Dear EarthTalk: Did global warming cause Hurricane Katrina or make its impact worse?
—John O"Dwyer, Hull, MA
No single storm or its intensity can be attributed to climate change alone, but scientists do believe that warmer ocean temperatures as a result of global warming may be intensifying the strength of hurricanes—and therefore could have contributed to Katrina's fury. The reason is that warmer ocean temperatures, like those that occur in the tropics between June and November, cause instability in the lower atmosphere, which, in turn, "fuels" developing hurricanes. Thus, if ocean temperatures rise a few extra degrees above normal, it follows that the ensuing hurricanes will gain added strength accordingly.
A recent study by climatologist Kerry Emanuel of the Massachusetts Institute of Technology (MIT) concluded that tropical storms and hurricanes in both the Atlantic and Pacific oceans have increased in both duration and intensity by a whopping 50 percent since the 1970s. These increases have taken place over the same time period as average temperatures at the ocean's surface, suggesting that this warming is responsible for the greater power of the storms.
Indeed, the hottest years in recorded history have been over just the last 15 years, and with worldwide industrial emissions of carbon dioxide at their highest levels ever, most scientists agree that human industrial activity is a significant culprit. Scientists have been predicting that worldwide sea level rises due to melting polar ice caps would bring about frequent flooding of low-lying areas as well as more frequent and intense hurricanes, among other weather irregularities. "My results suggest that future warming may lead to an upward trend in [hurricanes"] destructive potential, and—taking into account an increasing coastal population—a substantial increase in hurricane-related losses in the 21st century," says MIT's Emanuel.
Beyond reigniting debate about global warming, Katrina's impact is also highlighting the consequences of the rapid destruction of wetlands throughout the United States. Louisiana alone has lost more than a million acres of coastal wetlands since the 1940s, and some environmental leaders maintain that the installation of the levees surrounding New Orleans a half century ago led to the decay of nearby wetlands that historically served as buffers in protecting against flooding and other storm damage.
According to the environmental organization, Ducks Unlimited, which has pledged $15 million to help restore coastal wetlands in Louisiana damaged by Hurricane Katrina, as a general rule one mile of marsh can reduce a storm surge by about one foot. "Theoretically," explains Tom Moorman, director of conservation planning for the group's Southern Regional Office, "if you had a healthy chunk of marsh when Katrina hit, that could have mitigated some of the damage
the storm surge that hit the Gulf Coast reached some 29 feet, the highest ever recorded. But, in New Orleans, a few miles of marsh may have made a difference."
Dear EarthTalk: Where can I recycle my plastic CD jewel cases?
—Bianca Hoffman, Bridgeport, CT
Environmentalists have been worried about CD jewel case disposal ever since compact discs first became popular in the 1980s. Jewel cases are made out of Polyvinyl Chloride (PVC), a petrochemical-based plastic that is notoriously difficult to recycle and has been linked to elevated cancer rates among workers and neighbors where it is manufactured. Also, the lead often added to strengthen PVC can contaminate water, soil and air around PVC manufacturing sites.
Worse yet, because it contains a variety of additives and lacks a uniform composition, PVC is far less recyclable than other plastics. Its quality degrades after only two or three "cycles." Recycling operations are burdened by having to carefully sort out PVC since it melts into corrosive gases at lower temperatures than other plastics, contaminating whole batches while ruining equipment and raising health concerns. Greenpeace has identified PVC as the least recycled of the six major common plastics used in consumer, household and construction projects. Meanwhile, the U.S. Environmental Protection Agency (EPA) estimates that less than one percent of total post-consumer PVC is recovered or reprocessed.
As a result, most municipal recycling centers do not accept PVC products, meaning that millions of CD jewel cases either take up room indefinitely in landfills, where they won't biodegrade, or are incinerated. And unfortunately the burning of PVCs creates airborne dioxins, some of the most toxic carcinogens known to man.
While options for recycling CD jewel cases and other PVC plastics are limited, the Sammamish, Washington-based GreenDisk company will take jewel cases and any other hard-to-recycle "technotrash" (such as defunct printer cartridges, cell phones, compact discs, videotapes and rechargeable batteries) for a fee of $5.95 for up to 20 pounds. GreenDisk then turns the resulting raw materials into GreenDisk-branded office supplies including, you guessed it, CD jewel cases containing at least 76 percent post-consumer waste content. The company makes it easy by charging just one flat fee that covers the collection box and its shipment to the GreenDisk processing facility.
Another way to make use of old jewel cases—as well as the compact discs within—would be for art's sake. The website Make-Stuff.com suggests reusing jewel cases for picture frames or to show off collections of miniature items (like coins, stamps, butterflies or dried flowers), or as necklace holders. Meanwhile, compact discs themselves, also hard to recycle, can be re-used as reflectors, drink coasters, large poker chips or game pieces, or other fun stuff.
CONTACTS: GreenDisk, www.greendisk.com; Make-Stuff.com, ; Greenpeace, "Why PVC is Bad News," http://archive.greenpeace.org/toxics/pvcdatabase/bad.html.