Just came across this article and thought it would be fodder for the discussion here. I do want to point out though there is one error that I caught in the article. A 500 year flood doesn't mean something that happens once every 500 years but that in any given year there is a 1 in 500 chance of such a flood happening. From Newsweek http://www.newsweek.com/id/143787 [rquoter]Global Warming Is a Cause of This Year’s Extreme Weather By Sharon Begley | NEWSWEEK July 7-14, 2008 issue It's almost a point of pride with climatologists. Whenever someplace is hit with a heat wave, drought, killer storm or other extreme weather, scientists trip over themselves to absolve global warming. No particular weather event, goes the mantra, can be blamed on something so general. Extreme weather occurred before humans began loading up the atmosphere with heat-trapping greenhouse gases such as carbon dioxide. So this storm or that heat wave could be the result of the same natural forces that prevailed 100 years ago—random movements of air masses, unlucky confluences of high- and low-pressure systems—rather than global warming. This pretense has worn thin. The frequency of downpours and heat waves, as well as the power of hurricanes, has increased so dramatically that "100-year storms" are striking some areas once every 15 years, and other once rare events keep returning like a bad penny. As a result, some climatologists now say global warming is to blame. Rising temperatures boost the probability of extreme weather, says Tom Karl, director of the National Climatic Data Center and lead author of a new report from the Bush administration's Climate Change Science Program; that can "lead to the type of events we are seeing in the Midwest." There, three weeks of downpours have caused rivers to treat their banks as no more than mild suggestions. Think of it this way: if once we experienced one Noachian downpour every 20 years, and now we suffer five, four are likely man-made. It's been easier to connect global warming to rising temperatures than to extreme weather events—and even the former hasn't been easy. Only in this decade have "attribution" studies managed to finger greenhouse gases as the chief cause of the rising mercury, rather than a hotter sun or cyclical changes. (The last two produce a different pattern of climate change than man-made warming does.) Now the same "whatdunit?" techniques are being applied to droughts, downpours, heat waves and powerful hurricanes. "We can look at climate-model simulations and likely attribute [specific extreme weather] to human activity," says Gerry Meehl of the National Center for Atmospheric Research. The Midwest, for instance, suffered three weeks of intense rain in May and June, with more than five inches falling on some days. That brought a reprise of the area's 1993 flooding, which was thought to be a once-in-500-years event. The proximate cause was the western part of the jet stream dipping toward the Gulf of Mexico, then rising toward Iowa—funneling moisture from the gulf to the Midwest, says meteorologist Bill Gallus of (the very soggy) Iowa State University. The puzzle, he says, is why the trough kept reforming in the west, creating a rain-carrying conveyor belt that, like a nightmarish version of a Charlie Chaplin movie, wouldn't turn off. One clue is that global warming has caused the jet stream to shift north. That has brought, and will continue to bring, more tropical storms to the nation's north, and may push around the jet stream in other ways as well. Global warming has left its clearest fingerprint on heat waves. Since the record scorcher of 1998, the average annual temperatures in the United States in six of the past 10 years have been among the hottest 10 percent on record. Climatologists predict that days so hot they now arrive only once every 20 years will, by midcentury, hit the continental United States once every three years. Scientists also discern a greenhouse fingerprint in downpours, which in the continental United States have increased 20 percent over the past century. In a warmer world, air holds more water vapor, so when cloud conditions are right for that vapor to form droplets, more precipitation falls. Man-made climate change is also causing more droughts on top of those that occur naturally: attribution studies trace droughts such as that gripping the Southwest to higher sea-surface temperatures, especially in the Pacific. Those can fluctuate naturally, as they did when they caused the severe droughts of the 1930s and 1950s. But they are also rising due to global warming, causing a complicated cascade of changes in air circulation that shuts down rainfall. Hurricanes have become more powerful due to global warming. For every rise of 1 degree Celsius (most of it man-made) in surface temperatures in the tropical Atlantic, rainfall from a tropical storm increases 6 to 18 percent and wind speeds of the strongest hurricanes increase by up to 8 percent. As the new report acknowledged, "the strongest storms are becoming even stronger." Atmospheric conditions that bring severe thunderstorms (with hail two inches across and wind gusts of at least 70 miles an hour) and tornadoes with a force of F2 or greater have been on the rise since the 1970s, occurring about 8 percent more often every decade. Get used to it, and don't blame Mother Nature. [/rquoter]
OK. Here's my problem with the topic of global warming in general. There are thousands of articles like the one above that are quick to blame floods, hurricanes, droughts, etc. on global warming. That's fine. I think there is little doubt that temperatures are rising at an unprecedented level, at least when compared to the relatively little climatic data civilization has existed long enough to record. What I am interested in is an unbiased, non-political investigation to the cause of these rising temperatures and as someone standing on the sidelines, I have not seen such scientific analysis with my own eyes. Can someone please supply me with a report that shows BOTH sides of the global warming debate that clearly indicates through the scientific method, which aspects of global warming are theory and which are fact? I realize that this is a difficult request given the divisiveness of an issue that is at the forefront of the entire world's conscience, but I am really interested in some good, unbiased resources on the subject.
