Tipping Points – There Are Good Ones Too


Environmental scientists have come to use the term ‘tipping point’ as shorthand for the time, or set of conditions, at which a rapid phase shift in an ecological system commences.  Nearly always, they talk about phase shifts from a preferred to a far less preferred state.  Tipping points are bad.  But there can be good tipping points as well, when a system suddenly begins to shift from a bad to a better state.


Depending on your point of view, the tipping point on a roller coaster is either the start of an exhilarating journey, or a brief moment of abject terror.  Photo – Cedar Point, Ohio.

There are tipping points also in the affairs of men.  (And, yes, the sexism in that anachronistic phrase is deliberate, because most such tipping points in the past have been driven by the actions of male leaders.)  Canada seems to be at a good tipping point in its attention to climate change, under the leadership of its feminist Prime Minister and his female Minister of Environment and Climate Change (I don’t really believe gender or attitudes to same have much to do with this, but…).  The change in attitude and the growing momentum for action is very welcome; it is not happening too soon.

I first sensed a shift in our national mood re climate back in February.  I’ve commented twice on it in this blog.  A little over a week ago I participated in the Muskoka Summit on Environment, a two-day, biennial event in this tiny part of central Ontario, and the atmosphere, as well as the comments by the six invited speakers, were uniformly positive about the possibilities for curtailing climate change and the opportunities for Canada in playing a responsible, even a leading role, in that process.  The change in attitude from just eight months ago is amazing, and testament to the power of an election to alter a nation’s trajectory.  Australia take heed; you’ve been a distressingly effective partner to Canada on the world stage as your leaders and ours jousted in a friendly way to see who could rack up the most Fossil awards at climate conferences, but that duet is over.  Now you have the opportunity to continue as Canada’s partner in a completely different performance.  A lot will depend on what happens in your coming election, but you too can find your own tipping point to progressive, positive action on the climate file.

So, why am I so over-the-moon positive today?  It’s not because Canada has achieved some real progress on climate – we are just starting to move.  It’s because of the dramatic change in the political conversation.  Canada is seriously discussing the inevitability of a transition away from fossil fuels, and the benefits of making that transition rapidly.

Two important reports

Two reports became public at the end of May.  The first I heard about this was on May 30th when the CBC reported on a draft document prepared by Policy Horizons Canada a Federal think-tank that prepares medium-term policy advice for the government of Canada.  This document, Canada in a Changing Global Energy Landscape, reviews the state of the global energy market and trends as various countries transition towards renewable sources.  Its major conclusion is that the transition away from fossil fuels is likely to be a lot faster than expected, and that this will particularly affect high-cost fossil fuel producers such as Canada’s tar sands.

The authors argue that the transition towards renewables is being driven by three factors: reduction in prices for renewable technology, the growing digital economy, and leap-frogging by developing countries as they add new technology.  Advances in technology and economies of scale are reducing the cost of renewables-based electricity far more rapidly than expected, making renewables competitive with fossil fuels for most new supply.  The lack of a cost differential both hastens the transition from fossil-fuel based electricity in developed countries and the leap-frogging to alternative sources, skipping fossil fuel, by developing countries.  The leap-frogging, which has been seen in such areas of technology as telephones, allows a country to expand its energy supply without increasing greenhouse gas emissions.  The growing digitization of the global economy increases the demand for electricity rather than other forms of energy, and electricity can be supplied using many energy sources other than fossil fuels.  As a combined result of these three factors, the authors project a rapid transition globally from fossil to non-fossil sources of energy.

cell phone used in rural India SMALL 6a00d834522f2b69e201a3fcccd227970b

In many developing countries, cell phone technology has been rapidly embraced, bypassing development of a landline system completely.  Such leapfrogging on pathways of technological progress is also very likely in the choice of technology when developing countries are expanding their electricity grids beyond urban centers.  Photo © CABI Communications

In such a world, the demand for fossil fuels will remain weak, and countries such as Canada, which produce expensive hydrocarbons will be at a disadvantage.  The transition will affect higher-priced producers sooner and severely.  For Canada, the most important policy implication is that investment of government funds in the oil and gas sector, including in new pipelines, during this time of transition would be ill-advised on economic grounds alone – the investments are unlikely to recover their costs.  The report also notes that Canada is well-placed for a world economy based on renewables-based electricity.  We have mineral resources that will be valuable in a new digital economy, and the capacity to produce and export high-value clean electricity as well as the technical proficiency to lead in the development of technology to use electricity more extensively than we currently do – in transportation and in industrial processes in particular.  In other words, while an accelerated transition may be bad news for the oil patch, it could be good news for Canada.

The second report was published by the Canadian Centre on Policy Alternatives on June 2ndTitled Can Canada Expand Oil and Gas Production, Build Pipelines and Keep Its Climate Change Commitments?, it was written by J. David Hughes, a widely respected non-conventional fuels authority with 32 years’ experience at the Geological Survey of Canada, and now President, Global Sustainability Research Inc.

