Dear EarthTalk: Why are beaches and coastlines eroding and what can be done about it?
—Jesus Lopez, Santa Maria, CA
Beach erosion has both human and natural causes. The process of erosion carries beaches out to sea, but it also created them over millions of years from the rock-strewn shores that originally covered our planet. "Without erosion, we would not have the beaches, dunes and highly productive bays and estuaries that owe their very existence to the presence of barrier beaches," says Jim O"Donnell, a coastal processes specialist with the Sea Grant program at Woods Hole Oceanographic Institution.
Sand moves naturally through the actions of wind and the tide, but it is helped along by human actions, and the beach erosion problem is growing dramatically. The main causes are overbuilding right to the water's edge (a practice protected by federal flood insurance), rapid rises in sea level exacerbated by global warming, a gradual sinking of coastal land, and inept attempts to fix the problem.
Scott L. Douglass, author of Saving America's Beaches and a professor at the University of South Alabama, worked his way through college lifeguarding on the New Jersey shore. Like many beach experts, he's a major critic of the erosion-promoting effects of jetties, seawalls and dredging. Human activity has removed "more than a billion cubic yards of sand from the beaches of America, enough to fill a football field over 100 miles high," he points out. Douglass prefers beach replenishment, which he says "adds sand to the system," but he acknowledges that, with sea levels rising at a rate of six inches every 100 years, beaches may not be able to keep up.
Rising sea level means that wetlands and other low-lying lands get inundated, beaches erode, flooding intensifies, and the salinity of rivers, bays and groundwater tables increases. Sea level is rising more rapidly along the U.S. coast than worldwide, according the U.S. Environmental Protection Agency (EPA). In the next century, a two-foot rise is likely, but a four-foot rise is possible; and sea level will probably continue to rise for several centuries, even if global temperatures were to stop rising.
Orrin Pilkey, who directs the Program for the Study of Developed Shorelines at Duke University, believes that in many cases it would actually be cheaper to move buildings back from the water's edge than to fund 10 to 20 years of constant beach replenishment, but his ideas have not had many takers among shoreline communities. Some states and localities in the U.S. and around the world have "set back requirements," restricting development on the shoreline. Protecting and restoring natural barriers to erosion, like dunes, wetlands and vegetation close to shore are also natural, low-cost ways to fight erosion.
CONTACTS: Woods Hole Oceanographic Institution, (508) 289-2252, www.whoi.edu; EPA Coastal Watershed Factsheets, http://www.epa.gov/owow/oceans/factsheets; Duke University Program for the Study of Developed Shorelines, (919) 684-2206, http://www.env.duke.edu/psds.
Dear EarthTalk: Are raw foods healthier to eat than cooked foods?
—Kris Amitzboll, Coledale, Australia
Proponents of raw foods, sometimes called "living foods," believe that raw foods are much healthier for the body than cooked or processed foods. Followers of diets based wholly or largely on raw foods claim numerous health benefits, including increased energy levels, clearer skin, better digestion, weight loss and reduced risk of heart disease.
A purely raw food diet, as its name implies, is based on consuming only unprocessed, usually organic, whole plant-based foods, such as fresh (or dried) fruits and vegetables, nuts and seeds, beans, grains and legumes, other organic or natural foods which have not been processed, and freshly made fruit and vegetable juices.
According to the Living and Raw Foods website, raw, uncooked foods are believed to contain essential food enzymes which help the digestion process without relying on the body to produce the enzymes that are lost through cooking. It is also thought that cooking (heating foods above 116 degrees Fahrenheit) destroys vitamins and minerals and that cooked foods take longer to digest and tend to allow partially digested fats, proteins and carbohydrates to clog up our digestive system and arteries. In Living Cuisine, The Art and Spirit of Raw Food (available from best-cooking-books.com), raw food chef-to-the-stars Renee Loux Underkoffler argues, "Raw foods make optimal assimilation of nutrition easy, provide pure, clean energy for the body, and do not require a lot of energy for digestion."
Traditional nutrition experts refute this idea, though the American Dietetic Association (ADA) and others are doing studies regarding the possible benefits of a raw food diet. Claudia Gonzalez, a registered dietitian and spokesperson for the ADA says that eating all raw, all the time, is an "extreme" diet, but acknowledges, "If you eat more raw foods in your diet (without adding calories) that's always a good thing. Replacing refined, processed foods with raw foods is a healthy move. Eating a few raw meals a week can be great, but it's important not to go to the extreme."
Gonzalez, who has studied raw food diets, says it's hard to eat more than 1,200 calories a day in raw foods. While this might be great for weight-loss, she says, once the weight comes off, that might not be enough to sustain a person's energy, especially if they are doing physically demanding work.
If you decide to go raw, there are benefits to the environment as well. The lower you eat on the food chain, the less impact you will have on the Earth's resources. According to certified nutritionist and raw foods advocate Monica Dewart, "100 percent of the waste materials (seeds, peels, etc) of a raw diet are biodegradable and great for composting. This is the ultimate environmentally-friendly diet!"
CONTACTS: Living and Raw Foods, http://www.living-foods.com; Living Cuisine, available from: best-cooking-books.com/Vegetable_Cookery_Raw.html; American Dietetic Association, (800) 877-1600, http://www.eatright.org; Monica Dewart, firstname.lastname@example.org, http://www.thegardendiet.com/network/monica.