Mark Serreze: The Value of Climate Science


Modern climate science is based on facts, physics and testable hypotheses. There is ample room for debate about what to do about climate change, but the underlying science is rock solid.

Modern climate science builds on a long track record of scientific inquiry on environmental and health issues that has benefited society. Through scientific analysis, it was discovered that DDT, widely used as a pesticide, was becoming concentrated in the food chain. As a result, laws were passed to curb its use. Tetraethyl lead was once added to gasoline to reduce engine knock. Through science, we learned that lead in the environment poses severe health hazards, so the use of lead in gasoline was consequently phased out. It was through science that we learned how CFCs were destroying stratosphere ozone. In turn, through many decades of research, we have developed a strong understanding of how the climate system works, how humans are affecting climate, and what is in store if society continues to follow its current path without taking corrective action.

Until the middle off the 20th century, climate science was pretty much a backwater. Climatologists, by and large, were bookkeepers, compiling records of temperature, precipitation and other variables. From these records, much effort was spent classifying climate types around the world, ranging from tropical rain forests to monsoons to semiarid steppes to deserts. Climate data certainly had value to farmers and the home gardener, civil and structural engineers and the military planning. But the focus was largely on statistics, with relatively little emphasis on climate dynamics – the processes that control the climate system and how it may evolve. There were notable exceptions, such as Svante Arrhenius, who, in the late 19th century, speculated on how rising concentrations of carbon dioxide would lead to warming, but for the most part, climatology was a largely descriptive and rather boring field of science.

The shift from simple bookkeeping to a more physically-based view of how the climate system works paralleled developments in meteorology—the science of weather prediction. The rapid advances in meteorology following the Second World War, in turn, largely paralleled the development of numerical computers. With computers, it became possible to translate the physical processes controlling weather systems into computer code. It was readily understood that the physics controlling weather were part of the broader set of physics that control climate, which led to the development of global climate models, or GCMs for short. GCMs were quickly seen as powerful tools to understand not just how the global climate system works, but how climate could change in response to things like brightening the sun or altering the level of greenhouse gases in the atmosphere.

Using early generation GCMs developed in the 1970, pioneers like Jim Hansen of NASA, and Suki Manabe of the Geophysical Fluid Dynamics Laboratory in Princeton confidently predicted that our planet was going to warm up, and that the Arctic would warm up the most, something that we now call Arctic amplification. But the more mundane chore of compiling climate records never stopped, and indeed, its value grew, for it was only with ever-lengthening climate records that it could be determined if things were actually changing. And as these records grew, it slowly became clear that the planet was indeed warming. From numerous GCM experiments, it also became clear that this warming, and all the things that go with it, such as the Arctic’s shrinking sea ice cover and Artic amplification, could only be explained as a response to rising levels of carbon dioxide in the atmosphere.

Climate scientists of today need to know:

  • The processes that can change how the earth absorbs and emits energy
  • How the atmosphere and weather systems work
  • How the atmosphere interacts with the oceans
  • How the atmosphere interacts with the land surface
  • And how the land interactions with the ocean.

But whatever our area of specialty, we all try and make contributions to our understanding, but those contributions are, to the best of our ability, based on facts, physics, and sound methodology. In science, there is no room for wishful thinking. As a society, need to get past partisan bickering, step back, and listen to what climate science is telling us: the climate is changing, we know why, and the implications must not be ignored. This is the value of climate science.

Mark C. Serreze is director of the National Snow and Ice Data Center, professor of geography, and a fellow of the Cooperative Institute for Research in Environmental Sciences at the University of Colorado at Boulder. He is the coauthor of The Arctic Climate System. He lives in Boulder, Colorado.

Christie Henry on the Ecosystem of University Presses


Adapted from a presentation given at UGA by Christie Henry, Director, Princeton University Press

I have had the incredible fortune of living in the university press ecosystem for several decades, having moved in the fall of ‘17 to Princeton University Press, after twenty-four years with inspiring colleagues at the University of Chicago Press. University presses and the universities with which we partner are part of what I would describe as a metacommunity of ideas and knowledge—that is, a set of interacting communities linked by the dispersal of multiple, potentially interacting species.

