Why 12th December 2015 might have been the High Point in our Struggle to contain Climate Change.



Polar bears may be in more trouble than we had thought.  The environmental NGOs learned long ago that certain large animals were charismatic and could become valuable poster children for their conservation efforts.  That’s why the giant panda features on the corporate logo of WWF, the Worldwide Fund for Nature, formerly and still widely known as the World Wildlife Fund.  That’s also why the polar bear got chosen early on as a symbol for how climate change could speed up rates of extinction.  In early 2005, the Center for Biological Diversity (CBD), a U.S-based NGO, formally petitioned the U.S. government to list the polar bear, Ursus maritimus, as Threatened under the Endangered Species Act.  That request was made the same day the Kyoto Protocol on climate (which the U.S. had not signed) took effect.

Iconic image: polar bear on an ice floe.  This floe is larger than some, western Hudson’s Bay, 2014.  Photo © Paul Souders/Corbis

CBD argued that the polar bear was threatened with extinction because of climate change, as well as other factors including effects of oil and gas exploration in the Arctic, high levels of contaminants like PCBs in polar bear tissues, and overhunting of some populations.  The poignant image of the polar bear on an impossibly small ice floe became part of a very deliberate political campaign which ultimately failed.

Listing the Polar Bear

That the innocent petition to list the polar bear was really a well-crafted, politically-informed action was obvious from its timing.  The Bush administration was refusing to act seriously on climate issues (remember how scary the Bush administration’s resistance to action on climate change seemed back then), and listing the polar bear as Threatened under the Act would obligate the government to develop a species recovery plan, and that would force action to mitigate climate change.

In the event, the plan was less effective than CBD hoped.  To list a species under the Endangered Species Act, there must be scientific evidence that the species is declining in abundance throughout its range, including regions outside the geographic boundaries of the USA.  The polar bear is a wide-ranging species in environments that make field research difficult, and scientists provided mixed results.  Across the Arctic, there were some populations that seemed to be thriving, even growing, and others that were in decline.  Where bears were in decline, it was not clear that climate change was, at that time, a primary, or even an important but secondary cause.  Projections could be used to suggest climate would become more important in future decades – the bears depend for food on seals that use sea ice for rest areas and rearing of their pups.  If sea ice melted earlier in spring, bears would be on land, unable to get out to the pack ice and the seals.  But projections are never certainty.  The US Fish and Wildlife Service collected data, deliberated for three years, and eventually did assess the polar bear as Threatened.  Developing a management plan as required under the Act, which should conserve and aid recovery of the bears, took a further 8 years.  The plan was made available to the public on January 9th, 2017.  By then, the situation for polar bears had become significantly worse, the science was getting stronger, and the public had become fatigued by photos of polar bears on ice floes.  Meanwhile, the political climate within the USA had chilled dramatically on the idea of action to stem climate change.  Now we must wait for law suits to push the US government to implement its own species recovery plan for the polar bear.  Ironically, it is a recovery plan which shares the need to reduce CO2 emissions with the recovery plans for the two Caribbean Acropora corals, A. palmata and A, cervicornis.  These plans were also produced in response to pressure to list those species as threatened.

The effort to have the polar bear listed has been a failure because of two things: public fatigue, and weakness of conservation legislation.  First, the legislation.  Bureaucracies can be remarkably effective at not taking mandated action when the political leadership is not in favor of that action being taken.  The US Endangered Species Act empowers the Secretary of Commerce (via the US Fish & Wildlife Service and the National Marine Fisheries Service) to evaluate any species of animal or plant (other than single celled organisms and bacteria) for listing under the act, including species that do not occur within the USA, but are subject of international commerce, or concern.  In reality, some species are identified by agency staff and others are brought to the attention of the agencies by interested parties, including members of the public (otherwise, the enormous task would never get tackled).  Once identified as a candidate for listing, an evaluation using the best available science must take place to decide if the species is Endangered (in imminent danger of global extinction), Threatened (at some risk of becoming endangered in the near term), or not of concern.  Once a species is confirmed as Threatened or Endangered, certain restrictions on activities directly affecting it or its habitat come automatically into play.  And, the agencies are required to develop a science-based plan for recovery of that species to a non-threatened status.  Of course, all this good action depends on the government of the day being interested in acting.  In early 2015, NMFS published the recovery plan for the Caribbean Acropora species.  Two years later, the polar bear plan appears.  But in the meantime, the interest of the US federal government in reducing CO2 emissions has declined or disappeared.  And the Endangered Species Act lacks the kind of teeth needed to push a reluctant government forward.  Can we seriously anticipated that Scott Pruitt’s EPA is going to dedicate staff time or funds to reducing CO2 emissions in order to save the polar bear from extinction?  All the Fish and Wildlife Service can do is ‘encourage’ the EPA to act.  Hence the need for some law suits.

By public fatigue I refer to the common tendency of news to become old, and therefore no longer interesting.  We have seen evocative photos of polar bears for a long time now, many standing on far tinier ice floes than above, looking forlorn.  There is not much new here, and so, attention turns to how the naked emperor styles his hair, or whether Americans, carrying concealed weapons, are made safer if the government is rude to immigrants.  But wait.  There is now some new information about polar bears so maybe we can bring them back into focus.  Because if they were threatened in 2005, they are almost certainly more threatened in 2017.

On February 1st, The Guardian reported that a new paper in Science suggests extinction of the polar bear may occur sooner than expected.  The paper, published by Anthony Pagano, USGS and UC Santa Cruz, with 8 US and Canada-based colleagues, reports on the metabolic requirements of free-ranging polar bears on the sea ice in spring.  During Aprils of 2014 to 2016, Pagano’s team captured 9 adult female polar bears, collared them, took blood samples, laced the bears with radionuclide-labeled water, and tracked them for up to 9 days before recapturing and resampling blood.  The labeling and blood sampling enabled direct measurements of metabolic rate over the time between capture and recapture.  The collars carried video cameras and accelerometers that enabled the team to determine level of activity and whether locomotion was walking or swimming.  The cameras documented habitat and hunting success as well.  In addition, they obtained estimates of resting metabolic rate from one female captive bear.

Supplementary figure S2 from Pagano’s study showing the track taken across the sea ice over the days tracked for two bears (A = bear #3 over 9 days; B = bear #8 over 8 days), and the mean proportion of time spent by all 9 bears in different activities (C = 24 hr data from accelerometers; D = daylight hr data from video cameras).  Bear #3 scavenged one dead seal (green +) but otherwise did not eat.  It lost 12% of body weight during the 9 days.  Bear #8 gained 7% of body weight by scavenging at eight sites, killing seal pups twice (white X), and killing one adult seal (yellow *).

The polar bear is unique among bears in being essentially completely carnivorous.  Correspondingly, it turns out to have a resting metabolic rate comparable to that of other carnivorous mammals (higher than for other bears).  It also exhibits a higher than expected field metabolic rate, despite the fact that much of a bear’s time is spent in sit-and-wait hunting for seals to emerge for a breath of air and a rest on an ice floe.  Their bears spent about 66% of their time in sit-and-wait or otherwise resting.  They were walking about 28% of their time but swimming a mere 0.3% of their time.  These are comparable levels of activity for terrestrial carnivorous mammals.  The real surprise is in the higher than expected metabolic rates.  Field metabolic rate across the 9 bears was 1.6 times higher than previous estimates for adult female polar bears.  This higher than anticipated metabolic rate has direct, immediate consequences – polar bears must be more successful at hunting than previously thought – they need to consume about 12 thousand kcal per day to simply maintain body weight.

