On Knowing Your Ecosystem – A Coral Reef is Much More than A Coral and Some Fish

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A few years ago, in another life, I was listening to an M.Sc. student provide a progress report to her advisory committee.  She was tackling the problem of whether there were two, or just one genetically distinct population of sea-run trout using a particular lake in British Columbia.  The managers knew there were two runs of spawning fish, an early one and a later one; they needed to know if these needed to be managed as separate populations.  Our student’s problem was that this was a small lake and the late run had relatively few fish.  While she was only catching the fish for a fin clip and then releasing them, there was occasional mortality and she did not want to be responsible for further reducing a threatened population.  I asked what I thought was a simple question, “Can you tell the fish apart?”  She looked puzzled, and answered, “No, I haven’t run the DNA sequences yet.”  I looked puzzled, and said, “No, I mean can you tell the fish apart?”  She looked more puzzled, and her advisor, a population geneticist used to talking to ecologists, said, “Peter means, if you look at the fish carefully, can you see any differences among them?”  “Oh”, she replied, “I don’t know; I haven’t looked.”

She was a good student, but she had not yet learned an important lesson – get to know your animals.  It is a lesson that serves the biologist in good stead whenever the question being asked concerns the organism being used in the study.  That is not ‘always’, because biology is a field of study with a split personality.

Biophils and Mechanophils

There are those biologists – I’ll call them biophils — who are concerned about ecosystems, populations, individuals; and who ask questions at molecular, organismal, population or ecosystem level that concern how those creatures do what they do when they do it, and how all that doing creates a cohesive whole.  And there are biologists – I’ll call them mechanophils — who are concerned with biological processes that take place among molecules, within cells, or within and sometimes among individuals, that they believe are fundamental to life.  Mechanophils use ‘model systems’, ‘preparations’, ‘tissue lines’, and sometimes ‘animals’, but they are not concerned with what those creatures do or how, when or why they do it.  They are concerned with the specific process and how it functions in a living system.  I’ve always had trouble understanding mechanophils, because the questions they spend their lives on always seemed to me fundamentally less interesting than why, how, when, or what creatures do in the course of their lives.  I know many of them have trouble understanding biophils like me, who revel in the unexpected variety of life, never tire of just-so stories, but could never get excited about the intricacies of metabolic goings-on within five or six cells in the tail-end of a tiny worm of a single species that has lived in lab culture for generations.  What about all the other worms?  Fortunately, the biological world is rich enough to sustain a diversity of approaches.  Population geneticists are one group of biologists who regularly find themselves on the interface, attempting to communicate across this mechanophil – biophil divide, and the better ones are worth their weight in gold, simply as translators.

Getting to know your animals (or plants, or ecosystem) takes time, and university education increasingly sees that as time not well spent.  Far better to master a new technique for measuring the biological world more precisely, or for handling vast quantities of data, sifting through them hunting for patterns that might be worth pursuing.  It’s especially better to spend time mastering use of a new, expensive gizmo so that your results will be somehow flashier than anyone else’s.  Along the way, generations of students have missed the opportunity to explore the complexity which is the hallmark of life while getting to know their animals.

Physics envy

Biologists all suffer from physics envy, embarrassed that they work in a field that is never going to find the question that belongs with the answer “42”, and is certainly never going to develop a “theory of everything” that will consist of a line or two of arcane mathematical symbols, and will cause the whole world of science, for one brief moment, to exhale in unison a single sustained note of exaltation and awe.  No E=MC2 for biologists.

Especially when you study biology at the population or ecosystem level, biology lacks explicit axioms, and reveals a bewildering diversity of answers to any question posed.  Biologists should celebrate that diversity, but mostly we seek ways to minimize it.  That’s one reason why the mechanophils amongst us narrow their attention to a single preparation or model system.  And that is what helps drive reductionism in all branches of biology – strip away the unusual, reject the outliers, focus in on the modal result, and go ever deeper into what causes that modal result.  If the modal result happens 1% of the time, knowing in detail how and why it happens is only a modest step forward.  What about the 99% of the time?

physics envy degree_off

There is no good reason for talented biologists to feel inferior to physicists, even if we are not able to develop succinct equations that describe biological complexity.  Image © Ikcd.com

Physics envy is also why we long for instrumentation that can yield precise measurements quickly and easily, and why we reject fields of enquiry that necessarily require enormous amounts of time sorting through field samples, or data.  Phytoplankton ecologists know that chlorophyll concentration, as measured by a satellite scanning the ocean surface, is only a very rough proxy for the rich and dynamic phytoplankton community that is present there.  But they still devote considerable effort to studies in which the closest they get to phytoplankton is a measure of chlorophyll concentration.  Getting to know your phytoplankton takes far longer than downloading the chlorophyll data.  Yet, what do we miss when we reduce an entire community of creatures to the intensity of the green color they carry in their organelles?

Our physics envy also drives our desire for simple explanations, even when investigating things as complex as ecosystems.  We hope to find clearly defined causes for observed responses or patterns.  We believe that a simple explanation is necessarily a sign of ‘better’ science, but if life is not simple, why should simple explanations, simple hypotheses, simple rules be the expected outcome of investigating that life?  I am not suggesting that biologists throw away Occam’s razor, the maxim that when a simple and a more complicated hypothesis explain the observations equally well, the simpler hypothesis is the preferred choice.  But I am suggesting that we should not expect simple hypotheses to be sufficient explanations for reality in most cases.  We should be more skeptical of simple explanations than we sometimes are – if they seem too pat, they probably are.

It’s true that simple hypotheses make it possible to construct simple stories that serve to explain the living world.  But does that make those stories superior to more complicated stories built out of more complex hypotheses?  Simple stories can be too simple to be useful, but in a sound bite world, we seem to be forgetting this.  What is the likelihood of explaining a complex world when our simple explanations have been generated from data generated after stripping away the complexity that is always there in raw nature.  Biologists need to encourage their students to celebrate complexity, and be aware that simple stories will be rare when we study life.

The resilience of coral reefs

And so I ramble back to ecology of coral reefs, and two interesting papers.  The first, by Joe Pawlik of UNC Wilmington, Deron Burkepile of UC Santa Barbara, and Rebecca Thurber of Oregon State University, was published online April 27th in Bioscience.  The second, by George Roff and Pete Mumby of University of Queensland, appeared in Trends in Ecology and Evolution in 2012.  They both concern the factors determining the ecological structure of coral reefs and the resilience to disturbance possessed by reef systems.

