Pesticides Spark Broad Biodiversity Loss

Pesticides Spark Broad Biodiversity Loss

By Sharon Oosthoek and Nature magazine

Agricultural pesticides have been linked to widespread invertebrate biodiversity loss in two new research papers.

Pesticide use has sharply reduced the regional biodiversity of stream invertebrates, such as mayflies and dragonflies, in Europe and Australia, finds astudy published today in the Proceedings of the National Academy of Sciences.

Previous research has shown similar decreases in individual streams, but the study by Mikhail Beketov, an aquatic ecologist at the Helmholtz Center for Environmental Research in Leipzig, Germany, and his colleagues analyzed the effects of pesticides over broad regions.

The team examined 23 streams in the central plains of Germany, 16 in the western plains of France and 24 in southern Victoria, Australia. They classified streams according to three different levels of pesticide contamination: uncontaminated, slightly contaminated and highly contaminated.

The researchers found that there were up to 42% fewer species in highly contaminated than in uncontaminated streams in Europe. Highly contaminated streams in Australia showed a decrease in the number of invertebrate families by up to 27% when contrasted with uncontaminated streams.

Air-Conditioning Options

Air-Conditioning Options

Which is more energy-efficient--central air or window units?



Dear EarthTalk: Now that hot weather is coming, I want to upgrade my home’s A-C. Which are the most energy-saving models and should I go central air or window units?—Jackie Smith, Cary, N.C.

According to the American Council for an Energy Efficient Economy (ACEEE), energy consumption for home air conditioning units accounts for more than eight percent of all the electricity produced in the U.S., at a cost to homeowners of $15 billion annually. Besides the cost, all this cooling leads to annual emissions of about 195 million tons of CO2—or two tons per year for each American home with A/C.

Of course, foregoing A/C entirely is the most energy- and cost-efficient way to go, but some of us need a little cooling for comfort, especially in warmer climates. If A/C is a must, buying the most efficient model is the way to save money and pollute less. Fortunately, a new generation of much more efficient room and central A/C units means that upgrading will likely pay for itself in energy savings within just a few years.

The main factors to consider in choosing a new model are cooling capacity (measured in British Thermal Units, or BTUs) and Energy-Efficiency Ratio, or EER. To determine the correct BTU rating for a given space, multiply the square footage by 10 and then add 4,000. Meanwhile, a given unit’s EER is the ratio of cooling output divided by power consumption—the higher the EER, the more efficient the air conditioner.

According to the U.S. Department of Energy, national appliance standards require room air conditioners to have an EER of 8.0 to 9.8 or more, depending on type and capacity. Units with an EER rating of 10 or above typically qualify for the federal government’s ENERGY STAR label, which appears on especially energy-efficient appliances. Check out the ENERGY STAR website for lists of qualifying A/C models.