Publishers do like to interact with species of students and academics; in fact we depend on these interactions. And it’s quite well known that each of our ecosystems draws resilience and sustainability from one another; most often our relationships are mutualisms.

As within ecosystems, there are vital nutrients that flow through our systems, among the most important of which is knowledge. Universities are the deep-sea thermal vents of knowledge, pumping it out in amazing quantities at highly concentrated sites. And university presses help create a pelagic zone for this knowledge, putting it into circulation across the globe.

Like organic nutrients, knowledge is created, consumed, processed, recycled. And we must be aware of its potential to get stuck in dead zones, or in massive clumps of plastic debris. As a vital nutrient, knowledge is also essential for us to conserve, ideally to grow.

Currently our ecosystems are facing unprecedented climate change—we can consider it our own Anthropocene. How we define “anthro” in this case varies. But we certainly don’t want to be having conversations years from now about how to clone an extinct idea or population of knowledge, much as we are now having conversations about cloning mammoths and other extinct fauna.

Strategic plans for conservation depend on an understanding of threats and challenges, and especially the climate disrupters. Those inhabiting our ecosystems will find this overview familiar terrain, I suspect, but I think it’s important to trace the contours of our current stressed landscape.

The worlds of research and knowledge are experiencing fluctuations in funding that are as erratic as global temperatures, though not trending on an increase as global temperatures are. Just as increased snowfall doesn’t negate the reality of global warming, we know that increases in the population in higher education don’t mean our system is showing signs of health and well-being. Reductions in funding, and university budgets, have run like a rhizome through our communities, have disrupted library budgets, and in the university press world have resulted in events such as the recent University Press of Kentucky battle for survival under proposed state government cuts.

We have seen massive influxes of what I could call invasive species—those that disrupt or harm our systems, the economy, and even human health. Email, many say, is one of these species. So is fake news. So too is the volume of information, which is impacting attention span, and certainly causing some concern among book publishers of all species.  Some of these influxes are leading to an extinction of time, and this has a ripple effect, with impacts on critical system operations like peer review. And even if altruism has been recognized in dolphins and scrub jays, we know there are limits. There is less time for writing, and for reading. Though some positive trends outside of the academy point to growth of reading time, it’s not necessarily time spent with books, or with long-form writing.

There are also arguably more predatory species in our communities, from rapacious journals to those attempting to extract nutrients from our systems: the tyrannical form of the assault on higher ed. And some of these predators are known to live in the Amazon, but this verdant jungle is also important to visit from time to time for all that it harbors.

We know that species diversity drives ecosystem health and stability, and another threat is the lack of diversity in our ecosystems. We are at risk of genetic bottlenecks, those major events that decrease diversity and the gene pool—immigration legislation is among the most acute recent examples.

There are pressures to grow the reach of our ecosystems, our nutrient output, while at the same time reducing incoming nutrients. Open access expectations in the book world pose one of these pressures for university presses. So does the tenure and credentialing process in those disciplines that quantify book output as a key metric.

Okay, enough of the gloom and doom. Many historical moments of massive disruption are followed by a burst of evolutionary adaptations that lead to greater diversity. And I think there is a chance we are now in our own Cambrian Explosion, amidst great radiations of knowledge and books. We will need to be intentional about supporting and preserving these ecosystems.

A recent article in the Chicago Tribunewas titled “University Presses Deserve Protection,” much as ecosystems around the world need conservation and management.

Another recent publication from the science literature shifted the foci of biodiversity from mass of species to the diversity of functional traits of species in an ecosystem as a measure of resilience. This study focused on pufferfish, and one could argue we have some of these swimming in our collective waters. But universities are growing innumerable new functional traits, as are university presses. I’d argue we in the AUP world were preadapted to this need for an array of functional traits, as our lists of book species are diverse—we publish course books, textbooks, popular books, reference works, regional works, and monographs. And we as a community function much like a honeybee democracy, which in the face of threats takes the form of an incredible superorganism—without needing to sting.

New modes of communication have also increased outlets for knowledge sharing, and we just need to learn the best ways to research and curate these. Blogs have become a flagship species in our ecosystems, inspiring books, and have provided new platforms. There was a great article in Natureyesterday about the first science conference proceedings published in graphic form, a genre we all know could benefit from evolutionary change.

