Marine Geology, Climate and Sea Level

Guest: Mahlon C. Kennicutt II, PhD (College Station, TX), Professor of Oceanography, Texas A and M University. “The effect of oceans on human life.”

Dr. Kennicutt is a professor of oceanography at Texas A and M University with a specialty in oceans and climate change.

If Earth’s climate warms and the polar ice melts, he says, seal levels could rise and over several decades, they could rise substantially. He believes that greenhouse gases from human activity (cars and factories) are affecting Earth’s thermostat. These pollutants are quickly distributed over the globe and carry trapped energy which tends to melt ice.

Sharon asked if protection of terrestrial fresh water sources (other than polar ice) would be prudent. Dr. Kennicutt noted that rising temperatures would create more climatic extremes, with some areas wetter and some dryer. As is Pakistan, there would be extended droughts followed by violent floods. In wet areas, drought periods would be longer and closer together. So the answer is yes, absolutely. It is also wise to create diversion and runoff channels in dry areas.

There was considerable discussion of air humidity, and both Dr. Kennicutt and Sharon agreed that indoor, climate controlled air is usually too dry. It was noted that drought affects evaporation into the air but that most of the air’s humidity comes from the ocean. The warmer the temperature, the more water will vaporize, thus increasing the humidity.


The Earth has a fixed amount of water, most of which originated from the condensation of volatile gases as the Earth cooled four billion years ago. Global warming, however, could drastically change the balance between atmosphere, precipitation, oceans and ice sheets.

Will the changing balance be detrimental? According to Dr. Kennicutt, humans tend to occupy the margins, where land and water meet (50% of Earth population lives within 50 miles of an ocean and much of the rest live near lakes or rivers). Changes in sea level, increasing desertification, etc. could drastically impact human populations.

However, it is predicted that Earth’s carrying capacity for humans is about nine billion people (it is currently at 6.7 billion). Climate change could cause massive population migrations leading to conflict and starvation as resources become scarce and infrastructure becomes outdated.

Sharon noted that if you solved the water problem, everything else should fall into place.
Sharon asked about waves. Dr. Kennicutt explained that waves are caused by the moon’s tidal pull and by wind, which sets up rising and falling swells. As they near the shore, the waves eventually hit bottom and fall over themselves.

According to Dr. Kennicutt, one danger of global warming has to do with the effect of changes in the mean temperature of the ocean. This could have a huge impact on weather patterns and terrestrial life but also on marine ecosystems, which feeds a large percentage of the world population. When an environmental change exceeds the ability of an organism to respond, you get a “dead zone,” where there is no life and no oxygen in the water.

Many fertilizers used on land are extremely polluting when they reach the ocean. Crops deplete soil nutrients (such as phosphorous and nitrogen) and farmers must put it back in order to keep growing crops. But too much can accumulate as runoff in the ocean. The result is a proliferation of organisms that eventually depletes the oxygen.

Regarding the gulf oil spill, Dr. Kennicutt notes that it is impossible to eliminate all human error. At the time of the interview, he said that the spill is stabilizing and will be cleaned up, although skimming and disbursing chemicals only affect a small percentage of the spill. He also points out that far more oil spills into the ocean around Nigeria annually than was released in the