Since 2009, the Planetary Boundaries have been one of the most effective displays of the main drivers of global ecosystem crises, their “progress”, and their interconnections. In this framework, created from the Stockholm Resilience Centre's research, some items classified as not yet quantified have long been featured, and it was not until the end of 2022 that a definite result was reached for one of these items. These are the novel entities, the “new substances,” which have gone to join the other six of the nine planetary limits for which the highest risk threshold has now been exceeded.
Sarah Cornell and Patricia Villarrubia-Gomez were part of the team that first analysed the status of the planetary limit related to novel entities. They granted a lengthy interview to Renewable Matter that highlights not only the many facets of the topic, but also opens a window into the reality and essence of the research work.
Why has the spread of “novel entities” in the environment been included among the planetary limits we are surpassing at our increasing risk?
SC – The planetary limits framework explains how human activities have changed the planet, working from a set of relatively stable conditions that have proven to be climatically and ecologically resilient for thousands of years. The point is that particular types of chemical pollution can quite easily shift the functioning of the planet, not just at the human level, not just at the level of one or two species. More specifically, I would say they can change the co-evolution of the physical climate system and the living biosphere, and that is why novel entities or new substances fall within the framework of planetary boundaries.
Looking at the graphic outline of Planetary Boundaries, it appears that we are living in the midst of a “soup of novel entities.” So as a first step, it would be helpful to give a definition: what is meant by novel entities?
SC – They are all synthetic chemicals, which include plastics and other types of engineered materials and organisms, that were not previously present in the ecosystem. The planetary boundary framework takes as its baseline the Holocene, where the presence of these new fully synthetic entities is zero. But the definition also extends to natural elements such as heavy metals, which are transported in a variety of ways and end up being found in places where they could not possibly be except because of human activity.
PVG – After the presentation of our research results, we have often been asked how many substances we can actually cover with some form of regulation compared to the total number of substances produced. But it is practically impossible to include all of them. More than 350,000 different chemicals are produced globally today. For example, a report from a few months ago revealed that there are 16,000 different substances used in the production of plastics, and just 1% are covered by international legislation. And some thousands of them are very concerning because of their toxicity, while there is lacking public information for over 9000 plastics chemicals about where they come from, or in what they are used. In addition, there are very few cases in which toxicity tests of a substance are carried out with a suitable procedure to define its characteristics at the ecotoxicological level, which is akin to assuming that the effects of their dispersion in the ecosystem may affect only a part of it. This is obviously not the case. That is also one of the reasons we decided to use the Impact Pathway Analysis approach in our research, which allows us to have a broader understanding of these chemicals considered in their entire life cycle.
Is a tool such as the European REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulation, in your opinion, effective at least in terms of the census of “man-made” chemicals in the environment and their hazardous characteristics?
SC – The REACH regulation is a really important start, but there is a big problem with its implementation. Regulations are great on their own, but then intervenes the interaction between laws, directives, other regulations, markets, social norms, and, of course, the ways in which the biophysical world responds to changes and transforms these substances and assemblages of substances and matrices in different manners. All of this means that we need a much more in-depth analysis of the regulations themselves and their implementation. So, I believe that in terms of the effectiveness of REACH, we are still a long way off. It is effective in theory, but it remains an open question how effective it is in practice. Looking at all the steps – from extraction to production to consumption to final disposal in the environment – every aspect of the exposure to these substances should be evaluated and monitored if we want to understand their long-term and large-scale effects. And we cannot leave it to just one or two highly specialised industries to do that. This is a planetary problem.
PVG – When we are addressed, there seems to be only one question, “Alright, please give us a number to negotiate the new Global Plastic Treaty that is going on right now, we need a number.” It sounds simple, but it's really a matter of putting a number on what? Let's take microplastics: everyone is asking for numbers on microplastics in the environment, but the question is, in which environment? On the surface of seawater or the surface of river water, or in deep sediments, in the water column, in the atmosphere, and where in the atmosphere, where we breathe or in the upper atmosphere, in glaciers or in the soil? And what size of microparticle do you want to give a number to? Because depending on the size and the shape of the particle, it has a different impact physiologically, chemically, and on toxicity. And where do you measure potential toxicity? In animals? In tissues? And on what kind of plastics? Obviously, being able to actually put a number on everything would be the “silver bullet,” but in all these years that we have been doing research, we came to believe that providing a specific number would be extremely wrong.
SC - This has been my personal battle. The only thing the planetary limits framework can do is to define a boundary beyond which science can no longer predict what will happen. The boundary is a boundary, not a target, not a budget. There is this sort of magical mysticism around numbers, as if the two-degree limit that science has now pragmatically set for climate is replicable to define other limits in the same way. Do we need “two-degree equivalents” for chemicals or for biodiversity? These are inherently and irreducibly complex processes and phenomena, and to be fair, so is climate, except that for the past seventy years, we have created a narrative that climate is predictable to the level of one degree without decimal places. Yet, the numbers in the planetary boundary framework are by no means equivalent to what the two degrees represent for climate. So for novel entities to say that the boundary is “more than zero” is absolutely sufficient. Human activities have changed the chemical composition of the planet, the diagnosis is now clear; prognosis and treatment require more than a number, however. It is hopeless therefore to continually hear that politicians need a number, but a politician who really wants certain measures to be implemented never asks for a number, they would ask for quantification along with the history of the system behind it. Complex systems have a century of science behind them that asks not to reduce everything to numbers, unless you are really sure you are dealing with a deterministic system. And yet this message is not getting through.