Polar bears emerge from hibernation on land in the spring.  They depend on being able to access the sea ice from shore in the spring, because it is out on the sea ice that their seal prey live and raise their pups.  The bears need to catch lots of seals and pups in spring to recover their body mass and be ready for the tougher times in late summer, after the pupping season, and into the fall and winter.  In fact, only 4 of the 9 bears tracked by Pagano caught sufficient food to gain weight during the 8 to 11 days they were tracked.  Four others lost at least 10% of body weight.  Given that April is the time of year when polar bears must be putting on body mass to cope with the coming food shortages of late summer, and eventual winter hibernation, this is not good news.  Pagano and colleagues cite other evidence that polar bears may be experiencing hard times.   Previous researchers reported that 42% of adult female polar bears in the Beaufort Sea during the spring from 2000 to 2016 had not eaten during the week before capture. This rate of fasting was 12% greater than measurements from 1983 to 1999, suggesting that spring ice conditions are affecting prey availability for polar bears even before the summer open water period arrives.

The work of Pagano and his colleagues shows that polar bears have higher metabolic requirements than previously thought.  Given that the original argument for considering them threatened by climate change had to do with melting ice making their hunting more difficult, Pagano has just shown that the situation could be more dire than anticipated.  And this news comes as the Arctic continues to show unanticipated warm weather.

The Arctic Continues to Warm Rapidly

Latest data from the National Snow and Ice Data Center showing the extent of Arctic sea ice tracking low and very close to that for 2016.  Looks like we could get another record low minimal extent come summer.  More open water leads to more rapid ocean warming, and also makes life for polar bears more difficult.  Image © NSIDC.

NOAA’s National Climate Data Center, now cleverly renamed the National Centers for Environmental Information, reported on the 2017 global climate late in January.  Globally, 2017 was the third warmest year on record, at 0.84oC above the 20th Century average, and the warmest year that did not have an active el Niño.  It was also the 41st consecutive year in which global average temperature was above the average for the 20th Century.  As is becoming usual, the Arctic is behaving more extremely than more equatorial regions, and unseasonable warmth in Alaska made headlines in January 2018.  As of now, the extent of sea ice in the Arctic is trending low, tracking very close to the pattern seen in 2016.  The National Snow and Ice Data Center (US) reported recently that “January of 2018 began and ended with satellite-era record lows in Arctic sea ice extent, resulting in a new record low for the month. Combined with low ice extent in the Antarctic, global sea ice extent is also at a record low.”

It’s pretty clear what has been happening, and if trends continue we are going to see a much warmer Arctic in future years.  With less sea ice being formed and an earlier melt-back each spring, the situation for hungry polar bears emerging from migration in spring looks quite bleak.

To make matters worse, The Guardian reported on 31st January that the UK Met Office had released its latest five-year forecast for global temperature.  This indicated that enhanced warming over land and in northern latitudes was expected.  There is a 10% chance that in one of these five years, global mean annual temperature will exceed the +1.5oC target set by the Paris Agreement.  In other words, the world is warming as fast as, or faster than we thought.

Was 12th December 2015 the High Water Mark on Climate

So, let me get back to the point of this commentary.  Why do I think that 12th December 2015 may have been the high point in our effort to reign in CO2 emissions?  It is not just because the polar bear is having a difficult time, while the wider public forgets it is in trouble.

There are a number of different things being monitored now as part of the global effort to assess the state of the climate.  Extent of the Arctic sea ice, global average temperature, and extent of Arctic warming are just three of them.  One of the most important is the global rate of emission of CO2 and other greenhouse gases (GHGs); another is the concentration of CO2 in the atmosphere.  These tell us the current rate at which we are adding ‘insulation’, and the current level of ‘insulation’ of the planet.

The world had high hopes for our rate of emissions.  Data published by the International Energy Association (IEA) in March of 2017 had shown that the global rate of emissions from burning of fossil fuels had remained flat in 2016, for a third straight year, at 32.1 Gt CO2.  This was taken as a sign that the world had finally turned the corner in its effort to transition out of fossil fuels and lower emissions overall.

Graph released by IEA in March 2017, showing an apparent stabilization in the annual emissions due to use of fossil fuels.  Emissions were essentially unchanged during 2014-2016.
© IEA.

That optimistic sign withered in November 2017, when the Global Carbon Project reported on total annual emissions from fossil fuel use and the cement industry.  They reported that the global annual emissions of greenhouse gases, due to these sources, had increased 2% from 2016 to 36.8 Gt CO2, a new record.

The rate of increase in total global anthropogenic GHG emissions has slowed since 2010, but it has not stopped.  The estimate for 2017 is a 2Gt CO2 increase after three years without change.  The increase is largely due to the growing energy demands of a booming Chinese economy.  Figure © Global Carbon Project

It’s now clear that some of the slowdown was due to lingering effects of the recession in 2009.  The world economy showed real growth in 2017.  Despite the growing use of solar, wind, and other renewable power sources (including in China), our global economy is growing so fast that we continue to grow our use of fossil fuels.  When are we going to turn the corner and see real reductions in emissions?

Not surprisingly, with growing emissions there is a growing concentration of CO2 in the atmosphere as well.  I’m showing you the full record of CO2 concentration at Mauna Loa from 1958 onwards, but I’m also including the record of weekly means for the past year.  The former shows the now-familiar graph, going ever upwards, and flexing ever more vertically – the rate of increase in CO2 concentration is getting faster, not slower!  The latter shows how different this February is to February 2017, and hints at the levels we are likely to see this coming summer

The full record of CO2 concentration as recorded at Mauna Loa from 1958 onward.  No changes are evident in the trend – the concentration keeps going up and the rate of rise is getting greater!  Image courtesy NOAA ESRL

A plot of CO2 concentration at Mauna Loa for the past year.  Daily means are in blue, weekly means are the red lines, monthly means are the blue lines.  Viewed this way, the data show very clearly just how rapidly the concentration of this insulator is changing.
Image courtesy NOAA ESRL

For the week of February 4th, 2018, the CO2 concentration at Mauna Loa averaged 408.21 ppm.  A year ago, the average was 406.10 ppm.  Ten years ago, in early February 2008, it was 386.03 ppm.  The level of 350 ppm, which many scientists believe is a ‘safe’ level that would stabilize temperatures no more than about 1oC above preindustrial levels, was first met during the week of 20th April 1986, and concentrations less than this were last seen during the week of October 10th, 1989.  Getting back to 400 ppm is likely what is needed to keep below the 1.5oC goal of the Paris Agreement.  That is a concentration last seen in November 2015.  It is time we woke up to the fact that we are not achieving the goals we agreed to in Paris.

What about my Three Favorite Countries?

So with all this urgency to reduce CO2 emissions, what do we see around the world?  We can point to plenty of examples of good news – some countries are transitioning their energy sources successfully.  But take the three (advanced and wealthy) countries that I am most familiar with.

Australia continues its political schizophrenia.  Political leaders continue to espouse the economic benefits of increasing coal production and export, while the Great Barrier Reef, Australia’s environmental jewel, suffers one massive bleaching event after another, and Australia’s emissions continue to rise.  Australia’s record on CO2 emissions is abysmal.  The latest estimate available, emissions for the 1st quarter of FY2018 (July-Sept 2017), was the 2nd highest quarterly result in five years and confirmed a continuing upward trend.  Australia ranked 57th (3rd last) on the 2018 Climate Change Performance Index, compiled annually by Germanwatch, the New Climate Institute and the Climate Action Network and released in November 2017.  The commentary on Australia cited its very low performance with respect to emissions abatement, energy use, and climate policy, and its low performance on developing renewable energy sources.  As for climate policy… the Australian government at close of 2017 was opening up opportunities for industries to purchase international carbon credits instead of reducing emissions at home.  That was a move seen by some as merely prolonging delay in the country’s shift to a renewables-based economy.

