Poison Ivy Loves CO2

Thanks to an article in the Washington Post Health & Science section on 31 August 2010, we now know the real reason why man's emissions of CO2 are a catastrophe.  Jacqueline Mohan, an assistant professor at the University of Georgia's Odum School of Ecology has studied the relative growth rates of tree seedlings and poison ivy in atmospheres with what she supposes have the CO2 concentrations of 1950, 2007, and a projected level for the year 2050.  The Post article by Laura Hambleton claims that tree seedlings grow 8 to 12% faster with more atmospheric CO2, but poison ivy grows 149% faster.  The article neglects to tell us between which years or concentrations of CO2 these relative growth rates were measured.  A chart of average total leaf area per poison ivy plant is presented, however.  That chart indicates about a 2.2 times increase in leaf area in 2007 relative to 1950 and a 2.7 times increase in leaf area in 2050 using the projected atmospheric CO2 concentration.  Neither number provides the stated 149% increase in growth.  What is more, most of the increase in growth from the chart has already occurred as of 2007 compared to 1950.  The leaf area for the assumed 2050 case is only about 20% greater than that of 2007.

Nonetheless, if you are inclined to prance about in the woods with little to no clothing on, this is the most awful example of increased CO2 induced catastrophe that I know about.  Even worse, the article claims that the urushiol oil that people are allergic to is becoming more virulent.  However, we should not despair too much, since Donald K. Milton, a public health physician and director of the University of Maryland Institute for Applied and Environmental Health, says children are not playing outdoors as much nowadays as they did in his youth, so increased poison ivy is not having very notable health effects. 

But poison ivy is common on the East Coast, so be careful.  Anecdotal evidence was provided that suggested that there is an observed increase in poison ivy in the woods.  It was also noted that the increased growth of poison ivy may be partially due to the woods being more broken up with more perimeter areas which get more sunlight.  Will extreme environmentalists soon use that observation as an excuse to destroy homes and businesses, so that the woods along the East Coast can be allowed to become larger with less perimeter area in which poison ivy grows better?  Please do not inform them that I have suggested this argument.

Environmental Effects of Increased Atmospheric Carbon Dioxide

I wish to direct my readers to an excellent review of the climate literature on the subjects of global temperature and climate related to the observed increase in atmospheric carbon dioxide which has occurred since 1870. The rate of increase in CO2 has been faster since about 1950 than it was before that date. This review by Arthur B. Robinson, Noah E. Robinson, and Willie Soon was published in the Journal of American Physicians and Surgeons (2007) 12, 79-90 and was entitled Environmental Effects of Increased Atmospheric Carbon Dioxide. Because the article was written for physicians, it is well aimed for my audience of intelligent people, who may very well not be up on the latest jargon of climatologists or all the details of the many ocean cycles, etc.

The first figure of the article shows the temperature measured at the surface of the Sargasso Sea, which is a large area of the Atlantic, over a 3,000 year period using isotope ratios of marine organisms left in the sediment. The average temperature of this period is drawn as a reference and it is seen that the height of Greek civilization occurred during a warm period with a maximum temperature about 2 degrees Centigrade warmer than the average temperature, that the Roman period corresponded to a temperature period very near average, that the Fall of Rome and the Dark Ages corresponded to a period in which the temperature dropped by about 1 degree Centigrade, followed by the Medival Climate Optimum during which conditions improved in Europe, followed again by a decrease called the Little Ice Age, followed again by a return to a very nearly average temperature, where we are today. The French and Indian War and the American Revolution were during the coldest parts of the Little Ice Age, with conditions few living Americans would prefer to those of the present near average temperature. This figure is shown below:

They then show that the shortening of glaciers occurred well before increases in the atmospheric CO2 began. It began as a result of the warming ending the Little Ice Age. They show that the arctic temperature correlates very well back to 1880 with solar activity and does not correlate with atmospheric CO2. Then they show that the increase in annual mean surface temperature in the contiguous United States from 1880 to 2006 was 0.5 degree Centigrade per century. This is a temperature difference well within the 3 degree Centigrade variance over the last 3,000 years and one which few people would notice personally. A 0.5 C temperature increase is caused by an increase in solar activity of about 0.21% and the measured increase in solar activity from 1900 to 2000 was 0.19%.

During the recovery from the Little Ice Age, U.S. climate has improved with more rainfall, fewer tornadoes, and no increase in hurricane activity. Sea level has trended upward over the last 150 years at a rate of 7 inches per century. This sea level rise also began with the end of the Little Ice Age, rather than with the major increases in atmospheric CO2.

During the past 50 years, human use of hydrocarbons has increased 6-fold, but the increase in atmospheric CO2 has been only 22%. This increase in atmospheric CO2 has stimulated plant growth, which is good for both humans and other animals. Higher CO2 concentrations allow plants to grow faster and larger and to grow better in drier climates than otherwise. The Industrial Revolution has not only improved human life, but it has benefited plant life and the animals who depend upon plants. Increased warmth has also made life a bit easier for most plants and animals. The historical record of bursts in human civilizations also seems strongly to correlate with the warmer periods of the last 3,000 years.