Dear EarthTalk: Are the recent cyclones and droughts in Australia and elsewhere more evidence of global warming?
—Billy Hulkower, Los Angeles, CA
Scientists can’t blame individual storms or droughts on climate change, but many believe that human-induced global warming is increasing the severity and frequency of such weather "anomalies." Indeed, on February 2, 2007 scientists with the Intergovernmental Panel on Climate Change (IPCC) released a long-awaited 21-page report confirming "with 90 percent certainty" that increases in man-made greenhouse gases since the mid-20th century are raising the planet’s temperature and destabilizing the climate.
Besides hurricanes like Katrina that have affected the northern hemisphere, a number of high-impact tropical cyclones and typhoons have occurred around the world in just the last few years, with Australia’s mammoth Cyclone Larry topping the list in terms of intensity. That March 2006 storm battered the northern Queensland coast with 180 mile-per-hour winds, causing hundreds of millions of dollars in property damage and virtually wiping out Australia’s banana crop. Thanks to Australia’s top-notch weather forecasting and emergency preparedness, however, unlike Katrina, Larry claimed no human lives.
Meanwhile, higher global temperatures have at least worsened if not outright caused drought conditions around the world, and Australia has been no exception. A 2003 report by the Australia chapter of the World Wildlife Fund found global warming to be a key factor in the severity of the country’s 2002 drought, one of four especially harsh droughts in just the last 50 years. The 2002 drought, which many scientists consider to be still in effect, was particularly memorable as Australians endured higher daytime temperatures than had ever been recorded during any March-November winter season. Besides causing countless bush fires in the Australian Outback, the drought has led to a significant drop in agricultural production, causing hundreds of millions of dollars in economic losses, according to government data.
An original 1997 signatory to the landmark Kyoto Protocol calling for reduced greenhouse gas emissions, Australia’s government nevertheless has refused to ratify and adhere to the terms of the treaty. Prime Minister John Howard has taken a position similar to that of U.S. President George W. Bush, who considers the terms of Kyoto bad for industry.
But just because Australia hasn’t ratified Kyoto doesn’t mean it has refused to acknowledge the potential environmental impacts of global warming. The country has pledged $300 million over three years to implement various strategies to reduce greenhouse gas emissions. It has also signed onto the Asia-Pacific Partnership on Clean Development and Climate, an agreement with India, Japan, China, South Korea and the U.S. to develop technology that helps reduce greenhouse gas emissions. Whether such an agreement has enough teeth to take a bite out of global warming is anybody’s guess, but it and other endeavors to fight global warming will undoubtedly pick up momentum with the release of the landmark IPPC report.
Dear EarthTalk: Dairy products like yogurt always seem to come in packages of low recyclabilty (labeled "5," which our town won’t take). Why aren’t these containers more recyclable? And isn’t there a more eco-friendly container these companies could use?
—John Marble, Portland, ME
The ability to recycle a plastic item rests with many factors, including its material, its usability in new products once it has been broken down into its original components, and whether or not a market is in place that can facilitate transactions of the recycled materials from sellers to buyers.
Recycling polypropylene (designated with a "5"), the material used in many food containers, is technically possible. The challenge is in separating it from other plastics, including its own many variations, once it arrives at the waste station and beyond. Because of the difficulty and expense of sorting, collecting, cleaning and reprocessing plastics of all kinds, in many places it is only economically viable to recycle a few select types. These usually include polyethylene terephthalate (PETE, designated with a "1"), high-density polyethylene (HDPE, "2"), and sometimes polyvinyl chloride (PVC, "3").
According to the Society of the Plastics Industry, polypropylene is a "thermoplastic polymer," meaning that it has the density and resins that give it a high melting point, enabling it to tolerate hot liquid without breaking down. As such, it is used in a wide range of food packaging applications in which the product initially goes into the container hot or is later microwave heated in the container. It is also used to make bottle caps, computer disks, straws and film packaging. Its toughness, strength, ability to be a barrier to moisture, and resistance to grease, oil and chemicals also make it a very attractive material for many uses.
Environmentally friendly alternatives to polypropylene and other plastics are beginning to be developed, however. NatureWorks, a division of Cargill, has developed a corn-based plastic called polylactic acid (PLA). While it looks and functions like other plastics PLA is fully biodegradable, given that it is derived from plant-based materials. Whether it is composted or landfilled, it will biodegrade into its constituent organic parts, though there are debates as to how long that process takes.
Another pioneering company is Massachusetts-based Metabolix, which has partnered with corporate giant, Archer Daniels Midland, to make corn plastics that the company claims will "biodegrade benignly in a wide range of environments, including marine and wetlands."
A handful of natural foods companies and retailers, including Newman’s Own Organics, Del Monte Fresh Produce and Wild Oats Markets, are already using corn plastic for some of their packaging, though not yet to replace heat-resistant polypropylene. Analysts expect such plant-based alternatives to come on stronger and stronger in the days ahead as petroleum becomes more expensive and more politically unstable. Even Coca-Cola has started experimenting with replacing its traditional plastic soda bottles with a corn-based alternative. And last October, as part of its "green" overhaul, Wal-Mart announced it would replace 114 million plastic produce containers a year with PLA varieties, sparing about 800,000 barrels of oil annually.