The 57 countries ranked by the Climate Change Performance Index for 2018.  Canada, the USA and Australia all fall close to the bottom of the pack.  (Note that the chart includes three ‘unused slots) at the top because no country performed well enough to be there.)
© Germanwatch.org.

The USA, which was showing real international leadership at the time of the Paris Agreement, tried to reverse course with the election of Donald Trump.  After one year of his leadership (how does one lead a march backwards?), the US has formally announced the intention to formally declare, at the first permitted occasion, the intention to withdraw from the Paris Agreement.  The 2018 Climate Change Performance Index downgraded it from 43rd to 56th (one step ahead of Australia).  The CCPI commentary highlighted the Paris withdrawal and the dismantling of the Clean Power Plan as reasons for a very low policy performance but noted a strong engagement at the State and Municipal level and in the private sector for emissions, and energy-efficiency measures.  The backward march has proved a lot more difficult than statesman Donald Trump had anticipated and is being resisted in many sectors.  The Paris withdrawal cannot even be formally declared until December 2019, and will not take effect until December 2020 (after the next US election).  Despite the low CCPI ranking, the USA has continued to reduce emissions.  The US EPA has just released the draft annual inventory of emissions; it reports US 2016 total anthropogenic emissions were 6.55 Gt CO2e down 2% from the year before.  This decline, due largely to a shift from use of gas to use of renewables, continues a decade-long, but gradual, decline.

Not quite the steep decline in emissions that is needed to effectively combat climate change, but US total annual emissions again moved slightly downward in 2016, due largely to a shift from use of gas to alternative fuels.  Image © US EPA

How US emissions fare in 2018 and beyond is difficult to predict, because the Trump administration will no doubt continue to explore ways to move backwards.  The Trump 2019 budget, just released, cuts the EPA budget by a whopping 34% ($2.8 billion), and while it has zero chance of adoption, it signals priorities for the White House.

Canada also ranks low in the 2018 Climate Change Performance Index, at #51, barely ahead of the US and Australia.  The CCPI commentary notes Canada’s very low target for 2030 emissions, as well as very low performance on energy use.  Our current trajectory on cutting use of fossil fuels will not meet the weak 2030 target, let alone a target more appropriate for meeting the Paris Agreement commitment.  Canada is performing at a medium level in bringing renewables forward, and receives very high grades for its international climate policy efforts.  In other words, the people responsible for CCPI recognize the significant climate effort that has been made by the Trudeau government, following a long period of neglect of this issue.  Still, lots of us have been gently reminding Justin Trudeau, and Catherine McKenna, his Minister of Environment of the need to step up and set more realistic targets and really get started on the tough road forward.  The Trudeau government came to power in November 2015, and is now past the halfway point to our next election.  We have carbon pricing starting to be implemented, but there has been no sign yet of steps to raise the bar on where this country needs to get re Paris commitments.

In a sense, Justin, for all his virtues (and he looks very virtuous compared to his geographically closest head of state), is still playing that strange game of trying to ride two horses at once.  For understandable political reasons, he wants to court Alberta, and believes he can only do so by fighting to support growth in the tar sands sector.  So he endorses pipeline proposals.  He is also politically trying to hold on to his support in British Columbia, so he is talking up his positive climate actions there, while struggling to ensure that province will not block a particular pipeline.  It is not proving to be an easy ride.

A March 2017 Parkins cartoon that remains relevant as the fight over the Kinder-Morgan expansion continues.  Image © David Parkins.

Kinder Morgan, a US-based pipeline operator has an existing pipeline that delivers tar sands product to Vancouver for export.  The plan to ‘twin’ this pipeline, thereby tripling its capacity (funny how ‘twinning’ equals tripling), was seen by many as the easiest to approve of several pipeline proposals a few years ago.  After all, it would use an existing corridor.  But surging enthusiasm for protecting the amazing natural environment of British Columbia, plus a change of provincial government last fall, has made approval in greater doubt than it was, despite the fact that the federal government has already approved it, Alberta has labeled it essential, and Trudeau is on record saying it ‘will’ be built.

Kinder Morgan has plenty of pipe lying photogenically around western Canada, and certainly seems to want to put it in the ground and connect it up.  (I say ‘seems to’ because a recent news item hints that the economic argument for twining may be weakening.)  The Globe and Mail reported on 7th February that the President of Kinder Morgan Canada had said the pipeline could become untenable the longer it takes to obtain needed permits, but he stopped short of saying the company is close to abandoning the major expansion.  The company has already slowed spending on the pipeline and said oil shipments won’t start before December, 2020, at the earliest, one year later than planned. The expansion also faces numerous court challenges.

If we were being rational, the Canadian Federal government would be encouraging Alberta to expand refining capacity within its own borders and begin an aggressive transition towards use of tar sands bitumen as a raw material for an advanced chemicals industry.  It is long past time to think of this goop as fuel because, never mind the environmental arguments, the economics are no longer viable.  It is simply too costly to compete successfully with other fossil fuels.  As it stands, existing pipelines are sufficient for current demand, and while the price of the Alberta product (what did Harper call it… ethical oil) may one day rise back towards triple digits per barrel, I see no sign of that happening any time soon.  And, as Canada eventually comes to the realization that we really do have to lower CO2 emissions drastically, we will also realize that burning this stuff as fuel is simply not possible.  Still, given the way governments work, given what happens when pipeline companies have lots of unused pipeline pipe, and given what happens when anyone does anything that might hurt Our Most Holy Economy, I’ll bet this pipeline will ultimately get built, and perhaps even used a little bit.  And that will only further delay the struggle to bring climate change under control.

Perhaps it’s because it is now mid-winter, a time for dark and brooding thoughts.  Perhaps it’s because the evidence seems to be accumulating that most people tire of environmental arguments fairly quickly.  Perhaps it’s because the political tide, globally, seems to be turning towards a rather horrible nativist populism unlikely to make rational decisions on important questions.  Or perhaps it’s just because I am getting very tired of waiting for an environmental Godot.  But I really do fear, today, that when we look back on this time, we will see 12th December 2015 as the high point on climate action – the day the Paris Agreement was finalized.  Tomorrow, or next week, maybe I will see something to make me optimistic again.

We do live on a beautiful planet.  Sunrise thru the trees.  Image © psynovec/Shutterstock

Categories: Arctic, Biodiversity Loss, Canada's environmental policies, Climate change, In the News, Politics, Tar Sands | Comments Off on Why 12th December 2015 might have been the High Point in our Struggle to contain Climate Change.

Muddled Messages: The need for clarity in discussing the environmental crisis.


Those of us who express concern about sustaining the natural world see some urgency in the need to change our behavior.  We see value in natural ecosystems and danger if we do not sustain them.  Many other people do not share this concern.  Will more clarity bridge the gap?

On March 1st 1872, President Ulysses S. Grant signed into law the Yellowstone National Park Protection Act, establishing Yellowstone as the first National Park in the USA.  It was also the first in the world.  This action is taken by many people to mark the first flowering of ideas on conservation.  But conservation is more than the setting aside of tracts of land, or ocean, to be preserved in perpetuity.  And thinking about conservation started long before Grant signed that law.  In one sense, conservation began with a sense that all was not right with the world, and that humanity had a responsibility to conserve as much as possible of what was right.  But where did this notion of correctness in the state of the planet come from, and how do we justify it?