The physical structure of a coral reef is generated by calcifying organisms, chiefly corals.  They are called coral reefs because corals are so conspicuous as members of the benthic community and because coral-derived carbonate rock is a major portion of the rocky structure itself.  In recent years, for a variety of reasons, many coral reefs around the world have become degraded.  The abundance of coral, usually measured as percent cover of the substratum, has been reduced, and foliose algae, along with other sessile invertebrates, have taken over much or all of the space formerly occupied by coral.  In some cases, it is known that the rate of accretion of carbonate rock, or ‘reef growth’, has fallen or ceased because of the loss of living coral.  The change through time is so profound that it is common to speak of a phase shift from a coral-dominated to an algae-dominated reef system.

reef Vladimir Levantovsky effervescent photography tfile_oceans_big_13

Does this look like an ecosystem that could be modelled as three boxes: coral, fish, algae?  The complexity of a coral reef is amazing even when you have visited thousands of them.
Photo © Vladimir Levantovsky.

A prominent hypothesis to explain this rather dramatic replacement of corals hinges on ecosystem resilience, the presumed competition for living space among the corals, algae and other sessile invertebrates, and the possible role of herbivory in keeping algae in check.  This hypothesis (I’ll call it herbivore-mediated coral dominance) states that on a healthy (i.e. coral dominated) reef, herbivory by fish, sea urchins and other small invertebrates, curtails the growth of algae.  When coral abundance is reduced in such places, whether by storms, bleaching, diseases or pollution, corals reproduce and regenerate and recovery is achieved – such systems are resilient to disturbances to the coral community.  In contrast, on degraded reefs, subject to overfishing (and associated impacts due to human activity and poor reef management), if coral abundance is reduced by storms or other factors, the growth of algae is sufficient to rapidly take over the vacated space, impeding recruitment of corals, and the system shifts into an algal-dominated state that is then resistant to shifting back to one in which corals are abundant.  The degraded reef has proved less resilient to loss of coral and has not been able to recover, largely because grazing on its algae was not sufficient to keep their growth in check.

There are places in the Caribbean for which the evidence largely supports this hypothesis, but the Caribbean itself is not uniform, and when we look outside the Caribbean, evidence to support this hypothesis is far less prevalent.  Roff and Mumby review many ways in which Indo-Pacific and Caribbean reefs differ, and note in particular that coral recovery following disturbance was far more prevalent in the Indo-Pacific.  Based on 41 separate multi-year studies of Pacific sites, and 74 studies of Caribbean sites, spread over the period from 1965 to the present, they found that 46% of Pacific studies but none of the Caribbean studies showed ‘recovery’.  (They defined recovery as a loss of at least 33% of initial coral cover followed by recovery of at least 50% of the amount lost.)

Clearly, reality is more complex than the simple hypothesis of herbivore-mediated dominance of corals suggests, and Pacific reality seems to have very little to do with this hypothesis.  Roff and Mumby offer six separate, though not mutually exclusive, hypotheses that might account for the differences in resilience, and in coral and algal abundances among reefs.  The first notes the very different growth rates among corals; species of Acropora, in particular, are fast-growing, while many other coral genera grow quite slowly.  While Pacific reefs support over 30 species of fast-growing Acropora, only two species of this genus occur in the Caribbean, and both have been substantially reduced in abundance since the early 1980s, chiefly through disease.  This first hypothesis suggests that herbivory on algae can only facilitate recovery of coral abundances following a disturbance if fast-growing coral species are available to rapidly occupy vacant space.  Otherwise, despite herbivory, algae will still occupy the space before slow-growing coral species are able to fill it.  Under this ‘Acropora loss’ hypothesis, the difference in resilience between Pacific and Caribbean reef systems is due to the relative lack of fast-growing corals in the Caribbean.

Their second ‘functional redundancy’ hypothesis begins with the much greater diversity of herbivores in the Pacific.  Among herbivorous fish, Caribbean reefs support only 4 species of one genus of surgeonfish, 15 species of four genera of parrotfish, and no rabbitfishes, while Pacific reefs support 84 species of 6 genera of surgeonfish, 83 species of 9 genera of parrotfish and 23 species of rabbitfish.  This hypothesis states that a richer herbivore group will do a more effective job of curtailing algal growth because each of the different species does different parts of the job best, but they all work together.  Thus, even when overfishing has suppressed numbers of herbivores, the richer Pacific groupings are still able to keep algae in check, while the depauperate Caribbean groupings are less able to do that.

Their next three hypotheses proposed all concern the possibility that algal growth is faster in the Caribbean.  Perhaps there is faster recruitment of algal propagules onto bare reef rock in the Caribbean (hypothesis #3), or there are more nutrients available in Caribbean waters, favoring faster algal growth (hypothesis #4), or trace elements such as iron that can limit plant growth are more available in Caribbean waters (hypothesis #5).  Any one of these three possibilities would result in more rapid occupancy of reef space vacated by dying corals on Caribbean reefs, regardless of levels of herbivory.  Finally, as their 6th hypothesis, Roff and Mumby suggest that the differences in composition and abundance of fish communities in the Pacific and Caribbean are such that there is a higher absolute rate of grazing on Pacific reefs, such that algal have difficulty supplanting corals even when disturbances briefly knock back coral populations.

Roff and Mumby discuss the evidence in favor of or against each of these hypotheses and end by advocating the need for experimental work to discriminate among them.  And there the matter has seemed to sit since 2012.

In the 2016 paper, Pawlik and colleagues begin by summarizing the results of Roff and Mumby.  They then provide several examples of sites in the Caribbean where algal growth has proved largely independent of abundance of herbivorous fishes, or may even be enhanced when fish are abundant, likely because fish excrete nutrients that facilitate algal growth.  Then, they introduce us to sponges.

Xestospongia muta Joe Pawlik

One of the large barrel sponges, Xestospongia muta, on a Bahamian reef.  Photo © J.R. Pawlik

Sponges are typically more abundant on Caribbean reefs than on Pacific reefs, and are mostly heterotrophic, while Pacific sponges are primarily phototrophic, possessing algal symbionts much as corals do.  Sponges filter feed taking particulate matter – both plankton and POC (particulate organic carbon, also called organic detritus) – from the water column, but can also absorb DOC (dissolved organic carbon).  Recent research has shown that the role of DOC in sponge metabolism is as, or more important than the role of POC.  In fact, sponge biologists talk of a “sponge loop” in which sponges feed on DOC while exuding POC in the form of cellular detritus which is ingested by corals and various detritus-feeding invertebrates on the reef.  Meanwhile corals and algae are exuding DOC back to the water column.

