From the President: Tackling the Issues

Tackling the Issues
 
by Dave Rensink, HGS President
 
 
One of the nice things about being president of the HGS is that you are periodically asked to participate in some of our finest programs. HGS co-hosted a conference on coastal subsidence in early November with the Engineering, Science and Technology Council of Houston (ECH). The co-chairs, Cheryl Desforge (HGS treasurer-elect) and Glen Carlson (ECH), and their steering committee deserve high praise for organizing and staging the conference. The purpose of the conference was to discuss the data included in a 2004 NOAA study by Kurt Shinkle and Roy Dokka, which documented the relatively rapid rate of subsidence of surveyed benchmarks in south Louisiana. This study has precipitated a considerable amount of discussion, both positive and negative. HGS and ECH felt this topic deserved a full and public airing because of the short- and long-term significance of the causes of the subsidence. As the loss of wetlands moves from an environmental issue to an economic issue, the public’s demands for a solution will increase by an order of magnitude. This means the size of the projects and the resulting expenditure of public funds increase substantially. We believe project planners and decision makers need as broad an exposure as possible to all of the processes, both natural and manmade, that affect subsidence in order that they may make informed
decisions on potential mitigation projects.
 
If you heard Dr. Dokka’s talk at our November 2004 lunch meeting or read Art Berman’s article in the October 2005 HGS Bulletin, you are familiar with the issues of subsidence, and as a geologist, you are familiar with the causes. Although groundwater withdrawal may be a major cause of subsidence in the greater Houston area, it is certainly not the only cause. Groundwater withdrawal and shallow oil, gas and associated water production definitely contribute to subsidence in south Louisiana and southeast Texas, but they are most likely local in scope and are not the only causes. Yet, in the search for an easy solution to the problem, fluid withdrawal has become the only consideration in the minds of many. Conventional wisdom has once again obscured the pursuit of a solution. Man’s activities may have accelerated the rate of subsidence in certain parts of the Gulf of Mexico basin, but they did not start it. Basin subsidence, sediment compaction, salt movement, gravity gliding and growth faulting started over 160 million years ago when the Gulf of Mexico began to open. There is no reason to think these processes have stopped in the last 50 years.
 
Speaking of man influence of long-term processes, let’s consider global warming. In my opinion, it is difficult to refute the validity of global warming. In a general sense, the earth has been warming since the end of the last glacial epoch—10,000 to 12,000 years ago. I will agree that the earth’s surface temperature has fluctuated during this period, but the earth is generally warmer today than it was 12,000 years ago. Continental glaciers have been retreating and sea level has been rising as a result of solar heating since
long before the industrial revolution. Man’s influence on natural processes, specifically the increase in the concentration of CO2 and water vapor in the atmosphere, may have marginally increased the rate of the earth’s heating, but man did not start it. At worst, we may have successfully accelerated climatic conditions that would have occurred at some point in the future.
 
We are not likely to stop global warming, even if it were possible to immediately stop all CO2 emissions. The best that can be expected is to return to the previous rate of temperature change. It is also likely that it would take an extended period of time to return to the prior rate of change because of the inertia that has probably resulted from the warming of the oceans. It would be similar to expecting a loaded VLCC (very large crude carrier) to come to an immediate stop when the engines are stopped. There may be legitimate long-term reasons to reduce CO2 emissions, but the hope of stopping global warming in the immediate future is not one of them. If that statement does not elicit some
comment, either no one reads this column or no one cares. Before you write or call, remember your training. Natural processes tend to be cyclic. Why should the earth’s climate be any different? Not long before global warming became a global environmental issue, the primary climatic concern was the possible return of a mini ice age similar to that which occurred in Europe between 1300 and 1800.
 
Another piece of conventional wisdom to consider is the reason for the increase in the amount of water vapor in the atmosphere. Water vapor is far more prevalent in the atmosphere and may be a more efficient “greenhouse gas” than CO2. Yet, conventional wisdom says that the increase in water vapor in the atmosphere is a feedback effect of increasing air temperature (warm air is capable of holding more water vapor than cool air), and the amount of water vapor generated by burning fossil fuels is not a significant problem. Thus, conventional wisdom says that water vapor content is increasing only because air temperature is increasing, and the increasing air temperature is the result of increasing concentrations of CO2. The premise that the amount of water vapor generated by human activity may not be significant in relation to the amount of water vapor that can enter the atmosphere as a result of evaporation from soils, lakes and oceans is possibly correct. However, my point is that conventional wisdom has dismissed a potentially significant contributor to climate change as largely a non-issue because any increase in the amount of water vapor in the atmosphere is a direct result of man’s activities. Is that a true statement? Similarly, conventional wisdom seems to have dismissed earth’s ccentric orbit, its proximity to the sun, and its axial inclination toward the sun as major  contributors to climate change.
 
If you are looking for easy solutions, it is possible to make a good correlation between the increase of CO2 in the atmosphere and the increase in coal consumption worldwide since the 1930s. It comes as no surprise that approximately 90% of the coal consumed has been used to generate electricity. Nuclear energy is a viable alternative to coal in electric power generation, but you seldom hear anyone advocating shutting down coal-fired plants and building nuclear plants. There is also a belief that people who live down-wind of a coal-fired plant may be exposed to more radiation through the release of uranium and thorium from the coal than those who live in proximity to a nuclear plant. For those of you who are interested in statistics, the top five energy sources used in electric power generation in the United States are coal (52%), nuclear (21%), natural gas (14%), hydro (7%) and petroleum (3%). If there truly is a compelling reason to significantly reduce CO2 emissions, how do you want to do it and at what price?
 
HGS is hosting a Geo-Legends panel on Janua