Old Faithful, perhaps the best-known feature of Yellowstone National Park, the oldest National Park on the planet.  Photo © Yellowstone National Park, USNPS.

Over the last many years, a lot of people have expressed concern regarding the state of our environment.  Some have been professional environmental scientists while others are simply people who care.  Some have directed their concern to specific ecosystems or particular places while others have taken a global view.  Some have used logic and data to support their claims while others have argued on the basis of ethics, morality, or the teachings of particular religions.

It’s undeniable that the environment of 2018 is not the environment of 2000, or 1950, 1872, 1776, 1492 or any of numerous other dates in the past.  Our world has changed in small and big ways, and continues to do so.  The concerns being expressed all derive from the notion that our present environment, or our anticipated future environment, is a less desirable one than the environment of some time in the past.  What is often not clear, however, is the basis on which this judgement has been made, and the authority with which it is made.  My goal here is to try and sort this muddle out, and explain where the concern comes from.

Who really cares?

Our planet doesn’t give a damn.  Nor does the universe.  They do not care one whit about the state of the biosphere on Earth.  For billions of years in the early existence of planet Earth, it was devoid of life and therefore possessed no biosphere.  Scientists have yet to find convincing proof of the existence of life on any other planets in our solar system; those planets likely lack biospheres today.  But for the past 3 billion or so years, there has been life on Earth and over this time the biosphere has tended to become more complex in a number of different ways – sheer extent of biological activity, richness and variety of life forms, tonnes of biomass present.  The trends toward greater complexity have neither been constant nor linear, and there have been episodes of substantial reduction in complexity (notably the five global mass extinction events), but the overall, long-term trends have been positive.  Throughout all but a tiny fraction of these 3 billion years, these trends towards an increasingly complex biosphere proceeded unnoticed.  The biosphere itself does not care about its state, or even its continued existence, and so far as we know the overwhelming majority of living organisms do not give a damn about the state of the environment, other than in how changes in that state might directly impact their own individual lives.

But many people care, and in discussing their concerns they usually start with the implicit assumption that caring about the state of the environment is a natural and normal concern to have.  Given that there are many other people, perhaps the majority of the world population, who do not care, perhaps it’s worth exploring this shared concern.  Where does it come from?  What are we really caring about?  After all, it may be possible to explain why we care, helping other people understand the issue?  Or it may turn out that on careful reflection there is no reason why we should care, in which case we can all get on with our lives.

The biosphere, which one can almost imagine as visible in this 2015 NASA photo centered on Vancouver Island, doesn’t care about its state of health.  Nor does Earth care.  Nor the universe.  Nor, so far as we know, does any animal other than Homo sapiens, and then only some of us care.  Photo courtesy NASA Earth Observatory.

Developing ideas about environment

Our species of human, Homo sapiens, has existed on this planet for at least 200,000, perhaps 300,000 or more years.  Until recently, anthropologists agreed we had originated in sub-Saharan Africa, however a recent find in Morocco suggests archaic members of our species were present in North Africa 300,000 years ago.  A pan-African origin for our species is now seen as most likely, with populations mingling as they moved back and forth across the extensive savannahs that included what is now the Sahara.  Our species, and several other Homo species had culture 300,000 or more years ago, revealed by tools, use of fire, cooking of food, and ritual treatment of the dead.  They may have had a clear, and well expressed, understanding of environmental matters.  Or they may not.

We lack any direct evidence of what our distant ancestors thought about environmental change, and it would be dangerous to infer that they thought much about it at all.  (We also have absolutely no evidence that any species other than our own has ever thought much about environment.  But we also do not know for sure that elephants do not spend many hours thinking about the changing climate, or that humpbacked whales do not sing to each other about falling ocean pH.  And snapping turtles just might keep diaries concerning wetland degradation.)

With the dawn of agriculture, we can surmise that people must have become aware of environmental changes, especially seasonal ones, and environmental catastrophes such as forest fires and floods.  They had to be timing their management of crops and livestock in accord with seasonal cycles, and they recognized when unusual years ‘failed’ to produce needed warmth or rainfall, leading to crop failure and famine.  Given the widespread myths of great floods or other catastrophes in the folklore of present-day hunter gatherers, as well as in that of agricultural or other groups, it is reasonable to assume that awareness of typical seasonal cycles, and fluctuations in, or disturbances of these cycles, also existed in pre-agricultural populations.  (In that distant past, people undoubtedly thought of time as circular, operating on daily, monthly and annual – and perhaps longer – cycles.  Thinking of time as linear, as an arrow into the future, came much later.)

With the advent of a written record, we have more assurance of how people thought about environment (it’s even possible that the development of linear writing led to the change in thinking about time).  Certainly, Europeans in the Middle Ages recognized environmental changes, but their recognition was confined to changes in their local experience.  The idea that the environments of the planet as a whole might change through time resided only in the origin myths of peoples, as ways of accounting for how the world had come into being in a remote past; after its creation the Earth was thought to provide a more or less constant environment.  Departures from seasonal norms, whether cases of a year of extreme weather, a prolonged period of aberrant environmental condition such as a decade-long drought or the Little Ice Age which chilled Europe over some 400 years, or a short-term catastrophe such as a forest fire, an outbreak of insect pests or other pathogens, or an earthquake or volcanic eruption, were all recognized, talked about, recorded.  They were departures from normalcy.  Much thought was given to why such environmental changes had occurred, and supernatural causes were usually invoked.  Such short- or long-term aberrations in environmental conditions were recognized as ‘unnatural’, and often thought to arise as punishment for wrong behavior by humans.  In some other cultures they were just seen as the earthly consequences of actions by capricious gods; something that humanity and other organisms just had to put up with.

Thinking began to change, at least in Europe, with the renaissance and the scientific revolution.  Over the period from about 1500 to 1800, our view of the natural world changed in many ways.  We began to believe that the planet was much older, and to have changed considerably during its lifetime.  Lyell’s concept of uniformitarianism informed a new geology in which the form of the landscape had been created over time by slow, readily observable processes such as erosion by wind and water.  Darwin took such ideas into biology, and natural historians developed ideas about changes to natural living systems caused as responses by organisms to physical environmental change.  Fossils were transformed from lithic curiosities, or misleading cues planted by the devil to divert humans towards evil, into evidence of that lengthy, changing past.  There developed an appreciation that environmental changes occurred due to ‘natural’ rather than ‘supernatural’ causes, although these new ideas coexisted with a persistent belief in the superiority, and often the uniqueness, of humanity compared to other organisms, and a belief that the planet was provided for our use.  (By this time, western humans thought of time as an arrow, one that moved upwards, towards a teleological perfection.)  In addition, the holistic view of the natural world, long held over from Greek and Roman philosophy, was slowly supplanted by a more scientific, but also more reductionist and mechanistic one.  This objectified and particularized the natural world, set humanity outside of nature, and likely helped foster the idea that the natural order was to have humans somehow in charge.  With these ideas came thoughts about the goodness, the appropriateness, and the usefulness to humans of nature.  We could talk about a good environment and one that was less good.  Coincidentally, this willingness to think about the value of the environmental state developed at about the same time that the industrial revolution was offering abundant evidence of our ability to reduce that value.  No longer were humans innocent bystanders to the changes occurring around them; sometimes we had a major part in causing those changes.