Libraries and publishers are working to coevolve, crafting aggregations of content, and partnering on joint publications and initiatives.

Some evolution is at a slower pace, in the best of ways. The price of university press books in real dollars, accounting for inflation, has not increased in measurable ways at all. The nonprofit mission and ethos have been in a state of equilibrium, only rarely punctuated.

Technology is leading not just to artificial intelligence, but to new and real knowledge. Open peer review is using technology to bring in a wider range of reviewers, particularly more global ones. A recent great example is Bit by Bit: Social Science Research in the Digital Age:author and sociologist Matt Salganik worked with the Sloan Foundation to create the Open Review Toolkit. This platform facilitated feedback from around the world, at various scales, and generated a database of interested readers.

Technology has also helped to grow our landscapes, to aid in bringing our content to readers the world over on new platforms. New digital initiatives, from digital humanities, sciences, and social sciences, are animating scholarship, and the book.

And publishers are also focusing on the diversity of species—of readers, of authors, of reviewers—and that will ultimately drive our resilience, as it will the university’s ecosystem.

There are many compelling reasons to be part of the circulation and exchange between our linked metacommunities.

As I think about a field guide for those of you coming new to the AUP land, there are a number of entries in the field guide index I would point you to:

  1. Find your niche. Know your audience, especially the difference between a dissertation committee and a book readership.
  2. Look for conspecifics. Identify those species of books that are like yours, as there is strength in being part of a family. And then see where those species tend to gather, under which imprints.
  3. Think about your plumage. This includes your proposal, a vital signaling tool, but also your platform. What type of author species are you? What are the novel traits you contribute to the ecosystem? We look for functional diversity on our lists. But we are increasingly looking for how well your plumage works in the world—what we call your platform. Social media, while causing a lot of information overflow, has also become a vital signaling tool in the world of publishing—for scholarly and trade alike. Many of the signaling forms of earlier geologic eras, like print advertising, are not resonating—they are being replaced with Altmetric badges and Twitter followers, and these new efforts depend on partnerships between presses and authors.
  4. Think like bowerbird. Look for the houses that are constructed and decorated in ways that sing to you. Each publisher has its own niche, and we usually do a pretty good job of signaling that ourselves. Visit websites; visit booths in exhibit halls. And your journey should explore not just the construct of our houses, but how we get our birdsong out into the world—are we visible? are our prices reasonable? do we appear on syllabi? are our books translated widely?
  5. Sensory ecology is a wonderfully exciting field. Embrace the ways in which you can adapt this to publishing. Listen to your peers; listen to yourselves as you teach, and the books you use. Listen for the authors and books that are being mentioned in your own niche.
  6. Circulate like plankton. Find ways to share your ideas. If at conferences, be sure to test them out with publishers on-site. Though also be mindful of the conservation of energy rule for publishers—try to make sure the engagement is focused and meaningful.
  7. Be active foragers—do your research. There is so much information on press websites about their own DNA. Their priorities, strengths, weaknesses. The more you can align your approach to these strengths, the better.
  8. Be clear signaler, not stealth like anglerfish. Communicate with publishers with clarity and transparency, from the proposal to the project’s main hook, to your aspirations as an author, to the way to engage your readers with story.
  9. Prepare to be challenged by your conspecifics and your competitors. Peer review is critical by nature, but it also evolves stronger life-forms of books.
  10. Be a patient species—we know the book world sometimes seems to move at geologic time scales, but the results can be structures as magnificent and multilayered as the Grand Canyon.
  11. You may also occasionally need the tenacity of a bulldog.
  12. And nothing ignites the senses better than reading or listening to books—please make time to do so. It’s the best way to find models for different forms of writing, and to support the ecosystem with which you are now coevolving as academics.

Another reference to a recent article in Nature:

“Ecological theory suggests that large-scale patterns such as community stability can be influenced by changes in interspecific interactions that arise from the behavioral and/or physiological responses of individual species varying over time.“ Please be those individual species that respond and behave in ways that will stabilize knowledge, and so too the evolution of the book.


