only was the title inaccurate and misleading, but the article was clearly an opinion article, miscategorized as news.  The editors of Forbes might not have known that Spencer’s “NASA Data” was the same data that climate scientists use to reach a very different conclusion, but perhaps they should have noticed that no reasonable news story would describe climate scientists as “alarmists” 15 times. The business community considers legislation that would reduce our carbon emissions to be anti-business, and business newspapers such as Investors Business Daily, the Wall Street Journal, and Forbes often are biased toward the skeptic’s position. The bias shows up in story selection, opinions miscategorized as news, a disproportionate number of skeptics articles on opinion pages, and  in sensationalized headlines. From Forbes, the article was picked up as a news story by other business magazines, Yahoo! News, MSNBC, and skeptic’s blog sites, which had a field day with the article. It is sad that millions will have read the distorted article, but few will ever read the climate scientist’s rebuttal. The article will soon sink into obscurity,  but it will have accomplished it’s purpose, which was to spread doubt about climate change.

Reproducibility: Publication in a peer-reviewed journal is not the only requirement for a paper to become accepted as part of the science literature. The research must stand up to the scrutiny of other experts in the field and it must be reproducible by other scientists with comparable knowledge and skill. Spencer’s paper reached the news media before climate scientists had a chance to respond, but they soon found a number of obvious errors in the paper. Trenberth and Fasullo summed it up:”The model has no realistic ocean, no El Niño, and no hydrological cycle, and it was tuned to give the result it gave. The bottom line is that there is NO merit whatsoever in this paper.”  Given time, A.E. Dessler analyzed Spencer’s paper in detail and published a rebuttal. The abstract in Geophysical Review Letters reports the key points of his paper:

  • Clouds are not causing climate change;
  • Observations are not in disagreement with models on this point;
  • Previous work on this is flawed;  ( referring specifically to Spencer’s paper in Remote Sensing).

Clearly, Spencer’s paper had serious methodological flaws and was not reproducible. How did the paper get through Remote Sensing’s peer review process? The answer would likely not have been found, except for the publicity.

The Catastrophe: The editor of Remote Sensing, who had been trying to build the reputation of the Journal, considered the publicity a catastrophe. The instructions in Remote Sensing asks authors to suggest five reviewers, and it is possible that Spencer could choose five skeptics.  The editor would not have to pick from those, but apparently in this case he did.  In the next issue of Remote Sensing, the editor, Dr. Wolfgang Wagner, resigned and issued a public apology for this article saying, “With this step I would also like to personally protest against how the authors and like-minded climate skeptics have much exaggerated the paper’s conclusions in public statements.” “The problem is that comparable studies published by other authors have already been refuted in open discussions and to some extent also in the literature, a fact which was ignored by Spencer and Braswell in their paper and, unfortunately, not picked up by the reviewers. “ And he concluded, “But, as the case presents itself now, the editorial team unintentionally selected three reviewers who probably share some climate sceptic notions of the authors.”

© 2012 J.C. Moore

 

Is Global Warming a Hoax?

Tue ,10/05/2011

Sen. James Inhofe (R –OK) is famous for his statement, “Global warming is a hoax”. The local Tulsa newspaper often carries letters giving the opposing viewpoint. For example, Corey Cohen, recently wrote, “Sen. Inhofe, please cease your effort to stop EPA’s ability to limit greenhouse gas emissions. The science of global warming and climate change is obvious and known. For example, excessive CO2 in the atmosphere absorbs heat reflected from the ground and traps that heat in the atmosphere, melting glaciers and ice and snow packs all around the planet. A given molecule of CO2 in the atmosphere has a life of approximately 100 years. The implications are fairly obvious: rising sea levels, loss of fresh water for humans and unpredictable growing seasons for Oklahoma farmers and their winter wheat crops due to atmospheric heating.” (1)

Mr. Jack Williams replied (2) by “pointing out a few facts”  to defend Senator Inhofe’s position:

“1. More than 31,000 scientists signed a petition opposing the concept of man-made global warming.

2. More than 100 top climate scientists have expressed their opposition.

3. A dozen recognized scientists from nine countries who initially were global-warming proponents have changed their opinion and now oppose it in light of recently published information.

