Students marching on Ave. Parc, Montréal on 15th March, part of the worldwide student march that day, and one of the largest efforts in Canada. The kids understand what is happening. Image © John Mahony, Montreal Gazette.
So, what has been happening in the world of climate change and environmental decline? School students around the world are showing up the rest of us, and there is a continuing, some would say mind-numbing, flow of environmental news in the media. It is difficult for the casual browser to cut through the mass of information to see anything really new. Even as a scientist, more or less in tune with what is going on, I have difficulty sorting the wheat from the chaff. Not that there is anything wrong with chaff – we need the accumulation of detail in order to model processes and make future projections that are likely to fall even closer to reality. The following stories caught my eye over the past couple of weeks, mainly in the pages of Science or Nature, rather than in the general media. Mostly they confirm what we already knew but each adds needed detail.
Nicholas Gruber, an environmental physicist at ETH Zurich, Switzerland, with 17 co-authors from institutions across Europe, the USA and Japan, published an article in Science on 15th March, 2019. It was called “The oceanic sink for anthropogenic CO2 from 1994 to 2007” and dealt with the global distribution of inorganic carbon dissolved in ocean waters.
As we add CO2 to the atmosphere through our burning of fossil fuels, cement manufacture, and changes in land use, a portion of this ‘extra’ CO2 dissolves into the oceans. A second portion is taken up by plants and microorganisms and incorporated into soils and biomass on land. The remainder remains in the atmosphere causing the planet to warm.
In the ocean, CO2 combines chemically with water to form carbonic acid (H2CO3) which promptly dissociates into HCO3– and H+ ions, thereby lowering pH and acidifying the ocean. CO2 concentrations in surface waters are at or near an equilibrium with the atmosphere, but dissolved carbon is only slowly distributed to the deeper ocean, meaning that most of the ocean is less saturated than are surface waters. It is this slow redistribution of dissolved inorganic carbon to deeper waters that makes it possible for a continuing net flux of CO2 from atmosphere to ocean surface waters. Over time, over a long period of time, the concentration of carbon in deeper waters will become closer to that in surface waters, and the oceans’ capacity to absorb CO2 from the atmosphere will decline. One question Gruber and colleagues were exploring was whether the rate at which CO2 was dissolving from the atmosphere to the oceans was starting to slow down yet.
Oceanographers produce the neatest illustrations and I admit to being first attracted to this article by a wonderful diagram, looking a bit like a three-bladed, rather square propeller, that depicts how the rate at which carbon concentration was increasing at different latitudes and depths in the three oceans – Atlantic, Pacific and Indian – during the period 1994 to 2007.
The rate of increase in concentration of dissolved carbon is shown on a color scale from blue (low) to yellow (high) for different depths and latitudes in a slice taken through each of the three oceans from vicinity of Antarctica to the most northerly extent of that ocean. Figure © Science.
An amazingly effective way of compressing vast quantities of data into a single, understandable image. Still, what does it tell us? Over the period 1994 to 2007 the oceans of the world have continued to remove CO2 from the atmosphere. Gruber and colleagues estimate that 34 ± 4 petagrams of carbon (Pg C) moved from atmosphere to ocean during those years, an average of about 2.6 petagrams carbon per year. That’s a lot of carbon (2.6 billion tonnes of carbon or 9.5 billion tonnes of CO2 per year). Let that sink in for a minute: 9.5 thousand million tonnes of CO2, which is just 31% of the amount of CO2 we are putting into the atmosphere.
That those billions of tonnes of carbon dioxide did not remain in the atmosphere is just as well, because if they had remained there, that would really have boosted global temperatures. Gruber and colleagues refer to this fact as an example of the oceans providing a service to humanity – literally cleaning up after us!
Gruber and colleagues report that, as expected, the oceans have continued to take up anthropogenic carbon dioxide at about the rate they were in the early 1990s, however, their results show marked differences from place to place in the rates at which carbon is being distributed toward deeper waters (the redness in the figure marks places where rate of addition of CO2 is greatest). This variability is understandable given our knowledge of ocean circulation, but the extent of the differences was surprising. Future warming-caused changes to ocean circulation, such as the anticipated slowing of the Atlantic meridional overturning circulation (AMOC), which transports North Atlantic surface waters to deeper layers, could have serious implications for future rates of CO2 uptake by the oceans.