Andrew Nikiforuk comments in The Tyee, and Hughes’ article is available at CCPA.  Hughes focuses on what Canada needs to do to achieve the commitments already made under the Paris Accord (Canada’s INDC), and various proposals concerning the oil and gas sector.  In his first paragraph, he draws attention to Environment Canada’s projection for 2030 – on current policies Canada will be 55% above the level of greenhouse gas emissions it has committed to – and notes that we have ‘some serious work to do’ to achieve our Paris commitments.  He then examines in turn several scenarios for the oil and gas sector to 2030 – scenarios developed by the National Energy Board in Canada’s Energy Future 2016 which I discussed back in February – and Alberta’s recent decision to cap expansion of greenhouse gas emissions in the tar sands to 100 Mt CO2eq as part of its new climate change policy.  (Emissions were 68 Mt CO2eq in 2014; the new policy would permit continuation of present production and all planned production currently under development but any further expansion would have to use less CO2-intensive methods.)  Finally he turns to pipeline capacity versus need to transport product.

As in the report from Policy Horizons Canada, Hughes’ argument is not an environmental one.  It is entirely based on economics, plus the political requirement that Canada be able to meet the modest commitment made at Paris.  His conclusions are very clear.  None of the National energy Board (NEB) scenarios for expansion in the oil and gas sector are realistic if Canada intends to honor its commitments made at Paris, and additional pipelines will not aid Alberta’s oil and gas sector economically.

Hughes develops a ‘best-case’ scenario which uses the NEB ‘reference case’ and the Alberta emissions cap on the tar sands.  This includes just one major LNG export terminal in British Columbia (the province has plans for five terminals).  As his Figure 8 shows, under this plan, greenhouse gas emissions due to the oil and gas sector would represent 45% of Canada’s total at 2030, if Canada is to meet its Paris commitment.

Fig 8 Hughes best-case option emissions

In Hughes’ view, “it is hard to imagine even this ‘best-case’ scenario allowing Canada to meet the targets it has committed to in the Paris Agreement, given the levels of reduction that would be needed outside of the oil and gas sector”.  That reduction is 47% from 2014 levels by 2030.  It could not happen without substantial economic disruption.  His conclusion?  Barring an economic collapse, Canada will have to reconsider its planned oil and gas production growth if it is to meet its Paris commitment.  (Let’s remember that the Canadian commitment is insufficient to reach the 2oC temperature target, let alone the 1.5oC long-term goal.  The NEB scenarios for growth in the oil and gas sector are even less compatible with real progress on climate than Hughes is pointing out.)

Hughes’ comments on pipelines are based on the NEB growth scenarios.  He shows clearly that Alberta has sufficient pipeline capacity to transport all product if Alberta’s emissions cap of 100 Mt CO2eq is adhered to.  Others have shown this before, so his report reinforces the argument being made that new pipelines are not needed in the foreseeable future, no matter how strongly NEB, the industry or the governments of Canada or Alberta lobby for them.  Rail transport, which in Hughes’ view is safer and more cost effective than pipelines for shipping bitumen, can be used or not, but the existing rail capacity provides a tidy buffer to manage fluctuations in demand for transport.

Hughes goes further and demolishes the argument that getting product from Alberta’s oil patch to tidewater will yield better prices.  This was true during the period from 2011 to 2014 when the prices for West Texas Intermediate (WTI) and Brent oil diverged because of a glut within the USA caused by expanded fracking and the US embargo on oil exports.  That embargo has been lifted and the glut has evaporated.  Yes, Canada gets a lower price for tar sands oil than WTI, but that is because of the greater difficulty and cost in refining this product, not because it is not being delivered to sea ports.

Hughes also comments that of all the pipeline proposals, Energy East may seem to make some sense because it will enable oil to be transported to refineries in Quebec and the Maritimes.  But in fact, Enbridge’s Line 9, which was recently reversed, now brings western oil to Quebec, and there are pipelines connecting Maritimes refineries with US supply.  His arguments support ones made earlier by others.  After reading his report, I am even more convinced than I was in February that there is no business case for building Energy East.

Putting these two reports together, I am encouraged that arguments are being made on economic grounds that the transition away from fossil fuel has already begun and is likely to move quickly, and that Canada cannot ‘bring back’ the tar sands future of significant further expansion even if it wants to.  The message may be politically inconvenient, but it is being made to government and government may have to listen.  Far better to plan for an orderly wind-down of the oil and gas sector while building economic strength in other sectors, than to cling to the past and fail dismally.  Of course, from an environmental perspective, this is definitely good news.  Canada has no hope of meeting its climate commitments (and the even stronger commitments it is going to have to make if the 2oC target is to be achieved) while also growing its oil and gas sector, so any arguments that such growth is unrealistic help move us in the right direction.

