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This is an old revision of this page, as edited by William M. Connolley (talk | contribs) at 23:27, 28 February 2006 (→recent reverts: oh good grief). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Regional breakdown

I recommend a breakdown of potential impacts by region, where possible. It would make it so much more illustrative and relevant to people. Daniel Collins 3 July 2005 21:08 (UTC)

I now see there's an entry on the National Assessment on Climate Change, which is to adddress the US impacts, but it is in need of much attention at this time. Daniel Collins 4 July 2005 15:56 (UTC)

Shutdown of THC

I've moved a variety of things from various articles gulf stream, thermohaline circulation, north atlantic current about THC shutdown to here, which seems best. The discussion here reflects my interpretation of the IPCC view, which is much less alarming than some of the other text. William M. Connolley 13:54:14, 2005-07-30 (UTC).

"primary symptom"

"The predicted effects of global warming are many and various, both for the environment and for human life. The primary effect (indeed, the primary symptom) of global warming is increasing carbon dioxide and increasing global average temperature. From this flow a variety of secondary effects, including rising sea levels, declining output of global agriculture, increased extreme weather, and the spread of disease. In some cases, the effects may already be being experienced, although it is generally difficult to attribute specific natural phenomena to long-term global warming."

surely the increase in carbon dioxide is the primary cause of climate change? not an effect. if it is a symptom, what is its root cause? while global warming is likely to increase greenhouse gas levels in the atmosphere (methane release), this does not contribute directly to carbon dioxide increase in the atmosphere.

so I feel that the line "The primary effect (indeed, the primary symptom) of global warming is increasing carbon dioxide and increasing global average temperature." sould be reduced to "The primary effect is an increasing global average temperature."

--Naught101 01:41, 25 August 2005 (UTC)

the past forest fire stats since 1970 for North America

the past stats for forest fires for North America cannot be attributed to Global Warming with any credibility. This source attributes them the fuel buildup, and forest ecology change due to past fire suppression practices, plus the increased population in the western US. --Silverback 10:43, 13 September 2005 (UTC)

I've reviewed the new forest fire text, and while it is less hyperbolic, but it is still appears to be an attempt to start a new fear mongering front, and without much scientific basis, and in fact flies in the face current scientific trends in forest management. For instance the phrase about more "regular fires", is apparently intended to be a criticism, while it may well be a benefit, since fire suppression is thought to be responsible for larger more intense and destructive fires. The predictions of impact on forests are more well balanced between benefits and possible negatives than just about any impact that is considered. The reinsertion of the language on positive feedback is intended I think to suggest some kind of dire reunaway process, when forest fires are naturally self limiting, and the most common impact mentioned for global warming is actually more forest growth. --Silverback 07:31, 16 September 2005 (UTC)

The Loop Current Effect

Hurricanes Katrina and Rita both rode the warm Loop Current, but Rita crossed more cold water afterwards. Hurricane Camille probably went the length of the Loop Current and crossed virtually no cold water afterward - and made landfall as a Category 5. So a major question would be: is Global Warming increasing the SST (sea surface temperature) of the Loop Current?

Also, does it seem like hurricane tracks are more northwards than before? The more northward a track, the more likely the hurricane is to ride the Loop Current.

Simesa 13:28, 25 September 2005 (UTC)

When examining "more", consider the size of your sample. If you're examining an average, it is nice to have hundreds or thousands of measurements. How many thousands of hurricanes each year are you measuring? (SEWilco 13:54, 25 September 2005 (UTC))

A paper is coming from Dr. Kevin Trenberth on the topic of Loop Current water temperature and hurricane strength. Loop Current temperature in the Gulf of Mexico is directly measured by NOAA buoy #42003 . Part of this is in Simesa 23:12, 1 December 2005 (UTC)

Any idea whether/how to incorporate this on the effects of less snow on permafrost? Rd232 14:45, 8 December 2005 (UTC)

Cost of extreme weather events graph

(from Talk:Global_warming#Image:Cost-of-storms-by-decade.gif -- please see)

An extrapolation is not simply a way of displaying data. It is predicting beyond the data. A prediction like this is either original research or a simple pipe-dream, unless it has been published in a peer reviewed source it is out. Out from this article and any article. So, where has this extrapolation been published? Vsmith 04:16, 24 December 2005 (UTC)

I disagree. Extrapolation bars and curves are commonly referred to as "chart decorations" by graphic designers. They do suggest a prediction, which is what they are supposed to do, but they strictly reflect only the underlying data upon which they are based. The practice of printing extrapolations with historical data is commonplace in news, almanac, encyclopedia, and many other kinds of publishing, and is never considered original research. The graph is no more original research than if I were to reflect in the text of the article that, for example, "If present trends continue, the cost of extreme weather events could exceed 350 billion inflation-adjusted U.S. dollars per year by 2025." Don't you agree that is better said with a graph which displays the historical statement directly than with that sentence? James P. S. 08:23, 24 December 2005 (UTC)

This excerpt was requested here by Vsmith; please continue discussion at Talk:Global_warming#Image:Cost-of-storms-by-decade.gif.