4. Earth has undergone many cooling and warming periods during its history.

5. Carbon dioxide constitutes less than 0.1 percent of the atmosphere while water vapor, at least as effective a greenhouse gas as CO2, ranges from about 20 to 100 times its concentration, and is quite variable.

6. There has been no measurable increase in global temperatures during the past decade.

7. The polar bear population dramatically increased during the past decade, as has ice thickness on Antarctica.”

It’s always nice to get alleged facts in a numbered list, where it is possible to check them one by one.

Endorsements: Facts one, two and three, fall into  the category of endorsements, and as with many endorsement, it is not always clear how well qualified those who endorse the position are, or whether the numbers listed are significant. There are about 23 million graduates with degrees in science and engineering. If 31,000 scientists signed the Oregon Petition, that is about 0.13% of those – hardly significant. Even then, the petition appears to be a hoax. In 1989, the Petition was mailed to thousands of Bachelor of Science students. It was formatted to appear as if it came from the National Academy of Science, but the organization quickly responded that the information was misleading and “the petition does not reflect the conclusions of expert reports of the Academy.”  The mailing collected 17,000 signatures and 14,000 have been added since. Most anyone could sign it, many who signed were misled, and many were not scientists at all, as it is possible to get BS degrees in fields such as journalism, sociology, education, philosophy… (3)

Endorsements that matter: All the major scientific organizations in the world have endorsed a statement such as that of the American Chemical Society,  “Careful and comprehensive scientific assessments have clearly demonstrated that the Earth’s climate system is changing rapidly in response to growing atmospheric burdens of greenhouse gases and absorbing aerosol particles. There is very little room for doubt that observed climate trends are due to human activities. The threats are serious and action is urgently needed to mitigate the risks of climate change.” (4) A recent CNN poll found that 97% of scientists who are actively engaged in research in climate science agree that global warming is caused by man. (5) There is clearly a consensus among scientists on the matter and those making policy would be wise to heed it.

Warming and Cooling: Point four is a fact, but it is not relevant to what is happening today. The Earth has in the past had many natural warming and cooling periods but the current warming trend is not part of those. In the  past, ice ages and warmer interglacial periods have occurred in roughly 100,000-year cycles. These are attributed to the Milankovitch cycles. These cycles are small variations in the eccentricity, axial tilt, and precession of the Earth’s orbit that cause the amount of sunlight the Earth receives to increase and decrease in predictable cycles The cycles predict that a slow cooling trend, which began some 6,000 years ago, will continue for the next 23,000 years. The current warming trend is too rapid and in the wrong direction for the Milankovitch Cycles to be the cause. (6)

Greenhouse gases: Point five is also a fact, but it incorrectly downplays the role of  CO2  in determining the Earth’s temperature. In 1956, G.N. Plass calculated (7) that doubling the concentration of CO2 in the air would cause a 3 to 4 C increase in the Earth’s temperature. Many dismissed his work, as it seemed impossible that CO2, which made up only 0.03% of the air, could have such a large effect on temperature.   However, in 1997, J.T. Kiehl found (8) that, under clear sky conditions, CO2 accounted for 26% of the greenhouse effect – with water vapor accounting for most of the rest. More recent research (9) has confirmed their work, and CO2 has been labeled the “Control Knob” for the Earth’s temperature.  Recent research in the Journal of Climate, covering the last five ice ages, has experimentally confirmed Plass’ work. The Earth is warming because of the greenhouse gases we emit, and research finds the increase in CO2 is the main cause.

Temperature record: Fact six is based on the idea that 1998 was so hot, it couldn’t have been hotter since. However, NASA’s temperature record shows that 2005 and 2010 are tied for the warmest year on record and the last decade has been the hottest in recorded history – and the trend is yet upward (10). There have been attempts to discredit NASA’s temperature data by challenging the accuracy of the temperature recording stations, but a study of that issue by the American Geophysical Union found that claim to be false. (11) NASA has put men on the Moon and brought them home safely, and they certainly should be able to measure temperatures on the Earth correctly.