Governmental progress on climate

Beyond these two reports, there are the encouraging signs of new attention to climate coming from various Canadian governments.  At the First Ministers’ Summit in Vancouver in early March, PM Trudeau and the provincial premiers agreed that a price on carbon is needed across the country, although they did not agree to a minimum price.  British Columbia already has a broad-based carbon tax (although it has stalled at $30 per tonne CO2 since 2012).  Alberta has announced a tax ($20 per tonne) which will come into effect on 1 January 2017, with a rebate system set so that 60% of people will not pay any additional tax; the existing emissions levy on large industrial emitters will increase to $30 per tonne in 2017.  Ontario has announced a cap and trade scheme, integrated with the markets in Quebec and California that will phase in in 2017.  Ontario also has an ambitious climate policy being debated in cabinet, not always in friendly tones, which could include incentives designed to radically reform the use of energy in buildings and in transportation. Quebec has a cap and trade scheme in place and is planning additional measures.

Ontario’s plans, which are still under discussion in cabinet, were leaked to the Globe and Mail, and there has been substantial public criticism of the proposals.  Inevitably, politics will require some roll-back and some other adjustments.  But it is important that planning proceed, and that Ontario remain ambitious.  Much of the criticism comes from places that could be expected to complain about any changes to the status quo.

catherine-mckenna-and-justin-trudeau-at-swearing-in Chris Wattie Reuters

PM Trudeau and his Minister of Environment and Climate Change, Catherine McKenna, seen here at her swearing in, have a big challenge ahead of them – to take the evolving mix of disparate provincial actions on climate change and stitch them into a functional national plan capable of achieving appropriate emissions reduction goals for Canada.  Photo © Chris Wattie/Reuters

While the provincial and federal action are positive signs that Canada is finally getting serious about climate change, there are some vexing problems generated by the fact that, in the absence of any Federal leadership over ten years, provinces have developed their own, not always easily reconcilable policies.  While a national price on carbon is badly needed, it will be hard to implement when each province has its own policies some of which involve taxes (even if they are called levies) while others use cap and trade schemes.  As Shawn McCarthy made clear in a column in the Globe and Mail back in January, independent action by the provinces has created a balkanized climate regime that mirrors the provincial separation of electricity markets.  This is unfortunate, and will make more difficult the development of a nationally equitable system.  When one considers that the price of carbon is going to have to rise to several times the currently announced or operating rates ($150 to $180 per tonne CO2 by 2030, compared to current $20 to $30) if Canada is to comply with the Paris Accord, the Federal government has an immense task ahead of it.  Prime Minister Trudeau’s noted (and refreshing) preference for open discussion and consensus building is going to be put to a very stiff test.  People who want progress on climate will need to stand up and add their voices to support all proposals that seem to be moving us in the right direction.  Still, having useful proposals to support is a refreshing change from the bad old days of misdirection and obfuscation.  Remember Peter Kent’s famous claim that ‘Canada is halfway towards achieving its Kyoto commitment’ back when we were moving in the opposite direction (growing emissions) and getting ready to renounce that treaty.

Growing realism in the oil industry?  Perhaps not?

While there remain plenty of oil patch boosters in the industry and among politicians, there are signs that recognition of the reality the industry faces may be gaining ground.  Speaking to the Canadian Club in Toronto in late May, Brian Ferguson, Cenovus CEO, said that the world is going to continue to need oil for some time and that innovation is needed to make it possible to produce that oil in an environmentally safe manner.  He claimed that the industry has “basically solved” the environmental problems related to land, water and tailings ponds, and it now focusing on greenhouse gas emissions.  He went on to say that “We can and we will … reduce those emissions,” noting that his company’s goal is to produce oil that generates zero emissions in the production process.

Still, the lack of enthusiasm within the industry to invest in the R&D needed to make tar sands product cleaner suggests Ferguson’s opinion remains a minority view.  Barrie McKenna’s recent account of the difficulties faced by Nsolv, a Calgary-based company that is running a highly energy-efficient oil sands pilot project in Fort McKay, Alberta.  Nsolv extracts bitumen without water and a fraction of the natural gas that other tar sands producers do by injecting warm solvent instead of hot steam into the ground. The operation generates a quarter of the greenhouse gas emissions of conventional steam-assisted projects, and it’s profitable even at today’s low prices.  But Nsolv is having great difficulty raising funding from the industry to take its process to commercial scale, and word is the industry wants government to front at least 25% of the total.  This should be a no-brainer for an industry tagged as producing some of the dirtiest oil on the planet, and a high-cost product to boot!  McKenna refers to the ‘race to be second’ in describing the industry.

