Climate experience makes some corals more resistant to heat stress

Preserving coral reefs, and everything they provide to communities across the tropics, on a warming planet will require identifying what might make a coral less susceptible to heat stress.

One of the big questions being studied by a number of scientists in the community is whether past temperature experience can make individual corals (by individual acclimation or adaptation) or coral communities (by selecting for tougher species) more resistant or more resilient to heat stress. I've been leading field projects in the Gilbert Islands of Kiribati, where this whimsical coral can be found, because the unique El Nino-driven climate provides a great natural laboratory for studying that big question.

In the lastest publication on this research, my colleagues Jessica Carilli (the lead author), Aaron Hartmann and I describe how massive corals on the atolls which naturally experience more frequent heat stress appear to have been more resistant to the recent El Nino-driven ocean heat waves. For an accessible summary of our findings, I recommend listening to this past weekend's episode of CBC Radio's Quirks and Quarks. But you can also read the paper itself: the journal PLoS-One is online and open access to all.

The research involved drilling coral cores, Jess Carilli's area of expertise, from sites around three different atolls, followed by some exhaustive lab analysis by my colleagues. The logistics of collecting the samples from the outer islands was unbelievably complicated, even for someone who knows the challenges of working in a remote island country. Just getting all the gear to Butaritari (that's the seat beside my flip-seat on the plane), making it all work and bringing the samples back intact will probably go down as our greatest accomplishment in science. We owe a huge thanks to local colleagues Aranteiti Tekiau, Toaea Beiateuea, Iobi Arabua and the late Moiwa Erutarem, who sadly was lost at sea six months after our expedition.

In the month of May, I'll be fundraising for the in-country expenses of a planned, future expedition through the second Scifund crowd-sourcing science funding campaign. By sheer coincidence I will actually be in Kiribati during some coral monitoring during most of the Scifund campaign. I'll try to put trip updates on Maribo whenever I find internet access.

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Mountain pine beetle upends the Canadian emissions picture?

The lastest Canadian greenhouse gas emissions data looks very different if Canadian forests are taking into consideration.

There was some rejoicing over the fact that Canada's GHG emissions grew by only 2 Mt CO2e (that includes CO2 plus other GHGs converted to "units" of CO2) or 0.25% from 2009 to 2010, despite the fact that the economy was rebounding from the recession. But if you include land cover, land use change and forestry, GHG emissions grew by 86 Mt from 2009 to 2010.

Why such a large change? According to the Canadian government model, forests went from a net sink of 17 Mt in 2009 to a net source of 72 Mt in 2010 (see Table 7-1 in NIR). If you

break the GHG balance of forests up by region, the driver of this change was the "Montane Cordillera", or #14 on the map to the left. These forests of western BC were a net source of 100 Mt. The only other net sources regions in 2010 were the "Boreal Shield West" (#9 at 22 Mt), the "Pacific Maritime" (#15 at 5.7 Mt) and the "Taiga Shield East" (#4 at 1.7 Mt).

There are large, natural year-to-year variations in forest carbon balance, so it's important not to read too much into the jump from 2009 to 2010. What the 2010 number does reflect, however, is the very large amount of carbon, in the form of dead wood, in BC that is waiting to be respired to the atmosphere (if we don't use sequester it in buildings). For that, we can largely thank the Mountain Pine Beetle, the outbreaks of which have been linked to climate change. From the National Inventory Report:

The upward trend in dead organic matter (DOM) decay since the year 2000 reflects the long-term, growing effect of past disturbances, especially insect epidemics that have left substantial quantities of decaying DOM. Over the last decade, insect epidemics have affected a total of over 56 Mha3 of managed forests, with 72% being located in the Montane Cordillera reporting zone and corresponding to the epidemics of Mountain Pine Beetle. In contrast, much of the interannual variability of the GHG budget of managed forests hinges on the occurrence and severity of fires.