Sean Fleming: The Necessity of Water

Changes across the globe are placing unprecedented pressure on our water resources. Today, according to a United Nations report, more than one billion people do not have access to clean water, and 1.4 billion live in river basins where water use exceeds recharge rates. Another two billion or so water users will be added to the world’s population by midcentury. This population growth, together with expansion of agricultural and industrial production as poorer nations develop, is expected to increase global water demand by a stunning 55% by 2050.

Not only do these factors increase water demand, they also signify greater global exposure to water-related hazards, including pollution and flood risk, as more people settle on floodplains, for instance, and more municipal, industrial, and agricultural effluent is discharged into the environment. At the same time, there is a strong scientific consensus that the net increase in atmospheric greenhouse gas concentrations is large enough to detectably alter global climate. This can be attributed to activities like massive fossil fuel combustion, industrial livestock production, and widespread deforestation. Current projections suggest that the main hydrological effect for most basins will be to amplify the water cycle, which may increase runoff in many regions but reduce supplies in others. More importantly, it may widely increase the intensity of both the yearly rainy and dry seasons, further increasing flood and drought risks. And river channelization, damming, contamination, and upstream water withdrawals have so degraded aquatic habitat that many freshwater biological populations have collapsed, some species have been entirely extirpated from parts of their home ranges, and others are at risk of extinction altogether. We are facing a dark constellation of regional water resource disasters, growing and coalescing into what appears to be an emerging global catastrophe of human welfare and the environment.

To mitigate the impacts of these changes, we need to invest deeply in a coordinated, broad-based, and large-scale drive to create new science and technology that addresses the needs and aspirations of the current and future global populations in a healthy and sustainable way. Only time will tell which specific directions these innovations will take, but there are a few obvious paths. This includes:

  • Lower-energy, lower-cost, and cleaner desalinization technologies to sustainably extract fresh water from deep aquifers and the ocean
  • Further technology- and policy-driven improvements in the efficiency of water use and, in particular, water distribution systems
  • Public health steps to curb population growth in ways that are new and ambitious, yet fully respectful of individual rights and freedoms
  • And perhaps most importantly of all, improved environmental monitoring and prediction technologies, so we know what’s happening with our water resources today and what to plan for in the future.

There is justification for having faith that we can get real traction on water scarcity. The development of more water-efficient technologies for homes, farms, and factories is an obvious example. Indeed, water use in the United States has leveled off near 1970 rates in spite of both population and economic growth. Granted, unsustainable water practices during regional droughts, such as groundwater mining in California, revealed a chink in the armor. Furthermore, stabilization of water demand seems restricted, at best, to a handful of rich nations. Nevertheless, the overall statistic must be acknowledged as the stunning success, cause for optimism, and clear template for emulation that it is—a shining citadel on the hill, as it were.

Improvements in water quality are another example. Admittedly, over much of the world, rapid agricultural and industrial expansion are making water quality worse, not better. Shortages of potable water due to fecal contamination remains a huge issue globally; in fact, another UN report indicates that inadequate access to clean water kills more people through the associated disease alone than are killed by guns in war. And emerging contaminants, like pharmaceuticals and plastic breakdown products, are an increasingly worrisome threat. Yet improved awareness, legislation, and technology have yielded tremendous gains. The days of rivers ablaze— this happened to the Cuyahoga River in Ohio, which was so polluted with flammable contaminants that in 1969 it actually caught fire—seem to be over. Overall, water quality across the industrialized regions of the developed world is largely much better now than it was, say, forty or fifty years ago.

Another broad reason for optimism is the seeming paradox of water conflict. Ismail Serageldin, a former World Bank vice president, famously warned that the wars of the twenty-first century will be fought over water. It turns out, though, that water resource conflict and cooperation are surprisingly nuanced. While squabbles abound, actual shooting wars solely over water, even in regions that are both arid and troubled, are virtually nonexistent. And cooperation might be at least as common as conflict.

But with exploding global demand, this all might change.