Meanwhile there is growing evidence of just how environmentally damaging tar sand oil is.  A new paper by Environment Canada’s John Liggio and colleagues, published in Nature for 2nd June, reports that Canada’s tar sands industry generates a mass of secondary organic aerosols, an important component of atmospheric particulates, of from 45 to 84 tonnes per day. (A CBC report is here.)  This is comparable to the SOA produced by a large city and likely the second largest anthropogenic source of SOA in Canada (10th largest in North America).  Toronto, Canada’s largest city, produces about 67 tonnes SOA per day.  This environmental impact, the magnitude of which was not anticipated, must now be added to the greenhouse gas emissions, and the toxic compounds deposited on land and in waterways by this industry.  It is a dirty industry that should have been cleaned up long ago.  Closing it down sooner rather than later will be a good thing environmentally.

And the environment keeps shouting out that action is needed

While I am optimistic about the progress being made in developing Canadian policy on emissions, I am conscious of how time to act is getting shorter.  The fires around Fort McMurray were not an isolated event.  There were very serious fires in Saskatchewan last year, and this year’s fire season is not yet over.  The conditions that made Alberta ripe for wildfire are likely to occur with increasing frequency in coming years if climate change remains unchecked.  The Prairie Climate Centre, based in Winnipeg, recently reported on the anticipated increases in days of +30oC temperatures for the latter part of this century.  Fort McMurray currently gets about 3 of these days in a typical year, but by 2050 to 2080 that will increase to about 20 days.  Other locations across the Prairies show similar patterns of increase.  And every serious fire season liberates carbon into the atmosphere.

Meanwhile the Arctic sea ice extent peaked at 14.52 million km2 on March 24th, the lowest maximum since records commenced in the 1970s.  (The 13 lowest extents have been recorded during the last 13 years!)  It is now melting rapidly, and was estimated to cover just 11.1 million km2 on 1st June.  On that basis, climate scientist Peter Wadhams of Cambridge University has projected that the Arctic could be completely free of sea ice this September – the first time that is likely to have happened in 100,000 years.

Arctic ice extent 1 June 2016

Sea ice extent in the Arctic to end of May 2016, compared to previous years.  Figure courtesy NASA NSIDC.

And the data are starting to come in detailing the extent of the mortality across the Great Barrier Reef due to its severe bleaching earlier this year.  Terry Hughes, of the ARC Center of Excellence for Coral Reef Studies, James Cook University, led the monitoring effort to document this year’s event.  In a 30th May press release, he is quoted saying “We found on average, that 35% of the corals are now dead or dying on 84 reefs that we surveyed along the northern and central sections of the Great Barrier Reef, between Townsville and Papua New Guinea, … Some reefs are in much better shape, especially from Cairns southwards, where the average mortality is estimated at only 5%.”

map GBR bleaching 2016 Coral COEMap showing the northern 40% or so of the Great Barrier Reef, with symbols showing the extent of mortality of corals following bleaching.  High percentages of corals have bleached throughout this region, but many bleached corals are able to survive and get resupplied with symbiotic algae.  However mortality in the 50% or more range represents severe damage to the reef, damage that will take a decade or two to be repaired in terms of coral cover and physical structure.  Repair in terms of full representation of species present prior to bleaching could take much longer than this.
Map © ARC Centre of Excellence for Coral Reef Studies.

I expect to see a much more detailed presentation of the results when I attend the 13th International Coral Reef Symposium later this month.  Ultimately, I anticipate there will be a full report in science or Nature.  Stay tuned for more on this issue; apart from anything else, the juxtapositioning of the severe bleaching, new large foreign investments in coal extraction, and a muddled Australian political class that seems to want to have both coal and reefs while minimizing the need to curtail CO2 emissions, is making for a fascinating Australian election season.

The evident movement on climate change in Canada is very welcome, but it is also clear that we have not started to move too soon.  The task before us is immense, and the impacts of climate change are growing.

My next post is going to deal with coral reefs.  My intention now is to not have it be about how climate change and other indignities are killing them off, but rather to have it be about the fascinating worlds that coral reefs provide.  When I compare our planet to the others that encircle our Sun, I find the magnificence provided by life makes Earth a completely different class of world, and coral reefs are one of the two or three examples of types of place on this planet that should truly inspire awe.  Talking about how wonderful they are seems a far better way of celebrating coral reefs than dwelling continuously on the myriad ways in which we are making Earth a less hospitable place for them.  Hopefully, I will hear some new stories about reefs at the International Coral Reef Symposium.

Categories: Arctic, Canada's environmental policies, Climate change, coral reef science, Economics, In the News, Politics, Tar Sands | Leave a comment

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


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 | Comments Off on On Knowing Your Ecosystem – A Coral Reef is Much More than A Coral and Some Fish

Wildfire – Just One More Gift from Climate Change.


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.


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 | Comments Off on Wildfire – Just One More Gift from Climate Change.