Before you start screaming "cover-up", it is standard UN reporting practice, to not include land use, land cover and forestry in the "total" at the top of the GHG inventory tables. This is done for a number of legitimate reasons, not the least of which being that net emissions from forests must be estimated by models and, as I've said, the results vary from year to year because of climate variability. Nonetheless, it is striking that climate change, via its effects on Canadian forest, might be undoing the reported progress in curbing, or starting to curb is a better term, greenhouse gas emissions from some sectors of the Canadian economy.

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Climate in the era of humans

The latest episode of the radio show and podcast Big Picture Science is all about the idea that we have entered the "anthropocene" or era of man. The guests include William Steffan, talking about the anthropocene concept, and a host of others including yours truly discussing the evidence that humans are changing the climate, and how we can best describe that evidence to people.

On a related note, the Yale Climate Media Forum has a story up about whether culture matters in discussing climate change, based on my upcoming publication on belief and climate change. 

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Climate change debates and flags of convenience

One of the perverse thrills of paddling in Vancouver is cozying up to the massive container ships parked out in English Bay (right). A little while back, I paddled past one rusting behemoth with the word "Monrovia" painted in white on the red hull. Each letter was about the size of my little kayak.

Monrovia is the capital of Liberia, the country where that vessel is registered. There is no thriving trade between Liberia and western Canada. Merchant ships merely register in Liberia in order to avoid regulations and to reduce costs. Liberia is the flag of convenience.

As a scientist, I sometimes find the challenge of communicating about climate change similar to that of operating a ship according to the rules of your native country while the "competitors" take advantage of the lawless wilds of other nations.

People opposing the basic science of climate change in the public sphere need not adhere to the slow, rigorous method of hypothesis testing or build coherent arguments over time based on the balance of published evidence. That provides the rhetorical advantage of adopting whatever "flag" or argument is convenient that week, whether about sunspots, an error in an IPCC report, or temperature trends on Mars. If the argument is proven false in the court of public opinion, you adopt another flag. The sequence of arguments does not have to be logically consistent. The goal of the organized sceptic movement* is simply to keep the ship sailing.

The temptation for scientists to adopt the practices of the opponents in the debate is what the late Steve Schneider described called the "double ethical bind" in a famously mis-used quote:


On the one hand, as scientists we are ethically bound to the scientific method, in effect promising to tell the truth, the whole truth, and nothing but – which means that we must include all doubts, the caveats, the ifs, ands and buts. On the other hand, we are not just scientists but human beings as well. And like most people we’d like to see the world a better place, which in this context translates into our working to reduce the risk of potentially disastrous climate change. To do that we need to get some broad based support, to capture the public’s imagination. That, of course, means getting loads of media coverage. So we have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we might have. This “double ethical bind” we frequently find ourselves in cannot be solved by any formula. Each of us has to decide what the right balance is between being effective and being honest. I hope that means being both

The response to that honest, clear assessment of the communications challenge says enough. For years, that one line about offering up "scary scenarios" was itself a Liberia to many of Schneider's opponents.

It can be challenging to stay level-headed about communication in the face of often unscrupulous opposition. That's why I find that the keys to communication about climate change are not the usual suspects of technical expertise, passion, ability to drop jargon, etc. etc. In my experience, successfully communicating about climate change takes, more than anything else, patience and humility.

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* Note: It's important to separate the funded movement from individual people's doubts about the science of climate change, which can be grounded in science, culture, religion, politics, moral values, you name it. And there are vocal sceptics who rely on a consistent line of argumentation; perhaps Lindzen's earlier arguments about the water vapour feedback could fall in this category, though it's fair to say that ship has since migrated to other shores.

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Nutrient limitation missing from an otherwise good NY Times story on forests and climate change

The NY Times published a lengthy article about the climate implications of the forest diebacks and fires. It is, on the whole, a great and all-too-rare example of longform science journalism.

The article does miss one important point about CO2 fertilization, the increase in plant growth thought to come from adding more CO2 to the air.

Climate-change contrarians tend to focus on this “fertilization effect,” hailing it as a boon for forests and the food supply. “The ongoing rise of the air’s CO2 content is causing a great greening of the Earth,” one advocate of this position, Craig D. Idso, said at a contrarian meeting in Washington in July.

