Flash Flood in Arkansas Park Kills At Least 16


Police say at least 16 people have been killed in flash floods at a state park in western Arkansas. Reports say more than 40 people are still unaccounted for.

The park is situated in a valley between two heavily forested hills, near the Little Missouri River. The “little Mo” watershed got hit with 5″ to 9″ of rain within a very short period of time. The water level went from 3 feet to 23 feet between the hours of approximately 11:00pm to around 3:00am.

Bill Sadler from the Arkansas State Police said they would continue rescue efforts a long as necessary. The park does not require campers to register, so it was unclear how many people remained missing or if any people managed to escape the racing waters to pull themselves onto the shore.

CO2 -> plants -> hydrology

This is a few weeks old, but I haven’t seen much mention in the blogosphere. Perhaps I missed it.

A significant study by Betts et al. of the Hadley Centre in the UK examines the observational record for biotic-CO2 feedback on hydrology. Plant physiology is substantially affected by the increases in CO2, directly, without any reference to climate change. Betts confirms that the net effect of the increased availability of CO2 is to reduce water uptake by plants and increase total runoff.

Assessments of the effect of increasing carbon dioxide concentrations on the hydrological cycle that only consider radiative forcing will therefore tend to underestimate future increases in runoff and overestimate decreases. This suggests that freshwater resources may be less limited than previously assumed under scenarios of future global warming, although there is still an increased risk of drought. Moreover, our results highlight that the practice of assessing the climate-forcing potential of all greenhouse gases in terms of their radiative forcing potential relative to carbon dioxide does not accurately reflect the relative effects of different greenhouse gases on freshwater resources.

The BBC article that pointed me there concludes that this result reduces the likelihood of droughts (especially, I’d think, in biologically productive regions), and increases the likelihood of flooding. Similar articles appear elsewhere in the UK press. No sign of it over here. Here’s how the Telegraph spins it:

Dr Betts said that the effect was a double edged sword: “It means that increases in drought due to climate change could be less severe as plants lose less water.

“On the other hand, if the land is saturated more often you might expect that intense rainfall events are more likely to cause flooding.”

He said that until now scientific models had only looked at the effect of gases such as carbon dioxide, methane and nitrous oxide on global warming.

If one wanted to look at their full effect on flooding and drought, the effects on plants had to be considered too.

Dr Betts said he had communicated his results to the EA, who have been working on a Government study which said the flooding risk to rivers could increase up to 20 times by the 2080s.

This estimate would now have to be revised upwards.

What had the EA said to that? “They were very cross,” he said.

“Very cross” indeed. Hail Britannia!

Anyone have an idea out there what this “20-fold” business is about? Is the Telegraph out of control again? (And what’s the “EA” anyway?)

As for the big picture, it looks to me like another example of difficulties communicating across disciplinary boundaries. It’s hard enough to have climatologists and hydrologists communicating effectively, without having to bring plant physiologists into the loop. In the present case, what climatologists consider climatology has very little to do with the global change dynamics at issue.

Now climatologists don’t always have to be the intermediary and in this case we shouldn’t be. In fact biologists commonly consider themselves a customer of hydrology and so do hydrologists. In this case the coupling works the other way around and perhaps the phenomenon was missed for a while.

The push from the early 90’s to create an overarching discipline of “earth system science” that ought to be looking for and systematizing these sorts of couplings seems to have run out of steam from what I can tell. The troubles at NASA can’t be helping.

Cure Worse Than Disease?

Trenberth and Dai in GRL argue that injection of aerosol into the upper atmosphere reduces the vigor of the hydrological cycle, and thus is not a good compensation for greenhouse gas forcing. Even the abstract is behind the firewall! (That seems a bit counterproductive on any model of scientific publishing.) Here is the abstract:

Effects of Mount Pinatubo volcanic eruption on the hydrological cycle as an analog of geoengineering

Kevin E. Trenberth and Aiguo Dai
National Center for Atmospheric Research, Boulder, Colorado, USA

[1] The problem of global warming arises from the buildup of greenhouse gases such as carbon dioxide from burning of fossil fuels and other human activities that change the composition of the atmosphere and alter outgoing longwave radiation (OLR). One geoengineering solution being proposed is to reduce the incoming sunshine by emulating a volcanic eruption. In between the incoming solar radiation and the OLR is the entire weather and climate system and the hydrological cycle. The precipitation and streamflow records from 1950 to 2004 are examined for the effects of volcanic eruptions from El Chichón in March 1982 and Pinatubo in June 1991, taking into account changes from El Niño-Southern Oscillation. Following the eruption of Mount Pinatubo in June 1991 there was a substantial decrease in precipitation over land and a record decrease in runoff and river discharge into the ocean from October 1991–September 1992. The results suggest that major adverse effects, including drought, could arise from geoengineering solutions.