I've re-rm'd the graph. My objections at GW remain the same; I'll discusss it there. William M. Connolley 09:04, 24 December 2005 (UTC).

Here is the graph, for the record:

I am asking third party climate bloggers to independently comment on it and will report the comments back to Talk:Global_warming#Image:Cost-of-storms-by-decade.gif. I intend to replace the graph here after their review, unless any significant issues are raised. James P. S. 22:17, 24 December 2005 (UTC)

One expert nominated by a graph deletionist has already called the extrapolation reasonable, not implying the cause of the variation, NPOV, and only technically borderline OR. Therefore, I'm replacing it here and on mitigation pending outcome at Climate Change Action and Talk:Global_warming#Image:Cost-of-storms-by-decade.gif. --James S. 18:47, 28 December 2005 (UTC)

Your eagerness to add this graph is starting to shade into disrespect for your fellow editors. Please give sufficient time for agreement to be reached on Talk:global warming, and don't prejudge the outcome of that debate. Thank you. If you want to add the graph straight away, please add a version which contains only the historical data - this would be uncontroversial (I think) and useful to the reader. Rd232 00:29, 29 December 2005 (UTC)

Eagerness? I think it is very important information and so far there has been no evidence to the contrary presented. The person who originally removed it from Global warming has been making graphs with selectivly reversed x-axes. Wm. Connolley has agreed with the assessment, produced by a third-party reviewer that he himself suggested, that the extrapolation is reasonable, doesn't imply causes, has a NPOV, and is only borderline original. —James S. 01:09, 29 December 2005 (UTC)

Removed graph per discussion in Talk:Global Warming. Consensus there is that the fit isn't reliable. There is evidence that other fits would be better. Finally, the extrapolation considers no feedback effects nor physical limits - which intuitively should be there. Simesa 10:19, 29 December 2005 (UTC)

Simesa has falsely represented the clear consensus that the extrapolation is reasonable, does not imply information about the cause of the variation, has a NPOV, and is only borderline original. I invite anyone to see Talk:Global_warming#Image:Cost-of-storms-by-decade.gif for themselves, and I ask Simesa why he or she has made such a false representation:

Moreover, I dispue the claim that other fits would be better. I have several fits to the data. What evidence does Simesa have to support that any fit is better than another? What evidence does Simesa have that feedback systems can not be modeled with linear, transcendental, or combined non-linear models such as the 2nd and 3rd revision of the graph? —James S. 22:33, 29 December 2005 (UTC)

In Talk:Global Warming the following editors are critical of putting the graph in: Dragons flight, Guettarda, Rd232, NHSavage, Kmf164, Anastrophe, William M. Connolley, Stephan Schulz, Vsmith, bikeable and myself. Only one is in favor - you.

Simesa 01:55, 30 December 2005 (UTC)

I am not sure which graph that vote is referring to; I voted with those editors to exclude the first revision. Are you sure you are representing the vote correctly? —James S. 03:28, 30 December 2005 (UTC)

You make my point - what says that an exponential or low-order polynomial fit is adequate? Intuitively, there's a maximum to the damage simply because there's a maximum to the number of storms.

Simesa 01:55, 30 December 2005 (UTC)

Are you familiar with the process of regresion? The equations chosen were selected because they had the least sum-of-squares error, as measured by adjusting by the number of parameters and adjusted degrees of freedom. Do you have any evidence that a more poorly-fitting model would be a better prediction? Your intuition may be misleading you. Average storm strength is a function of the average wind speed (laminar and turbulent kinetic energy) in the 3D field, which is proportional to atmospheric energy over temperature (localized molecular kinetic energy.) Do you believe that there is a maximum global average windspeed? If so, what do you beleve it is? Do you believe the current global average windspeed is anywhere near it? —James S. 03:28, 30 December 2005 (UTC)

Yes, I am highly familiar with regression, having had several years of college math beyond calculus plus engineering. But it isn't the tightness of fit to pre-2001 data that's the question (although a higher-order polynomial would be better), it's the plausibility of the extrapolation when limits may come into play. The originator of the Saffir-Simpson scale said:

"When you get up into winds in excess of 155 mph you have enough damage," Simpson said in a 1999 interview with the National Weather Log, a publication of the National Oceanic and Atmospheric Administration. "If that extreme wind sustains itself for as much as six seconds on a building it's going to cause rupturing damages that are serious no matter how well it's engineered. So I think that it's immaterial what will happen with winds stronger than 156 miles per hour. That's the reason why we didn't try to go any higher than that," Simpson said.

