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Politics : The Environmentalist Thread -- Ignore unavailable to you. Want to Upgrade?

To: Skywatcher who wrote (32476)	2/17/2011 2:19:06 PM
From: Maurice Winn	1 Recommendation Read Replies (1) \| Respond to of 36917

Luke [Skywatcher], those aren't scientists. Those are weather modelers who don't do a very good or even partly good job and are more akin to tribal shamans. They chant incantations, wave palm fronds and sheafs of papers proclaiming doom. The fact is that over 100 years, temperature has increased a mere fraction of a degree, with much of that having increased last century. To claim that particular weather events are related to that is ridiculous. The claim that climate volatility has increased because of this non-existent 'global warming' is also silly. Science is at basis about cause and effect, with replicable observation, not coincidence or correlation. Correlation is not causation - a most fundamental blunder of most so-called scientists. Look here, weather modelers using garbage in = garbage out computers: <The scientists took all the information that shows an increase in extreme rain and snow events from the 1950s through the 1990s and ran dozens of computer models numerous times. They put in the effects of greenhouse gases — which come from the burning of fossil fuels — and then ran numerous models without those factors. Only when the greenhouse gases are factored in do the models show a similar increase to what actually happened. All other natural effects alone don't produce the jump in extreme rainfall. Essentially, the computer runs show climate change is the only way to explain what's happening. > People can write software to tell computers to put out whatever they want the computers to put out, no matter what data is put in. It's like the amusing number tricks where after a sequence of take this off that, add 34, divide by your age, count to 4, add the number of your toes, and hey presto, you were born on that date: mathematical magic. No, just arithmetical trickery for people who don't understand things. The computer modelers didn't mention cloud cover, altitude of and density of cloud cover, snow cover, plant cover, solar cycle and output. Those things have a very large effect on climate. Mqurice

To: Skywatcher who wrote (32476)	2/17/2011 4:32:26 PM
From: Alastair McIntosh	1 Recommendation Respond to of 36917

Comment On The Nature Paper “Human Contribution To More-Intense Precipitation” By Min Et Al 2011 There has been quite a bit of discussion on weblogs of the Nature paper [h/t to Marcel Crok for alerting me to the paper] Seung-Ki Min, Xuebin Zhang, Francis W. Zwiers and Gabriele C. Hegerl: 2011: Human contribution to more-intense precipitation extremes. Nature. 17 February 2011. Weblog posts include On Storms, Warming, Caveats and the Front Page Attribution of Extreme Events: Part II Flood Disasters and Human-Caused Climate Change The Nature paper as well as media coverage is selective on attributing reasons for an increase in extreme precipitation even if this is a robust finding. Of concern is the incomplete reasoning that they provide for explaining the increase in extreme precipitation, where Min et al write “Here we show that human-induced increases in greenhouse gases have contributed to the observed intensification of heavy precipitation events found over approximately two-thirds of data-covered parts of Northern Hemisphere land areas.” We have published recently on the role of land use change, by itself, as a possible explanation of an increase in extreme precipitation in certain regions. The model study reported in Nature ignored this possibility. Our papers on this subject, under the leadership of Faisal Hossain, include Hossain, F., I. Jeyachandran, and R.A. Pielke Sr., 2009: Have large dams altered extreme precipitation patterns during the last Century? Eos, Vol. 90, No. 48, 453-454. Copyright (2009) American Geophysical Union. Degu, A. M., F. Hossain, D. Niyogi, R. Pielke Sr., J. M. Shepherd, N. Voisin, and T. Chronis, 2011: The influence of large dams on surrounding climate and precipitation patterns. Geophys. Res. Lett., 38, doi:10.1029/2010GL046482, in press. Hossain, F., I. Jeyachandran, and R.A. Pielke Sr., 2010: Dam safety effects due to human alteration of extreme precipitation. Water Resources Research, 46, W03301, doi:10.1029/2009WR007704. Excerpts from the Hoassin et al 20010 paper read “For southern Africa and southern Europe, dams [and the associated landscape changes that result in its vicinity] appeared to have increased extreme precipitation (P99 events) by as much as 20% during the last century. Stations in southern India are found to have experienced a modest increase in the P99 value (Figure 3). In the U.S., the P50 (mean) and P99 values are found similarly sensitive to the effect of dams.” “Our study seems to indicate that the impact of large dams on extreme precipitation is clearly a function of surrounding mesoscale and land use conditions [e.g., see Pielke et al., 2007; Douglas et al., 2009], and that more research is necessary to gain insights on the physical mechanisms of extreme precipitation alteration by dams. The changes in land use, for example from added irrigation, add a significant amount of water vapor into the atmosphere in the growing season, thereby fueling showers and thunderstorms [e.g., see Pielke and Zeng, 1989; Pielke et al., 1997; Pielke, 2001].?” It appears that the focus of much of the media and in Nature is to prompte a narrowly confined explanation for increases in extreme precipitation (as being due primarily to added CO2 and a few other greenhouse gases). They have ignored other explanations due to human forcings; e.g. see ????Inadvertant Weather Modification – An Informational Statement of the American Meteorological Society (Adopted by the AMS Councul on 2 November 2010) as well as the role of natural variability in extreme precipitation weather events, as discucssed very effectively in the posts by Judy Curry Attribution of Extreme Events: Part I Attribution of Extreme Events: Part II. Site below has several links worth reading: pielkeclimatesci.wordpress.com