As water resource pressures mount, our efforts to manage these changes must grow commensurately. And at the heart of these efforts must be good hydrologic science, because without that, everything else will merely be a shot in the dark. Advances are required in two directions. First and foremost is improved ability to monitor water, and associated variables like land use and climate. This will be accomplished by growing our networks of ground observation stations, and by expanding the scope, accessibility, and accuracy of airborne and satellite remote sensing data. The second is to further develop our mathematical modeling and prediction technologies for watershed systems. Data analytics, statistical and machine learning-based prediction, and physical process simulation techniques – rivers in silicon, as it were – are how we test our understanding of watersheds and transform observational data and theoretical knowledge into a scientifically defensible and socially responsible basis for informed predictions and sound advice.

Water isn’t optional. Water is necessary for our very existence, for our continued economic development, and for the health of the web of life that supports us. It’s also limited in its availability, and there are no substitutes for it. Whatever path humanity chooses to follow, it will be up to hydrologists to present society with the options available, and the corresponding pros and cons, for the management of our water resources. And to do that, water resource scientists and engineers need to understand watershed systems in detail, and to accurately, precisely, consistently, and quantitatively predict the impacts on those systems from both natural phenomena and human interventions. Viewed from this perspective, it is perhaps not too dramatic to assert that the future of the world will depend, in a small but real way, on a quantum leap forward in our understanding of the physics of rivers.

Sean W. Fleming has two decades of experience in the private, public, and nonprofit sectors in the United States, Canada, England, and Mexico, ranging from oil exploration to operational river forecasting to glacier science. He holds faculty positions in the geophysical sciences at the University of British Columbia and Oregon State University.

Oswald Schmitz: Earth Environmentalism & Jazz

Pop music icon Joni Mitchell’s song “Big Yellow Taxi”, released during the headiness of the first Earth Day, ranks among the top anthems of the 1970’s environmental movement. With lyrics such as “They took all the trees and put them in a tree museum,” and, “They paved paradise and put up a parking lot,” it rebuked what humans were doing to nature in the interest of what was popularly deemed to be progress. The refrain, “Don’t it always seem to go that you don’t know what you’ve got ’till it’s gone,” adds a wistfulness for all that is lost in the name of such progress.

The song has a timeless ring given what humans are continuing to do to nature today. More than half of the global human population now lives in paved urban areas. And by all indicators, that number likely will grow to become two thirds of all humans, or even more, by mid century. It seems that there is no end in sight to humankind’s drive to pave-over nature. Indeed, the numbers of species that stand to be endangered in the name of such progress seems unconscionable. It is not surprising, therefore, that those who are committed to speak up for those species and champion their protection might become disillusioned. It seems that all we can do in the face of this unstoppable wave of global urbanization is to sing the blues, lamenting all those species that will surely go extinct, all the while losing hope that things will change.

Yet, this needn’t be a foregone outcome. Changing ways, however, require a shift in mindset about how we build urban environments. We need to stop simply being expedient by taking away all the trees, paving-over nature, and building from scratch. Instead we can and should capitalize on human ingenuity and creativity, to take care to design and build urban areas in ways that complement nature’s aesthetic and embrace its functional properties.

Take for instance a place that is near and dear to me: located a mere fifteen-minutes from where I live is part of an urban greenspace in which a river flows through a heavily treed landscape squarely in the middle of the city and several adjoining towns. I find it magical every time I step into the river at the crack of dawn, balancing against the surge of water pressure around my legs as I begin fly-fishing. I always take a moment and look up into the bordering forest to admire the kaleidoscope caused by the flecks of rising sunlight penetrating the small gaps within the dense forest canopy. The rising sun is nature’s alarm clock. There is not a person in sight, anywhere. The only sound comes from the singing birds, the flowing water, and me, breathing. Standing alone in this stretch of the river lets me forget my worries and reflect on what is good in life, including being lucky enough to have nature so close at hand.

One of the most important dividends of having healthy ecosystem functioning is the delivery of abundant, clean water. Forests on hillsides surrounding water bodies like my urban river play an important role in the delivery of clean water. By rooting to different depths in the soil, different tree species together prevent the soil from being compacted, which allows water to infiltrate and replenish soil moisture that eventually seeps down into the river. By rooting in the soil, trees prevent soil erosion during run-off events, which prevents the river from becoming murky with suspended soil particles. Such natural water treatment can help municipalities offset hundreds of millions of dollars in capital costs that would otherwise be needed to build water treatment facilities. Natural water treatment also offsets taxpayer funded water filtration costs that can run between hundreds of thousands to millions of dollars per year, depending on how much urban nature exists.