Take home message? The oceans continue to play a very important moderating role as the world warms, but there is a limit in how much longer they can continue to do this, and all that CO2 taken up by the oceans has serious consequences for ocean pH, and therefore for the lives of many marine organisms.
Anna Woodward of Lancaster University, UK, and four co-authors from British and Swedish institutions, provided a perspective on the human consequences of the changes taking place on coral reefs because of climate change. Their article, in Functional Ecology, was published on line on 28th March as Coral reef ecosystem services in the Anthropocene.
Reef ecologists are becoming aware that the reefs of yesterday are not coming back any time soon. The extra warmth added to ocean waters since the 1950s has changed the frequency and severity of el Niño events to produce more frequent periods of warmer than usual water, warm enough to lead to profound bleaching events. As a consequence, the rates of mortality of various coral species have been altered from what they were, with the result that reefs have less living coral present, living corals are, on average, younger, and the mix of species has also changed because some species are more susceptible to warming than others. Its still too early to say what the reefs that exist in 2050 will be like, except to note they will be fewer, less coral-dominated, and with a different mix of dominant coral species. But its not too early to admit they will be ecologically different to today, or to the reefs of the 1950s.
Woodward and her colleagues use this new awareness that reefs are changing in many ways to anticipate likely impacts of those changes on humanity. Hundreds of millions of people depend on coral reefs for their livelihoods, for important protein food, for coastal protection, and for esthetic, emotional, spiritual support. As coral reefs change, their ability to provide these services will also change, but at present there has not been sufficient effort made to understand the nature or extent of those changes. Woodward and colleagues review some of the ways in which other components of the reef ecosystem, such as fishery species, are likely to respond to changes in abundance and both age and species distribution of corals. The4y provide some useful suggestions for future research. I found this article important for highlighting the need to consider how the value of coral reefs must change as the reefs are changed, because if we understand more clearly the likely changes in fishery yield, storm protection, or effectiveness for stimulating tourism, we will presumably be in a much better position to plan for adaptation to these changed circumstances.
On the other hand, I was disappointed to see just how little Woodward and colleagues were able to provide in terms of definitive projections of future state, or even in terms of ways to advance the needed understanding. Beyond suggesting that the provision of an ecosystem service is governed by an interaction between ecological and societal processes that respectively deliver and select for the service, or advocating a trait-based approach to identifying how particular ecological actors, such as fishery species, will respond to particular changes in the reefs, they seem to suggest scientists are at the very beginning of understanding how changes to reefs will affect people.
It seems unlikely that substantial changes on coral reefs will not have impacts on adjacent coastal habitats such as seagrass beds or mangroves. Image © Smithsonian Institution.
I think it is also true that we have relatively limited understanding of how changes to reefs likely over the next couple of decades will ramify to impact those other ecosystems that share continental shelves with reefs. How will a general decline of reefs impact seagrass systems or mangrove forests? To what extent will loss of reefs lead to substantial ecological reorganization of tropical coastal seas. While this may all sound like reef scientists have been asleep at the switch, I fear it is safe to say that scientists more generally, and humanity more broadly, are both uncomfortably naïve concerning the degree to which our direct perturbations of specific ecosystems – such as reefs, or salt marshes, or tropical forests – will ramify across the biosphere. Hopefully, the article by Woodward and colleagues will spur reef scientists, in particular, to delve more deeply into the consequences of what we are doing. Otherwise, the Anthropocene is likely to be far nastier than most of us expect.
In the March 22nd issue of Science, Warren Cornwall of the National Sea Simulator in Townsville, Australia, provided a Feature article (Science is becoming more like a trendy magazine and less like a dreary technical journal every month) titled, The Reef Builders. Copiously illustrated with glorious pictures of corals spawning, it’s a pity it is hidden behind the paywall, instead of being on open access (I really do not understand why Science did this!).
