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Global warming – a world of extremes and biological hotspots

Posted on 9 October 2013 by John Abraham

An article just published in the journal Nature has helped advance our understanding of climate extremes and how the Earth of the near future will differ from our world as we have come to know it. We all know that as the climate warms, we will see more extremes – extreme heat and drought, storms and flooding – depending on where you live.

Regardless of the cause, it would be useful for policy makers and city planners to know when the future climate will depart from its normal variability. How much time do we have to act? A decade? A century?

This very question was the focus of the recent paper. The authors (Camilo Mora and colleagues at the Department of Geography, University of Hawaii) used the complete set of available climate models to calculate the year when the Earth's climate will move beyond what we have experienced in our recent past. In other words, in what year will the climate become more extreme than the year of the most extreme events we have witnessed in the last 150 years?

They looked at seven different climate variables, including temperature, precipitation, and ocean acidity. According to their results, the climate of the Earth will depart from its normal variability about 35 years from now (in approximately 2050) under business as usual human activity. On the other hand, if we take seriously the threat of climate action, we can push that date by some 20 years.

But this global average threshold is only part of the story. The authors recognized that climate change will occur more rapidly near the poles (for instance, temperature changes will be greater near the poles than in the tropics). However, the present climate in the polar regions is already more variable, and biologic systems and humans living there are more adapted to climatic shifts.

In contrast, in the tropics, given their more stable climate, it is easy for even small changes to surpass historical extreme records. In other words, the tropics will face unprecedented climates sooner. The problem is that these small climate changes pose serious challenges for people and species that are not equipped to adapt.

What this means is the authors find a "double jeopardy" situation. Humans, plants, and animals will live in the tropics and will be more susceptible to small changes, or they may reside in higher latitudes and experience the largest climatic shifts.

The study shows that the earliest expected occurrences of unprecedented climate change will occur in the tropics. That zone, with its richness in biodiversity, will see climate shifts a decade earlier than elsewhere. This is particularly true of coral reefs, which will see shifts about 20 years earlier than average. In the case of ocean pH, this variable moved into unprecedented states in 2008.

What can we do about this? It is commonly thought that increasing the natural habitats of species will be a significant help for this problem, but the authors came to a different conclusion. They point out that since the protected areas will undergo similar climatic shifts, they won't be of much use to suffering species. Also, since many of the tropical hotspot areas are located in low-income countries, the ability to fund adaptive strategies will be limited.

Finally, and perhaps most interestingly, the authors isolated key biological groups in order to compare the time they reach climatic thresholds to the average globe. Some of the biggest losers – coral reefs (already mentioned), mangroves, seagrasses, marine reptiles, cephalopods, and marine fish – will experience far earlier climate disruption than the rest of us. That should give no consolation; in a world as interconnected as ours, we will all feel these climate shifts sooner rather than later.

As for people, some 5 billion people, mostly in developing countries, could be facing unprecedented climates by 2050.

In my second paragraph, I presented a bit of a red herring by asking us how long we have to act. The real answer is, we are out of time. As this study shows, and other studies reinforce, many of the climate changes are already baked into the system. Even if we take significant and meaningful actions, many of the deleterious impacts will occur anyway.

So, should we do anything if we are already committed to some climate change? Failing to act will simply test our capabilities to adapt earlier and, unfortunately, we may not be ready for it (overwhelmingly unprecedented climates will occur among developing countries). Alternatively, we could act now, which will buy us and species critical time for adaptation. Failing to act risks saying goodbye to our climate and facing the implications that come with its departure.

While we ponder this, readers can go to Dr. Mora's site, which includes interactive maps of future climate change impacts.

Click here to read the rest

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Comments

Comments 1 to 13:

  1. More significantly than the proximity of those dates is what they apparently represent — the year from which we will never again have a year "as good" as our worst year ever to date. In other words, recent extremes would be seen as a reprieve. By that point the world is already a pretty different place.

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  2. While a one day weather event is not climate it is however worth noting that Sydney today is expecting a maximum temperature of 39 C. This will be the hottest day experienced in October and very very warm weather for mid Spring!  What does the summer hold for us?

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  3. This, more than any study I have read about, brings home to me the precariousness of our global situation, the frustration of knowing that we should have acted sooner and may be too late now, and a burning resentment towards those who know what we face but, to further their own greed, continue to lie and obfuscate in order to convince our politicians not to act.

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  4. I don't have access to the full text my comment on the results is just a best guess. So, looking at this article & the author's website, I deduce the average anual temperature data for RCP2.6 and RCP8.5 scenarios were calculated from a model run and the "cut-off" dates were shown when the model runs above historical variability until 2005.