The “sponge loop” is analogous to the “microbial loop” that cycles DOC through plankton, and it is about here that I have to struggle to understand because I spent a reasonably successful career maintaining that one could be quite successful studying coral reef ecology without paying attention to anything too small to see.  I maintained that if it was so small you could not see it with the naked eye, it could not be important in the ecology of fishes, and for many years, my lab was a microscope-free zone.  In retrospect, I am sure I had blinkers on.

Pawlik 2016 coral reef resilience Bioscience

Diagrams showing the difference between Caribbean and Pacific reef systems.  In the Caribbean (top) there is an abundant inflow of DOC (red), plus nutrients from dust (green), and a number of trophic pathways among sponges, corals, algae, plankton and fish.  On Pacific reefs, there is less influx of DOC, fewer (and mostly phototrophic) sponges, and relatively weaker trophic pathways among corals, algae, plankton and fish.  Figure © J. Pawlik and Bioscience.

Anyhow, Pawlik and colleagues go on to point out that unlike plankton, sponges are able to metabolize refractory DOC as well as the (much less abundant) labile DOC used by other organisms.  Refractory DOC is common in river water, and the Caribbean basin is the destination of at least three major rivers, the Amazon, Orinoco, and Mississippi, which carry 30.7, 4.3, and 2.3 teragrams carbon per year (TgCyr-1) respectively.  Most of this large amount of carbon is refractory DOC.  They also refer to the abundance of African dust which deposits important trace nutrients, such as iron, in the Caribbean.  Putting everything together, they suggest that a major, neglected difference between Caribbean and Pacific reefs, is that the Caribbean reefs exist in a relatively small basin with an abundant supply of refractory DOC, and the reefs support lots of sponges that feed on this material.  By feeding on the flux of DOC, and then shedding detritus as POC, the sponges are serving as a mechanism for importing organic carbon to the reef system, thereby enhancing possible metabolic rates of various organisms there.

Why have Caribbean reefs failed to prove resilient and recover coral abundance following disturbances such as diseases that reduced coral cover?  Pawlik and colleagues suggest that the Caribbean is much more trophically dynamic than the Pacific, because of the sponges, and algae are capable of growing more rapidly as a result.  They can often overwhelm grazing by fish and rapidly capture space lost to corals.  This is especially the case if fish abundances have been reduced by overfishing.  In the much more nutrient-limited Pacific, algae cannot grow as aggressively, even when herbivory is reduced through overfishing.

Putting the two papers together, I see a number of plausible hypotheses to explain the differences between the Pacific and the Caribbean in the interactions of corals, herbivorous fishes, algae and sponges.  The hypotheses are not all mutually exclusive (several of the mechanisms could be acting together), and sorting amongst them will be challenging.  But science is always more fun when it is challenging, and reality is likely hidden among these hypotheses.  The simple herbivore-mediated model of coral dominance (remove parrot fishes and algae out-compete corals) is nice and tidy, but clearly does not cover the complexity of reality.  It is time to do some careful, experimental research to understand the resilience of coral reef systems.

The need for hypothesis-testing research

Hypotheses are just ‘what if’ statements.  They offer plausible explanations of observations about the way the real world works.  But hypotheses cry out to be tested.  Indeed, they are just the stuff of a beer-fed conversation until they are tested.  Most will be proved wrong, and that is how science makes progress – by proposing all sorts of plausible hypotheses, rigorously testing and rejecting them one by one, until one or more prove difficult to reject.  In my view, we reef ecologists are not spending enough time testing hypotheses in the real world, and our understanding of the systems we study is not advancing as rapidly as it could.  (And before anyone jumps up and down and puts out a fatwa on me, let me add that I am NOT suggesting that reef ecology has a weaker record than other fields of ecology or of biology.  That this field of ecology is strong justifies me in demanding it get stronger.)

The fact is, hypothesis-testing is difficult and it takes time.  Even the generation of hypotheses is difficult, and hypothesis-generation requires that you know your animals, or ecosystems.  Too many students today learned all they are ever likely to learn about sponges in half a lecture in an introductory course in invertebrate biology – if they even got such a course, now termed ‘survey’ courses to indicate how trivial, old-fashioned, and irrelevant such courses are.  (I think the situation has deteriorated, but the fact I was able to get through 65% of my career operating my lab as a microscope-free zone, shows that even in the Dark Ages it was possible to avoid vast areas of important science in the course of becoming ‘educated’.)  I learned a number of new things (for me) about sponges by reading the Pawlik paper – I guess it’s never too late!

Testing ecological hypotheses is difficult because you mostly cannot bring ecosystems into the controlled conditions of a lab.  Field experiments require considerable ingenuity, take time to set up, and often take long periods of time before results are obtained.  Ecological processes mostly do not operate on timescales of hours or days.

Often there are no realistically possible manipulative experiments that could be done to test a particular hypothesis, and thus ecologists look for ‘natural experiments’ or use simulation models as alternative approaches.  Neither is as powerful in rejecting hypotheses as a real experiment, and tests using models, while they produce beautiful results in minutes or hours, are only as powerful as the models themselves.  If you do not know about sponges, you’d probably model the resilience of a Caribbean reef with only fish, corals and algae present.  No model can reveal the importance of particular processes, or organisms, if those processes or creatures are not included in the model!  I know we can use a combination of models, natural experiments and real experiments to test ecological hypotheses for coral reef systems – it’s been done before – but we absolutely have to know our reefs to design those tests.  Too few of us know our reefs.

field experiments

Field experiments come in many shapes and sizes.  MIT students sampling sponges were working from the underwater habitat, Aquarius, off the Florida Keys, as was the Georgia Tech student checking herbivore cages.  In the center, University of Queensland scientists monitor an ocean acidification experiment on the reef flat at Heron Island, GBR.
Photos L to R © MIT, MBARI, Georgia Tech

And so I plead for spending more time in the field learning about the ecological systems we want to study.  More field time for undergraduates, far more field time for graduate students and post-docs, and reasonable amounts of field time even for established researchers.  Not field time to run experiments, or carry out sampling programs that were dreamed up months ago, high and dry, while writing an imaginative research proposal, but time to tinker, to poke and prod, to watch and think about the system being studied.

I suspect I am swimming against the tide.  Gone are the days when graduate students got set free on a coral reef.  Now every hour of field time costs money and every dive requires an approved dive plan, multiple extra people to ensure safety, and sufficient pre-dive planning of the science to be done to ensure that every minute is productive.  Looking around, wondering, and even trying a few things out just for fun is frowned upon – we must operate more like armies marching into battle than as the curious, enquiring scientists we are supposed to be.  And yet, if reef science is going to provide new tools for more effective management, we need to be solving the critical questions.  To do this, we need to know our chosen ecosystem.