Our profound impacts on the biosphere

It is now clear that Homo sapiens has had profound impacts on the planet from at least as far back as the last Pleistocene glaciation (~110ka – 11ka) or even into the Eemian interglacial (~135ka – 110ka) which preceded it.  The widespread extinctions of terrestrial megafauna during the last glacial period, on all continents except Africa, arriving so suspiciously soon after the arrival of our species, are now attributed substantially to over-exploitation by Homo sapiens.  We were (are) a highly effective hunter, although (non-anthropogenic) climate change and other ecological changes may have modified the pace of some of these extinction events.  Only in Africa had megafauna experienced our species during our earlier evolution and our development of hunting skills. That African megafauna had been able to evolve defenses against us, and it still persists (although many members are now perilously close to extinction).

This Late Quaternary Extinction (LQE) eliminated 34 genera of large mammal in North America (72% of mammals >44kg in weight), 50 genera (83%) of such animals in South America, and 14 genera (88%) of such large mammals in Australasia.  The 2006 review by Paul Koch, UC Santa Cruz, and Anthony Barnosky, UC Berkeley, published in Annual Review of Ecology, Evolution and Systematics documents how removal of these creatures had profound effects upon the ecology of those continents.  In addition, our inferred early use of fire to manipulate landscapes to favor certain desired species, had its own impacts.  Imagine how different the world would be if the megafaunas of other continents had been spared until today.

Graphs showing the percentage of animals (by body size) that became extinct during the late Quaternary extinctions on each continent.  Note that the largest 2-3 size classes all became extinct at this time on all continents except Africa.  Image © Annual Reviews


Modeled history of deforestation due to agricultural expansion between 1000BC and 1000AD in Europe.  Land unmanipulated by humans no longer exists on that continent.
Image © Elsevier Ltd.

With the advent of agriculture, our environmental impacts grew.  It is very likely that parts of Europe saw multiple episodes of deforestation, abandonment and afforestation during the Holocene, but one recent modeling study (by Jed Kaplan, Ecole Polytechnique Fédérale de Lausanne, and colleagues and published in Quaternary Science Reviews in 2009), which looked only at the effects of land clearing for agriculture, reveals a dramatic deforestation of Europe between 1000BC and 1000AD, and continuing to the present.  Only northern Scandinavia and Scotland escaped having their forests converted largely to grasslands.  By 1000AD a ‘natural’ environment scarcely existed anywhere in Europe, although there were, and remain, extensive rural regions.

With population growth, and with the advent of the industrial revolution, our impacts on environment grew.  But our awareness of these impacts grew more slowly.  We saw, and commented on, local deforestation, local pollution, even a general local lack of game, but we did not see the broad scale at which our impacts were being felt.  While we recognized that it was our own over-exploitation that had removed those trees or game, and our careless discarding of wastes that led to the pollution, we also knew that just over the next hill, or across the bay, there were untouched environments waiting for us to use them.  Our destructive tendencies were cause for alarm, but it was local and modest alarm.  It took Christmas Eve of 1968, and a photograph of Earth in the sky of the moon, to move us to an understanding of the planet-wide scope of our destructiveness, and to an awareness that over-exploitation was occurring on a planetary scale and could not continue – if ethics would not stop us, simple physics would.  At least that is how thinking evolved for those of us who thought about such matters; many others remained immune to what we were doing to the planet, focusing their attention on the amazing, even inspiring, growth of the human enterprise.

Earthrise, Earth floating in the sky of the moon, photographed 24th December 1968 by Bill Anders, from Apollo 8, is a photograph, widely reprinted, that changed how people thought of this planet.  Photo courtesy NASA.

It’s worth noting also that our understanding of our impacts in the marine realm remain trapped largely in the ‘pre-Earthrise’ world in which we see and understand local calamities, but do not appreciate the global extent of these.  Overfishing has globally reduced the biomass of fishery species alive in our oceans by 90%, and yet most of us still see the oceans as large, remote, wild, and untouched by us.  If the global demise of coral reefs, driven by repeated bleaching due to the rising sea surface temperatures caused by climate change, can teach us one thing, it will be that we are having disastrous, planetary-scale impacts on the oceans, just as we are doing on land.

History of ideas on conservation: a European beginning

There is a prevalent history of the conservation movement that implies our evolving thinking on this topic was a North American phenomenon.  This history begins with President Grant’s creation of Yellowstone National Park.  It honors Theodore Roosevelt, John Muir, and Aldo Leopold among others for conjuring up, during the period from 1870 to 1940, the idea of conservation of wild lands as the right thing to do, and I will visit their shrine shortly.  A more accurate history recognizes the important, 17th – 18th century, European development of ideas about the value of the natural world, and the need for humans to reign in the capacity of their capitalist economies to destroy that world.

In 1990, in a short commentary in Nature, Richard Grove, Cambridge University, described this European portion of the story as a direct consequence of colonialism.  In Grove’s view, beginning in the 16th century with the flowering of expansionist voyages of discovery of foreign lands, European colonialism provided a growing awareness of the detrimental impacts of European economic activities on newly ‘discovered’ lands.  Europeans were aware that the industrial revolution had caused damage to European environments, but these were already simplified and tamed before industry arrived.  The impact of imported industry on previously less obviously altered colonial environments was impossible to miss.  Indeed, by the 18th century, the great mercantile corporations such as the British East India Company provided opportunities for scientifically-trained thinkers, employed as medical doctors or as managers of overseas commercial ventures, to observe directly the deleterious environmental consequences of deforestation, ill-though-out agrarian reforms, or other economic ‘investments’ in tropical colonies.  Coming to these tropical colonies, fresh from a Europe showing much evidence of negative environmental consequences of industrialization, these individuals were well-placed to observe and correctly interpret the environmental consequences of rapid resource exploitation, and by the late 18th century they were using such experience (plus their colonial governance power) to formulate progressive policies on forest and watershed management in the colonial regions under their control.  (Grove acknowledges that in some cases, these colonial Europeans were influenced by Eastern concepts of the relationship of humans to environment – the new thinking was not a purely European product.) What got exported back to Europe, along with raw materials, was a set of ideas concerning environmental value and ecosystem service, even if those terms were not expressly used.

The idea that natural environments contain intrinsic value beyond the economic value of their resources, and that economic ventures, when not managed (=constrained) appropriately, can perturb those environments and disrupt, reduce or eliminate that intrinsic value was a major step forward in thinking about our relationship to the natural world.  The value identified was sometimes a value of direct economic benefit to human activities – intact forests protect soils, and regulate water flows in ways that are often beneficial to nearby agriculture.  Such a value would now be termed an ecosystem service.  Other times value was seen as not obviously beneficial to human economic activity, but still important to the ecological integrity of a place, to the maintenance of its biodiversity, or (in modern parlance) to its ecological resilience.  Regardless of the type of value, the intrinsic value of nature is a value given by, and relevant to, humanity – value does not exist outside the human sphere.

The flowering of conservation in North America

This body of European thought on environment travelled to America, a new nation with extensive ‘natural’ landscapes, and it was there that the idea of environmental conservation as a societal good was refined.  I put ‘natural’ in quotes here for a reason.  We now know that native peoples had manipulated North American landscapes to a considerable degree, but the conquest of the Americas was accompanied by a major killing off of those populations and a substantial collapse of their economies – so great a collapse that the resulting regrowth of forests caused a global dip in atmospheric CO2 around 1610!  This clearing out of the past made it possible for colonists to consider vast tracts of the land as virgin country untouched by humanity – a perspective that was incorrect in North America, but also one that could never have developed in Europe or in Asia.

