Funmurphys: the Blog

Wow! After 4 years of graduate school I have completed all my coursework for the Master’s Degree. This is amazing to think about! I took one course at a time, focusing on the journey rather than the destination. But here I am!

My thesis year is next. I plan to research my fingers to the bone and defend my thesis in Spring 2009. And then graduate! I enjoyed my classes, and now I’m looking forward to independent research on wind-driven storm surge. If I had started the Master’s program earlier maybe I could have helped those folks in Myanmar to avoid getting clobbered by Cyclone Nargis. But I’m sure there will be other chances to save lives . . .

The University of Colorado web site has this nifty Grade-O-Matic feature that calculates your grade point average whenever you complete another course, and the Grade-O-Tron meter says my GPA is 3.763. I guess I’m not gonna flunk out of grad school after all! I even managed to pull an A- in Fluid Dynamics. Any course with “dynamics” in the title is tough.

My Oceanography class was neat because we used real data and analyzed all the layers in the world’s oceans. Ocean water masses form in certain regions and retain those same properties even when they travel long distances. The Atlantic Ocean is most stratified. For example, here is a meridional cross section of the Atlantic Ocean at 30 degrees West:

http://acd.ucar.edu/~drews/AtlanticSection30West.jpg

That big purple blob descending from the upper left-hand side of the plot is Antarctic Intermediate Water (AAIW). The AAIW water mass stabilizes at about 1000 meters deep and spreads all the way up to 10N. AAIW is cold and fresh from ice melt; cold enough to slide below the warm tropical salty water, but fresh enough to stay above the saline North Atlantic Deep Water. Way cool!

I took a couple of classes on climate and the human affects on same. From what I learned, the vast majority of climate scientists believe the earth is getting warmer, and a smaller majority believe that humans are a major cause of this warming. One of my classes was taught by Roger Pielke Sr., who might be considered a climate-change skeptic (and he’s a real scientist, not like Rush Limbaugh). Dr. Pielke agrees that increased carbon dioxide is a warming perturbation, and that humans produced the CO2 increase. But he contends that land-use change (irrigation, urbanization, agriculture) is a bigger factor in anthropogenic global warming. When you water the desert and farm it, the decrease in albedo (brightness) absorbs more sunlight and warms the planet. Pielke showed some stunning examples of the changes humans have wrought on the land surface! Stunning in terms of the albedo change and the total percentage of the land surface we have have touched (40%). I carried out a simulation experiment on Aboriginal Australia with the Community Atmospheric Model (CAM) that supported Pielke’s contention that land-use changes can be comparable in magnitude to CO2-driven changes, but my study region was too small to apply this finding to the entire globe.

In Genesis 1:28 God tells mankind to subdue the earth and have dominion over all other living creatures. Genesis 1:28 strongly implies that humans can have a very real affect on the planet’s ecosystem, for better or worse. So from the Biblical perspective it’s reasonable to conclude that human activities can indeed alter the global climate. We aren’t big enough individually, but there are 6 billion of us, and we’ve been fiddling with the earth for quite a few years now.

I looked for evidence relevant to carbon dioxide forcing. Can human-raised levels of CO2 really warm the planet? Is there any historical analog to the current situation? The timing of CO2 vs. temperature changes in the Antarctic ice cores is a little hard to determine precisely, because CO2 has a nasty habit of diffusing deeper into the snow before compaction. A good scientific publication is: “Timing of Atmospheric CO2 and Antarctic Temperature Changes Across Termination III”, by Nicolas Caillon et. al.; 14 MARCH 2003 VOL 299 SCIENCE www.sciencemag.org, page 1728. They postulate the following sequence:

1. Time 0 years: Antarctica gets warmer due to orbital forcing (the trigger).
2. Time 800 years: Change in ocean circulation leads to global rise in carbon dioxide.
3. Time 5,000 years: Northern Hemisphere completes its de-glaciation, caused by CO2 amplification of the original orbital forcing.

Caillon states that “the CO2 increase clearly precedes the Northern Hemisphere deglaciation (Fig 3).” One might think that we have 5,000 years to wait before the Northern Hemisphere completely de-glaciates, but don’t get cocky! – Termination III is not a perfect analog to today’s situation. The point is that increased CO2 really can, and has, forced higher global temperatures.

On a final note: Science in action is really good to see! Conclusions really are reviewed, examined, and questioned by other smart people. We scientists are human, but we are committed to finding out the truth. Sometimes the scientific process includes disagreements along the way. I’m excited about my entry into the process!

Tags: climate