Bleaching of the Great Barrier Reef

The recent GBR bleaching has proven to be quite severe.  That it impacted the remote northern third of the region so severely does not portend well for the global future of coral reefs.  Yet I have hope that some good may come of it because of the effort made by the Australian marine science community to document it, and to follow up with longer-term study of what happens after the bleaching is over.  That it was scientist-driven, and knowing a number of the scientists involved, gives me hope that something more is going to result than a precise description of just where, when and how much reef was lost.  Such information can be useful, but we need to get beyond simple monitoring of the collapse of coral reefs.  I hope that there will be plenty of effort during subsequent months and years to document the recovery, and to test competing hypotheses for what is happening and why.  Only in this way are we likely to generate a sufficient understanding of how reefs respond to a warming climate that we will be able to generate realistic approaches to mitigate damage or to assist reefs to recover.  There are going to be more bleaching episodes on coral reefs, and our future looks increasingly likely to be one without coral reefs.  Even if that dismal possibility is the eventual outcome of our current enthusiasm for fossil fuels, it would be nice to know that the reef science community did all it could to understand what was happening and seek remedies.

Overall, I hope to be pleasantly surprised by the quality of coral reef science that will be on display at the 13th International Coral Reef Symposium in Honolulu in just four short weeks from now.  I dream of being proved completely wrong about the extent to which our current crop of reef researchers know their animals and ecosystems.  Maybe coral reef science is far more robust than I give it credit for.  But if so, shouldn’t somebody be busily testing that multiplicity of hypotheses that Roff and Pawlik and their colleagues have presented?  And shouldn’t there be wider recognition that the simple herbivore-mediated model of coral dominance is way too simple?  And shouldn’t we be making a major effort to understand the consequences of a global pattern of enhanced frequency of bleaching events?  And shouldn’t we all know that there is lots we do not know about this amazingly complex ecosystem, and be trying to learn more?

If we only manage to monitor the progressive decline of coral reefs as successive bleaching events occur, we will simply be monitoring one important aspect of the sixth extinction.  A detailed documentation of the step by step, species by species, set of extinctions that form the sixth extinction could be a mammoth undertaking that would take many scientist-hours, but it would also be of little real value after it is all over.  I’ll have my fingers crossed for Honolulu.

pygmy seahorse 6th-m-ocean-art-2015-alexander-franz-1200

There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy.  Incredible image of a pygmy seahorse.  Photo © Alexander Franz.

Categories: Biodiversity Loss, Climate change, coral reef science, Stories from a Coral Reef | Leave a comment

Wildfire – Just One More Gift from Climate Change.

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The Fort McMurray fire

The Canadian news this past week has been filled with harrowing tales of the plight of people caught up in the Fort McMurray wildfire, and reports have spilled over into the international press.  It began the afternoon of Sunday May 1st when two blazes erupted southwest of Fort McMurray, a city of 80,000+ people, in the heart of Alberta’s tar sands country.  One fire was brought under control, but the other worsened and an initial voluntary evacuation order was issued for one suburb, Gregoire, on Sunday afternoon.  Firefighters continued to battle the fire and the voluntary evacuation order remained in place through Monday, primarily because of air quality concerns.  By late Monday the fire had consumed over 1000 ha of bush.  Conditions worsened on Tuesday with continued hot, dry weather and high winds.  What had been a voluntary order became a mandatory evacuation order extended to several suburbs.  By Tuesday evening the order was extended to the entire city.

Wildfire_near_Highway_63_in_south_Fort_McMurray_May42016_leadimagesize DarrenRD

People fleeing Fort McMurray on 4th May via Highway 63, as flames fill the sky.
Photo © DarrenRD CC-BY-SA-4.0

Some people, leaving on Monday and Tuesday had headed north towards motels and accommodation facilities associated with various mining corporations.  These people had to move again, going south of the city this time, as did people who had gone to the first evacuation center set up just south of the city.  The fire kept changing direction as the winds swirled around.

On Wednesday May 4th the Province declared a state of emergency and the fire continued to grow.  Mandatory evacuations were extended to several locations surrounding Fort McMurray. About 10,000ha of land had now been burned, and at least 1600 homes had been destroyed.  The fire was burning so hot that trees were exploding into flame and the fire was generating its own winds and lightning.  The fire continued to grow, and had consumed 85,000 ha by May 5th, 100,000 ha by May 6th and 156,000 ha by May 7th.  As of May 9th, it had expanded to 204,000 ha, and was moving north-east towards the Saskatchewan border, away from the city and most of the oil infrastructure.  Some 2,400 homes have been destroyed but over 80% of the city and all critical infrastructure has been saved.  Nevertheless, the situation remains dangerous, and it will be some days or weeks before people are able to return home.

Wildfires continue burning in and around Fort McMurray, Alta., Wednesday, May 4, 2016. (Jeff McIntosh/CP)

Fort McMurray is invisible in this photo of the fire taken on 4th May.  Image © Jeff McIntosh/CP

One atypical consequence of the Fort McMurray fire has been its effect on the global oil supply.  Because of the extreme fire risk, and because many of their staff were busy trying to save, and then to flee from their homes, tar sands operators shut down pipelines and suspended production and upgrading operations.  About 1 million barrels per day of oil production is on hold until the worst of the danger passes.  Fortunately, from an economic perspective, the relative soft global oil market has weathered this disruption relatively easily, but Canada’s GDP growth expectations have been further scaled back by economists.  The irony of the ‘climate-change leads to severe wildfire in the heart of the tar-sands’ has not gone unnoticed in Canada, but fortunately most of us have had the decency to focus for now on the plight of the thousands of displaced people.

To give a sense of the size of this fire, Maclean’s has published a series of maps showing the burned area superimposed on several cities elsewhere in North America.  It is a big one.

Vancouver & New York vs FM fire

Area burned by the Fort McMurray fire at May 4th (dotted black line), May 5th (red line), and May 7th (pink area) superimposed on maps of Vancouver and New York.  Images © Maclean’s.

Wildfire on the rise

Nor was this the only wildfire in Canada last week.  Across Canada, until last week there had been 1,156 fires reported this year which together damaged 53,000 ha.  Of these 149 were currently active, 15 out of control.  The number of fires to date is almost twice the average, and the area burned is ten times the normal rate over the past decade.  Currently, there are 5 significant fires burning in British Columbia, 29 in Alberta, 17 in Saskatchewan, and two on the Manitoba-Ontario border.  While most are human caused, the exceptionally warm and dry weather that western North America has been experiencing this year is what has set the stage for an exceptional year.  That hot, dry weather is a result of el Niño and climate change.