Encouraging nature as part of the urban built environment has benefits as well. Roadway trees creating urban forests filter out air pollutants such as ozone, nitrogen, and sulfur dioxides, and small particulates that cause respiratory ailments. They also provide natural air conditioning by cooling urban areas through shading. This in turn prolongs the life of infrastructure like paved roadways. It also reduces the need for energy generation that would normally be used to cool buildings and thereby reduces emissions of greenhouse gasses and air pollutants that accompany that energy generation. Urban trees help storm-water percolate into soils rather than run-off across impervious surfaces to flood urban drainage systems and watercourses, thereby reducing the concentrations of pollutants in the water supply. Estimates indicate that the value of these services to a given city could again amount to hundreds of thousands to millions of dollars. The replacement value of the trees alone can reach hundreds of millions of dollars, even after accounting for maintenance costs including tree pruning and removal, leaf pick-up and disposal, and utility-line clearing.

Urban trees offer personal health benefits as well. People living in neighborhoods with high densities of roadway trees are characterized as having higher perceptions of personal physical and mental health, of feeling younger, and of having lower incidence of cardiac and metabolic ailments than people living in the same city but in neighborhoods with fewer trees. It also encourages people to eat healthier diets, especially less meat and more servings of vegetables, fruits and grains. These health indicators persist even after accounting for differences in socio-economic factors and age. Estimates show that these lifestyle effects are equivalent to having $10,000 more in personal annual income.

The rise in urban ecological science is heralding a new era to help urban planners think more creatively about nature-informed design. Some of that creativity may come from combining natural features—such as varieties of plants with different physical structures that complement each other in their functioning—into new kinds of construction processes. Green roofs, roofs of buildings that are covered by all variety of plant species in a growing medium, are one such example. Bioswales are another. These gently sloping landscaping elements create a drainage course—a modified ditch or local depression—that is filled with natural vegetation or compost. They are usually built alongside streets or in parking lots. They collect and hold water from surface runoff to filter out silt and pollutants, thereby cleaning the water before it eventually enters a city’s storm-water sewer system.

Humanity’s influence on the Earth is forcing us to stretch our collective imagination into many realms that we have never considered before. But we have considerable scientific knowhow to support human ingenuity and thus meet the challenge of devising creative new ways to protect all the jazz. Designed landscapes change microclimates, flows and concentrations of water and nutrients, and emissions and concentration of pollutants. Hence thoughtful design must ensure that these changes lead to positive functional outcomes. Planted landscaping can even build natural habitats for many species thereby creating opportunity to lower their endangerment, as nature gets paved-over. But it requires thinking hard about the exact kinds and ways of creating habitats and how they are spatially arranged. At a minimum, that knowledge tells us that we should keep the trees whenever we pave paradise and put up a parking lot.

Oswald J. Schmitz is the Oastler Professor of Population and Community Ecology in the School of Forestry and Environmental Studies at Yale University.

Eelco Rohling: A view from the ocean for Earth Day

On April 22, we celebrate Earth Day. Mostly, we use this holiday to demonstrate support for environmental protection.

The oceans cover some 72% of Earth’s surface; this is why we sometimes call the Earth the “Blue Planet.” Yet, in a time when people are talking about “the best deals,” the oceans are getting an extremely shoddy one.

Humanity is stretching the global oceanic ecosystem to its limits. Major impacts come from global overfishing, and from the physical destruction of critical pristine environments such as coral reefs and mangrove coasts. Combined, these reduce species diversity and richness, as well as breeding potential and resilience to disease. Our impacts on coastal systems are also strongly reducing the natural protection against wave- and storm-damage. We’d be wise to be more appreciative of, and careful with, our key food supplies and protection from the elements. After all, with 7 billion of us to feed, and with almost half of these people living within 100 miles from the sea, we have it all to lose.