Dr. Idso and others assert that this effect is likely to continue for the foreseeable future, ameliorating any negative impacts on plant growth from rising temperatures. More mainstream scientists, while stating that CO2 fertilization is real, are much less certain about the long-term effects, saying that the heat and water stress associated with climate change seem to be making forests vulnerable to insect attack, fires and many other problems.

The CO2 fertilization effect is limited, because plants require more than just CO2 to do their job:  photosynthesis. Water is certainly a limiting factor, but nutrients are just as important. In experiment after experiment, scientists find that the CO2 fertilization effect is short-lived without additional inputs of nutrients, particularly nitrogen.

One of the reasons CO2 fertilization may have accelerated plant growth in parts of Europe and North America over the past few decades may be the fact that we've inadvertently been fertilizing the plants with nitrogen, as well as CO2. We'll actually be talking about this in GEOB400 in a couple weeks. For the 6.7 billion or so of you who were unable to register this semester - yes, yes, the class is too small, I hear that all the time - I wrote about this on Maribo a few years ago, in a cross-post with Eli and Tamino:

One culprit is carbon’s chemical sibling nitrogen, that’s #7 on your periodic table if you’re scoring at home. Like many siblings, carbon and nitrogen are quite co-dependent, and, one might argue, a bit resentful about the whole thing. Carbon fixation - photosynthesis, plant growth – is limited by the availability of nitrogen. Though only up to a point. If there’s too much nitrogen, things get saturated, and the carbon-based plants pout and refuse to grow more.

You might find it strange that nitrogen is limited, given that N2 or di-nitrogen gas makes up the majority of the atmosphere. However, N2 is unreactive. It only becomes available to plants when converted to reactive form by microbes. In the process of making fertilizer and burning fossil fuels, we not only have increased the rate at which this conversion happens, leaving more nitrogen in our soils and waterways, we've emitted nitrogen in other reactive, gaseous forms, like nitrogen oxides or NOx...

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The folly of broad statements about adapting to climate change

In my climate change course, we devote a week to discussing climate and past civilizations. Among the goals of that week is to erase the notion that climate change is inherently "bad", or inherently "good", from the student's minds. The effects of climate change on any system, whether a society or an ecosystem, depends on the adaptive capacity and the rate of the climate change. The same climate change that spelled the end of the Norse settlements in Greenland did not affect (ed. crowd-sourced copy editing) the well-adapted Inuit of the region.

A recent, and controversial, book hypothesizing that the Easter Islanders were not done in by "ecocide", as argued by Jared Diamond and most archaeological evidence suggests, led to some discussion about the societal resilience to climate change. All roads lead to climate these days, I guess.

Judith Curry concludes a post on the subject with this statement, which supports a dangerously simple view of adaptation to climate change:

Occam’s razor suggests that we should tend towards simplest theories.  However, in complex coupled social-ecological-environmental systems, simple theories are almost certain to be too simple.  The complexity of such coupled systems precludes simple cause-effect analyses.   If we are arguing about such a system on the scale of Easter Island, what hope do we have of understanding and managing such interactions on  continental or even global scales? Ecosystems eventually adapt to climate change and insults from humans.

The comments about Easter Island notwithstanding - we argue about places like Easter Island because it all happened in the past and thus evidence is disputable, not because we can't understand complex systems - this statement concludes with exactly the type of simple, blanket view of complex problems that we should be teaching students to avoid. Theories like "Ecosystems eventually adapt to climate change and insults from humans" are indeed too simple!

Ecosystems do adapt. In a broad sense. But the question is not if they can eventually adapt, because we don't live in eventually. And, regardless of the time frame, we must remember that adapt itself is a vague term. To estimate the impacts of climate change, or other human insults, in the real world, we need to delve deeper and dispense with the vague generalities:

1. Define eventually: At what rate can the system adapt? Is the change happening faster than ecosystems, or people, can adapt such that they stay in the present state?
2. Define adapt: What exactly does adaptation look like? Say, coral reefs can "adapt" (in a collective, rather than an individual biological sense) to climate change by killing off the less resilient species and growth forms. That, for example, may be what is happening in South Tarawa where I do field work. You've got reefs dominated by a single, weedy species, and little habitat diversity. This new adaptation may not be desirable for those who depend on the ecosystem.