The link between wildfire and climate change is not one that permits us to say ‘this fire was caused by climate change’.  Climate change alters fire risk, making the likelihood of fires greater.  Individual fires are still caused by appropriate weather and forest condition, and by lightning or human carelessness to provide the ignition, but with climate change these conditions occur more often.

One of the many consequences of climate change is a heightening of wildfire risk in many regions.  With warmer weather comes increased evaporation leading to dryer soils and plant material.  Early in the spring, prior to leafing out, forests can become particularly dry if there is no rain, and that is what has happened in western Canada.  Even in central Ontario, where fire risk is generally low relative to more northerly locations because of the generally more mesic conditions, Natural Resources Canada estimates a significant increase in fire risk by mid-century.  In a 2013 paper in Ecological Applications, Yan Boulanger of the Laurentian Forestry Centre, Canadian Forest Service, and five colleagues, provided estimates showing that in the central Ontario region where I live (Muskoka and points north), the fire incidence, measured as number of wildfires per 100,000 ha per year was likely to increase from 0.01, the average over 1961 to 1990, to 0.06 by mid-century, while the annual area burned would grow to 0.19% per year from its average from 1961 to 1990 of 0.03%.  These increases are both about 6-fold, a substantial increase in fire risk even if it remains relatively low compared to that at points north or west.

Nor is 2016 the first year that increased wildfire occurrence has been seen.  The fires in Saskatchewan in 2015 were similarly memorable, and other countries have witnessed similar increases.  The current rate of deforestation in south-east Asian countries is high because climate change increases risk of fires getting out of control.  And Australia was experiencing extreme fire conditions several years ago during hot summers.  The record fires in Victoria in 2009, at that time the worst in Australian history, claimed 163 lives and caused more than $4 billion in damage.  Serious fire hit Australia’s south-east again in 2013, and record fires hit South Australia in 2015.  While serious wildfire has long been an Australian given, the sense there is that fires are becoming hotter, bigger, and more destructive, and that climate change is to blame.

Apart from the damage, and risk to life, that wildfires can cause, fire liberates vast stores of carbon locked up in forests thus adding to our greenhouse gas problem.  Indeed, in Canada, the shift towards more frequent and more extensive fires could be a major impediment to achieving our tepid commitment on emissions reductions under the Paris Accord.  Those commitments are already proving a difficult task and an increase in wildfires makes their achievement even more difficult.  Canada’s emissions reduction plans, such as they are, have relied to a large extent on improved management of forested lands to contribute by using forests as effective sinks for carbon.  But as our fire risk rises, there is real danger that our forested land (remember, Canada holds the world’s largest extent of boreal forest in the world) will become a net source of CO2, meaning that we will have still more emissions to curtail to bring total emissions below 2005 levels.  Of course, I expect that Canadian politicians will turn themselves into pretzels maintaining that emissions due to wildfire should not be counted, but the fact remains that the emissions will be there and they will be warming the planet.

And then there is water

Climate change leads to many different changes in our environment.  In my immediate neighborhood, the pattern of precipitation is set to alter during the remainder of this century so that we will get about 10% more rain and/or snow by mid-century, but with a shift in seasonality of precipitation to favor the winter and spring.  As a consequence, as reported in a recent report from the local Muskoka Watershed Council, our winters are set to become much wetter, while our summers and falls are going to be dryer.  (The drying results, not from reduced rainfall during those months – the rainfall in summer and fall is not expected to change much at all – but by increased evaporation and transpiration due to the warmer weather.)  As a consequence, the pattern by which water flows through our ecosystem – the hydrology – is set to become substantially different to today.  This changed hydrology is likely to lead to greater risk of severe flooding in late winter and spring, and a much reduced flow during summer and fall.  The more seasonal flow will impact local, small-scale hydroelectric power generation; the health of our wetlands, streams, and rivers; and the maintenance of lake levels on our recreational lakes.  I find the fact that many seasonal residents are currently demanding that ‘the government’ do a better job of maintaining lake levels, and preventing spring floods, somewhat amusing – no level of government is mandated to keep lake levels constant here, and even if one were, that task will likely become impossible within a few decades.  When flow is strongly seasonal, you cannot keep water levels constant.  (Those readers who live near tidal water may find the whole idea of a constant water level peculiar – I agree with you.)

Submerged-Dock Rosskokadotcom

The ‘culture’ in my part of the world increasingly assumes that water levels in lakes remain constant, even during the spring thaw.  They do not, as this submerged dock reveals, and with climate change making water flow markedly more seasonal in this region, seasonal fluctuations will become more extreme than at present.  Photo © Rosskoka.com.

In many parts of the world, the effects of climate change on hydrological systems are becoming profound.  Present day migrations from North Africa and the Middle East, while usually reported in terms of societal disruption and strife, are more fundamentally caused by the progressive drying of that large part of the world, a drying that will continue as climate warms.  It was crop failures that triggered the movement of rural people to the cities of Syria as failed farmers looked for work to buy food for their families.  The increased pressures in crowded cities led to tension, to relatively ham-fisted crack-downs by authoritarian governments, to civil war, to IS, and to mass migration as people look desperately for a place they can eke out some sort of existence.  As climate changes, such causal sequences will repeat in other places.

The progressive drying of the American south-west would also lead to mass migration were it not for the fact that mostly Americans can afford the infrastructure to pump water from deep underground, or pipe it vast distances from places where it is more plentiful to places where it is not.  But North America is over-using its aquifers, and these vast stores of water, accumulated through millions of years, are being diminished, while surface supplies are being stretched far more than they should be.  There are many things California should be doing with respect to water, including far tighter regulation of the amount used in agriculture, or to wash cars or keep lawns unnaturally green, but mostly, at present the approach still seems to be to improve the delivery systems rather than to reduce demand.  An ironic example of the complexity of this issue: Saudi Arabia is leasing land in California to grow forage for livestock back home – compared to the Middle East, California has lots of water.  As climate changes there will be ever more stories of water shortage and water conflict in the US south-west, and the amount of water available to use will inexorably decline.  Given that California agriculture contributes 13% of US agricultural products, and 14% of US agricultural exports, climate change could have substantial impacts on food prices and food availability in many places, simply because it is likely to further reduce water availability in California.

