And evolution had more than a one hundred year head start on global warming (with the public!)
Climate scientists and educators can actually learn a lot from the long battles over the teaching of evolution in schools.
Tuesday, January 08, 2013
We really have work to do
Climate scientists and educators can actually learn a lot from the long battles over the teaching of evolution in schools.
Monday, January 07, 2013
Thursday, January 03, 2013
Climate change in the age of truthiness
Does reality shape our beliefs, or do our beliefs shape "reality"?
A fascinating paper by "Did the Arctic Ice Recover? Demographics of True and False Climate Facts" by Lawrence Hamilton examined this question using polling data on people's beliefs about climate change and their knowledge of several key climate facts, including that the Arctic sea ice is decreasing.
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Record low Arctic sea ice, September 16, 2012
(NASA/Goddard Scientific Visualization Studio) |
Hamilton argues that two things are at play here. One is simply science literacy: if you are right about the facts, you likely believe climate is changing. The other is what experts call "biased-assimilation": you choose or seek facts that match your worldview. The results are not that surprising in light of all the research on public perception of scientific issues. On the ice question, wrong answers are predicted by the responses to political and belief factors in the poll.
This post was inspired not so much by that core finding, as by something in the background polling data: more people (70%) knew that there is less Arctic sea ice(than 30 years ago) than knew that CO2 concentrations were increasing (~60%) or than knew the meaning of the greenhouse effect (~55%).
The fraction of the respondents aware of the increase in CO2 concentrations is not in itself surprising. Though lower than what most of us in the science community would like to see, it is decent considering low public literacy on so many different science issues. What's really striking is that more people know about an impact of climate change than the main driver of climate change.
This raises two interesting, and quite different questions, which I'll leave for readers to answer:
1. Do climate change communicators and the media work so hard to connect human-caused climate change to physical events that they neglect to reinforce the basic causes of climate change? Maybe we really are doing a poor job of communicating the basic facts.
2. Does it matter? In more explicit terms, does everyone need to understand the guts of what is causing climate change, or is it enough to know the impacts, and trust that there are people with expertise who know why it is happening? Many communication and sustainability experts I encounter argue that public education about climate science is largely irrelevant; so long as people trust there's a problem, something that education about science alone cannot change, and see benefits from possible solutions, what is the difference?
One note on the latter: Though I find this attitude is troubling, as I should being in a profession centered around education, it is food for thought. After all, we make decisions everyday predicated on science that we do not understand. We take medication. We use computers. And, as Richard Alley reminds regularly in presentations, we use, or at least trust the concept of, heat-seeking missiles, whose development hinged on the discovery that CO2 is a greenhouse gas.
Monday, December 17, 2012
Changing the IPCC to better meet the needs of international climate policy
One seemingly minor and unreported component of the recent UN climate talks in Doha highlights the drawbacks of old-school scientific assessments and the need to modernize the IPCC process. It is especially relevant given last week's leak of draft IPCC reports and the ensuing discussion about changing the arduous and close IPCC assessment process.
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| IPCC Chair Rajendra Pachauri addresses the COP18 in Doha |
Put aside for a moment whether you or I think either goal is attainable; in fact, the final Doha text itself raises that question right off the start:
Noting with grave concern the significant gap between
the aggregate effect of Parties’ mitigation pledges in terms
of global annual emissions of greenhouse gases by 2020 and aggregate emission pathways consistent with having a likely chance of holding the increase in global average temperature below 2 °C or 1.5 °C above pre-industrial levels
The parties to the UN climate talks agreed to evaluate the temperature targets, because of concern in developing nations, particularly the small island states, that +2°C warming will lock-in unacceptable climate impacts. The outstanding question at Doha and the last meeting in Durban was how will those evaluations happen.
At the bottom of the agreed Doha text, after all the publicized issues like the Kyoto extension, long-term agreements and financing arrangement, is the plan:
79. Decides that the review should periodically assess, in accordance with the relevant principles and provisions of the Convention, the following:
(a) The adequacy of the long-term global goal in the light of the ultimate objective of the Convention;
(b) Overall progress made towards achieving the long-term global goal, including a consideration of the implementation of the commitments under the Convention;
After outlining some of the logistical details, come the guts (italics are mine):
86. Decides to establish such a dialogue under the guidance of the subsidiary bodies on aspects related to the review in order:
(a) To consider on an ongoing basis throughout the review the material from the Fifth Assessment Report of the Intergovernmental Panel on Climate Change as it becomes available, as well as relevant inputs referred to in decision 2/CP.17, paragraph 161, that are published after the cut-off date of the Fifth Assessment Report, through regular scientific workshops and expert meetings and with the participation of Parties and experts, particularly from the Intergovernmental Panel on Climate Change;
The Doha text effectively states that the UN climate policy process requires something more "nimble" than the IPCC. This matches what many in the climate science and policy community have been saying since the last IPCC assessment was published in 2007. The IPCC is an amazing institution, with no real parallels in science. In what other field have the countries of the world agreed to gather panels of experts to conduct exhaustive, lengthy assessments of all the science on a subject, which are then open for review by anyone in the science community and representative of the government, and all on a volunteer basis? The IPCC process, though hardly perfect, is without peers.