By the middle of the 19th century, the considerable untapped economic value of the natural resources of vacant land was being recognized.  In parallel with this growing awareness of economic value, there was a growing appreciation of the other intrinsic values of natural environments, and of the damage that could be done to environmental value during the process of resource extraction.  To these ideas of value, was added a spiritual part.

John Muir was born in Scotland in 1838.  His family emigrated to the USA in 1849, settling in Wisconsin where John grew up.  Wanderlust led him to California by 1867, where he spent the rest of his life.  The Yosemite Valley, which Muir first saw in 1868, had a profound philosophical/spiritual impact on this young man.  That impact stayed with him, helping force his development into a leading thinker and writer on the essential, spiritual value of natural landscapes, their forests and their wildlife.  In hundreds of articles, published in the Atlantic, Harpers, and other eastern magazines, and over 10 books, Muir ostensibly wrote about his travels throughout North America (especially the west).  In reality, he was defining a philosophy centered on the intrinsic value of natural ecosystems, including their spiritual value, the propensity of human activities to destroy that value, and the need for national governments to protect natural lands as a part of the shared wealth of the nation.  Muir had considerable influence on President Theodore Roosevelt, who visited Yosemite with Muir in 1903, and subsequently signed Yosemite into existence as the nation’s second national park.

John Muir had a major influence on the early conservation movement through his writings about the natural world, in particular, the Yosemite Valley.  Image courtesy Wikimedia Commons.

The other major influence on Roosevelt’s thinking about conservation came from Gifford Pinchot, who he appointed head of the US Forest Service.  Pinchot, a professional forester and initially an ally of Muir’s in the struggle to protect natural lands, eventually fell out with him over the relative importance of intrinsic, spiritual value and resource-based, economic value of natural landscapes; a difference in perspective that exists still within the environmental movement.

The ideas of people like Muir and Pinchot had major influence on the initial development of a conservationist environmental philosophy which valued natural places and the resources they contained, and sought to protect them.  Muir, after all, was the co-founder of the Sierra Club, the oldest environmental organization in existence.  Their ideas were expanded, and imbedded in the new science of ecology by a later generation including Aldo Leopold and Rachel Carson.  Leopold, who started out as a wildlife manager, and, like Pinchot, saw environmental value primarily as the economic value of sustainably managed natural resources, evolved into one of the great environmental philosophers.  His A Sand County Almanac, published in 1949 a year after his death, remains in print and continues to inspire people who think about environment.  In its Foreword, he wrote (using ‘land’ as we would use environment, ecosystem or biosphere),

“We abuse land because we regard it as a commodity belonging to us.  When we see land as a community to which we belong, we may begin to use it with love and respect.  There is no other way for land to survive the impact of mechanized man, nor for us to reap from it the esthetic harvest it is capable, under science, of contributing to culture.  That land is a community is the basic concept of ecology, but that land is to be loved and respected is an extension of ethics.”

Rachel Carson’s Silent Spring, published in 1962, took the ‘land ethic’ of Leopold and applied it to a particular problem – the use of DDT and other novel chemicals.  A science editor for the US Fish and Wildlife Service, Rachel Carson had a gift for language, and three highly successful books on the sea under her belt by the time she tackled DDT.  She documented the problem, and its causes.  But she went far beyond what most investigative reporters would have done – she pointed to the ethical failure that permitted industry to create damaging products and to continue successfully to promote them long after the environmental, medical and other damage they cause was recognized and understood.  She did not operate entirely alone, but she played a major role in expanding the perspective of environmentally concerned people beyond the preservation of iconic natural places or species.  If Leopold could lament, as he did in his essay The Land Ethic, published as part of A Sand County Almanac, the lack of an ethic “dealing with man’s relation to land and to the animals and plants which grow upon it”, and argue that extending ethics to our relations with the natural world is “an ecological necessity”, by Carson’s time, the environmental movement fully embraced the idea of such an ethic.

Today, most conservationists acknowledge that natural ecosystems posses many sorts of value, including spiritual and esthetic value and the economic value accessible through the exploitation of their natural resources, and they are comfortable with the notion that ethical behavior requires that in interacting with the environment, one should do so in ways that ensure the long-term sustainability of that value.  Even on one’s own land, it is morally unacceptable to act in ways that diminish the effective operation of the ecosystem.

But individual environmentalists still differ on the relative importance they attach to these two types of human-defined value.  Within the modern conservation movement there continues a tension; some leaders, such as Peter Kareiva of the Nature Conservancy, emphasize economic value and novel ways to leverage that value to achieve protection for natural places or endangered species (see an article here), while other leaders such as Michael Soulé, at UC Santa Cruz, and founder of the Society for Conservation Biology, argue passionately for the importance of non-economic, spiritual or esthetic value as the driver of conservation, and the risk of commodification of nature if too much attention is given to the economics of resources (see a 2013 article here).  In the view of Soulé and others, if we cease arguing for the ethics of conservation, we will lose the battle against human short-sightedness and selfishness.

Where does the value of natural systems come from?

At their core, the national park movement within the USA (and as exported to many other countries) and the broader conservation/environmental movement began with the idea of preservation of undeveloped landscapes, for the long-term benefit of nations.  That core has been expanded and enriched by the integration of ecological ideas concerning the functioning of natural systems.  But ‘preservation’ remains, and it implies that there is a state of nature that is static, and can be retained so long as human activities detrimental to that state are prevented.  That static primeval nature has always been a myth, because the planet is not in stasis and because natural lands untouched by human impacts do not exist.  The myth developed largely because of the peculiar history of colonization of North America, and it has been able to endure because the processes causing change in ecosystems, especially when viewed at a landscape scale, are mostly slow-acting and almost invisible.  The pace of change is nearly always so slow relative to the lifespans of humans that it is not noticed.  While there is occasional, calamitous, often highly destructive, change due to fire, flood, earthquake, eruption and other geological events, it is now the activities undertaken by industrial economies, first to extract natural resources, and then to prepare land for agricultural or urban use that are most obviously damaging, and state-altering to ecosystems.

This brings me back to the question I started with:  Why do so many of us believe that there is value in natural ecosystems that is not present in systems extensively modified by human endeavor to provide superior agricultural, industrial, residential or cultural landscapes?  What is wrong with a vision of the future that pictures the entire planet tamed to serve human needs?  I suggest these two questions can be answered by focusing first on hubris.

Cultural evolution over the past 500 years or so has shifted our common view of time from circular to linear.  Modern culture sees history as a linear process towards a succession of goal states, and we have been remarkably clever at convincing ourselves that the new is always also the better.  Over the past 500 years or so, conventional wisdom assumes our lives have become much better.  While there are innumerable examples of progress, which can be summed to suggest betterment, I think the question of whether or not we are now absolutely better off than we were 500 years ago is a question still worth pondering.

For example, the global number of refugees and other forcibly displaced people has almost doubled from 33.9 million in 1997 to 65.6 million in 2016.  Not included in those numbers is an estimated 22.5 million displaced since 2008 by environmental disasters (many linked to climate change).  These numbers are larger, in absolute terms, than at any time in human history.  In addition, while the world has been successful in cutting the extent of extreme poverty from 30% of the global population in 1990 to 10% in 2015, there are large discrepancies among countries, and evaluations of relative wealth that use higher levels of expenditure than $1.90 per person per day (the World Bank criterion for extreme poverty) reveal increases in the numbers of poor people in many middle-income and wealthy countries.  More anecdotally, did the creation of smart phones, Facebook, Google and Twitter all usher in a clear net improvement in the quality of our lives?  Our rush to embrace the new may not be a certain way to assess changes in the quality of our lives.