That's science. You don't just assume away an answer ("oh, we'll be just fine") based on a pre-conceived notions of what's "good" or "bad". You gotta analyse the data, do the math, unpack how the system works.

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Climate change: An accounting problem

The latest RealClimate post, which describes the latest ice melt data from Greenland, features this really important figure. It illustrates an issue that arises every semester in my climate change course, and is, in a sense, fundamental to understanding to biogeochemical cycles and issues like why carbon is accumulated in the atmosphere.

The figure shows model-based annual anomalies (thanks ED) of snowfall (reddish-orange), water loss through surface melt and runoff (yellow) and net accumulation of mass (blue), all in Gt/yr. The key point is that an ice sheet shrinks not simply because it is melting (yellow), but because the loss of water through melt (yellow) is greater than the gain through snowfall (red). The difference is the change in mass (blue). It is an accounting problem; like your bank account, you need to look at the debits and the credits to know whether the balance is changing.

This is the same fundamental concept that  underlies carbon dioxide accumulation in the atmosphere, and as MIT management expert John Sterman has shown, befuddles most people. Carbon dioxide is accumulating in the atmosphere not simply because we are burning fossil fuels and clearing land, but because the flux in to the atmosphere from those sources is greater than the flux out (to land, and the oceans).

As an aside, in my climate change course, one of the many ways we discuss these points is by watching the infamous "CO2 is life" advertisements created a few years back by the Competitive Enterprise Institute. The "Glaciers" video cites scientific evidence for snowfall-driven growth of ice sheets in the interior of Antarctica to suggest that ice sheets around the planet are not shrinking. The mistake in the ad is that in order calculating whether an ice sheet is shrinking, on net, you need to do the full accounting of all inputs (from snow) and all the outputs (from melt), not just cherry pick one part of the ice sheet, or one flux in or out.

The CEI ads, by the way, are hilarious. If you've not seen them, you really must. They are well worth two minutes out of your day; the Onion News Network couldn't have come up with fake ads that funny.

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24 Hours of Reality, 365 days a year

If you missed it live, all of the videos from the 24 Hours of Reality are available online. Pick a region of interest and watch the video. Each hour is comprised of a short introductory video, a local speaker delivering a variation of Al Gore's presentation about climate change, followed by a panel of experts back at the studio talking about the science and the issues.

The panel members rotated throughout the 24 hours based on expertise, and who could stay awake. Kudos to Paul Higgins from AMS for doing the overnight shift as well as some of the daytime panels. It's worth watching the highlights from multiple hours and/or watching multiple panel discussions, as the rotating cast made for some fascinating and interesting conversations. I was a part of panels that included Al Gore and four scientists (Kotzebue, Alaska, Hour 4) as well as mix from academia, broadcasting the UN, Hollywood and NGOs (French Polynesia, Hour 5; Dubai, Hour 16).

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Climate reality... What a concept.

Starting a 8pm EST on Wednesday night, the Al Gore's Climate Reality Project will be doing a 24 hour live broadcast of people around the world talking about climate change. Here's their pitch:

24 Presenters. 24 Time Zones. 13 Languages. 1 Message. 24 Hours of Reality is a worldwide event to broadcast the reality of the climate crisis. It will consist of a new multimedia presentation created by Al Gore and delivered once per hour for 24 hours, representing every time zone around the globe. Each hour people living with the reality of climate change will connect the dots between recent extreme weather events — including floods, droughts and storms — and the manmade pollution that is changing our climate. We will offer a round-the-clock, round-the-globe snapshot of the climate crisis in real time. The deniers may have millions of dollars to spend, but we have a powerful advantage. We have reality.

I'll be taking part in some of the expert panels back in the studio, discussing some of the science and some of the issues after the on-site presenters are finished (for updates on times, follow me on Twitter: @simondonner).