It is also very old school. The IPCC is a product of the late 1980s, before the internet, before smart phones, and before we had overwhelming evidence for a human role in climate change. The IPCC assessments are the product of a long, exhaustive writing and reviewing process. They can only be completed every few years, and can not reflect research conducted within 1-2 years of when the assessment are published. As such, they do not cover some recent findings or advances in modelling. The process, and the desire for consensus, also leads to conservative decisions, like the decision to exclude then-uncertain contributions from ice sheet melt in the summary estimates of future sea level rise in the last IPCC assessment.
That sea level rise dispute likely drove the inclusion of the published after the cut-off date to the Doha text. The projections of sea level rise published after, and in response to, the last IPCC assessment presents a very different future for low-lying small island states, many of which were already lobbying for the lower temperature target. There's a good chance the lack of a permafrost methane feedback in most climate models, and hence conclusions of the upcoming fifth IPCC assessment ("AR5"), will lead to similar disputes after that assessment is released.
This raises an important question: If the UN negotiation process requests quicker turnaround reviews of climate science, reviews conducted by IPCC members, why continue doing full IPCC assessments after AR5? It is time to move to shorter, faster targeted reviews of key outstanding issues and areas of scientific uncertainty.
Friday, December 14, 2012
"Game-changing" leak from the IPCC reports? Please.
The supposedly game-changing evidence - that there may have been a great change in the sun's impact on the climate than previously thought - is just a classic case of rhetoric trumping data.
Notice there are no numbers in most of the quotes that Alec Rawls pulled from the IPCC report. Just because something is greater than previously thought does not mean it is a lot greater or a lot more important [besides, as Skeptical Science nicely reminds us, Rawls explanation makes no sense].
A couple years ago, I discovered that I am actually half an inch taller than what I had previously thought, a funny thing to discover at my age. That doesn't mean I'm going to try out for a NBA team, though I do suspect my 4-19 hometown Toronto Raptors could use some help at small forward.
The science is almost irrelevant here. The real issue is the nature of the IPCC. It does not conduct original research. The IPCC reviews and assesses the scientific literature on climate change through an exhaustive multi-year process. If there was some "game-changing" discovery about the sun's impact on the climate or any other key issue in the IPCC draft reports, that discovery would already have been reported by scientists in the literature that the IPCC reviewed.
At the absolute minimum, the discovery would be have been reported in scientific papers submitted to a journal before the long-passed deadline for the IPCC, and if the papers were by now published or publicly available, the contents would have been presented by the authors at prominent scientific conferences like last week's AGU meeting, which is so well reported that "AGU" was actually trending on twitter for half of the week.
If there was some "game-changing" discovery, we probably would have already heard about it in the news and we certainly would have heard it on blogs like Watts up with that.
Friday, November 30, 2012
The lowdown on COP18 in Doha
With that in mind, I thought it is worth reviewing just what is up for debate in Doha. The summit, as I see it, is being dominated by three key issues:
1. Renewing the Kyoto Protocol
That's right, Kyoto is still around. Those involved - the European countries,
The big stumbling block is accounting for the "hot air" permits. A number of eastern European countries in which greenhouse gas emissions dropped precipitously after the breakup of the Soviet Union, have been able to sell emission credits to countries who have not met their Kyoto targets. It looks as though several countries will have extra emissions credits once the first commitment period comes to an official end this year. Naturally, they'd like to carry the credits over to the second commitment period. Doing so, however, would compromise the new targets being discussed; with few big emitters participating in round two, the remaining non-eastern European countries would be able to meet the otherwise ambitious reduction targets with small actual changes in emissions.
