It isn’t every day that water quality researchers get to spend a weekend at a music festival for work purposes. Nor is it every day that a cup of the waste water effluent near that festival contains enough MDMA and ketamine to provide a clinically-active dose of ecstasy. But when researchers from Kaohsiung University in southern Taiwan visited the “Spring Scream” music festival, which brings 600,000 visitors every April to nearby Kenting, they found just this. Along the way, they illustrated the fundamental importance of timescale for understanding the Anthropocene.
One of the hardest things for humans to wrap their heads around is the immensity of geological time. It is difficult enough for us to fathom the world our great grandparents lived in, even harder to contemplate the world beyond our own ephemeral individual lives, and harder yet to start imagining time before the advent of our own civilizations. But deep time—the hundreds of millions of years that existed long before the evolution of multicellular life, let alone animals, let alone mammals like us—is something our human brains wrap around as easily as a flea circumnavigates the Superdome.
I think this is what makes the importance of the Anthropocene so difficult for some people to appreciate. It is not the particular present concentration of CO2 that is the concern. Nor is it the absolute global temperature. These have occurred before. What is unprecedented is the rate of change. And to fully appreciate the rate of change, one needs to fully, deeply understand deep time and the scale upon which the Earth has generally seen change.
If there is one defining feature of the Anthropocene, it is perhaps the suddenness of change. Rapid change in extinction rates, rapid changes in land use, rapid changes in climate and the composition of our atmosphere. One look at a plot of CO2 concentration over the past 800,000 years is enough to drive home this point. Or for a more playful look, I recommend XKCD’s take on the issue of time.
Scientists therefore must carefully consider what sort of timescale on which they should study the Anthropocene. Are yearly measurements enough? Or monthly? Daily?
Jiang et al. did all three. They measured the concentration of “emerging contaminants”—human-derived chemicals found in the natural environment that include prescription drugs, personal care products, and illicit substances—from several rivers, estuaries, and beaches in southern Taiwan. (For an overview of the concerns raised by these chemicals see this Water Quality Association fact sheet.) Scientists often measure the concentrations of emerging contaminants on a seasonal or monthly basis. But the concentrations of these compounds are closely tied with human activity, which varies as quickly as a large group of humans can drive up to a nice spot on a riverbank and start consuming their favorite mind-altering chemicals (including, of course, their favorite latte).
What is perhaps most interesting is the researchers measured wastewater on a daily basis immediately prior to, during, and after the music festival. Wastewater treatment plants are generally not designed to remove emerging contaminants, so unsurprisingly, they found concentrations of caffeine in concentrations of 10 – 14 mg per litre (one cup of coffee contains 95 mg). More concerningly, they found concentrations of erythromycin (a highly active antibiotic), codeine, gemfibrozil (a blood lipid management drug), and acetaminophen at concentrations high enough to cause significant risk to aquatic organisms. It is also worth noting that risk to aquatic organisms is based on the concentrations of a single chemical at a time—the impacts of cocktails of substances are complex, and not well-understood.
Finally, perhaps unsurprisingly, they found concentrations of illicit substances (including MDMA, ketamine, and pseudoephedrine) in high enough quantities to individually cause clinically active effects in 500 mL (about 2 baking cups) of water. And just like in aquatic organisms, the impact of these together on a human is not well understood.
When the researchers examined the samples they took on a monthly basis, they did see an increase in emerging contaminant concentration, but not to near the extent they did when they measured on a daily basis. If conservation and environment officials only measured impacts on a monthly basis, these short-term but potentially incredibly significant events easily might be missed. In this case, the rapid spikes in contaminant load that are associated with human activity are easily missed when the timescale at which we take measurements is mismatched with the timescale of significant changes in the environment.
So how is Jiang et al.’s research relevant to the Anthropocene? To see, we must consider how we understand the Anthropocene–by understanding that human-caused changes are incredibly quick relative to deep time. And by understanding, perhaps even more importantly, that we (like many other organisms) are fragile beings whose physiology similarly responds on incredibly rapid timescales. For example, the length of time it takes for extreme heat to kill a human can be measured in a matter of hours, and measuring only changes in mean temperatures over long scales does not give us the precision we need to understand the impacts that anthropogenic warming will have on us. In fact, we are experiencing greater numbers of extreme events in the Anthropocene that happen on incredibly short time-scales. The interaction between mean conditions and number of extreme events is complex, but at least in climate, it appears that greater mean temperatures lead to greater numbers of heat waves. While heat waves are short in timescale, even on human timescales, they lead to large numbers of human deaths, with a recent estimate that up to 69% of deaths from a heat wave were directly attributable to anthropogenic climate change.
So what timescale do we measure the Anthropocene on? The answer is likely “all of them”.