climate

TRYING TO REASON WITH HURRICANE SEASON

As I write, river flooding and cleanup from Hurricane Florence in North and  South Carolina are ongoing. The storm was not a major one in terms of maximum sustained winds--only a Category 1 on the Saffir-Simpson scale when it made landfall at Wrightsville Beach, near Cape Fear, NC.  But the storm approached the coast very slowly, and moved only very slowly once it made landfall. That, and the areal extent of of the storm, resulted in quite a beating for the eastern Carolinas. 

Satellite image of Florence approaching the Carolina coast. 

WE DON'T HAVE TO SHOW YOU ANY STINKIN' FACTS (1)

We are currently mired, at least here in the US, in a political and cultural milieu where truth, facts, and logic are not only ignored by many citizens and alleged leaders, but are actively resisted. (2)   This drives scientists especially crazy, as we are trained and wired to argue and act based on hard evidence and logic. Our efforts in this regard are wildly imperfect, but it is a universally agree upon ideal, and in our world, while facts can be modified and tested, they cannot be ignored or denied.

Alfonso Bedoya in the famous "no stinkin' badges" scene from the Treasure of the Sierra Madre.

 

For years there has been a great deal of (justified) hand-wringing over how scientists can and should communicate with the general public--how to translate complex and specialized concepts into understandable terms, without oversimplifying or trivializing them. These concerns have accelerated lately with respect to the deliberate obfuscation and politicization of issues such as climate change, sea-level rise, and environmental protection.

Climate Change Effects on Karst: It Depends

Karst development is strongly influenced by climate, both directly (via the moisture balance and temperature regime) and indirectly. The indirect effects include biogeomorphic impacts of biota, and base level changes associated with sea-level and river incision or aggradation. The literature on cave and karst landscape evolution has plenty on the general influence of climate on karstification, the role of base-level changes, and speleothems as proxy records of climate change.  There is little on how (or whether) direct effects of climate change influence the rate or nature of karst development.

Talking Climate

In 1997, world leaders met in Kyoto, Japan to discuss how to confront, combat, and adapt to climate change. Eighteen increasingly warmer (on average) years later, a new set of climate talks start in Paris (France, not Kentucky) today (30 November), and continue for 12 days.

Some U.S. politicians have already courageously declared that the U.S. will do nothing, no matter how compelling the evidence, how severe the problems, or what the rest of the world thinks. As we get a new round of public commentary during and after the Paris talks, two recent studies—one journalistic and one academic—are worth considering.

Connecting the Dot Factors

The standard conceptual model for pedology, soil geomorphology, and soil geography is often called the “clorpt” model, for the way it was portrayed in Hans Jenny’s famous 1941 book The Factors of Soil Formation:

S = f(cl, o, r, p, t) . . . .

This equation states that soil types or soil properties (S) are a function of climate (cl), biotic effects (o for organisms), topography (r for relief), parent material (p), and t for time, conceived as the age of the surface the soils are formed on, or the time period the soil has been developing under a given broad set of environmental controls. This factorial approach, considering soils as a function of the combined, interacting influences of environmental factors such as geology, climate, and biota, was originated by V.V. Dokuchaev in Russia in the 1880s, popularized in English by C.F. Marbut in the 1920s and 1930s, and developed by Jenny into the familiar clorpt form.

Why Them? Why There?

In Johnson County, Kentucky, today, lots of people along Patterson Creek are wondering “why me?”  A flash flood Monday (July 13) tore through that eastern Kentucky community, leaving three people dead, a dozen missing at one point, and destroying about 150 homes and who knows how many cars, barns, etc. (news story).

As a Kentuckian, and as a veteran of a couple of hurricanes back in 1996 in North Carolina, I sympathize with wondering why you, or your community, got hit while others didn’t. As a geomorphologist and hydrologist who was worked on flash flooding in the southern Appalachians, I also wonder about the scientific aspects—why the severe flood event in this particular location?

Make no mistake—the area around Flat Gap is not the only one in Kentucky that has gotten a lot of rain recently, and high water, runoff, soil erosion, and filled-up sinkholes are common lately throughout eastern and central Kentucky. But why the much more severe flooding at Patterson Creek?

Did they get more rain?

Makin' It Rain

  No, not like this.

Dang, it’s been raining a lot lately.  Today, for instance, here in Mercer County, Kentucky, Herrington Lake’s level has risen almost 2 m in the last two weeks. Discharge of the Dix River has topped 1000 cfs (28.3 cms) twice in the past week, where the mean flow for early July is about 40 cfs (1.1 cms) over the past 71 years. We had another gully-washer, frog-choker rainstorm this morning.

If it seems to have been an unusually wet summer here in Kentucky, you’re right. The graphic below shows departures from normal (mean) rainfall totals for June. That pinkish blob in north-central Kentucky, showing 8 inches (203 mm) above normal is the Lexington area.

This follows a wet spring hereabouts. Below is the departure-from-normal precipitation map for April, 2015, a month in which one-day precipitation records were set in Lexington, Frankfort, and Louisville.

Climate and History: Geography Matters

 

Just finished John Brooke’s Climate Change and the Course of Global History: A Rough Journey (Cambridge University Press, 2014). If nothing else, the book is a remarkable achievement with respect to the breadth and depth of literature and ideas brought to bear, including history, geography, geology, anthropology, economics, climatology, ecology, and archaeology. Brooke also makes a compelling case for a significant role for environmental change in general, and climate change in particular, in influencing human affairs and history (and, of course, vice-versa).

The Perfect Floods of Texas

 

As I write, there is flooding in central Texas, and more to come. The focus is rivers and creeks in the San Antonio and Guadalupe River systems in the Balcones Escarpment area along the San Antonio-Austin Corridor, with effects beginning to felt downstream.

Destroyed trees along banks of the Blanco River, Wimberly, TX, after the flood of 24 May, 2015 (photo by Jay Janner, Associated Press).

Soil Erosion and Climate Change

 

A lot of us in the geoscience business are concerned these days with interpreting ongoing and past, and predicting future, responses of landforms, soils, and ecosystems to climate change. As one of my interests is rivers, I have noted over the years that in a lot of the literature on paleohydrology the major changes, such as major influxes of sediment, seem to occur at climate transitions, rather than after climate changes or shifts have had a chance to settle in and exert their impacts for awhile.

A related issue is the relationship between precipitation, temperature, runoff, erosion, and vegetation. As climate changes both temperature and precipitation regimes change. And as every physical geography student knows, moisture availability is not just about precipitation, but the balance between precipitation and evapotranspiration (ET). So, if both temperature and precipitation are increasing (as is the case on average on much of the planet now), whether available moisture increases or decreases depends on the relative increases of precipitation and ET.  

Soil erosion on cropland.

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