2. Slow march to a universal emissions agreement
3. Financial and technical assistance to the developing world
Over the last three summits, the developed countries agreed to mobilize $100 billion per year by 2020 to help the developing world address climate change, a subject I've discussed at length here and in other forums. One conduit for the money is the new "Green Climate Fund" (GCF), being managed by the World Bank, which is just setting up offices in Korea.
In Doha, all the country representatives will consider the report of the initial GCF board and decide on the relationship between the COP process and the GCF. It's the ugly machinery of policy. It's not glamourous, but it is important. The project documents talk about developing a "Results Management Framework". Before rolling your eyes, give this some thought. The framework will include how to do monitoring and evaluation, allocating funds based on results and developing performance measures. This stuff matters. For example, the verdict is still out on the plan to raise "fast-track financing" of $30 billion over the 2010-2 period; most major developed nations provided funds, but depending on what you count as "new" and "additional" funding, it does not add up to $30 billion, and in many cases, the money was only provided as a loan. That experience shows just how important ironing out the logistics of these programs matter: it might not garner headlines, but the grunt work on rules and regulations is critical to making sure funds are provided and used effectively.
In the end, is it all about the money?
All the management frameworks in the world won't help if the developed world does not "mobilize" - aid, matching grants, private investments, etc. - the money. The currently empty GCF is just part of the package. Though is only supposed to be one conduit of the $100 billion per year by 2020, the it is increasingly assumed to be the most important one (at least symbolically, as it is all we hear about). Yet the developed countries seriously disagree on how, when, and how much, to capitalize the GCF.
Right now, the documented recommendations for raising new funds (outside of private investments) include carbon pricing, taxing financial transactions, redirecting fossil fuel subsidies and emissions trading regimes for shipping and aviation. It is hard to see the world coming to an agreement on any of these, at least in the near term; you could argue that we're more likely to agree on an emissions reduction plan, which would have no mechanism for those reductions, that a global transaction fee going to address climate change.
Canada, which gets tarred in the media for lack of action on emissions policy, could actually end up as the inspiration leader to opponents of climate financing. After the last UN summit in Durban, Canadian Environment Minister Kent said the government would refuse to supply any money to the Green Climate Fund until all major emitters accept legally binding reduction targets. There is, as of yet, no evidence the stance has changed.
In other words, Canada is more or less arguing to hold adaptation hostage because we can't agree on mitigation. That's why experts are not joking when they say that the world might be better off if the Canadian government did not send any representatives to Doha.
Monday, November 26, 2012
Inconvenient meeting: the optics of talking climate policy in Qatar
Optics has never been the strength of the Conference of the Parties to the UN Framework Convention on Climate Change, currently happening for the 18th time in Doha, Qatar. Every meeting draws stories and editorial cartoons mocking climate change negotiators flying around the world, riding in huge inefficient cars, and staying in air-conditioned suites.
But... c'mon.
Whose idea was it to hold the climate meeting in the country with the highest greenhouse gas emissions per capita on the planet? Qatar is not just winning the per capita GHG race, it is Usain Bolt. No other country is even close. The per capita emissions are 43% higher than the runner up (2008 data from CDIAC). Could there possibly be worse PR for a climate meeting?
I hope I am wrong, and this all turns into a positive message for change.
Wednesday, November 14, 2012
Open thread on "Dirty Weather"
I'm curious to hear reactions to this year's 24 Hours of Reality multimedia event Dirty Weather, happening live around the world for the next day. It's an honest effort to get people talking about climate change, but it also may rub some the wrong way, something I heard a lot from people last year.
Are you watching (or did you watch)? Is it effective? Boring? Too dramatic? Too cautionary? Or did you not even know it was happening?
All thoughts are welcome, provided everyone is civil!
Make robots, save endagered species and help fisherman in Haiti
The latest round of Scifund Challenge began on Monday. There are lots of exciting projects this time around, from monitoring endangered species, to helping understand what's happening to Haitian inland fisheries, to making robots.
Salome Buglass, a new student with me here at UBC, is looking to raise funds to study how Tobago's coral reefs are recovering from two coral bleaching events in the past decade. Check out Scifund page for details on the project.
Here's the video:
Thursday, November 08, 2012
Storm surges, sea level and climate change
In the inevitable discussion about the relationship between climate change and Hurricane Sandy, there's been much focus on the storm surge. Hallelujah.
There are a lot of ways climate change could influence tropical cyclones. In the past, most of the public discussion had focused on warmer water temperatures driving more intense storms, based largely on research by Kerry Emanuel and others. The water temperatures are, however, just one factor.
