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  1. Semi-related: Speaking of extreme weather, has there been any recent discussion/observations regarding what is being experienced in the Southeast of the U.S. (and to a lesser extent the Southwest) and how the unusually dry, hot season relates, if at all, to climate science? (I mean aside from the obvious trends of rising temperatures associated with AGW.)

    My understanding is many regions are actually facing the prospect of running out of water.

    Comment by J.S. McIntyre — 9 Oct 2007 @ 9:45 AM

  2. J.S. McIntyre — Here is my amateur take on this. The Intertropical Convergence Zone (ITCZ) has been moving north over the last several years. The result in Brazil is that the southern part of the Amazon Basin is turning into a warm and dry savanna.

    I suspect much the same effect is occuring in the Southeast United States, but don’t ask me to explain why. :) The Handley Centre report on regional climate changes for the year 2050 predicts this conversion to savanna, I believe.

    Comment by David B. Benson — 9 Oct 2007 @ 12:31 PM

  3. Just got a solicitation from Frederick Seitz. What the hell is he talking about?
    Thanks

    Comment by John Williams — 9 Oct 2007 @ 2:31 PM

  4. I’ve read that you need 40 inches + inches of precipitation for forests to grow and thrive. Savanna’s require 10 to 30 inches. 30 to 40 inches yield savannas with some trees to areas of sparse woodland. Average rainfall per year drives the bio-geography.

    Comment by catman306 — 9 Oct 2007 @ 4:28 PM

  5. John, re Seitz/Oregon petition, see: http://rabett.blogspot.com/2007/10/those-who-dont-remember-history-are.html

    Comment by Hank Roberts — 9 Oct 2007 @ 5:06 PM

  6. Re: #4 The Llanos in Venezuela receives 40-60″ of rain a year and is a beautiful, seasonally inundated, savannah http://www.venezuelatuya.com/llanos/indexeng.htm?yPPip8duSp8M Whether or not an area supports forest or grassland is dependent upon rainfall timing (winter or summer), rainfall intensity (long duration or short, intense events), soil type (permeable or impermeable) and the presence and type of grazing animals. Fire, natural or anthropogenic is also critical. Here in Houston I live on what was a savannah despite getting 52″ of rain a year that is equitably distributed. It’s the horrid clay soils that does the trees in along with a flat landscape that contains few natural fire breaks. Our soil might as well be brick once it dries out. Hopefully the folks at GISS who are publishing the stuff on how the Amazon Rain Forest does well in reduced rainfall conditions are aware that fire and soil type can have a synergistic effect that leads to forest retreat with even small drops in rainfall. Factoring in human behavior is even more difficult. If climate scientists are going to include vegetation changes as drivers in long term predictive models, they need to get this right. As always, better interdisciplinary cooperation is needed. For example, I think the folks in the western US were caught off guard on how intense the reaction of pine beetles and fire season intensity to warmer weather would be.

    Comment by Andrew Sipocz — 9 Oct 2007 @ 5:45 PM

  7. J.S. McIntyre (#1) wrote:

    Semi-related: Speaking of extreme weather, has there been any recent discussion/observations regarding what is being experienced in the Southeast of the U.S. (and to a lesser extent the Southwest) and how the unusually dry, hot season relates, if at all, to climate science? (I mean aside from the obvious trends of rising temperatures associated with AGW.)

    My understanding is many regions are actually facing the prospect of running out of water.

    To add to what David B. Benson wrote, although in a slightly different language I believe, climate models have predicted the expansion of the Hadley cells – which has been observed, although I believe what has been observed has been somewhat larger than was predicted. With the expansion of the Hadley cells, you move the high pressure zone between the Ferrel cells and the Hadley cells northward, and with this bring about a drier climate. This is what is expected to result in a permanent dust bowel in the US South West under Business As Usual, and I believe it also in part explains the drying out of California which is already taking place.

    Same latitude, I would expect the same sort of thing in the US South East. Climate models show a considerable rise in temperature in the South East – roughly to the same degree as the South West. (Central US? Not as much – but then there is there is the drying out of the continental interior which is supposed to be strongest during the summers.) Likewise, the climate is supposed to change by 2080 in the continental US to the point that we won’t be able to grow wheat south of the Canadian border.