Polar Bears:  It’s true that the Polar bear population has increased, but not because the Polar ice is increasing. The bears were hunted nearly to extinction, and their population is increasing because restrictions were placed on hunting them from aircraft . Recently, Polar bears have been put on the threatened species list, not because of their numbers, but because their habitat is disappearing.  Satellite measurements of the Arctic sea ice have shown that both the volume and extent of the sea ice has decreased remarkably over the last 30 years. (12) Polar bears are uniquely adapted to live and hunt on the Arctic Sea ice. As it disappears, so will the Polar bears.

Claiming something as “fact” does not make it so. And, even facts can be misleading if the inferences drawn from them are in error.  If Senator Inhofe bases his position on facts such as those listed by Mr. Williams, it is easy to see why he incorrectly thinks global warming is a hoax.

(1)http://www.tulsaworld.com/opinion/article.aspx?subjectid=62&articleid=20110313_222_G2_CUTLIN933913

(2)http://www.tulsaworld.com/opinion/article.aspx?subjectid=62&articleid=20110403_62_G2_InhisM784632

(3) http://jcmooreonline.com/2010/01/29/the-oregon-petition-how-can-31000-scientists-be-wrong/

(4) http://en.wikipedia.org/wiki/Scientific_opinion_on_climate_change#General_science

(5) http://articles.cnn.com/2009-01-19/world/eco.globalwarmingsurvey_1_global-warming-climate-science-human-activity

(6) http://jcmooreonline.com/2010/12/31/science-global-warming-and-the-ice-age-mystery/

(7) http://www.aip.org/history/climate/co2.htm#M_25_

(8) http://journals.ametsoc.org/doi/abs/10.1175/1520-0477%281997%29078%3C0197:EAGMEB%3E2.0.CO;2

(9) http://www.sciencemag.org/content/330/6002/356.abstract

(10) http://data.giss.nasa.gov/gistemp/2010november/fig2.gif

(11)http://www.agu.org/pubs/crossref/2010/2009JD013094.shtml

(12) http://climateprogress.org/wp-content/uploads/2011/01/NSIDC-12-10.gif

(c) 2011 J.C. Moore

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Science, Global Warming, and the Ice Age Mystery

Fri ,31/12/2010

In the early 1800’s, scientists began a search for the cause of the ice ages. That search has led to a discovery of the factors that affect the Earth’s temperature, an understanding of the current global warming, and the solution to the mystery of the ice ages. *

The Data: Science is a way of understanding nature by using observation and reason. Man has always been keenly interested in the weather, but temperature records before 1850 were mostly historical accounts of storms, heat waves, or when bodies of water froze. Thermometers came into use in about 1850, allowing more accurate temperature records. One of the most useful records is NASA’s graph of the Earth’s annual mean temperature, which was compiled from ships logs, weather stations, and satellite measurements. It serves as a scorecard for telling whether the Earth is getting warmer or cooler. NASA’s data has small random variations from year to year because of factors such as sunspots, weather events, ocean currents, and particulates from volcanic eruptions. However, NASA’s graph shows that the Earth’s temperature has clearly trended upward since 1880 – with the exception of a curious plateau from 1945 to 1975 followed by a steeper rise in temperature. The Earth’s mean temperature is now 1.3 F higher than in 1880, and the last decade has been the hottest on record. Any theories or causes put forward to explain the global warming trend must be consistent with the temperature observations.

Possible Causes: Nineteenth century scientists realized from geological evidence that the Earth had gone through many ice ages that alternated with ages of warmer climate. Much of the early research on global warming was a search for the cause of the ice ages. Scientists found that many small variables cause the Earth to warm and cool, but the main three causes are the Sun, particulates, and greenhouse gases.

The Sun’s output seems to have been reasonably stable over the last several million years. Satellite measurements over the last 30 years have shown that while solar radiation has declined ever so slightly during that time, the Earth continued to warm – so clearly changes in the Sun’s output is not the cause of the recent warming. The amount of sunlight the Earth receives does, however, depend on the Milankovitch Cycles. These cycles are small variations in the eccentricity, axial tilt, and precession of the Earth’s orbit that cause the solar insolation, the amount of sunlight the Earth receives, to vary slightly in predictable cycles. Ice core data shows that ice ages tend to occur in roughly 100,000-year cycles that match the timing of the Milankovitch cycles. The temperature between the ice ages and the warm periods, however, are much greater than would be caused by the changes in solar radiation alone. Though a clue to the cause of the ice ages, the Milankovitch Cycles are not the cause of the current warming. They predict a minor cooling trend, which began some 6,000 years ago, will continue for the next 23,000 years. The current warming trend is too rapid and in the wrong direction for the Milankovitch Cycles to be the cause.