Other important issues include how climate change may affect upper levels winds, which can 'shear' off storms; El Nino events, which itself affect upper level winds; mid-latitude pressure systems, which divert storms and affect their dissolution; patterns of ocean temperature change and hence storm generation and path; atmospheric moisture, and in turn, rainfall. All of these are complicated and uncertain. When the experts try to add it all together, the verdict is that it's hard to say just how climate change will affect tropical cyclone frequency and intensity.
The one area in which we can speak with some certainty is cyclone impacts - things like storm surges - rather than cyclone formation and frequency.
There's no reasonable doubt that the global mean sea level has risen due to climate change. The rise to date is largely because of thermal expansion of sea water; water gets less dense and expands as it warms (above the maximum density, 4 deg C for freshwater). If we are wrong about that, we may as well throw every physics textbook in a bonfire, but don't let me give the first year students here any ideas.
Here's the sea level data from Battery Park in New York City since 1856
The rise of almost 40 cm is not entirely due to sea level rise. As is explained clearly in this article by Chris Mooney, land subsidence, a New York legacy of the end of the last ice age, account for roughly half of the observed change. The rest is largely driven by global sea level rise. Thanks in part to climate change, the storm surge from Sandy was certainly higher than that of an identical hurricane at the identical time in the tidal cycle striking the coast 50, 100 or 150 years ago.
Now the difference noted here - 20 cm or so - is not large. Keep in mind, though, that there's a non-linear relationship between the surge height and the "run-up": how far the water runs up on to land. An increase in surge height can have a disproportionate affect on the the distance water travels inland and the erosive power. The exact relationship depends on the profile of the shoreline and the type of ground or sediment; this is evident in the stunning before and after Sandy images of the New Jersey coastline put together by NOAA (or images from the Japanese tsunami).
You might argue this is not so different from the ocean temperature argument: if everything else is equal, the same cyclone passing over warmer water will be more intense. The problem is that, in reality, everything else is never equal. That, in effect, is the theme of my article on sea level variability in Kiribati and the video we put together, using footage I'd gathered during field trips to Kiribati, about the causes of the loss of the island of Bikeman.
Monday, October 22, 2012
Sequestering carbon in the ocean is hard to do, and even harder to measure
The proponent of the iron dumping off Haida Gwaii last month, Russ George, claims to be a hero who is trying to fight climate change. Most other observers see him as a businessman hoping to raise money selling carbon offsets or carbon credits.
It is hard to see how this could ever become a credible business. In order to sell carbon credits, you'd to:
a) need to prove fertilizing the ocean with iron does lead to long-term storage of carbon in the deep ocean, an open question discussed in my previous post,
b) be able to measure how much carbon was stored
Even if (a) is proven correct, the accounting problem (b) remains.
This is where the Willmers et al. paper comes in. Kelp forests, common on the west coast, are among the most productive marine ecosystems, sucking carbon out of the atmosphere at high rates. You haven't been diving until you've had to unravel yourself and your gear from metres long strings of kelp. Willmers et al. calculates that kelp forest store about ten times more carbon is sea otters are present, because without the otters eating the urchins, the urchins eat all the kelp. As such, there could be a carbon incentive, and potentially a market, to maintaining healthy otter and kelp populations (no easy feat).
The problem? Just as in the iron case, it's really hard to measure how much of the carbon taken up by the kelp gets exported to the deep ocean, where it would be sequestered long-term. Since there's no precise data, the authors provide estimates of carbon export over a range of 1% to 50% of the kelp carbon uptake. This no fault of the authors: deep carbon export from productivity on the surface is hard to measure and predict, so they've chosen an uncertainty range. The huge range is reasonable for the discussion section of a paper on carbon uptake in kelp forests. But it won't fly with accountants who need to sell the carbon credits.
(Photo credit: Monterey Bay Aquarium)
Tuesday, October 16, 2012
Is the iron fertilization project off Haida Gwaii a science experiment, business opportunity, or uncontrolled geoengineering?
News outlets around the world are buzzing with evidence of a recent attempt to fertilize the ocean off the BC coast with iron pushed by a US businessman and funded in part by a group called the Haida Salmon Restoration Corporation.
The driving force behind the project, Russ George, is notorious in oceanography circles for the company Planktos, which tried and thus far has failed, to create a carbon credit business out of fertilizing the ocean with iron.
The current project is like a bad movie script, complete with the a maverick businessman, international treaties, global environmental challenges, local environment costs, possible exploitation of innocent people, you name it.