So, fire and water; that only leaves earth and air, and climate change affects air directly, not least by warming it and enhancing the likelihood of more violent storm events.  So what about earth?  One of the first ways in which rising sea level has impacts on the land is through salt water intrusion into groundwater.  We often hear that small Pacific island nations are at danger of sinking forever beneath the sea due to climate-caused sea level rise.  The image of an entire small nation disappearing beneath the sea in an Atlantis reenactment captures the imagination, but this is only the final step in the onslaught by a changing climate.  Salt water intrusion can make fragile island aquifers unsuitable for agricultural or human use long before the island nation disappears beneath the waves.  Reduced rainfall (especially on low islands which typically have low rainfall) can impede groundwater recharge sufficiently that human use rapidly exhausts the resource.

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Funafuti atoll, the capital of Tuvalu, has an average elevation of 2 meters.  Low-lying islands like this are most at risk of saline intrusion into aquifers as sea level rises.  Photo © Worldatlas.com

In 2014, a Geoscience Australia science team undertook a climate change vulnerability assessment for the islands of the Pacific.  For both low rainfall and sea level rise impacts on groundwater, they showed that low islands characteristic of atolls had the highest vulnerability, and for many islands of this type, throughout the Pacific, that vulnerability was very high.  Climate change will create severe water stress on such islands long before sea level rises sufficiently to permanently erase them.  That does not make the situation for small island nations any easier; it makes it a whole lot more difficult.  While some mitigation is possible with careful management of use of aquifers, small, low-lying islands will lose their aquifers eventually – this is a climate-induced problem for which there are no real solutions.

Let’s remember also that low-lying, coastal plains, supporting some of the most fertile productive land around the world, while less poetic than tiny tropical islands, will also suffer salt water intrusion as climate changes and sea level rises.  These lands will lose their fertility to the detriment of millions of humans dependent on the agricultural products grown.

I started talking about forest fire.  I’ve ended with images of tiny islands running out of fresh water.  Climate change is real.  It is happening now.  It will get worse if we do not rein in our emissions of greenhouse gases.  Its effects on our environment and our lives come in many different forms – physical, biological, sociological, economic.  And some of those effects are problems for us that have no solutions.  The challenges of adapting effectively to a changing climate are profound, and not always solvable.  Better to do our level best to halt climate change in its tracks.

Categories: Canada's environmental policies, Changing Oceans, Climate change, In the News, Tar Sands | Leave a comment

Have We Already Tipped? My growing concern about the challenges we face.

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The scientists at the Scripps Institution of Oceanography who manage one of the two sets of instruments atop Mauna Loa (NOAA manages the other set) announced on April 20th that concentrations of CO2 exceeded 409 ppm for the first time in recorded history.  While concentrations will soon fall slightly as a summer of photosynthesis commences in the northern hemisphere, they are unlikely to dip below 400 ppm again until we significantly reduce emissions.  Meanwhile, the rate of increase of the overall level is faster than it has ever been.  Looking at things more broadly, the planet has not seen levels of CO2 this high for several million years.

March 2016 global temp NOAA

Like a raging infection – the planet’s fever just keeps on going.  Image courtesy NOAA.

Temperatures are also at record highs.  NOAA’s latest monthly global analysis reports that the combined land and ocean temperature in March 2016 was the warmest on record (since 1880) at 1.22oC above the late 20th century average, and that it exceeded the previous record March (set only last year) by the largest increase (0.32oC) ever for any month of the year, beating out February 2016, the prior record holder.  Further, March 2016 is the 11th consecutive month of record high temperature, the longest such run in history.  Record warmth was present in the northern and in the southern hemisphere, on land and in the ocean and in most individual countries.  The combined temperature over the first three months of 2016 is also the highest on record.

While the record temperatures are partly a consequence of the now-weakening el Niño, which is itself turning out to be the longest, and possibly also the strongest el Niño ever recorded, they are also a reflection of our continued emissions of CO2.  We are doing a very effective job of warming the planet, and along with the warming come other changes.  The drought in California and other parts of the US south-west continues despite some good rains courtesy of el Niño.  The rains just were not good enough and snowpack in the Sierra Nevada was just 87% of average levels when it peaked in late March.  Despite the fact that aquifers have not yet come close to being replenished, demands to lift the water conservation measures introduced are becoming louder – Californians need to wash their cars.  Aljazeera has written of a “state of chronic drought” in the American south-west.  In the Arctic, for the second year in a row, ice formation this winter has fallen short and the maximum extent is a new low.  The National Snow and Ice Data Center has announced that the maximum extent was achieved on 24th March at 14.52 million km2, 13 thousand km2 less than the previous record set just last year.  With more open water, the Arctic warms more rapidly.  I think we are beginning to see a pattern here – a world warming rapidly out of control.

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Sea ice in the Arctic, summer 2015.  Image © Stefan Hendricks

Record coral bleaching

The el Niño has now ushered in the longest continuous global coral bleaching episode in history, and bleaching is not over yet.  I covered the bleaching of the northern Great Barrier Reef in my last post.  While the heavily damaged Great Barrier Reef is now experiencing less warm conditions, bleaching has recently started on the western Australian reefs, and can be expected to march through the Indian Ocean over the next few months, before cropping up again in the Caribbean and northern Pacific this summer.  One begins to wonder if there will ever again be a pause – a month or two with no bleaching on any reef anywhere – before the last of our coral reefs succumb.

The el Niño can also be blamed for severe forest fires in the Philippines, Malaysia and particularly Indonesia.  One consequence of these fires (which are largely human-set, but aided by the dry conditions set in place by el Niño) is an enhanced rate of CO2 emissions, a spike in atmospheric CO2, and yet more warming.  Oh yes, the melting of glaciers proceeds, and may now be unstoppable.

And then there are the other environmental stresses

In the oceans, sea level is rising faster, and pH is falling as CO2 leaks in from the atmosphere.  Coastal dead zones are not going away, and there are signs that the oxygen minimum layer of the open ocean is expanding as waters warm.  Anoxia and low pH have been features of the oceans in every prior mass extinction event, and the oceans have typically taken several million years to recover.

On land, we continue to eliminate forests.  While FAO, always being optimistic, is quick to point out that the rate of deforestation has fallen significantly in the past 25 years, the world lost 129 million ha of forest since 1990.  That is an area almost the size of South Africa.  The actual loss of natural forest (including regenerated as well as old growth) was nearly double this (239 million ha) because a lot of natural forest is being replaced by other forms of treed land including palm oil plantations.  Current deforestation rates generate 1.5 Gt CO2 in emissions each year, and the total amount of forested land is 3.2% less than in 1990 with most of these losses in the tropics.  If we could grow our forested land, we could create a significant new sink for CO2.  We also continue to overuse freshwater supplies, overfish many fishery stocks, and continue to pollute air, land, and water.  Needless to say, the threat to biodiversity is undiminished, but I doubt many people will see biodiversity loss as troubling until we get a lot further down that particular slippery slope.