Particulates cause the Earth to cool by reflecting incoming sunlight back into space. The role of particulates in cooling the Earth became apparent in 1816 when ash from the explosive eruption of Mt.Tambora caused that year to be called “the year without a summer”, worldwide. The curious plateau in NASA’s temperature record from 1945 to 1975 was primarily caused by particulates from sources such as WW II, atmospheric nuclear testing, and increased industrialization. Research during the early 1970’s showed a huge increase in aerosol particulates from power production, factories, and vehicles – and some alarmists even speculated that we might cause another ice age. Particulates are visible and cause immediate health problems, so by 1980 most industrialized countries had restrictions on particulate emissions. Particulates cannot be the cause of global warming, but reducing their sources can cause the temperature to rise as can be seen in the temperature record after 1980.

The Greenhouse Effect was discovered in the early1800’s when scientists realized that the Earth was kept warm at night because the atmosphere trapped invisible heat rays rising from the surface. Around 1860, John Tyndall identified the invisible rays as infrared radiation and found the main gases that trapped the heat rays to be water vapor and CO2. The amount of water in the air remains relatively constant because of the water cycle. When the humidity is low, water evaporates, and when the humidity gets too high, it rains. However, CO2 has no such restrictions. Since CO2 makes up only a few hundredths of a percent of the air, it was at first dismissed as a possible cause of warming, especially since it was thought that plants and the oceans would absorb any excess.

In 1896, Svante Arrhenius, while still pursuing the idea that variations in CO2 might be the cause of the ice ages, laboriously calculated the effect of cutting the amount of CO2 in the atmosphere by half. He found that doing so would lower the temperature of Europe by 4-5 C, perhaps enough to bring on an ice age. He also found that doubling the amount of CO2 might raise the temperature of the atmosphere by 6-7 C. No one was concerned as Arrhenius’ model of the atmosphere was very crude and it was inconceivable that the amount of CO2 in the air could ever double. Some scientists speculated that man should intentionally add more CO2 to the air to ward off another ice age.

As models of the atmosphere improved, a number of scientists tried to get a better estimate of the effect of doubling the amount of CO2 on the Earth’s temperature, but the increasing complexity of the models made the calculations daunting. A breakthrough came with the development of computers. In 1956, G.N. Plass calculated that doubling the concentration of CO2 in the air would cause a 3 to 4 C increase in the Earth’s temperature. ** Many dismissed his work, as it seemed impossible that CO2, which made up only 0.03% of the air, could have such a large effect on temperature. However, in 1997, J.T. Kiehl found that, under clear sky conditions, CO2 accounted for 26% of the greenhouse effect – with water vapor accounting for most of the rest. More recent research has confirmed their work . Clearly, CO2 could have a significant effect on the Earth’s temperature if it was increasing. But was it?

CO2: In 1900, Arvid Hgbom calculated the amount of CO2 emitted by industrial sources and, surprisingly, found that man was adding CO2 to the atmosphere at roughly the same rate as volcanoes. No one thought much of it as, at that rate, it would take centuries for the amount of CO2 to increase significantly. However, after a protracted heat wave during the 1930’s, Guy Callendar re-examined previous temperature and CO2 measurements and found not only that the Earth was getting warmer, but also that atmospheric CO2 concentrations were increasing rapidly. Callendar’s work was mostly ignored, but a few scientists began monitoring the concentration of CO2 more closely. Their results were sporadic but, by 1958, Charles Keeling had established accurate procedures for measuring atmospheric CO2. His lab was eventually moved to the Mauna Loa observatory, far away from most CO2 sources. His graph showing how CO2 varies with time, now called the Keeling curve, proved to be an important piece of evidence. It showed that the oceans and plants were not taking up CO2 nearly as fast as man was producing it. Over the last century, the atmospheric CO2 concentration has risen from 280 parts per million (ppm) to 385 ppm, a 38% increase, and the Earth’s temperature has risen by 0.8 0C, well in line with Plass’ prediction. The role of CO2 as the major cause of global warming had been convincingly established. There is yet one more piece of evidence that confirms that conclusion.