Here's the latest report by the Intergovernmental Panel on Climate Change: http://www.ipcc.ch/press/index.htm A Wikipedia article that talks about criticisms of the IPCC (the strongest of these seem to argue that it is too conservative in its estimates of the significance of man-made global warming): http://en.wikipedia.org/wiki/Intergovernmental_Panel_on_Climate_Change
Thank you. I've read the report before and was disturbed by how easily someone at a glance could misinterpret the committee's analyses having not read the following disclaimer in their report. While this report does seem to be a scientific report on global warming. For an issue as contentious as global warming has become, its use of only language to discern between law, theory, and mere speculation is very ambiguous and confusing. It leaves the door open for speculation. I think a report of this nature should have statements in bold and large font saying "These are undeniable facts" or "These are theoretical projections based on logical, but limited, available data", etc. When one reads the IPCC reports using the below definitions for "Treatment of Uncertainty", certain very controversial aspects of global warming take on different meaning. "Treatment of uncertainty The IPCC uncertainty guidance note1 defines a framework for the treatment of uncertainties across all WGs and in this Synthesis Report. This framework is broad because the WGs assess material from different disciplines and cover a diversity of approaches to the treatment of uncertainty drawn from the literature. The nature of data, indicators and analyses used in the natural sciences is generally different from that used in assessing technology development or the social sciences. WG I focuses on the former, WG III on the latter, and WG II covers aspects of both. Three different approaches are used to describe uncertainties each with a distinct form of language. Choices among and within these three approaches depend on both the nature of the information available and the authors’ expert judgment of the correctness and completeness of current scientific understanding. Where uncertainty is assessed qualitatively, it is characterised by providing a relative sense of the amount and quality of evidence (that is, information from theory, observations or models indicating whether a belief or proposition is true or valid) and the degree of agreement (that is, the level of concurrence in the literature on a particular finding). This approach is used by WG III through a series of self-explanatory terms such as: high agreement, much evidence; high agreement, medium evidence; medium agreement, medium evidence; etc. Where uncertainty is assessed more quantitatively using expert judgement of the correctness of underlying data, models or analyses, then the following scale of confidence levels is used to express the assessed chance of a finding being correct: very high confidence at least 9 out of 10; high confidence about 8 out of 10; medium confidence about 5 out of 10; low confidence about 2 out of 10; and very low confidence less than 1 out of 10. Where uncertainty in specific outcomes is assessed using expert judgment and statistical analysis of a body of evidence (e.g. observations or model results), then the following likelihood ranges are used to express the assessed probability of occurrence: virtually certain >99%; extremely likely >95%; very likely >90%; likely >66%; more likely than"
No one knows what the exact mechanisms of global warming will look like, but the simple fact that more energy into a system requires dissipation of that energy in one way or another. Extremes are a given imo, I just can't tell you which ones. Mega hurricanes, many hurricanes, or simply a shift in rain patterns (and energy dissipation).... who knows? As far as the scientific debate goes.... it's over. It was fierce debate for 20+ years, but consensus has been reached as to the cause of global warming. There is a tendency to elevate an opposing view for the sake of debate and fairness, but the worlds climatologists and the founder of the weather channel do not have an equal amount of credibility on the issue. People project their own poorly understood concepts of science and self serving interests into the public debate, and the public continues to misunderstand scientific theory.
i thought the "500 year floods" were just made up for insurance purposes. i didn't think they were accurate statistical propabilities.