As regular readers of Maribo, or people who heard my talk at AMS this spring know, I've been an advocate of what one might call a "humbler" approach to outreach about climate change. That approach is informed by my field research in the Pacific Islands, some related historical research over the past five years, and my outreach experience; the argument for it is described in a paper currently in press with the Bulletin of the American Meteorological Society (more on that later). I'll be bringing some of that thinking to portions of the broadcast.

In case you are not a child of the 80s... the title of this post is a play on a Robin Williams comedy album from the Mork and Mindy days.

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Was Hurricane Irene caused by climate change?

Every major weather event raises the same debate over the same unanswerable question: was it caused by climate change?

And every time, some prominent name or public figure, fed up with media coverage or with the persistence of skepticism about science or the lack of action, throws statistics out the window and says yes. Or says something like "Irene’s got a middle name, and it’s Global Warming", as 350.org founder Bill McKibben wrote in the Daily Beast. That in turn draws legitimate pushback, further polarizes the public discussion about climate change, and makes some long-time participants of the debate want to smash their head against a wall.

The good news is that this cycle has been going on for long enough that people have finally began to reword the question. In Climate Central, Michael Lemonick tried "Is climate change making this storm worse than it would have been otherwise?". That is a slightly better than the staple question, but still demands more certainty than can really be provided by the evidence.

The New York Times asked the subtly different, but far more sensible question: "Are hurricanes getting worse because of human-induced climate change?". By shifting from the particular storm to the sequence of storms over time, it becomes a question we can actually answer with data and statistics. As the article by Justin Gillis finds, scientists including NOAA's Tom Knutson, who I worked with on a related subject, are divided on the interpretation of past data on hurricane intensity.

Hurricane Irene was a reminder of one of factor that should draw more attention in the climate change and hurricanes discussion: rain. The worst damage from Irene came from the heavy rains and floods in Vermont and surrounding areas (the above photo is from CBC News). You can see the data yourself on the USGS real-time streamflow page for the state, a fantastic resource for everyone from regional planners to recreational paddlers (my old haunt the Millstone River in New Jersey reached almost triple the flood stage on Sunday) which may be subject to budget cuts.

If I had to place money on which feature of tropical cyclones or hurricanes would increase the most because of climate change, I'd bet on rainfall, ahead of other metrics like intensity (wind speed) or surge height. Warmer water means more evaporation; warmer air can hold more water.

That doesn't mean the flooding in Vermont was caused by human-induced climate change. But it might mean that we can get more agreement on the answer to the New York Times question.

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Faster sailing across the Central Pacific: Wind speeds and El Nino

The new paper by Young et al. about increasing wind speeds and wave heights over the past twenty years created a bit of a buzz in the climate science world, not to mention the sailing world. Finally some good news, the windsurfer in me first upon seeing the paper.

The paper itself does not speculate about whether human-caused climate change is the driver of the global trend in wind speeds. That may have been a wise choise, as it would be difficult, statistically or dynamically, to attribute the rend in the reasonably short time series (~23 years) to any single forcing factor.

The spatial pattern, however, is quite striking:

If there were no labels on this figure, I'd have guessed it was the trend in sea surface temperatures over the same time period. The steepest trend is in the Central Pacific, including the waters around the Gilbert and Phoenix Islands of Kiribati.

In a map of temperature trends over the past two to three decades, the Central Pacific should jump out because of the increasing frequency of "Central Pacific" El Nino events, also known as El Nino Modoki. The more freuqent occurences of the "CP" El Nino is a subject of much research, and has been attributed by some authors to climate warming. The CP El Nino is responsible for a number of mass coral bleaching events, including 2002-3 in the Phoenix Islands, 2004-5 in the Gilbert Islands, and 2009-10 across the whole region.

It is not surprising to find a similar -- at least visually, take this with a grain of salt, I've not done the statistics -- spatial pattern in the surface wind speeds across the Pacific. More frequent Central Pacific warm events likely means larger pressure gradients, more convergence, and higher winds across the region (my paper in  the Atoll Research Bulletin describesa CP El Nino event in relatively lay terms). More analysis will need to be done, but at first glance, the wind speed trends over the Pacific appear to be driven by temperature trends and the status of climate oscillations, which themselves may be driven in part by climate change.

