Jan. 30, 2010: Our readers write

Is it getting hot in here?
Far and away the very largest contributor to global warming is the sun. This “device” has been warming the plant for multi-million (zillion?) years. This all assumes “warming” is energy or the motion of atoms (grouped into molecules.) Except for a few random meteorites striking the planet we’ve had the same number of atoms forever. Hopefully the last 50 plus years of space exploration does not significantly offset the gain of molecules from objects striking the planet.
During the first zillion years the land mass of the planet was primarily vegetation. This growth has the unique process called photosynthesis, which can convert the sun’s light energy into chemical energy and then group various molecules into useable matter. Of course the matter already existed in other forms. If one assumed that matter was continually generated the mass of the planet would increase. A significant increase in mass could impact the orbit which would have an impact on the climate.
As man developed many theories in the last zillion years, he began to change the planet to suit his needs/desires. This has resulted in at least two major effects on the sun’s warming process. First, much vegetation has been removed resulting in much less photosynthesis. Second is the replacement of this vegetation with substances of a significantly different reflective/absorption character.
Man has harnessed much of stored photosynthesis-manufactured matter and is continually reconverting it to produce energy. This energy is not being used to reconvert into matter at the same rate it is being consumed. Assuming that this change is having no impact on the number of atoms/molecules on the planet it would not impact the total mass and ergo the orbit.
A very interesting future contributor to this situation is man’s discovery of how to capture the global warming from the sun and convert it to useful energy without going through the photosynthesis process.
The future of solar-generated energy will be significant. I won’t likely be around to witness it. Of course, then the sun could go out too.
Jim Hatcher
Elizabethtown

Walmart can lead the way
As a dietitian, I was excited to hear that the nation’s largest retailer is taking action to help Americans eat healthier, but I hope the company addresses gaps in its plan. Walmart is planning to reduce prices on produce and urging its suppliers to cut back on sodium, trans fat, and sugar in their products, but it must also work to reduce demand for meat and other high-fat foods.
Our nation’s obesity epidemic reflects increased intake of meat, cheese, oils, and frozen desserts, according to a recent review of food availability over the last century. To truly fight obesity, Walmart must encourage consumers to ditch unhealthy processed meat and choose vegetables, fruits, whole grains, and other plant-based foods.
Studies show that diets high in plant foods help prevent obesity, and they also help ward off heart disease, type 2 diabetes, and some cancers. Walmart is one of the few companies with the power to alter eating habits, but to be successful, the company’s plan must be based on the latest evidence on diet and health.
Susan Levin, M.S., R.D.
Director of Nutrition Education
Physicians Committee for Responsible Medicine
Washington, D.C.