From what I have learned so far, it looks like the only redeeming thing out of this event is it will give my biogeochemistry class something to discuss next week. I'll tackle my two science-based concerns, then discuss the two broader issues:
The science of fertilization
Iron is limiting to algae growth in much of the open ocean, which means if you add iron to the ocean, algae will uptake more carbon from the atmosphere via photosynthesis. However, creating a plankton bloom does not necessarily permanently remove carbon from the atmosphere. For that, the organic carbon produced through photosynthesis needs to be sequestered in a some reservoir which, unlike algae or most plants, has a long-life time (otherwise, it could decompose and be returned to the atmosphere as carbon dioxide).
If you were trying to sequester carbon by fertilizing a grassland, the key would be getting that the organic carbon produced by the grasses into the deep soil, where it will stay for a reasonably long time. In the ocean, the organic carbon needs to be exported to the deep ocean, and stay there, ideally getting buried sediments. There it could conceivably remain for thousands of years, rather than returning to the atmosphere. So you need to track the sinking of carbon from the surface, through dead plankton, fecal pellets of things that eat plankton, etc.
And, yes, I wrote fecal. If you want to do biogeochemistry, you do have to talk about feces, it is one of the most important mechanisms through which the planet recycles key nutrients.
The key question then is not "How big is plankton bloom?", but "How much carbon was exported into the deep ocean?". This has been the subject of a huge amount of research in the past 20 years. The scientists quoted in the news articles are extremely critical because they know iron fertilization is very complicated. This group does appear to be doing a suite of follow-up measurements, the details of which I do not. Without a huge investment in such measurements over very long periods of time - and I mean months to years, not days to weeks - it would be hard to take this project seriously.
The ancillary benefits
One of project rationales appears to be that it might help the local ocean and ideally the salmon fishery. To use a popular word, this is a bunch of mularkey. I'm not an expert on salmon, and I can't speak to the specific details of marine ecology off Haida Gwaii. The NW Pacific Ocean is not enclosed fish farm where adding some fertilizer means more algae for the fish to eat and thus more or bigger fish. In an open system with complex ecology, the long-term effect of the bloom on the fishery is highly uncertain.
The supposed salmon connection strikes me as a marketing cover story. It's no secret that the proprietor of Planktos who set up this organization with the Haida has been trying for years to create an business selling carbon credits or offsets through iron fertilization of the ocean. Even the current incarnation with the Haida has a clear carbon credit aim. The web-site lists a "sea" and "trees" side to the business. The trees side is directed towards forest restoration, clearly with the goals selling carbon credits for protecting or restoring the old growth in the region. Salmon is king here in B.C., slapping 'salmon restoration' onto a project gives it an air of nobility.
The media coverage has done a decent job representing these points about geo-engineering and marine ecology, thanks in part to the outrage among scientific experts who have been quoted. I'll close with a two non-scientific aspects of the coverage which I found a bit troubling:
The role of the Haida
Every story I've seen mentioned the possibility that Russ George is "taking advantage of the Haida". This claim may be well intentioned. Unfortunately, it is also rather paternalistic. It plays into some very old-fashioned racial assumptions, implying that the first nations people were bamboozled by some white man with money and fancy ideas. It may just be that the local people chose to be involved, not out of ignorance, but out of an understanding of the potential financial benefits of setting up a carbon offset business.
Is this geo-engineering?
Michael Tobis raises this important point. The existing geo-engineering treaty is non-binding, meaning the language in the treaty is aspirational and there are no penalties to ignoring the proposed ban on geo-engineering projects.
But we need to ask a broader question. If there were a legally-binding international ban on geo-engineering, would this stunt count? If every one-off dump of iron filings into the oceans counts as geo-engineering, shouldn't every tree planting project?
Definitions will really matter here. A binding treaty would need to set some minimum climate or carbon impact on projects, otherwise a lot of what people and companies do as a part of their everyday business will count at geoengineering. We need to, er, see the forest for the trees. A geo-engineering treaty should be there to control against dangerous large-scale experiments, like reducing the incoming solar radiation, not every carbon sequestration effort.
Given this last point, I think if we are to prosecute the organizers of this stunt off Haida Gwaii, it should be for the marine pollution, like an oil spill, rather than the attempt at geoengineering.
Wednesday, October 03, 2012
Search trends show more interest in the Pacific garbage patch than other ocean threats
As I mentioned on Twitter yesterday, ocean acidification appears to be surpassing coral bleaching in the public imagination, at least according to a comparison of Google searches over the past few years.