    I think this presentation is somewhat incomplete because the clear cut-off cannot be determined reliably as a single model predictive power is small in short timescale.
     I would rather prefer to see an ensemble (such as CMIP5) run and the range (of say 1-sigma uncertainty) be shown as the possible cut-off date. Such presentation would give me better perspective, in adittion of being a better response to usual deniasts' trolls.

    However, (Anual Temp) is the only one aspect of climate change. Other aspects, like increased droughts & floods (that are predicted to affect my SYD neighbourhood) are not shown but they are more serious and delta Temp, IMO. For example, the news of a record hifgh 39 C for Sydney today, brought by tonyabalone@2 is not my biggest problem. The bigger problem is that SYD (in fact the entire East Coast of AUS) is experiencing serious drought (I don'r remember any rain for last 2-3 months) which makes the conditions for all species (including all my garden) so difficult. One day of 39 C wouldn't be that bad (it would go as weather variability) but the underlying drought is the reason most of NSW has been declared as "extreme" or even "catastrophic" fire danger by RFS.

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  5. malamuddy @ 3,

    the frustration of knowing that we should have acted sooner and may be too late now

    Although I appreciate the sentiment, we should be careful not to say it's "too late now", because that feeds into another denialist meme (the final step along the path from "It's not happening" through "It's not us" then "It won't be bad" and "It's cheaper to adapt").

    A good analogy would be an overweight person eating a chocolate eclair and then cursing themself, saying "Oh, no, I couldn't resist the temptation, now I've eaten it and it's too late to go on a diet". Sure, having eaten that eclair they will now have to work harder to achieve their weight goals, or else they will forever be further from that goal than they would have been had they not eaten that eclair with all else being equal, but that doesn't mean there's no benefit in working on their weight problem from that point forward.

    Likewise, we may reach a point where it becomes impossible for us to limit warming to 2 C, say, but that's not an argument for inaction — it's still better to limit warming to 2.5 C than 3.0 C, or to 3.0 C than 3.5 C, and so on. It is possible that a tipping point will be reached at some point along that line but there's no point basing our actions on the idea that it's "2 C or bust". The overweight analogy would be like saying "Oh, well, I've eaten that eclair, I'll might now die of a heart attack in 30 years because of that, so I may as well not bother trying any more".

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  6. Jason B, I couldn't agree more. We don't know exactly what the effects of 2 or 2.5 or 3 or 3.5 degrees C rise in temperature will be, but it seems very likely to me that the more we can slow down or limit the rise in temperature and ocean acidification, the more time we will give ecosystems, species and human societies to adapt. We urgently need to act now to prevent massive damage (and we should have acted decades ago), and every year of inaction probably condemns future generations to worse suffering, but I can't imagine a situation in the next 50-100 years in which action on global warming would be "too late" in the sense that it wouldn't do any good. Even if there is a several degree rise in temperature, accompanied by large increases in chronic hunger among humans and widespread extinction of many species, efforts to limit GHG emissions may still buy time to allow for adaptation to new climates and prevent a lot of further suffering and save many species from extinction.

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  7. Rob Nicholls @ 6

    I am interested in what "actions" should be taken and what effect they will have.  I assume you mean limiting GHG emissions (and I am glad you didn't focus on CO2 solely.)  

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  8. It's more bad news. However, all projections are, in the end, estimates of the future, not hard predictions. That's why it isn't too late to take action to mitigate global warming. I disagree, however, with some other commenters, that it is never too late to take action. Presumably, positive climate feedbacks could potentially become forcings in their own right. At that point, nothing we could do would have the slightest difference longer term. We'd only have adaptation left as a strategy, if adaptation were at all possible at that point.
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  9. Terranova - well the obvious action is reduce GHG emissions. The tricky bit is what methods do governments have to do this that are politically acceptable to their electorate. CO2 and black carbon are by far the most important emissions and furthermore they are more sustitutable for than say CH4. If you want to pursue this discussion however, perhaps it would be best to look for a more appropriate. I cant speak for Rob, but to me, the simple, direct and effective solution is ban on building more coal-fired power stations (unless they have full CO2 removal). Let the market work out the best alternative. Coal industry (except for steel) gets a 30 year sunset, better than asbestos got. Of course the right-winger would scream stuff about "freedom" and so many countries would have look at carbon tax or trading schemes instead which are a whole lot more complicated.