Considering the complexity of systems, on the other hand, is the goal of the Impact Pathway Analysis approach that we mentioned earlier…
PVG – Yes, by considering the different life cycle stages of these substances we can identify what the different potential quantification is at the time of production, use, release, and impacts into the environment. When these chemicals enter the environment, they change certain processes for which we can identify different control variables, and using a systemic approach we can see what their interconnections are. We have observed that the main variable that controls or potentially could control the others is production. Therefore, if you put a cap on the production of plastics, which is ultimately 99% fossil fuels, you could have a modulation a balancing, or a reduction of other controlled variables within the system. For example, some of my colleagues in the Scientists' Coalition for an Effective Plastics Treaty, in which we arranged to participate in the UN plastics treaty negotiations, have calculated that plastics polymer production causes four times as many greenhouse gas emissions as aviation on a global scale. Thus, plastics are a key player in climate change, and there are people trying very hard not to bring this issue into the debate. Currently, the ecological transition aims to reduce the use of fossil fuels for energy production, but on the other hand, plastics production is expected to triple over the following years. That is why in the debate the issue should be approached on a systemic level, not focusing on specific aspects such as microplastics in the environment or recycling.
Plastics are at the “core” of your research. But which are the more specific issues related to this area? How do you approach the topic of “plastics”?
SC – There is something of an awakening around this subject when I think that even as recently as five years ago, even among scientists we were saying to each other, “Well, plastics can't actually be that dangerous since everyone says it's safe.” We were working with environmental toxicologists, and the recurring question was, “But is it really that bad?” I think it is almost impossible to eliminate the human factor in the assessment of what is safe or risky, good or bad, so we need to piece together a “story” that is analytical and systemic and at the same time recognise that this is a problem that unfairly exposes people to risks, a problem of winners and losers, exploiters and exploited. One of the concerns we have is that to bring together the story of ecological and eco-toxicological damage and human health damage, we are constrained by the fact that monitoring strategies were, until recently, blind to these issues. Hence, we are under a lot of pressure to keep them as they were, so that we have comparable data. It means that you can analyse one problem at one level, but you end up overlooking others. This all brings up the topic of the relationship between science and politics. Twentieth-century science presented a bulky paper and handed it over to politicians, saying, “Here's the data. Give us good policies.” In the 21st century, the confrontation is multi-stakeholder, widely visible and the discussions very heated. This puts scientists in definitely new and uncomfortable positions. There would be much need for co-learning processes between science and politics, especially in strategy formulation, but I don't think policymakers are thinking about that.
Speaking of policies, are the strategies adopted to date on a global or national level, in your opinion, at least potentially effective?
SC – I think the big “umbrella” strategies, at least at the European level, are already in place through guidelines such as the precautionary principle, the “polluter pays” concept, and prevention at the source. It is a mix of policies, however, that need to be implemented together. I am talking about cross-scale analysis and monitoring, polycentric governance, policy coherence and integration. These are proven approaches to environmental management, and even here Europe has a legacy of decades of policies, such as the Habitats Directive or the water directives, that cover multiple scales and make implementation more coherent.
Could the development of green chemistry and bio-based materials help reduce the spread of more hazardous substances in the environment?
PVG – This kind of chemistry is not my area of expertise, but what I can say, based on the narratives (mis)understood in policies and society that I have been experiencing in these past years, is that there is a lot of confusion, especially regarding terminology. Often, biodegradable is used as a synonym for compostable. And plant-derived bioplastics then become synonymous with compostable, and all of that in turn has become somehow another synonym for circular economy. But if the additives you add to the mix are derived from fossil fuels, or are the same as those added to fossil-fuel plastics, in the end you will have nothing but a “traditional” plastic in which only the main polymer is different (e.g. corn or sugar cane). Eventually, I think what we should do is assess how essential all the plastics we are using and producing really are. Which plastics do we really need? If some are absolutely necessary, then it's fine to look for the safest alternatives we can get. But maybe we don't need plastics to pack a single coconut, as I’ve happened to see in supermarkets…
One final question. As reported in the article published in Environmental Science & Technology, environmental monitoring is targeted at known novel entities. What about the “unknown” ones?
SC – This brings us back to the start, to the image of the “soup of new entities” and their definition. I think this definition should be open, precisely because we as humans have the ability to create substances that have completely unpredictable ecological or climatic effects than we previously thought. So, in that sense, the name novel entities is sort of a deliberately broad umbrella, which, however, becomes a real issue in the context of, for example, plastics, where we need very specific policies. It's not enough to tell people not to produce substances that may or may not have planetary impacts on timescales of 10,000 years or more. But at the end of the day, that is what we are asking for.
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