Simesa 09:30, 30 December 2005 (UTC)

Based on reports of $200 billion in 2005, the above graph based on the same data ending in 1998 predicts the 2005 results more accurately. It also has a wider confidence interval, addressing many of the objections to the other graphs. —James S. 20:48, 1 January 2006 (UTC)

There still has to be physical significance behind the projections. Yes, 2005 fits because New Orleans was hit (and because it was uniquely low-lying) and the Gulf Coast was hit by both Katrina and Rita. But you're predicting three times that much new damage every year by 2010? Thirteen times that every year by 2020? That would be around 90 city hits through 2020 - not only would we expect people to learn from these, but these cease to be independent (that is, we should expect cities to start being hit more than once), invalidating one of your assumptions. Simesa 08:58, 14 January 2006 (UTC)

Proportion of extreme weather costs attributable to global warming

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Does anyone have any good sources on this? —James S. 08:28, 3 January 2006 (UTC)

I suggest browsing the IPCC report, and Roger Pielke's blog http://sciencepolicy.colorado.edu/prometheus/. There's lots of good stuff there that you won't like (I often don't). For example this: http://sciencepolicy.colorado.edu/prometheus/archives/disasters/000653exchange_in_todays_.html William M. Connolley 10:39, 3 January 2006 (UTC).

Great stuff! The citation by Evan Mills of this work and Choi & Fisher in Clim. Change 58, 149 (2003) seems to be the best quantifications. —James S. 22:43, 3 January 2006 (UTC)

Reducing carbon dioxide emissions from a high to a low scenario would reduce the impact on losses and insurers’ capital requirements for extreme windstorms by 80%. Action to reduce society’s vulnerability to some inevitable impacts of climate change, for example through more resilient buildings and improved flood defences, could also result in considerable, but targeted, cost-savings.

" 1% increase in annual precipitation would enlarge catastrophe loss by as much as 2.8%." -- Choi, O. and A. Fisher, "The Impacts of Socioeconomic Development and Climate Change on Severe Weather Catastrophe Losses: Mid-Atlantic Region (MAR) and the U.S." Clim. Change 58, 149 (2003.) —James S. 20:01, 7 January 2006 (UTC)

Thats all very well, but it says *would* not *has*; nor does it predict such an increase. William M. Connolley 20:35, 7 January 2006 (UTC).

What? That is their derivation from historical data. Have you read the article? —James S. 20:41, 7 January 2006 (UTC)

Also http://www.bom.gov.au/info/CAS-statement.pdf may be useful. The rapid increase of economic damage and disruption by tropical cyclones has been caused, to a large extent, by increasing coastal populations, by increasing insured values in coastal areas and, perhaps, a rising sensitivity of modern societies to disruptions of infrastructure. William M. Connolley 20:28, 26 February 2006 (UTC)

Extreme weather and stuff - needs work

This page needs some work done on the reasons and the extreme weather. It needs better sourcing from scientific papers and rather less from New Scientist and stuff. In my opinion the primary source should still be the IPCC TAR, updated (if you've got it...) by the AR4 drafts, and various papers (e.g. Emanuel) since then. I've made a start. This table (and the real sources in the other chapters) is useful.

I've removed (sorry) this:

The radiative forcing which causes global warming also leads to increases of average global wind speed. Because, at higher temperatures more water is evaporated and transpires, leading to increased precipitation, which in turn adds greater amounts of kinetic laminar and turbulent mechanical energy, or wind.

which is simply garbled. If there is evidence for increases in wind speed from observations or future modelling, please show it. The TAR table I ref'd refers to likely future increases in cyclone speeds but not global wind speeds. The atmosphere is complex: more radiative forcing equals more wind speed is simplistic. increased precipitation, which in turn adds greater amounts of Kinetic energy is simply wrong: increased ppn doesn't of itself do much to wind speed at all. http://www.antarctica.ac.uk/met/wmc/zonm-u-ghg3-2030-2070.png, for example, shows zonal mean windspeeds for 2030-2050 avg and 2070-2090 avg - care to guess which is the red line and which the blue?

William M. Connolley 11:10, 3 January 2006 (UTC)

Evaporation happens at the molecular level due to brownian motion, and precipitation occurs in large particles with accumulated potential energy falling. The drafts in a rainstorm are well understood. Is there any evidence that the water cycle doesn't convert thermal energy to mechanical wind? —James S. 22:54, 3 January 2006 (UTC)

Of course, now that I think about it, most wind comes from differences in barometric pressure. Obviously that must have a thermal source due to the lack of giant air compressors and giant vacuum hoses in the sky. But what is the proper scientific way to describe the causal chain from thermal power to pressure changes? Volume expansion of heated air? —James S. 22:57, 3 January 2006 (UTC)

Methane hydrates?