Received 27 April 2007; revised 4 June 2007; accepted 26 June 2007; published 1 August 2007.

Keywords: Pinatubo, hydrological cycle, geoengineering.

Greenhouse forcing enhances the hydrological cycle, but in general not enough to compensate for evaporation, leading to much headscratching among the general public about how increased flooding and increased drought could both be valid predictions.

I think their overall conclusion, that we should not rely on geoengineering to extract us from our predicament, is true enough for another reason I have rarely seen cited; if we don’t have the political structures to limit climate disruptions it is hard to see how the decisions to control any geoengineering effort can be put in place.

This isn’t to say that T & D are wrong, of course.

If they are right it raises some interesting questions, in the context of this summer of astonishing flooding here in Texas and neighboring states, in the UK, in China, in Korea. To what extent do existing anthropogenic aerosol emissions already suppress the otherwise anthropogenically enhanced hydrological cycle?

Global Wierdness Index

The South Asian Monsoon is turning out to be quite exceptional.

I think there should be a global index of how anomalous the global weather is at any given moment. It’s not obvious what the right metric would be. Because everything is more or less coupled to everything else, anomalous weather in one place should be accompanied by anomalous weather elsewhere.

It certainly is hard to avoid an intuitive sense that flooding is rampant this (northern hemisphere) summer.

update: An F2 tornado hit Brooklyn NY on the day I wrote the article. Urban tornados are rare and this one caused quite a lot of disruption.

update: A blogger at Wired chimes in.



Texas, however, has at last settled down into the wretchedly and uneventfully hot, humid and sunny pattern I had been warned about…

unusual Texas meteorology (Austin Statesman)

Here’s a little more detail on our atypical summer from our local daily news source, the Statesman. (Note, if you are visiting from the Future, welcome. Sorry that these stories may already have expired. I hope you are comfortably cool and dry in the Future.)

http://www.statesman.com/news/content/news/stories/local/06/29/0629junerain.html

“June comes in as the third- or fourth-wettest month of the year,” said Lower Colorado River Authority meteorologist Bob Rose. “But usually the rain occurs earlier in the month.”

Rose said a ridge of high pressure usually forms after the first couple of weeks of June, preventing storm systems from moving across the state. But this year the ridge of high pressure has split to the east and west, allowing a stationary upper-level low-pressure system to spin over the state, drawing in moisture from the Gulf of Mexico.

Rose said the forecast for the summer looks wet.

“Long-term models say this pattern may be over Texas for a couple of weeks and bring scattered activity to the area,” Rose said. “This pattern is not typical at all for June.”

While the 19 inches (revised upward) in Marble Falls in 24 hours was very local, similar problems are occurring elsewhere in Oklahoma and Kansas as well as in Texas. Here’s a map of recent flooding in Texas:

http://www.statesman.com/news/content/news/stories/local/06/29/0629weathermap.html

Local humorist John Kelso on the benefits of the local climate shifting toward more rain, which he calls “global dripping”:

http://www.statesman.com/news/content/news/stories/local/06/29/0629kelso.html

examples:

When you get to work in the morning there’s not some jerk in the elevator asking, “Hot enough for you?”

You don’t have to spend a lot of money on sunblock.

That overpriced $750,000 loft in downtown Austin you just paid for might be worth it, since it’s on the third floor, which may save your carpet.

Pet grooming is easier. You can shampoo your dog and just set him outside to rinse.

Update: Another month has passed, basically raining most of the time. I blogged further on July 27.

Weird weather

18 inches of rain in 24 hours, yesterday, just upriver from us at Marble Falls TX. The flood control people (the LCRA = “Lower Colorado River Authority”) are going bonkers trying to smooth this event out and parcel out minimal flood damage. More rain is expected in the Colorado basin this week.

Such rainfalls are not unheard of in Texas, but usually they are associated with tropical storms, which this one isn’t.

Here’s hoping we don’t get one of those soon.

No individual event is caused by climate change. By definition, “climate change” loads the dice in favor of certain types of events. Theory (Allen and Ingram, Nature 2002, v 419 pp 224 – 232) indicates an increasing likelihood of such severe local precipitation events in the foreseeable future.

Update: more here.