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Corcovado, Costa Rica.  Forests are a major refuge for biodiversity.  Photo © Matthew Karsten

Our population and economic growth

Currently 7.4 billion of us live on this planet.  Our global growth rate has continued to fall since 1962, when it stood at 2.1% per year, but despite this, we expect to number an additional billion in 2030, reach 9.5 billion by 2050, and 10.9 billion by 2100 – that is a 47% increase in numbers between now and then.  Most of this increase is coming in Africa, South and Southeast Asia.  We can be cheerfully optimistic about the declining rate of increase and the fact that global population is expected to peak sometime around 2100, or pessimistic about the growing demands on our environment that 3.5 billion more people will impose.

Our global economy is also growing, in part simply because of population growth.  Global per capita GDP is also growing, however, as individuals on average become slightly richer.  While per capita GDP scarcely grew at all during the 1000 years prior to 1950, it has been growing more or less continuously ever since with the world average now about $8000 per year.  Economic theory vested in ensuring positive GDP growth is in wide use.  The standard economic argument is based on the premise that economic competition inevitably increases economic efficiency, so that goods of more value are created with less labor and materials.  In order to ensure continued employment, it is therefore necessary for societies to ensure growing economic production so that the amount of labor required does not diminish.  If the population is also growing, maintenance of employment requires still more economic growth, and if there is a trend towards increasing income inequality, the rate of economic growth needs to be kept even higher to ensure that the 99% do not become disillusioned with their lot in life and prone to social unrest and violence.  So long as we continue to live within this paradigm, we are condemning ourselves to an increasingly fruitless search for increased economic activity, with all the additional stresses which that growing economy places on the environment.

From the perspective of environmental science, I see the growth in population and economic activity as major impediments to any attempts to bring our unsustainable use of the environment under control.  Our global economy is now sufficiently large that it results in the emission of about 36 Gt CO2 per year to the atmosphere.  As the two graphs below show, emissions due to our global economy seem to have only just leveled off despite the fact that emissions intensity has declined about 30% since 1990.  While results for 2014 and 2015 make me optimistic that we are starting to divorce economic growth from emissions (decarbonizing), two points do not make a trend, and I do not think we are able to claim that emissions from economic activity are now declining.  The projected 47% growth in our population during the remainder of this century is going to demand at least that much growth in the global economy, even setting aside any desire for continued growth in individual wealth.  (In this increasingly unequal world, there will either be substantial wealth redistribution or an effort to ensure continued increase in per capita GDP, so I am betting we are looking for an overall growth in excess of 47% for global GDP by 2100.)

CO2 emissions due to energy use global

CO2 emissions due to economic activity have been strongly linked to GDP growth over the years, however reduction in carbon intensity (decarbonization) due to the shift away from use of fossil fuels, and to the shift in the economy away from resource-intensive manufacturing is now making it possible for emissions to grow less quickly than the economy.  Figure © Global Carbon Project.

emissions intensity trend 1990-2015 Guardian 1105

Graph showing the improvement in emissions intensity of the global economy since 1990, and the growth of emissions over the same period.  We would have to reduce emissions intensity far more than this to counteract the anticipated growth in the size of the economy during the remainder of the century.  Figure © Nature Climate Change.

At the present time, increasing global GDP by 47% must result in a substantial (though less than 47%) increase in the energy required to sustain that activity.  Doing this while simultaneously bringing CO2 emissions down to near zero appears to be a gargantuan task.

The growing population and growing economy do not just impact the environment through CO2 emissions.  There is the 47% more food, 47% more potable water, and 47% more living space required for the larger population, never mind the increased demand for other resources to sustain the economic growth.  Looking at our situation from this perspective is almost enough to cause me to roll myself up in a tight ball in a shady corner and try not to think about reality.  And yet, we do need to look at our situation in its totality, and recognize just how great a task we have in front of us.

For a start, I believe that the world community should be ramping up efforts to speed up the demographic transition in those parts of the world where fertility remains high.  Far better for all of us to “fail” to achieve a world population of 10.9 billion by 2100 by accelerating the decline of fertility than by subjecting millions of people to the inhuman hardship of abject poverty in a world economy that is unable to grow fast enough to raise their standards of living.  Such a “failure” might permit us to live with dignity in a global economy that is not half again as large as it is now, and an economy that has found effective ways to make money on activities that repair the ecosystems on which we depend, in place of the economy which thrives on environmental despoliation.  In any event, our environmental challenge (which is only partly a climate challenge) must be viewed in the context of our population growth and our global economy, both of which make the challenge a good bit bigger.

Nations do not yet understand the true extent of our environmental challenge

The true message of climate change has not got through to the rank and file of the political class, never mind the masses of ordinary people.  Scientists who present truly alarming long-term projections of such things as glacier melting are dismissed as “extremists” while scientists who present their results more cautiously, and with an optimistic tone, are seen as talking about “environmental” issues – issues that are important, but not as important as jobs, energy, national security.  Environmental issues are not existential.

Most people who are not scientists can remember that we have solved many environmental problems in the past, and will surely solve such problems in the future as well.  Few people who are not environmental scientists recognize how deeply entwined environmental problems can be with our lives.  For example, our growing population suggests we will need more arable land to provide food for the extra 3.5 billion people expected by 2100.  A sea level rise of 2 meters will wipe out vast areas of currently fertile lowlands, and the changing climate will increase aridity in many agricultural regions.  These problems have a nasty habit of coming together to make things really, really difficult.  The notion that things might become so difficult that a desirable solution is not attainable does not seem prominent among most who think casually about such things.

Trudeau signing Paris accord 22 Apr 16 Mary Altaffer-AP

Canada’s Justin Trudeau signing the Paris Accord, Earth Day 2016.  Photo © Mary Altaffer/AP

On Earth Day 2016, there was a big ceremonial signing of the Paris Accord at the UN offices in New York.  Many world leaders were present to add their names and say a few inspirational words.  Most nations will have to ratify these signatures over coming months.  It was a wonderful photo op, but it did nothing for our climate except to add a few more tonnes of CO2 to the atmosphere as all those dignitaries flew to New York and back home again.  Canada’s new climate-positive Prime Minister was there trying to show that with the change of government last October we have got our groove back on the environmental front.