Yet our deal with the oceans is even worse than that. That’s because the oceans also get to be the end-station for everything transported by water, which includes plastics as well as toxic chemicals. To boot, we have for many decades unceremoniously dumped vast quantities of society’s unwanted waste products directly into the oceans. Although legal frameworks have been introduced to limit dumping directly into the sea, illegal practices are still rife. In addition, indirect dumping via rivers—whether wittingly or unwittingly—remains a major headache.

As a result of our wasteful demeanour, we are leaving a legacy of oceans (and wildlife) that are visibly filling up with long-lived non-biodegradable plastics, which leads to graphic news coverage. In consequence, plastic pollution is now being billed by some as our oceans’ biggest threat today. It’s certainly a very visible one, with up to 240,000 tons of plastic floating in the oceans. And that amount is equal to only 1% or less of the amount of plastic that is available for entering the ocean every year. This illustrates the massive potential for the plastic problem to explode out of control.

Much less visible, but just as devastating, is the pollution of our oceans with highly toxic and long-lived chemicals—especially human-made PCBs and other organic compounds, along with concentrated heavy metals. PCBs are among the very worst threats because they are so long-lived and so toxic.

Some 10% of all 1.3 million tons of PCBs produced have made it into the oceans already (that is, about 130,000 tons). While this is alarming enough by itself, there’s up to 9 times as much waiting to be released and make its way into the oceans. All we can do to stop that from happening, is prevent any stored PCBs from making it into the open environment. So far, this has been done to 17% of the stores, while 83% have yet to be eliminated.

PCBs have become widespread in marine organisms, from coastal and estuarine waters to the greatest depths of the largest ocean: the Pacific. They cause an endless list of severe health problems, deformities, hormonal unbalance, immune-system weakening, cancer, and a decrease in fertility. Like most long-lived pollutants, PCBs accumulate into higher concentrations through the food web. Their accumulated impacts in whales already drive important infant mortality, as females pass lethal amounts of PCBs to unborn or suckling calves.

Nutrient-pollution is another big issue. This may sound like a strange type of pollution. After all, wouldn’t more nutrients just lead to more happy life in the ocean? When nutrients come in reasonable amounts, then the answer is yes. But when the nutrient flux is excessive—we then talk about eutrophication—all manner of problems develop. And the flux of artificial and human and animal waste-derived nutrients is excessive in many estuaries and coastal regions. Together with ocean warming, this has caused a rapid global expansion of regions where decomposition of massive algal blooms strips all oxygen from the waters, resulting in vast “dead zones” with completely collapsed ecosystems.

Finally, there is the sinister, lurking threat of global warming and ocean acidification. The current rate of warming has been successfully documented through scientific study, and is 10 to 100 times faster than ever before in the past 65 million years. Meanwhile, ocean acidification is caused by the oceans absorbing roughly a third of our carbon emissions. By now, the oceans have become about 0.1 pH unit more acidic than they were before the industrial revolution; that is an acidity increase of 25%. Projections for a business-as-usual emissions trajectory show a 0.3 to 0.4 pH unit change by 2100. In humans, a 0.2 pH unit change results in seizures, coma, and death. Fish, and most other vertebrates, are equally sensitive.

If the changes are slow enough, organisms can evolve to adapt. But researchers are very concerned about the extreme rate of acidification. For coral reefs, the combination of warming and acidification is certainly implicated in massive bleaching and die-off events that are going on around the world already. And let’s not forget that coral reefs house one third of all oceanic biodiversity, while oceans cover more than two thirds of the Earth surface.

The Oceans, by Eelco RohlingSo here’s my plea

We really need an Earth Day, but we need an Ocean Day as well—to build awareness about  this critical part of our planet.

At a passing glance, the oceans’ problems remain hidden under a mesmerising veil of waves and reflections. We need to remind ourselves to keep looking beneath the surface, and to keep taking this critical system’s pulse, lest it dies without us knowing about it. Maybe then we will realise how urgently we need to stop using it as a dumping ground and infinite food larder. That we instead should look for sustainable ways forward, not just for life on land, but also for life in the oceans.

Our attitude going forward will make or break society. Chances are very high that a marine mass extinction will drag us, the ultimate overpopulated top consumer, along with it.

Eelco J. Rohling is professor of ocean and climate change in the Research School of Earth Sciences at the Australian National University and at the University of Southampton’s National Oceanography Centre Southampton.