The section on the oceans is possibly missing something about methane hydrate release. As I understand it, these will be destabilised by warmer, less dense waters above them. I think I'm right in saying that this is believed to be at least partly responsible for the Paleocene-Eocene event. Shall I add something? It's not my specialist subject. --Plumbago 17:56, 4 January 2006 (UTC)

Change to More Extreme Weather

I made the following changes:

"The Intergovernmental Panel on Climate Change (IPCC) third annual assessment report stated "there is no compelling evidence to indicate that the characteristics of tropical and extratropical storms have changed." There is, however, limited evidence from a relatively short time period that storm strength is increasing..."--Smithsmith 20:02, 28 January 2006 (UTC)

Its always nice to see people using IPCC as their authority. Some skeptics even seem to dislike it: how odd! Be aware that the AR4 is nearly due, though, and storm frequency has been an active topic recently. William M. Connolley 20:10, 28 January 2006 (UTC).

I would also make a humble appeal that the reference to the Time Magazine article be deleted. This magazine is a popular news and special interest magazine, not a scientic journal. Also the reference to the The Independent under "Decline of Agriculture" section in my humble opinion should be deleted.--Smithsmith 20:37, 28 January 2006 (UTC)

Negative versus positive

Is the purpose of this page to only talk about the negative effects of global warming (i.e. change title to "Negative effects of global warming")? For sure the negative effects may outweigh the positives and maybe some would say there are no positives, although this seems unlikely. I thought that with warmer temperatures and more rain there had been speculations about longer growing season's, etc, and extra carbon dioxide having a fertilizing affect (more food to feed the world). Maybe that is too minor to mention. Anyways at the moment this page looks very one-sided, although maybe that is the way it really is (although in life only good effects or only bad effects from any change is rare I would say). Anyways, just my two cents. Delete this at will ;-) Ian Schumacher 01:01, 1 February 2006 (UTC)

To add to this, haven't some models predicted more stable weather?Ian Schumacher 01:05, 1 February 2006 (UTC)

I believe you are right, Ian. There seems to be a lot of people who want to make sure we are sufficiently alarmed on the matter of global warming. It is what others call the "Chicken Little Effect", and it states that "the likelihood of public funding for a project is directly proportional to the degree of misery perceived by doing nothing." It is only natural that climate scientists would be biased toward pushing the misery option. --Smithsmith 03:13, 2 February 2006 (UTC)

Thank you for making your own biases clear. William M. Connolley 09:52, 2 February 2006 (UTC).

recent reverts

The article says:

Increasing temperature is likely to lead to increasing precipitation

And N bumped this up to Increasing temperature is very likely to continue to and I don't know what the evidence is for that. I've added a ref to the SPM which explicitly states the "likely" .

I removed, and N re-inserted:

Wind produced from differences in barometric pressure has increased as radiative forcing increases the relative amount of daytime thermal expansion of air, and is also expected to continue to increase.

Curiously, he added the citation-needed bit, which seems to indicate he knows of no source for this. I don't think its true.

Again, N replaced "may" with the bold bit in This has been shown to cause, and is expected to continue to cause heavier rainfall and I'm not sure that is justified.

William M. Connolley 12:43, 25 February 2006 (UTC)

Those changes are completely inconsistent with the rest of the article. Just search for each instance of "precipit" and see how far those edits are from the rest of the article. I inserted the "citation needed" tag to remind me to find a source for that. Is there any question that mean wind speed is increasing? I've read that from multiple sources. I hoped that you had one handy. --James S. 19:29, 26 February 2006 (UTC)

Well please find the citation *first* and add the text after. I know of no evidence that global mean wind speed is increasing, and since you can't find a citation, I don't think you do either. William M. Connolley 20:24, 26 February 2006 (UTC).

Added. --James S. 08:50, 27 February 2006 (UTC)

Removed. Your ref seems completely besides the point. You need to justify steps a,b,c in your (a) wind produced from differences in barometric pressure has increased (b) as radiative forcing increases the relative amount of daytime thermal expansion of air, (b) and is also expected to continue to increase. I don't see your ref as justifying any of them. Kindly quote from it.

Also, I added a nice link to the TAR to justify just "likely"; presumably in order to too feel too embarassed about your "very likely" you removed that, but it doesn't seem very honest. William M. Connolley 21:25, 27 February 2006 (UTC)

I was (a) being too conservative in an abundance of caution, and (b) trying to make all the sections self-consistent. I believe the certainty is easily such that "very likely" should be preferred. --James S. 23:18, 28 February 2006 (UTC)

Will you please stop making this stuff up. You're now down to using deceptive edit summaries - you have simply reverted, restoring all the wind speed nonsense etc. I've pointed out that your so-called ref is simply irrelevant. Please answer to the point. William M. Connolley 23:27, 28 February 2006 (UTC).

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