    However, as of yet I know of nothing regarding the present situation in Atlanta being attributed to climate change. Not saying that it isn’t out there. Just that I haven’t run into it as of yet.

    I will do a little digging, though.

    PS Incidentally, I have seen some attribution of the considerable drop in water level in the Great Lakes to climate change – but nothing technical as of yet.

    Comment by Timothy Chase — 9 Oct 2007 @ 6:34 PM

  8. Re: Atlanta drying out?

    I found this in the news, but it is dealing with conflicting projections…

    The most recent National Assessment of the U.S. Global Change Research Program, part of a government analysis published in 2001, used two models to examine climate in the Southeast.

    The kinder, gentler model from the Hadley Centre for Climate Prediction and Research in the United Kingdom estimated a wetter, warmer future: Rainfall may increase 20 percent to 25 percent, mean annual temperatures could increase 2 degrees Fahrenheit by 2030 and 4 degrees by 2100. By contrast, the Canadian Centre for Climate models simulated a dry, scorching future with rainfall decreasing by 10 percent and temperatures rising 3 degrees by 2030 and 10 degrees by 2100.

    But a more recent—and controversial—study, published in the April issue of the American Meteorological Society’s Journal of Climate, theorizes that prior studies overestimated the number of rainy days in the eastern U.S., imposing a cool bias.

    Tuesday, September 18, 2007
    Fighting for water
    By Janet L. Conley, Associate Editor
    http://www.dailyreportonline.com/

    Comment by Timothy Chase — 9 Oct 2007 @ 6:53 PM

  9. Yes, and the issue with running out of water is that what looks like a relatively low but sustainable supply turns toxic as algal blooms grow in the warm water drop toxins. So even where volume of water available is not a major issue yet, the toxins from the algae are seeing supplies becoming unusable very rapidly. This is a global problem and is hitting big cities.

    Sydney is recognising the issue exists but is still head-in-the sand about the potential rapidity of a turnover of the water quality. Algal blooms are not called blooms for nothing – they can happen over a sunny afternoon to an entire water body.

    http://www.theage.com.au/news/National/Algae-covering-most-of-Warragamba-Dam/2007/09/27/1190486462486.html
    September 27, 2007
    The layer of blue-green algae on the surface of Warragamba Dam – Sydney’s main water supply – now covers 75 per cent of the surface area and is likely to remain all summer…
    …”It is not a health risk whatsoever, even though part of the rigorous testing that Sydney Water and Health undertake has detected some microsystems – which are a group of molecules which contain some toxicity…
    But the toxicity is well documented as being acute…
    http://www.nzherald.co.nz/section/1/story.cfm?c_id=1&objectid=10468612
    3:20PM Monday October 08, 2007
    Toxic blue-green algae had already killed dogs, sheep and cattle that drank from the lake, Dr Barbara Dolamore, a Christchurch Polytechnic Institute of Technology (CPIT) senior lecturer in biochemistry and molecular biology, said today.

    http://article.wn.com/view/2007/10/08/Drinking_water_advisory_in_Dunes_City_to_stand/?section=StoryResults&template=cheetah-search%2Findex.txt
    Drinking water advisory in Dunes City to stand
    October 08, 2007

    Residents near Siltcoos Lake who draw their drinking water from the lake are being told it will be at least another week before they can use their main source…
    …rather than collapsing as hoped, algae levels are actually holding steady

    So in every locality where water flow is low and temperatures are high the residents are in real danger of total cut off of municipal water supplies.

    IPCC is a bit too broad brush to identify these point failures, but these are surely evidence of climate change and its impact on people. Again, we should stop haggling over the cause and start global efforts at providing means for the people of Dunes City, Adelaide, Sydney and hundreds of others to efficiently make potable water out of toxic supplies. Maintaining sterility at source is now a dream of better times gone by – we have to adopt personal responsibility for water quality and supply within our own property.

    Comment by Nigel Williams — 9 Oct 2007 @ 7:00 PM

  10. Thanks, Andrew Sipocz. As usual the real world is much more complicated than a simple idea. There are many contributing factors to the creation of a savanna in addition to rainfall.

    So how long does the drought in the Southeast have to last before it’s recognized as ‘climate change’?

    Comment by catman306 — 9 Oct 2007 @ 7:17 PM

  11. Re #11

    So how long does the drought in the Southeast have to last before it’s recognized as ‘climate change’?