But have we?  Canada’s Intended Nationally Determined Contribution (INDC) to reducing emissions under the Paris Accord is a 30% cut in emissions from 2005 levels by 2030.  It was determined during the Harper administration, has been widely criticized as one of the weakest commitments among major emitters, and is a commitment for which we do not yet have adequate policy in place.  Currently, we are on track to fail to achieve the timid goals set by the Harper government, and Justin Trudeau’s new government knows that.  I hope he, and his Minister for Environment and Climate Change, Catherine McKenna, do lie awake some nights wondering how they are going to bring the nation kicking and screaming towards some actions that will meet, and then greatly exceed this goal, because failing to achieve Harper’s goal would be an ignominious defeat.

They will have their work cut out for them.  Leaders of some Provinces – British Columbia, Quebec, Ontario – feel they have done quite a bit already, and are not in the mood to do more before the rest of the country catches up.  Others – Alberta, Saskatchewan – are pleading for compassion while they cope with economies in considerable disarray following the collapse of the oil boom, and talking optimistically about how things will be better once oil comes back.  Rachel Notley, the leftist Premier of Alberta, who came to power as the oil boom was collapsing, has moved rapidly to the right, struggling to put in place some measures to curtail CO2 emissions, while still protecting the damaged, but politically powerful oil sector.  (She did not move as far to the right as the government she replaced, but her response to the need for a price on carbon has been timid, so far.)  Taxes on emissions during production of tar sands crude are coming, but slowly and gently, because everyone in Alberta, apparently including Notley, is under the illusion that growth in the tar sands will begin again soon.

Canada has to reduce its emissions by 30% by 2030, but the pace of reduction must continue and be rapid enough to bring emissions to just 20% of 2005 levels by 2050 if the goal of keeping warming to no more than 2oC is to be achieved.  These calculations assume that the world will continue to allow Canada to “use” its current, overly large share of “emissions space”, rather than a smaller share appropriate to its population (and countries like India and China may have some thoughts on that matter).  Any hope of getting to the aspirational 1.5oC maximum temperature increase (which Catherine McKenna, to her credit, pushed for in Paris), requires that Canada bring emissions down effectively to zero by 2050.  (See my earlier post on the challenge Canada faces, and also the excellent analysis by Drs. Simon Donner (UBC) and Kirsten Zickfeld (Simon Fraser U).)  Bringing emissions to zero by 2050 is not compatible with being gentle on the oil and gas sector during their time of travail.  The quicker Canada’s fossil fuel industry winds down the better.

If Canadians can pull their heads out of the tar sands for just a moment and look around, it should be clear.  The train has left the station.  There will be some recovery in the Canadian oil sector, but it will not boom because tar sands oil is too expensive to extract, and demand is going away.  Either that, or there is going to be a boom just before we finally tip into climate catastrophe.  Since I do not want catastrophe, I will continue to argue that we have all the pipeline capacity we need for the oil sector of the future, and I’ll also advocate for a national carbon tax that 1) establishes a carbon price no less than the average of the British Columbian and Quebec prices, 2) that is broadly based to capture all sectors and uses, and 3) is one that increments annually.  This tax should be reduced or waived completely in those parts of the country which have a comparable price in place.  Without the price, we Canadians are simply not going to reduce our emissions.

I’ve frequently commented on the similarities between Australia and Canada.  Australia should have one advantage over Canada in coming to grips with the need to reduce CO2 emissions.  It cares for, and deeply values, the Great Barrier Reef.  Yet, in Australia, in the midst of the worst bleaching the GBR has ever encountered, governments are actively promoting the coal industry and shipping and dredging to get the coal through the GBR to India and China.  The current bleaching on the Great Barrier Reef is turning out to be the worst bleaching experienced there, and has been particularly surprising (and deeply disappointing) to scientists because the worst-affected region has been the far north, that part of the reef system that is most remote, least impacted by tourism, fisheries or on-shore pollution, and therefore most likely to be able to resist warm temperatures successfully.  Yet the Australian press is filled with pious assurances from political leaders about their concern for, and recognition of responsibility to care for the reef, similarly pious claims to climate purity, and proud announcements of major new international agreements to mine and export large quantities of coal, shipping the coal through newly built ports along the Queensland coast.

To a Canadian, the Australian governmental claims re climate have an eerie Harperian tone, while the claims about caring for the reef sound much like the words any not-particularly-green politician spouts on opening a new recreational area, national trail, or wildlife reserve.  Nice green words.  What is interesting about Australia from my perspective is that they are getting increasingly close to a national election, and the coverage of the destruction on the Great Barrier Reef has been extensive.  Will it make a difference, and will Australia begin its march back towards environmental responsibility.  Time will tell.

Finally, we should reflect very briefly on the political circus just south of Canada.  The world’s capacity to reduce CO2 emissions sufficiently absolutely requires that the USA play a leadership role.  Its 6.9 GtCO2 per year mean that the USA cannot be ignored, and the rest of the world cannot keep the planet within 2oC without the USA playing its part.  Yet, the USA seems to have ample people still in total denial, including a majority of both houses of the Congress.  One leading candidate for President believes CO2 is harmless or good (Cruz), another (Trump) has no coherent climate policy, others would rather not talk about it, and Congress and many States are actively attempting to block the imposition of modest CO2 caps on power plants.  Unlike Canada, the USA has been making steady if modest progress in decarbonizing its economy, but progress on the climate front has been driven by a committed President who has faced obstruction at every turn.  There will be an election in the USA in November.  Who they choose as President will be important, but equally vital will be the composition of the Senate and the House of Representatives.  Our global struggle to keep the planet habitable could be aided, or brought to an abrupt halt by what happens in millions of polling booths across the USA this November.  Just a little scary, right?

So, have we already tipped?

I began by asking if we had already tipped or not.  In the real world, there are tasks that turn out to be too difficult to accomplish.  The task of wrenching the atmosphere back to the state it was in in the mid- to late 1980s (with CO2 at 350ppm) could be one of these.  It is a gargantuan task that cannot be done by a single actor, a single team, a single nation acting alone.  It is a task with definite societal costs as well as opportunities, and progress to date does not inspire confidence that the world community is up for it.  If we fail, the Anthropocene will prove to be a very different kind of place and we will come to look back at the Holocene with nostalgia.  We will also likely have to settle for a less equal world, and a world in which even the best laid plans by the most honorable of people will sometimes fail because the environment, far from being the stage on which we people act out our lives, will be a violently thrashing entity, tossing us about like the puny primates we are.  We will likely survive, but culture, civilization, and humanity will all be severely strained.  I hope we have not tipped onto that dismal path.  Time will tell.

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Categories: Arctic, Canada's environmental policies, Changing Oceans, Climate change, Coal, Economics, In the News, Politics | 2 Comments