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Food prices and the ongoing biofuel debate

People worldwide are being affected by a rise in the price of food. The causes are complex and interacting: last summer's drought in Russia, the price of oil, speculative trading in commodities, economic instability, political unrest on the Middle East, you name it. As Tamino mentions, some people sceptical of efforts to reduce greenhouse gas emissions blame the increase in food prices on those efforts, namely the cultivation of biofuels like corn ethanol. Though I think Tamino's post misses the point of this debate.

The impact of corn ethanol, or an individual drought, or any other individual factor, on the price of a global commodity is very hard to quantify. The diversion of the U.S. corn crop to ethanol production over the past decade has undoubtedly affected food prices, despite U.S. government claims to the contrary. The various factors have interacting, nonlinear effects on the price of each commodity, and the commodity prices each affect the others, so it is hard to work out, say, a coefficient for each driving variable. But that's not the problem.

The real problem with any "climate change mitigation = more corn ethanol = higher food prices" argument is the first part: the claim that producing corn ethanol is addressing climate change.

In reality, the use of ethanol from corn as a fuel might actually result in greater greenhouse gas emissions than the use of gasoline, because of the land and energy required to grow the corn, harvest the corn, and convert the corn to ethanol. As such, the primary motivation for the expansion of corn ethanol production in the US is not climate change. Ethanol production is about appeasing regional interests, maintaining of the agricultural subsidy system and reducing reliance on imported fuels, probably in that order. 

The only reason that corn ethanol gets promoted by politicians in the U.S. as a solution to climate change is that in the current political atmosphere, very few actual climate change mitigation proposals can pass, and because of some effective lobbying and the power of the Presidential primary process, expanding corn ethanol production looks like climate change mitigation to the public.

Throw out the word biofuels and people might think action is being taken to address climate change. Look at the acutal conversion efficiencies and total lifecycle greenhouse gas emissions of the current feedstocks in the U.S. and you find a different story.

There is definitely reason to be concerned about the market effects of diverting so much of the U.S. corn crop to ethanol production. The real key to the story, the one to to look for in the coming months, is the price of meat. The majority of cereals and oils, the commodities for which the price has spiked the most, are used to generate animal feed. If you look back to 2008, you’ll see that the price of meat is likely to spike next.
This dynamic demonstrates the real battle we face in the future. It’s not food vs. fuel, it is feed vs. fuel. If the world wants to keep using the most productive croplands to provide biofuel feedstocks, we had better be prepared to eat less or much more expensive meat.

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The MVP of climate change communication

The Center for Climate Change Communication at George Mason is giving out the third Climate Change Communicator of the Year award. Voting is open until April 15th.

The award raises a question that comes up around award time in the sporting world. Is the most valuable player the one who produces the most - say, hits the most home runs - regardless of the success of their team? Or is the most valuable player the one who captained or contributed the most to a successful team?

If you believe the former, then the communicator of the year is the one who racked up the most statistics, be it blog posts, policy briefings, public talks, op-eds, etc. Given the rough state of public and political discourse on climate change, maybe this is like voting for the slugger on the last place team. One could argue that the most valuable communicators may not score well using the standard individual metrics, but doing more to advance the "cause".

That raises a second question: for what should we award a climate change communicator? Advancing public understanding of the science? Or influencing public or political opinion on climate change policy or solutions? These are two very different goals. The most valuable communicators might in fact be ones who best help audiences differentiate between science and judgments made based on science. In that view, the most valuable communicator will not be the strongest advocate for action.

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Climate communication: Be aggressive or be humble?

There's continuing disagreement inside and outside the scientific community about not only what scientists should say about climate change, but how they should be saying it. The communications literature states there is not one right approach, but a range of different approaches which may be suitable depending on the audience.