    If the experience in Australia is anything to go by, about 15 years.

    Comment by James Killen — 9 Oct 2007 @ 7:58 PM

  12. Also speaking of extreme weather, but to be filed under the heading of anecdotal evidence is the statement yesterday by the Director of the Rockefeller Center ice skating rink yesterday on the occasion of its opening day in Manhattan.”This is the first year we’ve competed with the beaches.” The high temperature in Central Park was 87F. Normal high for the date is 66F.

    The beaches were indeed open over the weekend, as temperatures were above 80F, all weekend and well past the official closing date of the beaches on Sept.16.

    Comment by Lawrence Brown — 9 Oct 2007 @ 8:14 PM

  13. Maybe more — any single llocal event is going to be lost in the local variation (California has had droughts of hundreds of years, looking at the lakebed sediments — the last couple of centuries have been a rare wet spell, unfortunately for city planners who assumed they were normal).

    You have to look beyond the local record, to detect a climate change signal unambiguously.

    Comment by Hank Roberts — 9 Oct 2007 @ 8:29 PM

  14. RE #s 3 and 5: There’s more on the Oregon Petition revival over at DeSmogBlog. John, the author of that DSB post would really like a copy of the package you received.

    Comment by Steve Bloom — 10 Oct 2007 @ 1:24 AM

  15. Timothy Chase (#7):

    This is what is expected to result in a permanent dust bowel…

    Does this mean the Northwest back passage will be open?

    Comment by Gareth — 10 Oct 2007 @ 2:21 AM

  16. Regarding the sun-earth interactions.

    We know, that the warming during 1910-1940 was largely contributed by the increased sun activity. We also know, that this increase in glob. temps. was only slightly smaller than modern era of warming. It is proposed, that even if we stopped CO2 now, we have additional warming of cca. 0.5C for several decades, mostly due to thermal inertia of the oceans. Is similar warming “committment” to be expected from the warming during 1910-1940 and if so, can that be observed now?

    Or, put it differently, when did the climate fully equillibrated after 1910-1940 increased sun activity?

    Comment by Alexander Ac — 10 Oct 2007 @ 5:59 AM

  17. Re 8

    i.e. no one has any idea what is going to happen to climate in the SE USA. The only thing for certain is that it won’t be the same in a hundred years as it is now – there’s a stunning revelation for you!

    Comment by Paul — 10 Oct 2007 @ 6:22 AM

  18. Re #40: [I’ve read that you need 40 inches + inches of precipitation for forests to grow and thrive.]

    You can get forests on much less rainfall than that. Here on the east side of the Sierra Nevada we get about 8″ average annual precipitation at the base (most of that falling as snow in the winter). That of course increases as you go upslope, but mixed pine forests extend down to 6000 feet and lower. On the mountains to the east, there are even drier forests that are mostly juniper & pinon pine.

    Comment by James — 10 Oct 2007 @ 3:31 PM

  19. In response to #1:

    There is no GW in the Southeast, at least where I am (SC). As far as I know, that is not disputed (the Southeast is a cool spot on all the maps in the IPCC report).

    As far as droughts go, it’s pretty dry, but I tend to think that is largely due to the AMAZING lack of hurricanes over the past two years. August-September is normally the wettest part of the year in this region, due to the high number of tropical storms and hurricanes that sweep through in those months. Haven’t seen one of those things in a couple of years now … *cough!*

    Comment by Rob Huber — 16 Oct 2007 @ 9:33 PM

  20. I heard on 60 Minutes today that, due to increased forest fires in the western U.S. due to global warming, that by 2100 50% of the forest cover will be gone (fires will be too frequent for the trees to regrow). They showed an ancient Ponderosa Pine forest in Arizona where centuries-old trees have been killed by this year’s fires and won’t regrow (and the big Ponderosa pines have been able to survive the pre-global warming fires). I live near Oregon and was driving over the Cascades a couple of weeks ago, and was astonished to see that all the trees at the top of the pass I was driving over had all burned (and all looked dead). 60 Minutes noted that the fire season is now 2 months longer than it used to be, and there never used to be forest fires at the higher elevations and now they occur every summer, since the snow melts earlier and isn’t there to stop them.

    Comment by Diane Wills — 21 Oct 2007 @ 10:35 PM

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