Ice Ages: It was now possible to solve the mystery of the ice ages. The Milankovitch cycles alone cannot explain the changes in the Earth’s temperature during the cycles, but the process becomes clear if CO2 is included. The ice core data shows that the concentration of CO2 falls to about 180 ppm during an ice age and rises to about 280 ppm during the warm part of the cycle. The changing CO2 concentration happens because the solubility of CO2 in water varies with temperature. In the part of the cycle where the Earth is warmed by the increasing solar radiation, the oceans release CO2, which further amplifies the warming by the greenhouse effect. In the part of the cycle where the solar energy decreases, the oceans cool, the CO2 dissolves again, and another ice age begins. The concentration of CO2 in the atmosphere is the “control knob” for the Earth’s temperature – and we have now turned the knob up to 380 ppm and are moving it even higher. The Earth will surely get warmer.

* Much of the historical data came from this excellent AIP article.

 **  Recent research in the Journal of Climate, covering the last five ice ages, has experimentally confirmed Plass’ estimate of the climate sensitivity.

(C) 2010 J.C. Moore

Is It Climate Change or Global Warming?

Tue ,02/11/2010

The term climate change and global warming are often used interchangeably as they refer to the same environmental problem. Some people prefer to use climate change as climate is more evident to us and climate change is not as controversial as global warming. It is probably okay to use either term, but for those who like precision in language, we will take a tour through climate science to sort out the difference.

Climate and Weather: It is said that no one can predict the weather and that is true as no one can predict very far in advance whether it will rain or storm or how cold or hot it will be. However, if we observe the weather of a region over a long period of time, a pattern emerges. That pattern is the climate and, though we cannot predict the weather accurately, we have a much better chance of predicting climate. If we observe such things as the high and low temperatures, the amount of rain, when the first frost and the last freeze usually occurs, a pattern emerges. The climate is quite important to us as it determines the crops we grow, the types of house we build, and the clothing we wear. Climate determines the plants, animals, and insects that live in our region and even the types of health problems and diseases. The factors that determine climate have been observed to vary slowly with time and we expect the climate in a region to remain relatively stable over long periods.

Climate Change: In the last century, and particularly in the last three decades, we have noticed that climates in many regions of the Earth are changing. The daytime high temperatures are higher, the nighttime lows are warmer, the patterns of drought and rainfall have changed, and storms seemed to have become stronger. Frost occurs later in the year and the last freeze occurs earlier, which has caused gardening zones to move. The ranges of many species of plants, animals, insects and bacteria have shifted, and there has been invasions of non-native, sometimes invasive, species into new areas. Our observations have shown that the climate is definitely changing, and those changes are sure to have consequences for us.

Global Warming: Since the early 1800’s, scientists have been concerned with whether our use of fossil fuels has affected the temperature of the Earth. With an increasing understanding of the role greenhouse gases play in stabilizing the temperature of the Earth, scientist wondered whether burning fossil fuels might affect the energy balance of the Earth. Burning carbon fuels releases carbon dioxide, CO2, which they knew to be an important greenhouse gas and there was speculation about whether an increase of CO2 in the air could actually cause the Earth to warm. Critics of the idea argued that water was a much more important, that the relatively small amount of CO2 in the air would not make a difference, and that the amount of CO2 man produced was minuscule compared to what was already there.

The Role of CO2: With a better understanding of the atmosphere and the advent of computers, G. N. Plass in 1956 was able to calculate the climate sensitivity of the Earth to CO2. He found that doubling the concentration of CO2 in the air would cause a 3 to 4 °C increase in the Earth’s temperature. A number of more recent studies have confirmed his work and have shown that, though the concentration of CO2 in the air is small, it accounts for about 25% of the greenhouse effect. Certainly, increasing the amount of CO2 in the air should cause the Earth to warm. In the last century, our emission of CO2 has increased from a minuscule amount to over 50 billion tons annually and the concentration of CO2 in the air has risen from 280 parts per million (ppm) to 385 ppm. But, has that caused global warming?