Attention to ocean acidification and coral bleaching is now far surpassed by attention to the Pacific garbage patch.
Many factors may be at play here, including NGO and media focus on the Pacific garbage patch. Regardless, I can't help but wonder if the dominance of the garbage patch points to the power of the visceral, and the inherent struggle communicating "invisible" environmental changes, like ocean chemsitry changes, and in some ways, even climate. Sure, coral bleaching is visceral, but it is also foreign to most North Americans, and the causes of bleaching are invisible. But garbage? People can all relate to garbage. You can see it and smell it. Garbage is also a good metaphor; the ocean is literally our dumping ground.
Thursday, September 27, 2012
Blast from the past: Canadian Environment Minister Kent, in 1984, on climate change
This 1984 documentary, hosted by former journalist and current nemesis of climate activists and policy experts Peter Kent, comes courtesy of the CBC's fantastic digital archives. Oh, the times they are a changing.
Wednesday, September 19, 2012
Limiting global warming to 2 deg C is unlikely to save most coral reefs: a discussion
The paper might look like the same old, same old from scientists about climate change and coral reefs, a bunch of sky-is-falling pessimists out to spoil the release of the 3D version of Finding Nemo. Certainly, go ahead and see the movie, it provides a pretty scientifically accurate picture of life on a “healthy” coral reef in terms of the oceanography and the behavior of reef organisms (except for the small matter of the talking fish, and, really, if a Great Barrier Reef clownfish did evolve the power of speech, wouldn't it have an Aussie accent?).
It's worth also learning about what is new in this paper, and what we understand about the threat coral reefs face.
The general findings of Frieler et al. might not come as a surprise to people following the scientific research on climate change and coral reefs. The paper does, however, employ some important new methods and offer valuable new analyses. I'll point to three keys:
1. The focus on "global" temperature thresholds
Frieler et al. relates the projected frequency of heat stress events – what I often call ocean “heat waves” – in coral reefs worldwide – that can cause coral bleaching to global mean temperature change, the metric discussed so often in policy circles, the public and the press. In past studies, including several of my own (Donner et al., 2005, 2007), we estimated the frequency of bleaching events under different future greenhouse gas scenarios. In those studies, we are able to show the difference in the outcome for coral reefs between futures with different levels of atmospheric carbon dioxide (and other greenhouse gases). For example, my “Coping with Commitment" (open access) paper concludes with a discussion of the level of atmospheric CO2 necessary to avoid one definition of "dangerous" impacts to coral reefs.
In those past analyses, though, if you wanted to know what the coral reefs picture looked like under some specific global mean temperature increase – like, say, the proposed 2 deg C threshold – you’d need to take apart the results and find the point in the emission scenarios were global average warming reaches (or, depending on your question, stabilizes) at that level. In response to a request in advance of the UN Copenhagen climate summit in 2009, a group of colleagues and I did that analysis (pdf) for the Caribbean and found a clear difference between the coral reef outcomes in +1.5 C and a +2 C world. Frieler et al is the first paper to do a comprehensive analysis of coral reef outcomes under different temperature thresholds for the whole planet.
2. More robust analysis of uncertainty
Frieler et al. is based on output from a huge range of climate models and scenarios, unlike previous work which employed only one or a few models. The study employed output from 19 different climate models running up to seven different scenarios, working to 32,000 model “years”. Are the numbers just inside baseball? Actually, the approach is important for two reasons. First, the vast quantity of information about the possible futures allowed the team to essentially invert the results; instead of looking at the coral reef results in the individual scenarios, the climate model output was all combined together to create a relationship between global average temperature change and the temperature change at all the reef sites around the world. This enabled the previously mentioned analysis: rather than look at the bleaching frequency for different reefs under different emissions scenarios, this study was able to look at the bleaching frequency for different reefs based on the global mean temperature change.
Second, with so many models included in the analysis, the study was also able to calculate a more complete range of uncertainty in the results. My past studies, for example, employed output from individual models which were determined, from analysis, to best represent the month-to-month and year-to-year variability in tropical ocean temperatures (important since coral bleaching is a response to unusual warmth, or “heat waves”). The approach is quite sensible, but naturally led to the question: what do the other models say? Frieler et al. answers that question, and the answer is that, in general, the results are robust across all climate models.