To: Skywatcher who wrote (32476)	2/17/2011 4:35:14 PM
From: Alastair McIntosh	Respond to of 36917

Flood Disasters and Human-Caused Climate Change [UPDATE: Gavin Schmidt at Real Climate has a post on this subject that -- surprise, surprise -- is perfectly consonant with what I write below.] [UPDATE 2: Andy Revkin has a great post on the representations of the precipitation paper discussed below by scientists and related coverage by the media.] Nature published two papers yesterday that discuss increasing precipitation trends and a 2000 flood in the UK. I have been asked by many people whether these papers mean that we can now attribute some fraction of the global trend in disaster losses to greenhouse gas emissions, or even recent disasters such as in Pakistan and Australia. I hate to pour cold water on a really good media frenzy, but the answer is "no." Neither paper actually discusses global trends in disasters (one doesn't even discuss floods) or even individual events beyond a single flood event in the UK in 2000. But still, can't we just connect the dots? Isn't it just obvious? And only deniers deny the obvious, right? What seems obvious is sometime just wrong. This of course is why we actually do research. So why is it that we shouldn't make what seems to be an obvious connection between these papers and recent disasters, as so many have already done? Here are some things to consider. First, the Min et al. paper seeks to identify a GHG signal in global precipitation over the period 1950-1999. They focus on one-day and five-day measures of precipitation. They do not discuss streamflow or damage. For many years, an upwards trend in precipitation has been documented, and attributed to GHGs, even back to the 1990s (I co-authored a paper on precipitation and floods in 1999 that assumed a human influence on precipitation, PDF), so I am unsure what is actually new in this paper's conclusions. However, accepting that precipitation has increased and can be attributed in some part to GHG emissions, there have not been shown corresponding increases in streamflow (floods) or damage. How can this be? Think of it like this -- Precipitation is to flood damage as wind is to windstorm damage. It is not enough to say that it has become windier to make a connection to increased windstorm damage -- you need to show a specific increase in those specific wind events that actually cause damage. There are a lot of days that could be windier with no increase in damage; the same goes for precipitation. My understanding of the literature on streamflow is that there have not been shown increasing peak streamflow commensurate with increases in precipitation, and this is a robust finding across the literature. For instance, one recent review concludes: Floods are of great concern in many areas of the world, with the last decade seeing major fluvial events in, for example, Asia, Europe and North America. This has focused attention on whether or not these are a result of a changing climate. Rive flows calculated from outputs from global models often suggest that high river flows will increase in a warmer, future climate. However, the future projections are not necessarily in tune with the records collected so far – the observational evidence is more ambiguous. A recent study of trends in long time series of annual maximum river flows at 195 gauging stations worldwide suggests that the majority of these flow records (70%) do not exhibit any statistically significant trends. Trends in the remaining records are almost evenly split between having a positive and a negative direction. Absent an increase in peak streamflows, it is impossible to connect the dots between increasing precipitation and increasing floods. There are of course good reasons why a linkage between increasing precipitation and peak streamflow would be difficult to make, such as the seasonality of the increase in rain or snow, the large variability of flooding and the human influence on river systems. Those difficulties of course translate directly to a difficulty in connecting the effects of increasing GHGs to flood disasters. Second, the Pall et al. paper seeks to quantify the increased risk of a specific flood event in the UK in 2000 due to greenhouse gas emissions. It applies a methodology that was previously used with respect to the 2003 European heatwave. Taking the paper at face value, it clearly states that in England and Wales, there has not been an increasing trend in precipitation or floods. Thus, floods in this region are not a contributor to the global increase in disaster costs. Further, there has been no increase in Europe in normalized flood losses (PDF). Thus, Pall et al. paper is focused attribution in the context of on a single event, and not trend detection in the region that it focuses on, much less any broader context. More generally, the paper utilizes a seasonal forecast model to assess risk probabilities. Given the performance of seasonal forecast models in actual prediction mode, I would expect many scientists to remain skeptical of this approach to attribution. Of course, if this group can show an improvement in the skill of actual seasonal forecasts by using greenhouse gas emissions as a predictor, they will have a very convincing case. That is a high hurdle. In short, the new studies are interesting and add to our knowledge. But they do not change the state of knowledge related to trends in global disasters and how they might be related to greenhouse gases. But even so, I expect that many will still want to connect the dots between greenhouse gas emissions and recent floods. Connecting the dots is fun, but it is not science. rogerpielkejr.blogspot.com