While the Syrian refugee crisis is usually described in political terms, it has environmental root causes in a devastating drought that forced people into the already crowded cities causing unrest, savage crack-downs and civil war.  Are we better off when more of us than ever before undergo forced migration?  Photo of refugees arriving on Lesbos © Angelos Tzortzinis/Getty.

I also suggest that as our technological capacities have grown, we have been quite good at convincing ourselves that we know a lot more than we do.  A portion of the resistance to acting on climate change derives from a widespread belief in our collective ability to engineer our way out of any problem that arises.  Indeed, this faith in our ability to solve all the problems has been instrumental in maintaining our complacency in the face of an exploding global population, the rapidly approaching global crisis in potable water supply, and our rampant pollution of our coastal oceans.  Every issue is observed in isolation, as a problem to be fixed, with utter confidence that the new technologies needed to do that fix will be invented in time.  Our confidence is such that we routinely ignore such minor details as the 2nd Law of Thermodynamics, which tells us it is very difficult to build order (such as a complex ecosystem) out of disorder (a degraded one), or the even simpler idea that a perpetually growing economy (assuming the economy uses real resources) is incompatible with a finite planet.  We glibly assume we will develop agriculture that will feed the 2.5 billion more people that the planet will hold by 2050, ignoring the fact that plants have had millions of years to perfect photosynthesis and it remains a low-efficiency process.  Is all of this not hubris?  The conceit of a naked ape who thinks he is all-powerful?

Thus, the concerns of many people about the value of natural ecosystems, and the need to ensure they survive, despite our careless deprivations.  We are only naked apes with less than perfect creative capacities, and limited ability to see into the future.  Under such circumstances, the precautionary principle should be invoked – we must do our best to minimize our impacts on the planet because past history has shown us that our impacts can often be decidedly bad.  The values we assign to nature are human ones, and hidden behind them is the knowledge that we are now quite capable of creating a world which is far less amenable to our own existence than the one that we currently occupy.  The need for conservation, the reason for valuing environmental sustainability, arises because experience tells us we are much more likely to cause critical damage to natural ecological processes than we are to build an environment that does a more effective job of providing ecosystem services than the natural one it replaces.  And, yes, less likely to provide the spiritual and cultural values we see in those natural ecosystems.

The Anthropocene is a game-changer

If I had set these thoughts down in 1950 (unlikely thoughts for a kid more interested in exploring tidepools), I could stop here.  Now that we live in the Anthropocene, however, there is a new complication that must be taken into account.  Many of our actions over past years have combined to cause global change at a pace that is far faster than in previous times.  Whether we consider the pace of warming, of ocean acidification, of sea level rise, or even the pace at which novel chemical compounds are being released into the environment as pharmaceuticals, fertilizers, pesticides, or microplastics, the pace of change is far higher than at nearly any time in geological history.  Never mind the nature of the changes.  The pace of change is taxing the capacities of species, and the natural ecosystems they comprise, to respond, adapt and evolve.  Because of this, conservation has suddenly become far more difficult.  Setting aside a new national park in the Anthropocene is no guarantee that the ecological systems of that place will be sustainable into the future.  In fact, we can be quite sure that all that will have been done is ensure that that place will proceed to change, possibly to degrade, in ways that are different to what would happen if no protective status was put in place.

The idea of a primeval nature, with intrinsic value worth protecting from human interference was always a myth.  But setting aside places like Yellowstone and Yosemite did secure locations to continue changing along slow paths, ones to which the biota was well adapted, and ones imperceptibly slow to most humans.  That simple approach to conservation is no longer valid, because our planetary-scale disruptions of the biosphere continue to have their effects.  To truly achieve environmental sustainability in the Anthropocene, we must continue to act locally to protect selected valued places from our local deleterious impacts, while we simultaneously act globally to rein in those other actions that are pushing major changes at the planetary scale – a tough challenge indeed.

This graph shows that, as of 2017, our emissions of greenhouse gases continue to rise, despite all the effort directed to climate change in recent years.  They continue to rise because the increase in our demand for energy far exceeds the rate at which we are transitioning away from use of fossil fuels to provide that energy.  The future is unknown, but most projections are gloomy – getting to <2oC increase in global mean temperature is going to be very difficult. 
© InsideClimate News.

Furthermore, in the Anthropocene, with a human population of 7.5 billion heading towards 10 billion by 2050, and with rapid industrialization under way across many countries that were, until recently, agrarian, our impacts locally and globally are bigger than ever and growing larger still.  Therefore, the much more demanding task now required if we are to maintain environmental sustainability must be undertaken at a time when our actions have a capacity to inadvertently perturb ecosystems that is far greater than it has ever been.  This is why I and many other people are so deeply concerned about the environmental crisis – the challenge we face now is way bigger, and way more complex, than ever before, and there is no certainty that we are capable of success.  It’s essential to maintain an optimistic, can-do attitude re the need for environmental conservation.  It’s hubris to think it’s going to be easy.  It would be foolhardy indeed to give up, become complacent, and assume we will somehow muddle through.  In many ways, we are like dinosaurs, peering into the sky, watching the asteroid descend.  Only this time, we are the asteroid.  What are we going to do next?

Categories: Biodiversity Loss, Climate change, Communicting science, Economics, Land Use | Comments Off on Muddled Messages: The need for clarity in discussing the environmental crisis.

Sobering News on Coral Reefs – But We Knew It Would Come to This


The journal, Science, began 2018 with an issue including an update on the status of coral reefs around the world.  Led by Terry Hughes of James Cook University, Australia, a consortium of 25 authors, from around the world though mostly from Australia, compiled data on the history since 1980 of 100 coral reef locations from 54 countries around the world.  For each year from 1980 to 2016, each location (10 to 10K km2 in area) was reported as bleached, severely bleached (more than 30% of coral bleached), or not bleached.  This data set was compiled from published records and from direct observation by individuals known to the authors.  By using only 100 well-documented sites, the authors were minimizing the errors that creep in when well-studied or easily accessible sites are over-sampled relative to others, or when new sites are continually added (almost always in the year when they are seen to bleach).  Temperature histories were also compiled for each location, and years were classified as el Niño. La Niña, or neutral years.  This article (as usual locked behind a paywall) was well covered in the mainstream media.

Hughes and colleagues report a trend to diminishing ‘return-time’ for bleaching events that will be devastating for coral reef systems.  The global mean return-time between one bleaching event at a location and the next is now ~6 years, a decrease from 25 to 30 years in the 1980s.  Since faster growing corals take a decade or more to recover from the mortality caused by a bleaching event (and slower growing corals much longer) it’s obvious that the damage now being caused by bleaching is beyond the capacity of coral reefs to repair.  This information on shortening of return-times confirms a hypothesis put forward in a 2005 paper in Global Change Biology by Simon Donner (then at Princeton, now at UBC) and colleagues that return-time will continue to diminish as the planet warms and could be less than 2 years for the great majority of reefs by 2035 or so.  One intriguing twist – Donner and colleagues based their estimate on projected tropical sea surface temperature (SST); Hughes and colleagues have found no link between annual mean SST and frequency of bleaching, and argue that it is local patches of unusually warmed water, sort of marine weather, that leads to bleaching in a location.  Looking into the future, using projected mean SST, is not likely to be an accurate way to predict bleaching frequency, although it remains true that with SST projected to continue rising, the frequency of bleaching events will surely go up until bleaching is an annual, or near annual event.  That will surely happen within the next couple of decades.