3. Influence of ocean acidification
Frieler et al. estimates the possible influence of ocean acidification on coral bleaching. Past studies, including my own, have roughly looked at the potential “positive” effect of thermal adaptation by individual coral species (physiological acclimation or actual genetic adaptation to warmer temperatures) or communities of coral species (the tough species survive, etc.) on future projections of coral bleaching and reef health. Until now, however, they have not looked at the possible inverse effect of rising levels of carbon in the ocean. There is some experimental and observational evidence that with more carbon dioxide dissolving in the ocean, corals may bleach at lower temperatures (e.g. Anthony et al., 2008). This not a certain outcome in every, or any, case; research on synergies between bleaching and acidification is still ongoing.
So in Frieler et al., we do a sensitivity analysis: how would this opposite effect of ocean acidification on bleaching thresholds affect the future bleaching projections? The general answer is, not very much, because by time the acidification effect is large enough to substantially alter the bleaching thresholds, most coral reefs are already experiencing dangerously frequent bleaching events. I recommend digging into the online supplement that accompanies the article for more on this subject.
So what?
In the end, perhaps what’s most striking about the study is that despite many methodological differences from previous work, the results are not surprising. In that sense, the paper shows how robust the overall climate forecast is for coral reefs.
Frieler et al. also points to the importance of identifying the corals, habitats or entire reefs that are more resistant (can withstand a heat wave) or more resilient (can recover from a heat wave) than the norm, figuring out what exactly makes them tougher, and then targeting conservation at reefs with the right characteristics. This was the subject of a recent analysis by McClanahan et al. in PLoS-One (open access), and is the inspiration for my field program in Kiribati.
Wednesday, September 12, 2012
Are Caribbean coral reefs on the verge of collapse?
The decline of the reefs has been rapid: in the 1970s, more than 50% showed live coral cover, compared with 8% in the newly completed survey. The scientists who carried it out warned there was no sign of the rate of coral death slowing.
Coral reefs in the Caribbean certainly are, in a mean sense, in a serious state of decline. The presentation of the data in the Guardian, however, could lead to confusion.
The data is based on the preliminary report (pdf) of a Global Coral Reef Monitoring Network (GCRMN) workshop held earlier this year. The graph at right, taken from the report shows the decline in "percent coral cover" averaged across all reefs with observations in the GCRMN data (black) and an earlier study by Gardner et al. The percent cover dips to ~8% at the end of the longer GCRMN dataset.
That means that the average percent coral cover at the reef sites in the dataset is 8%. It does not mean that less than 8% of reefs had any live corals.
This two statements are the difference between the optimist saying glass is half-full and a mistaken pessimist saying only half of the glasses have any water at all. If less than 8% of the reefs in the Caribbean featured any live coral, then Caribbean coral reefs would not be on the verge of collapse. They would have already collapsed.
This is merely a potential (mis?)interpretation of the wording of the article. The greater concern about the Guardian coverage is that it appears to have missed the three key findings listed right in the Executive Summary. Here's a snapshot:
The first two points stress that the status of coral reefs varies greatly across the Caribbean, from the relatively high cover reefs of the Cayman Islands to the lower cover in places like the US Virgin Islands, which were affected by recent bleaching events. The headline should be that "some" Caribbean coral reefs appear to be on the verge of collapse.
This matters. The sites that have bucked the downward trend just might be able to teach us something about how coral reef resilience to climate change and local disturbance, and maybe even give us some insight into management and marine park design. That's point #3, and the one of the major inspirations for doing this type of analysis in the first place.
Tuesday, August 21, 2012
Drought and ethanol crunch U.S. corn crop
The U.S. shifting from fueling animals with corn to fueling cars with corn. I wrote about this a few years ago in a piece in Momentum Magazine, and my colleague Chris Kucharik and I alluded to this inevitability in our 2008 paper on corn ethanol production and the Gulf of Mexico 'Dead Zone'.
Corn production has close to doubled since the early 1980s due to technology, fertilizer and the like increasing crop yields, and to an ethanol-driven increase in planted area over the past decade. Thanks to the increase in production, the U.S. was, until a couple years ago, able to produce all the corn ethanol without really denting the total amount of feed produced (or the amount of what I've labelled sweeteners and others, which includes high-fructose corn syrup, seeds, glucose / dextrose, floor waxes, xathan gum, pens, lecithin, breakfast cereals, adhesive tape, etc; OK, I admit, I made one of those up, but seriously, only one, and I could be wrong, that one may actually come from corn).