The climate blogosphere got in a tizzy in January about an advance copy of the text of a talk to be presented by Kevin Trenberth at the recent American Meteorological Society. The debate centered around Trenberth's idea that certainty about climate change is so great we should invert the common "Is this event caused by climate change?" line of questioning. As it states in the abstract, "Given that global warming is unequivocal, the null hypothesis should be that all weather events are affected by global warming".

All the talks from the "Communicating Climate Change" session (One and Two) at AMS were recorded and are now available for viewing online.  Trenberth's talk and my own presentation "Making the climate a part of the human world" provide examples of two very different ways of thinking about communication of climate change (viewers be patient, the audio of my talk doesn't kick in for about 90 seconds). You might say the different methods of analysis - I take a deep historical perspective to explain the confusion of today - lead also to clear differences in what I can best describe as temperament. A simple breakdown would be that Trenberth goes on the offensive (i.e. prove me wrong) while I've been told my approach is almost defensive (i.e. let's be more humble, there's a good reason the science is hard to believe). Obviously, I'm partial to the latter, it is my research after all. I do accept that there may also be a time and a place for the former too.

Update: More discussion of these questions at Class M and Rabbet Run.

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Creating a Climate for Change: Public lecture and webcast tonight

Alex Clapp from Simon Fraser University and I are presenting at a free public event tonight in downtown Vancouver sponsored by the Pacific Institute for Climate Solutions, a research consortium run by the area universities. For those not in the lower mainland, there should be a live webcast as well.

This event Creating a Climate for Change will explore scientific and social factors that influence the public's uncertainty about climate change, including socio-cultural barriers such as long-held beliefs that weather is beyond human control.

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Open waters around Baffin Island this New Year

At a casual meal on the weekend, I met a couple in town from Iqualit. The capital of Canada's northern Inuit territory of Nunavut is located on Frobisher Bay in southern Baffin Island.

They told me that when they left home in mid-December, the ice on Frobisher Bay was not frozen. I almost coughed up my food; that can't be possibly be typical for December. According to the visitors, the Bay is normally frozen a month or two, or more, before Christmas, allowing people to head out on the ice for hunting, celebrating, etc.

The upper chart is the ice thickness as of December 27th, according to the Canadian Ice Service (for all you sea ice junkies who follow the NSIDC's daily updates on the Arctic, CIS has a great and I suspect underused site). The southern half of Baffin Island is on the upper right. Frobisher Bay is the more southern of the two long bays on the right, the one that is entirely blue (i.e. water). Iqualit is at the very northwestern tip of the Bay.

The bottom chart shows the ice thickness "anomaly" - the departure from normal thickness (click on it for full size) - for mid-December. Normal is based on a multi-decade average. You can see that Frobisher Bay and the surrounding waters are all in the red - they are owed some ice.  Some of the bay has frozen since these images were prepared.

The low ice thickness across the Arctic is part of a long-term trend. The current low in the SE Arctic has also been driven by the prevailing weather conditions over the past couple months. As was reported in the CBC News yesterday, a lingering high pressure system has held temperatures well above normal and limited ice formation.  That is the same weather pattern that directed the cold Arctic air masses to east coast of North America and to western Europe and caused the huge early winter snowfalls. So when you hear scientists say that record snowfalls could be related in part to climate warming and the melting Arctic, this is what they mean.

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Climate change and the Caribbean coral bleaching, again

There's an upswing of skepticism about climate change of late, thanks in part to the crazy season in the US (and I'm not talking about the baseball playoffs, although they have been pretty surprising too). While the pundits argue, the climate keeps on moving.

When I give talks about climate change and coral reefs, I almost always use the two slides on the right. The first slide is a map of "degree heating weeks" (DHW), a measure of accumulated heat stress experienced by corals, in the Caribbean in mid-October in 2005. Severe bleaching and coral morality is typically observed when the values of DHW exceed 8 deg C-week. Basically, the same long period of warm water temperatures that helps spawn the destructive 2005 Atlantic hurricane season caused unprecedented coral bleaching event in the eastern Caribbean.

