By Ralph C. Martin
In the biography of Rachel Carson, by Linda Lear, it is so apparent that Carson recognized science as a process. She had to forgo a Ph.D. at Johns Hopkins University because of poverty and family tragedies. Nevertheless, from the 1930s to the 1960s, she persisted in her pursuit to reveal the broadening body of scientific understanding with “the voice of both scientist and poet, in love with the wonder in nature that she had discovered.” Her critical analysis of scientific methods and data garnered credibility.
Science is not a static proper noun. Sometimes we hear declarations that a certain method or product is the way to go because science says so. Scientific results, especially in biological systems, are within a range of probability, under a given set of conditions. Science is never finished.
Decades ago, I was ready to declare that there was enough scientific evidence to show that grazing cattle moved daily from one paddock to the next would gain weight faster than those moved every week. Nova Scotian farmers were not so sure as we deliberated in the middle of a pasture field, with an attentive audience of ruminating bovines.
Grazing research is hard to do because there is so much variability among grazers and grass and how they interact, across extensive areas. Furthermore, young cattle do not always cooperatively stick to their assigned groups and nimble-fingered humans may remove fencing components at remote locations.
My gallant student, Nathan, helped me fence the replicated strips for daily movers and weekly movers (who had a paddock 7 times larger). The summer of the first season confirmed that daily movers had gained faster. Now all we had to do was repeat the trial in 2 more years and publish the results.
Imagine my surprise in the spring of year 2 when the daily movers gained weight more slowly. That was not how I understood the world. I was relieved that they gained faster in the summer and fall. In the spring of year 3, the daily movers again gained weight more slowly and then in the summer and fall gained faster.
In that experiment (https://journals.uair.arizona. edu/index.php/jrm/article/view/9581, I learned nuance and respect for the farmers who debated with me in our initial pasture discussion. In the Maritimes, in the spring, grass grows so fast that if you lie in it, you can feel it tickle your nose as it keeps rising before your eyes. At least that’s what I told my students, and none actually did the test to prove me wrong.
By observation of grass and clover, we inferred that the weekly movers on the larger paddock had access to rapidly re-growing grass and clover, in the spring. Later in the dry and warm days of summer and slow growth period of the fall, the daily movers gained faster because they were moving to fresh, fully replenished forage plants, every day. If testing had been over 10 years (very difficult to fund), we may have seen the impact of high value plants disappearing, without opportunities to regrow, under spring weekly moving.
Citizens are now pressing scientists to develop a vaccine or a cure for COVID-19. While waiting, we could listen to the scientific results advising us to “reduce the rampant consumption that drives deforestation and wildlife exploitation” (https://bit.ly/ 2DWF1vO ). Perhaps Nature will make us wait for a cure until we practice prevention.
Given the inquisitive creatures we are, we often pursue scientific hypotheses to immediately improve our lives. If a method works, we are tempted to assume that there are no harmful effects because none were evident. My colleague, Bert Christie, was fond of saying “absence of evidence, is not evidence of absence.”
The precautionary principle is to avoid unacceptable harm that is scientifically plausible but uncertain. It takes time and can be expensive to test impacts, especially interacting and cumulative impacts over time. Assessing relationships in systems takes perseverance and grit.
Science is a process of learning more about the world and universe around us and how we can live within ecological dynamism. If we keep cutting to the chase of what works for our immediate benefit and ignore long-term impacts, then ecological systems will eventually exclude us. In her book “Silent Spring,” Rachel Carson explored impacts and showed how the process of science can teach respect. ◊