The primary results from the study of 100 reef locations, showing A) the pattern of bleaching across the 100 locations from 1980 to 2016, B) the cumulative pattern of bleaching events, and the progressive loss of unbleached locations during the same time period, C) the pattern of severe and of all bleaching events among locations showing that most locations have been bleached multiple times, and D) a comparison between return-times for successive bleachings at specific locations during the first 19 and the final 17 years of the record – return-time is clearly becoming a lot shorter.  Figure © Science.

Hughes and colleagues also report that of the 100 locations they examined, only 6 have yet to experience a severe bleaching event, and all 100 have been bleached at least once.  The severe 2016 bleaching event impacted 75% of the 100 locations monitored (remember these are places from 10 to 10k km2 in area, and ‘severe’ means more than 30% of all coral there bleached).  This is comparable to the severe 1997-98 bleaching event, which impacted 74% of these sites.  As of the end of 2016, the median number of severe bleaching events per site is now 3 since 1980, and 31% of locations have experienced 4 or more (up to 9) such severe events as well as many less severe events.

Globally, the annual risk of bleaching, for any reef location, has increased from 8% in the early 1980s, to 31% by 2016, while the risk of severe bleaching has increased from 4% to 17% over the same period.  The pattern of bleaching likelihood, severity, and frequency differs among the four major geographic regions considered.  The Caribbean/West Atlantic began to experience regular bleaching events earlier, and the average location there had been bleached over 4 times by 1998.  Widespread bleaching, affecting more than 50% of locations in this region has now occurred 7 times, more than twice as often as in the other three regions.  In the 1980s, bleaching risk was highest in the Caribbean/West Atlantic, and the Pacific, but bleaching risk has increased most strongly in the Indian Ocean and in Australasia, so that in 2016, risk is comparable across all four regions.

Plot showing the trend in frequency of bleaching per year for the 100 locations monitored.  The risk of bleaching (proportion of locations bleached) has increased in all regions since 1980, but the pattern of increase in risk is quite different for the Caribbean/West Atlantic than for the other three regions.  Figure © Science.

While Hughes and colleagues are appropriately objective and dispassionate in reporting their results, this paper shows that coral reefs are on a journey toward oblivion.  Quoting their own words,

“The time between recurrent events is increasingly too short to allow a full recovery of mature coral assemblages, which generally takes from 10 to 15 years for the fastest growing species and far longer for the full complement of life histories and morphologies of older assemblages. Areas that have so far escaped severe bleaching are likely to decline further in number, and the size of spatial refuges will diminish. These impacts are already underway, with an increase in average global temperature of close to 1°C. Hence, 1.5° or 2°C of warming above preindustrial conditions will inevitably contribute to further degradation of the world’s coral reefs. The future condition of reefs, and the ecosystem services they provide to people, will depend critically on the trajectory of global emissions and on our diminishing capacity to build resilience to recurrent high frequency bleaching through management of local stressors before the next bleaching event occurs.”

Using the reef story to motivate action on climate change

The imminent demise of coral reefs as we know them provides the reef science community with a powerful weapon for the battle to convince the global community that the need to deal with climate change is critical.  The empirical evidence is abundant that coral reefs have already sustained substantial damage from human impacts, and that the damage caused by climate change has reached a level that exceeds the regenerative capacity of reefs.  What we are witnessing is the progressive elimination of an important, complex, and productive ecosystem from this planet.  It is happening because the pace and extent of our warming of the planet has exceeded the capacity of the chief structural architects of this ecosystem to survive and rebuild, and it is happening over the span of one human lifetime or less.  What is happening to reefs is akin to the disappearance of ALL rainforests on the planet in the space of one human lifetime.  That our modest warming of the planet can result in so extreme a consequence for one sensitive ecosystem should be an urgent warning to us.  What other serious consequences of climate change are happening, or about to happen?  And isn’t it time to stop our foolish dumping of greenhouse gases into the atmosphere?

Yes, it’s a powerful weapon.  But are we going to be able to use this weapon effectively to sway the minds of others?  To do that, the reef science community has to be able to project a clear and unambiguous message to the world community.  I think we have been making strides towards doing that, but our message is frequently mixed, because we are scientists first, rather than communicators.

So, in the interest of effective communication, I suggest framing a message around the following 6 points:

  • ONE Coral reefs are important ecologically, economically, culturally, wherever they occur; and they directly sustain the lives of millions of people on this planet, many of whom have played only a tiny role in releasing greenhouse gases (GHGs) to the atmosphere. There is ample information on the value of coral reefs, but many people still do not appreciate how valuable they are;

To casually permit the eradication of coral reefs on this planet through our careless dumping of GHGs into the atmosphere removes vital coastal ecosystem services, while also degrading the lives of millions of people with only tiny roles in that pollution, who are directly dependent on reefs economically, culturally and spiritually.  Photo of reef at New Britain, Papua New Guinea.  Image © David Doubilet, National Geographic Creative

  • TWO Coral reefs are deteriorating globally at a rapid, and increasing rate due to several human impacts. Coral bleaching, a stress response caused by ocean warming can result in substantial mortality of corals, and is now a major factor in reef decline.  Our releases of GHGs to the atmosphere cause the warming, and the frequency of bleaching events causes damage that already exceeds the regenerative capacity of reef systems;

Bleached coral off Lizard Island, Australia, in 2016.  Photo © XL Caitlin Seaview Survey

  • THREE The pace of deterioration is such that the future condition of reefs, and the ecosystem services they provide to people, is now critically dependent on the effectiveness of global GHG emissions reduction;

Even ‘large-scale’ propagation of corals for transplant to degraded reefs is ineffective when the return-time of severe bleaching events is 6 years or less.  It’s too little, too slowly, and corals are limited in how fast they can grow.  Photo of Indonesian coral farm © SA Simbolon

  • FOUR The future that is likely even under the most optimistic IPCC scenarios (i.e. +2o or +1.5oC above preindustrial) looks marginal for coral reef systems. Current trajectories of GHG emissions, which are insufficient to restrict warming to +2oC, are also woefully inadequate if we want to have any coral reefs on this planet beyond mid-century;

Although the Paris climate agreement commits the world to reduce emissions of GHGs and keep warming below +2oC, global emissions continue to rise.  Warming well above +2oC looks very likely by the end of the century.  Image © Global Carbon Project and Inside Climate News.

  • FIVE On the other hand, with aggressive GHG emissions abatement, coupled with vigorous management of reef systems to address our other negative impacts, we could achieve a post-2050 world with viable reef ecosystems continuing to provide the important ecosystem services they now provide;

It will be difficult, perhaps impossible, to retain reefs as rich as this one on our planet later this century.  But achieving this is a goal worth striving for.  It will require aggressive containment of GHGs as well as excellent management of local stressors of coral reefs.  Photo of Red Sea reef, winner in 2015 Underwater Photographer of the Year competition, © Lynn Wu.

  • SIX Coral reefs are not alone among ecosystems in being affected by climate change. While the impacts of climate change on reefs are already both extreme and starkly clear, reefs provide an early glimpse of the danger we are causing to many other parts of this planet’s biosphere through our careless dumping of GHGs into the atmosphere.  We need to take much better care of this planet.

Poem by Joe Miller.  Text Image © The Friend

Categories: Climate change, Communicting science, coral reef science, In the News | Comments Off on Sobering News on Coral Reefs – But We Knew It Would Come to This