"As a result, some climatologists now say global warming is to blame" What percentage is "some," exactly? Sounds like it's a minority. If it was a a majority, they sure as heck would have written that.
The river levels up here in Iowa were already high due to the massive amounts of snowfall we had up here this past winter. They had never fallen to normal levels before these latest rains hit.
I don't know if they are accurate statistical probabilities but was listening to a discussion about the Iowa floods on NPR a meteoroligist stated this was the definition of 500 year flood or 100 year flood as being a probablity in any given year as opposed to something that occurs once every X number of years.
The consensus used to be the earth was the center of the universe. The debate is not even close to over. Folks are claiming an apocalyptic conclusion based on a few hundred years of climatology data of varying rigor and applying that as significant to a system that has been around for a few billion years. Brilliant!
You're logic is flawless. People have been wrong before, ergo they have no clue what they are talking about now. Never mind that the circumference of Earth was measured in 275 B.C. and it was dogma and not empirical data that held a geocentric universal view for millennium. The debate among climatologist as to the cause of global warming is still over. That's not to say there isn't a great deal of debate over global warming, there is... but it's degrees and percentages, rates and unknowns in feedback systems. Keep latching onto "apocalyptic" language to distract from the analysis of factual data.
The 100 and 500 year floods are statistical probabilities. They are calulated using a drainage area's cross sectional volume and climatic data. One of the problems with them is that they use Manning's Equation Q=CIA, where Quantity= The Coefficient of Runoff x Rain Intensity x The drainage Area; you apply the Quantity of Water to a cross section of a creek or river to see up to what elevation it fills it. Manning assumes a constant rate of runoff but in reality, as you build more houses, roads, flatten grades for farming etc. etc. the amount of water that runs off instead of sinking into the soil gets higher and the rates of concentration get quicker pretty fast. It also fails to account for periods when the soil is already at it's saturation point and will absorb no more rain, like when it's already been under heavy snowfall or in our area, when you've already had 20 inches of rain last week. The Corps of Engineers has to try to draw lines for regulatory purposes but the truth is, they are just static guestimates. The central rivers in the US have flooded forever and massively. We have tried to regulate the flooding so we can develop in the flood zones but in a double whammy that actually adds to the flooding and throws human misery into the story. * this must just be "The Folly Of Civilization" Week*
It is the height of arrogance for our scientists to assume that they have it all figured out. The climatologists *think* our industrial activity is the driving force behind the warming trend. It's the easy scapegoat, because it is the only thing that can reliably be tracked. Here's something to ponder in the larger picture... It has been documented that large volcanic eruptions can precipitate several years of cool if not cold weather, drastically influencing growing seasons and causing crop losses. Perhaps the added warming effect of all this extra CO2 will mitigate the temperature swing if that were to happen in the near to medium future. In that case, we'd all be heroes for saving humanity. Yes, I'm talking a bit tongue-in-cheek, but rather than freaking out about global warming, I'd rather reduce fossil fuel use so we have better air quality. That is something that can be quantified much easier than trying to make data from a few hundred years fit to a timeline that is so much longer. It may be hot, but at least the air is clean...
I don't have time to worry about global warming. I'm still worrying about that bird flu that was supposed to wipe us out. The gullibility of the masses through media is frightening.
I love how whenever someone wants to disagree with the majority they try to paint themselves as some wise, above-it-all iconoclast of unparalleled superior wisdom, looking down on the drooling masses. The same response occurred almost word for word in a thread about 9/11 being a government plot, not to mention just about every other thread where people want to disagree with conventional thinking. If you don't like the party line, then everybody else is an unthinking sheep? Uh... OK. Maybe people believe something different from you for legitimate, well thought out reasons? GASP! Say it isn't so! If they disagree with you they must be mindless zombie idiots, right?
I concur, this holier-than-thou attitude annoys me greatly. do some research people. I will be the first to admit I dont know enough to even comment on the subject matter. I just hope that it's not gonna wipe out my family!
Funny thing is. . . 20 yrs ago . . .that was the exact attitude of the GLOBAL WARMING CROWD Rocket River . . .gooses and ganders I reckon
Is it also arrogance though to be dumping tons of CO2 and other pollutants into the atmosphere and assume that nothing will happen in spite of evidence to the contrary? Like it or not we are already engaged in a mass experiment regarding the planet.