Acropora millipora spawning in a tank at the National Sea Simulator, Townsville, Australia. Tourists to the Great Barrier Reef can book night dives to see this, assuming they can be at the reef on the right night. Photo © Mikaela Nordborg, AIMS
The article reports on the research program of Madeleine van Oppen, now at Melbourne University, and the late Ruth Gates of University of Hawaii. Ruth died, far too young, in October 2018, and I was gratified to this fruitful collaboration is continuing despite that setback. Van Oppen, Gates and their collaborators and students have been pioneering efforts to manipulate the genetics of corals and their algal symbionts to see if it is possible to breed greater resistance to warmer water. Such genetic research, using techniques ranging from straightforward selection of apparently more resistant individuals for breeding to use of genetic engineering techniques such as CRISPr-Cas9 for directly manipulating the genome, is nothing new in animal husbandry or crop science, but it is radically new in the world of coral science.
To begin with, there is the problem that many corals breed just once a year, on a particular night. If you don’t catch them at the right moment, you have to wait a year for the next opportunity. Then there is the nasty fact that the algal symbionts, single-celled dinoflagellates of several species, live in intimate, intracellular association with the corals. Using conventional approaches to collect genetic material from cells yields a mixture of coral and algal sequences. And third, there is the daunting challenge, political as well as ecological, of putting lab-reared corals back into the ocean to see if they are indeed a tougher strain. Australia has a long and unhappy history of introducing creatures that became unwanted pests on its landscape, and the last thing anyone wants is a plague of ‘bad’ corals on the Great Barrier Reef.
Corals being grown under controlled conditions at Australia’s National Sea Simulator.
Photo © Christian Miller, AIMS.
And yet, if we do not explore all possible tools to assist coral species, we are very likely to watch them disappear one by one as oceans warm. Far better to explore possible ways to strengthen corals’ abilities to survive warming, than to engage in the harvesting of coral nubbins to be fragmented and grown up in a coral nursery and then planted back on the reef. While reef restoration, as it is called, is being practiced in many places around the world, I fear there is little point in rearing and then out-planting tiny colonies of corals that will simply bleach the next time warm water passes by. Such activities may be useful in small, high-value locations adjacent to tourist enterprises, but they seem unlikely to be a solution to our killing off of coral reefs. In fact, such activities, if inaccurately portrayed as real solutions to the reef dilemma, could damage the overall effort to do something for reefs, because they divert activity and interest away from more difficult, but more effective, choices. The research done by van Oppen and colleagues is very different to the broad sweep of reef restoration activities, few of which even have much of a scientific underpinning. Meanwhile, the most effective way to do something to aid the world’s coral reefs? Cut our emissions of CO2 as drastically and rapidly as possible and seek additional solutions to suck CO2 from the atmosphere. One irony, not mentioned in Cornwall’s article, is that all the time van Oppen works to build stronger corals, the Australian government continues to promote coal mining and export, while failing, year by year, to reduce its own unconscionably high emissions of CO2. Not the attitude one might expect from a government that carries the responsibility of caring for the largest coral reef system on the planet.
The final article I want to mention, by Guillaume Chapron, Yaffa Epstein, and José Vicente López-Bao, of the Swedish University of Agricultural Science, Uppsala University (both in Sweden), and Oviedo University, Spain, respectively, appeared in the 29th March issue of Science. It was labeled an Insight or a Perspective, and titled A rights revolution for Nature. This one is on open access, so accessible to all.
Chapron and colleagues have written a short 2-page article reporting the status of efforts to grant rights to Nature. I was surprised to see it in Science; but pleased also. Maybe there really is movement in that direction.
I’ve discovered in recent months that when I suggest that, perhaps, the Biosphere has a right to exist, and humans have a duty to sustain it, you get a mixture of puzzled and outright incredulous looks. At least in North America. What on earth is Sale talking about now? And yet, I’ve also discovered that the more I suggest that the Biosphere has rights, the more sensible a proposal that sounds to me.