Now, ethanol production is coming at the expense of feed and exports. Last year, feed production was the lowest since 1995, which was a low corn production year, and exports were at the lowest since 2006. In the 2008 paper, we predicted this would happen simply because of land availability. There's only so much productive cropland not already needed to for other grains and oils that can be used to produce high-yielding corn. In order to reach the goal of 15 billion gallons of corn-based ethanol per year, corn would have to be diverted from its other major uses, namely feed and exports. I'd like to claim I was brilliantly prescient, but the math was pretty straight-forward (though very very time-consuming to do properly, a reminder that science is often about the grunt work, not the exciting discovery).
This year, despite the devastating drought, there's still plenty of corn being produced. Total corn production is right at the level of the middle of the last decade (the 2003-2007 average, to be precise). The supply issue is about ethanol, which is expected to use up almost 42% of this year's corn crop (figure at left). The drought is exacerbating the effect of ethanol production on the availability of crops for other uses. According to the USDA's preliminary estimates for the 2012/2013 crop year (the last set of data on the chart above, listed as 2012 for convenience), the drought will drop overall corn production by about 13% from the previous year, but ethanol production will only drop by 3%. Feed production will be the lowest since the 1988 drought, a low level not generally seen since the 1970s. Similarly, exports will be the second lowest since 1980. The tight supply of feed and decline in exports, together with speculation about those same two things, is affecting prices, which can in turn affect food availability in other parts of the world.
There's been much talk of whether this year's drought and any impending price-driven food crisis can be linked to climate change. That's impossible to answer definitively. Instead, we should think about the following: This year is an example of how poor climate change mitigation decisions - corn ethanol production, an answer that was looking for a question - can make the world less resilient to climate change.
Monday, July 30, 2012
Proposed pipelines undermine Canada's climate target for 2020
The carbon emissions embedded in bitumen that would be transported by the proposed pipelines across BC would not only dwarf the emissions from the province itself, as I discussed last week. It would completely undermine not just B.C.'s emissions reduction policy, but the entire country's policy. The graph shows the estimated gap (i.e. necessary reductions) between the most recent national emissions estimate (2010, 692 Mt) and the policy goal for 2020 (17% reduction, ~607 Mt). The emissions embedded in the proposed Northern Gateway pipeline (82.5 Mt) is alone almost as great as the Canadian 2020 emissions gap (85.3 Mt). Add the Kinder Morgan twinning, and the carbon emissions embedded in using the pipelines would make a mockery of any efforts to reach the federal target.
We'd be reducing emission from the country, but increasing emissions in other countries. The climate does not care whose balance sheet lists the carbon. Maybe if the federal government wants to referee this growing inter-provincial battle over the pipelines, it needs to be willing to talk climate.
Tuesday, July 24, 2012
Pipelines would dramatically increase carbon emissions from BC, depending how you count
Carbon emissions received little attention in the coverage of this looming BC-Alberta dispute. The annual flow of carbon through the proposed Enbridge Northern Gateway pipeline, presuming it is fully operational, is equivalent to more than all current greenhouse gas emissions from British Columbia, home to 4.5 million people. Add the proposed addition to the Kinder Morgan pipeline, as well as current oil exports from the province, and the total oil exports is equivalent to almost 2.5 times current BC emissions and 3.5 times the provincial emissions target for the year 2020.
True, carbon exports are not usually counted in emissions budgets. The emissions are credited to jurisdication where that carbon is actually oxidized to create carbon dioxide.
That carbon might not count on our balance sheet, but maybe responsibility is about more than the finer points of accounting. After all, the climate does not care where the carbon is burned.
Friday, July 13, 2012
Coral reef decline disproportionately impacts the developing world
The International Coral Reef Symposium (ICRS), on right now in Cairns, Australia, is generating headlines about the plight of the world's coral reefs in the face of climate change and ocean acidification. Perhaps we should call it ocean change.
Amid the Disney movies and all the colourful documentaries about coral reefs, it is easy for people in the mid-latitudes to miss the fact that coral reefs provide valuable "services" - food, shoreline protection and income - to millions and millions of people most of whom are in the developing world. For a paper in Bioscience five years ago, David Potere and I calculated the number of people living close to coral reefs. The map below shows coral reef locations in red, with dot size exaggerated for viewing purposes, and the per-capita GDP shaded in green. According to our analysis over 63 percent of the people were living within 100 km of coral reefs, a total of 415 million people, reside in countries with a per capita GDP less than US$5000 (in 2003 dollars).
In the past few years, scientists have finally woken up to this fact, and though I am not there, I can tell you that a lot of the work at conferences like ICRS is now devoted to the human implications of coral reef decline and to finding good adaptation strategies.
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