Wednesday, June 27, 2007

Go organic to fight global warming!

Need another reason to buy organic food?

According to findings from the ongoing Farming Systems Trial at The Rodale Institute, organic grain farming, including low- or no-till soil preparation and cover cropping, actually increases carbon sequestration in the soil by 15% - 28% compared with conventional farming techniques. Translation: 15% - 28% percent less carbon dioxide goes into the atmosphere because it's bound up in the soil. This is in addition to reduced carbon dioxide emissions from farm equipment on organic farms (no-till means fewer passes over the field with a gas-guzzling tractor and about one-third less carbon emissions), and from the production of petroleum-based fertilizers. Add to that buying local AND organic, and you eliminate still more greenhouse gas production from food transport. Wow!

So what does carbon sequestration mean, and why do organic farms have more of it? Well, the folks at Rodale have a couple explanations:

One is that organic cultivation focuses on building up carbon-based organic matter, or humus, in the soil. Humus refines soil texture and holds nutrients and water. Soil rich in humus is more naturally fertile, and holds a more consistent level of moisture, even in the face of heavy rains or drought. Plus, humus is made of carbon! On a conventional farm, application of nitrogen-rich chemical fertilizer stimulates soil organisms to break down any humus in the soil very quickly, and when they do, they release carbon dioxide into the atmosphere. On an organic farm, humus is added to the soil and breaks down very slowly, so it feeds the plants over a long period of time, AND releases much less carbon dioxide.

Another reason has to do with mychorrhizae - microbial fungi that are naturally present in organic soil. These mychorrhizae actually work symbiotically with plant roots, helping them to take up more water and nutrients from the soil in exchange for a 12% share of the (carbon-based) energy that the plants make using photosynthesis. This means that plants working together with mychorrhizae are doing more photosynthesis and fixing more carbon dioxide from the atmosphere into the soil, in addition to being healthier and more disease resistant. Synthetic fertilizers and pesticides used in a conventional farming system actually kill off some of the mychorrhizae and stop this symbiotic carbon sequestration from occurring.

But how much greenhouse gas are we talking here? Is this enough to put a real dent in global warming? Here are some numbers to put this into perspective:

If all 160 million acres of corn and soy grown in the US were transitioned to organic, they'd be sequestering about 580 billion extra pounds of carbon dioxide per year. That's like taking 58.7 million cars off the road, or about 25% of the cars in the US. Yow! If ALL American cropland went organic, it'd be like taking more than half the cars in the US off the road.

Check out this video (starring Percy Schmeiser) about the Rodale findings, and be sure to add "eat organic food" to your list to-dos for reducing your carbon footprint, right up there next to compact flourescent lightbulbs, carpooling, or riding your bike!

Thursday, June 14, 2007

Hormone havoc - this is news?

With some fanfare, the US EPA announced this week that it will begin screening 73 popular agricultural & residential pesticides to find out whether they might be endocrine disruptors. The screening would be the initial phase of a multi-stage review that would not consider new restrictions on pesticides until after many exhaustive rounds of testing.

What's an endocrine disruptor? It's a chemical pollutant that, at low levels, can mimic hormones in the human body. This is problematic when the pollutant plugs into our body's hormone receptors during key phases of human development, blocking or scrambling the developmental signal that the hormone should have been sending. The scrambled signal can result in long-term health problems - in lab animals, effects like feminized males, hermaphrodite offspring, low sperm counts and sterility. Endocrine disruption is also being studied as a mechanism in the development of cancer.

We've been hearing a lot about endocrine disruptors ever since the groundbreaking 1996 book, Our Stolen Future, introduced them to a general audience. In 1997, Congress ordered the US EPA to begin looking at whether the thousands of pesticide products it reviews and registers each year might be interfering with the endocrine system. Ten years and tens of thousands of new pesticides later, EPA is finally making a list: 73 chemicals to be reviewed.

Given all that independent researchers have already discovered about endocrine disruptors, and all the red flags that two decades of studies have already sent up about specific pesticides, EPA seems a little behind the curve here. There's already plenty of evidence to warrant their consideration of new restrictions on several chemicals like atrazine, which has been shown to turn male frogs into females at stunningly low doses.

Considering the long-term implications for human (and wildlife) health, it seems absurd that EPA has taken so long to even begin looking at this critical phenomenon. Though I'm sure the pesticide industry has been happier while EPA simply looked the other way.

Friday, June 8, 2007

Blue frogs

Though not actually blue in color (unless they're one of these guys), frogs everywhere are apt to be feeling a bit blue upon hearing last week's news that three widely used organophosphate pesticides (or "OPs") have been found to be even more toxic to frogs than was previously thought.

In a study published last week in the journal Environmental Pollution, scientists at the University of Southern Illinois, Carbondale and the U.S. Geological Survey report that the breakdown products of insecticides diazinon, chlorpyrifos, and malathion are far more toxic to certain native California species of amphibians than the original pesticide chemicals, which are already highly toxic. In other words, these highly poisonous chemicals get even more poisonous to frogs after they enter the body and begin to be digested, or after they've been hanging around in the environment for a while and begin to degrade - 10 times more toxic in the case of diazinon, and 100 times more toxic in the cases of chlorpyrifos and malathion.

Frogs may be a "canary in the coal mine" for pesticides because of their moist, permeable skin, but according to one of the lead researchers on this study, Dr. Gary Fellers, these findings do not bode well for other species, including birds, mammals and humans.

OPs are widely implicated in the declines of several amphibian species in the California Central Valley and in downwind mountain areas that are prone to pesticide drift. U.C. Berkeley scientist Tyrone Hayes has also found that the nation's #2 most popular herbicide, atrazine, can cause hermaphrodism and other serious health effects in male frogs, even at very low levels.

These findings implicate pesticide contamination in a widespread decline in amphibian populations across the country, and even worldwide.

People must heed the warning of these green (and increasingly blue!) canaries in the proverbial coal mine, since we depend on the same water that frogs do, and a growing body of scientific evidence indicates that we are also being affected. Consider the recent finding from a researcher at Indiana University School of Medicine that rates of premature birth in humans are highest each year during the same months that pesticide and fertilizer levels spike in surface water, and lowest in the months when pesticide and fertilizer levels are lowest (link). Or, the finding that that children conceived in Indiana during the months of high pesticide use score lower on standardized tests than children conceived in months with low pesticide use (link).

While municipal drinking water treatment systems kill bacteria that could threaten human health, they seldom remove chemical contaminants - including pesticides and their break down products. Filtering your tap water to remove some impurities is a quick fix, but it is urgent that people act now to keep pesticides out of our waterways. For starters, please support farmers that don't use pesticides by buying locally-grown organic foods whenever you can, and sign up for PESTed's Action Alerts to stay in the loop about pesticide issues in North Carolina, and what you can do to make a difference.