Perhaps I should give some background. Climate change and the broader environmental crisis have brought home to me that humanity cannot go on treating the planet as a larder full of things to use and discard. We currently use the goods and services we extract from Nature at rates that cannot be sustainable in any real universe, and certainly not in ours. But getting that fact across to other people is extremely difficult. We of a western, market-based, Judeo-Christian-influenced society simply don’t get the fact that the planet is finite, and capable of generating, or regenerating resources at rates that are also finite and limited. And the human enterprise has far outstripped those rates. We are literally using up the planet. And yet, we, cocooned in our comfortable, middle-class social system, do not see the damage we are doing first-hand. That almost all the fish in the local supermarket come from far away, and usually from fish farms, is not noticed by most shoppers, and yet it is a radical change from the situation in our supermarkets just a decade or so ago. The same is true of produce. Because I live in a wealthy western nation, I can be assured my supermarket will have fresh fruit and vegetables, plus plenty of meat and seafood, in copious quantities and endless variety, every day of the year despite what is happening out there beyond in the places where this food is grown or acquired. The same is also true for all the other things I might require. I will be one of the last people to discover there is no longer enough to go round. And this is surely unfortunate, because I have grown up believing (or at least, I live in a society in which the great majority of people have grown up believing) that I am entitled to use as much as I want, because that is why this wonderful planet-larder is here.
Members of my society do not believe it is possible for the larder to become emptied out, and our eyes tell us all is well, whenever we go shopping. Given these facts, how do we become convinced we need to change our ways? Telling us of the damage we are doing to the planet has relatively little effect, because the state of the planet is of no concern. A little bit of environmental damage here and there? Oh dear, that is a pity. But the economy has to continue to grow.
What we need is to become convinced that we have a duty to nurture the planet, and there are a few ways in which this might be done. One of these is to use the legal system. Most humans live in societies with laws. In some of these societies the laws are obeyed more often than not. We understand the concept of law, the idea that the government can enforce certain behavior by penalizing misbehavior, because there are laws stipulating same. But mostly our legal systems do not suggest that we have a duty to sustain the natural world. In fact, for the most part, our legal systems have grown up in a whimsical fantasyland in which there are people and property. People own property. They can buy and sell it. Carve it up and even eat it. But property itself has nothing. And other than people, there is only property.
Now I’m exaggerating of course. But only to make an important point. Our legal systems have been very good and producing order in the interactions among people. We’ve also been very creative in expanding the concept of personhood to include inanimate human constructs such as corporations. Sometimes these non-human persons are immortal (as are corporations unless they declare bankruptcy. But we have also been very good at leaving the natural world out of the equation. Humans, corporations and their property exist in some kind of space, an environment, and that space can be used to dump things we don’t want, with no penalties for doing so. Or we can take from that space things which it needs to sustain itself (to our ultimate detriment) also with no penalties. But if we were to suggest that that space in which we all live, that environment, that Biosphere, was also some form of person, who had rights and duties, that would change things dramatically. And that is what the global effort to grant rights to Nature is all about.
There are many representations of the Andean Earth-Mother goddess, Pachamama. The Ecudorean constitution of 2008 was the first to establish the right of Nature, as Pachamama, to exist, to be sustained, and to continue its natural functions. Revealing the universality of the concept, this version is by Australian contemporary artist Jassy Watson, of Bundaberg, Queensland.
In their brief two pages, Chapron and colleagues do a good job of summarizing progress on the effort to establish rights in law for Nature, or components of nature. They have a (rather incomplete) table listing notable examples of successful efforts to grant rights to nature, and they contrast efforts, such as that of Ecuador which granted rights to Nature writ large and that of New Zealand, which granted rights to a single river system to be a legal person. They also point out that granting rights in law does not ensure people will embrace the duty to respect those rights – a wide range of ethnic, religious, racial, and gender groups will recognize the truth of that statement with respect to human persons. It’s not surprising if it also applies to non-human persons. Nevertheless, implementing law which grants rights to Nature could help us make the required transition from treating the planet as our larder of things to use to treating our planet as the complex system it is, a complex system which includes ourselves, and which sustains our lives. I’m glad these ideas found an outlet in Science!