The Temperature Scorecard: The temperatures over the Earth vary widely from place to place with the weather and the season. However, the temperature of a particular place measured over a long period of time has a pattern and we can use the pattern as a scorecard. There are temperature records that go back to about 1850 and these have given us a way to keep track of whether the Earth is warming. By using ships logs, weather stations, and satellite measurements, NASA has compiled the Earth’s annual mean temperature from 1880 to the present. Though it varies widely from year to year, the Earth’s annual mean temperature shows an upward trend and the Earth is definitely getting warmer.The scorecard shows that over the last century the Earth has warmed about 1.3°F, which does not sound like much. However, since that is the average over the whole Earth, it represents a tremendous amount of energy and it is the energy in the atmosphere that drives our weather and determines our climate.

So there we have it, a cause and effect relationship. Climate change is caused by global warming, which in turn is caused by the increasing CO2 in the atmosphere, and the CO2 is increasing because of our use of fossil fuels. Though it is probably irrelevant whether we call it climate change or global warming, it is very relevant that we understand the relationships and think about our role. The way we use fossil fuels has consequences for us and for the rest of the species on the planet.

(c) 2010 J.C. Moore

The “Global Warming Is a Myth” Hoax

Sat ,05/09/2009

The article that claimed ” Global Warming Is a Myth” was a hoax.

In 1997 the Wall Street Journal proclaimed in a headline,” Science Has Spoken, Global Warming Is a Myth”. Ironically, the next year,1998, turned out to be the hottest year on record. The authors of the article were Arthur B. Robinson, a biochemist, and his son Zachary W. Robinson, a BS chemist. The main point of their article was that while the concentration of carbon dioxide in the air had been going up, the temperature of the Earth was actually going down. They claim their data proved manmade global warming was a myth. However, inaccuracies in their data and their methods made their proof meaningless. But, was it a hoax?  

 The Robinsons took their data from a paper credited to the Marshall Institute. Their graph1 is copyrighted so the trend lines they use to prove their point have been drawn in on NASA’s graph below.  The blue line on the graph is Robinson’s projection of  what the greenhouse warming of the Earth would be if  it were caused by the increasing concentration of CO2 in the air. That agrees rather well with NASA’s data. However, they claim the green line represents the actual trend in the temperature of the Earth from 1980 to 1996. You can see that the green line bears no relationship to what actually happened and their conclusion is clearly wrong.

 Robinson's Claimed Data

Couldn’t NASA”s data be wrong? Not likely. NASA’s data agrees well with that published by the World Meteorological Organization and both take their data from works published by scientists and climatologists in refereed journals. It is curious that the Robinsons used data from the Marshall Institute, a lobbying group funded by Exxon Mobil. The Marshall Institute’s paper was an analysis of satellite temperature data of the upper atmosphere. The analysis had mathematical errors, assumed an incorrect relationship between upper atmosphere temperatures and those at the surface, and had never been subjected to review by climatologists.

 The article was clearly a hoax.  The authors claimed to speak for all scientists when, in fact, very few scientists then or now agree with them.2 They took their data from the Marshall Institute, a lobbying group, while ignoring much better data from the World Meteorological Organization and NASA. They made sweeping conclusions about climatology when neither author had experience or credentials in the discipline. They did not submit their conclusions for review by other scientists as is customary. They violated, in several ways, the ethical standards set forth in the American Chemical Society’s Code of Conduct. 3 Sadly, the hoax has been continued by newspaper columnists, think tanks, “dissident scientists”, and many senators and congressional representatives who use ideas from Robinson’s article to this day. Its time to put this hoax to rest.

 References:

(1) See page 2 of the article at:   http://stephenschneider.stanford.edu/Publications/PDF_Papers/RobinsonAndRobinson.pdf

 (2) Science organizations are now very clear about this. Every major scientific organization in the world has adopted a statement that global warming is occurring and that human activity is the main cause. For a list of  the organizations and their statements see:  http://en.wikipedia.org/wiki/Scientific_opinion_on_climate_change#Academies_of_Science

 (3) See:  http://temp.onlineethics.org/codes/ACScode.html   The Robinson’s held themselves  out to be chemists and were therefore subject to the ACS code of ethics adopted in 1994. It, in part, addressed the ethics of publishing science articles in the popular press – as in the case of Cold Fusion.