In 2007, my colleagues and I published a study examining of the likelihood of the 2005 "hot spot" occurring with and without human influence on the climate system. The study contrasted model simulations of the Caribbean with historical data and then computed the statistics of extreme ocean temperature events. The second slide summarizes some of the key results of from study. In a nutshell, our best analysis concluded the 2005 Caribbean "heat wave" would likely be on the order of a once in a thousand year event, had there been no human-generated greenhouse gas or aerosol emissions since the Industrial Revolution ("natural forcing"). By the 1990s, the human forcings increased the odds to once in 10-50 years. And continued warming under "business as usual" would make such heat waves happen in three out of every four years.

Five years later, a Caribbean "heat wave" has happened again. I've been writing for months that there was a strong likelihood of extensive coral bleaching in the Caribbean this fall according to NOAA's advance forecast of sea surface temperatures (in fact, we had a good inkling of this last summer). Now we're getting reports of bleaching from observers in the Caribbean. Add this to the observations (following predictions, once again!) from Southeast Asia and the Equatorial Pacific, and we have what may be the most, or second most, extensive "global" coral bleaching event in recorded history.

For all those writing about this event, keep in mind the predictions. This is what the scientific community predicted was likely to happen. An event which we calculated would be a once in a millennium occurrence without human impact on the climate, happened again five years later.

There are caveats, for sure. There is uncertainty in the model simulations of interannual variability which can affect the specific calculations of odds (see the 2007 paper for some details). And once-in-a-thousand year events can in reality happen five years apart; we'd need to collect data for thousands and thousands of years to properly calculate the statistics. Obviously, that's not feasible, which is the very reason we have computers help us do the math on these problems.

The real climate doesn't care about the political climate.

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Coral Reefs at SciFest 2010 in St. Louis

I'll be giving a talk about coral reefs and climate change on Saturday as a part of the annual SciFest in St. Louis. If you're in the neighbourhood, drop by and learn "about how climate change threatens coral reefs across the planet, and what we can all do to help them survive."

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Obama and Chu on piecemeal climate policy

This is from US President Obama's interview in Rolling Stone:

When I ask him [Stephen Chu] how we are going to solve this problem internationally, what he'll tell you is that we can get about a third of this done through efficiencies and existing technologies, we can get an additional chunk through some sort of pricing in carbon, but ultimately we're going to need some technological breakthroughs

It is an interesting and rather pragmatic characterization of the solution. The pricing could, of course, drive efficiencies, use of efficient technologies and the development of new breakthrough technologies. But we're seeing how a comprehensive pricing scheme is a practical and political nightmare. Implementing a national or international pricing scheme that touches on a limited set of carbon-generating activities, let one alone taxes carbon across the board, has been hard enough (in the case of Waxman-Markey, you end up with a complicated bill that alienates even the supporters of action). 

Maybe people are finally coming to the realization that a piecemeal solution might actually work the best.   If we can use adopt "wedges" thinking, rather than one grand solution, to reducing emissions, why not do the same for the policy that encourages the emissions reductions?

In Obama's words:

We may end up having to do it in chunks, as opposed to some sort of comprehensive omnibus legislation. But we're going to stay on this because it is good for our economy, it's good for our national security, and, ultimately, it's good for our environment.


 

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Glacier melt and water supply in North America

We often here about glacier melt in Asia threatening the water supply for the downstream population. Faux controversies about a single line in the IPCC reports aside, the potential decline in South Asian water flows is certainly a critical concern given the hundreds of millions of people dependent on those rivers.

It is easy to forget that many North American communities, particularly in the Canadian prairies, also depend on water that originates in mountain glaciers. Case in point, the stunning figure at right.
The shows the model-calculated river discharge of the North Saskatchewan River (at Whirlpool Point), which flows across Alberta and Saskatchewan, with (light blue) and without (dark) blue the contribution from glaciers in the Rockies. The figure was reproduced by Natural Resources Canada from an article by Comeau et al. in Hydrological Processes.

The key change, obvious from the figure, is that without the glacial water source, there will be a huge decrease in summer water flows. The result is a more typical snowmelt-dominated hydrograph (chart of seasonal river discharge), similar to something you'd see in another part of the continent.

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