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  10. I can’t help but be reminded of a post over at Tamino’s Site that concluded with:


    I’ll continue to do what I can, come hell or high water. Expect both.


    (http://tamino.wordpress.com/2011/05/07/hell-and-high-water/)

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  11. James Hansen has frequently warned us, with his usual prescience, that a rise in 2°C above the pre-industrial is likely to be achieved by mid century and constitutes dangerous global warming producing an increased incidence of climate extremes. Hence his admonition on the need to keep average global surface temperature below +2°C.

    More recently (2012) he has shown that the Gaussian distribution of heat is shifting to the right and as explained by Dana Nuccitelli, the consequences for climate, humanity and other animals are not beneficial.

    Why do we continue to ignore the findings of science the advice scientists or find it surprising when oft repeated?

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  12. TonyW,

    I disagree, however, with some other commenters, that it is never too late to take action.

    I didn't say it will never be too late to take action, and I don't think anyone else did either. What I warned against was saying "it's too late now".

    Presumably, positive climate feedbacks could potentially become forcings in their own right. At that point, nothing we could do would have the slightest difference longer term.

    That's precisely what I addressed when I said "It is possible that a tipping point will be reached at some point along that line but there's no point basing our actions on the idea that it's "2 C or bust". The overweight analogy would be like saying "Oh, well, I've eaten that eclair, I'll might now die of a heart attack in 30 years because of that, so I may as well not bother trying any more"."

    It is hypothetically possible that at some point we will pass a point of no return. It's highly likely that we won't know that point when it happens, it will only be apparent with a great deal of analysis and hindsight. If we pass that point and nothing we do from then on will make a difference, there's no point in assuming that we will. We assume that we won't pass such a point, and if we don't, we gain. If we are wrong and we do pass such a point, then at least our efforts will have delayed it.

    And there really is nothing we can do now that will make the slightest difference in the longer term, for a suitable definition of "longer". That doesn't mean that our efforts aren't worthwhile.

    We'd only have adaptation left as a strategy, if adaptation were at all possible at that point.

    Adaptation doesn't get easier if we allow the climate to get worse. It isn't better to say, for example, "Oh, well, we passed the 2 C threshold, let's give up on trying to mitigate and just adapt", because adapting to 2.5 C is easier than adapting to 3 C, and so on. The costs of climate change are a monotonically increasing function of the degree of climate change; it may be discontinuous at certain (unknown) points, where it suddenly jumps up a lot higher due to passing a tipping point, but it will always be more expensive and more difficult to adapt to if we allow it to get higher regardless of how high we have allowed it to get.

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  13. #5 Jason B

    A good analogy would be an overweight person eating a chocolate eclair and then cursing themself, saying "Oh, no, I couldn't resist the temptation, now I've eaten it and it's too late to go on a diet". Sure, having eaten that eclair they will now have to work harder to achieve their weight goals, or else they will forever be further from that goal than they would have been had they not eaten that eclair with all else being equal, but that doesn't mean there's no benefit in working on their weight problem from that point forward.

    A better analogy might perhaps be you chopped your arm off in a moment of hallucianitory insanity.  You ignored that you knew it would make things worse for you but none the less, Murdoch etal told you it was "the shizzle".  Sure, superb surgeons can rattach it and you will get some function back (Geoengineering) and if you are rich (Annex 1 nations) you might get back better use then someone who can't afford the best sugeons (developing world), none the less it isn't going to return to "how it was", there is too much forcing for that to occur.

    I still see people expecting Government to do the heavy lifting for them, blaming Government for their own emmissions.  It's long past time to blame others and we have to start blaming the people who look out at us from the mirror.  We are the emitters, we are the obese, the smokers (insert whatever analogy works for you).  It's nonsenseical on the one hand to keep emitting, while imploring Government to stop us, that's like asking your mother to tie your shoes for you because you're to lazy.  

    We do need Government to act to stop the free rider problem BUT we can start.  We can act, we can cut back, we can apply peer pressure.  We can not turn the A/C on, we can not drive, we can stop flying etc etc.   Demand side reduction is the only thing that might mitigate the damage we've done, while still proceeding with supply side change.

    If Government acted tomorrow with supply side changes, it would take decades to roll out the necessary infrastructure to ensure substantive emissions reduction and this article brings home the urgency of acting now.  

    So, what are the options ? Keep emitting while we wait for someone esle to do something on our behalf ?

    Professor Kevin Anderson (Tyndal Climate Centre) explains it nicely here in this lecture

    http://www.youtube.com/watch?v=RInrvSjW90U

    I am not holding myself up as a role model, just pointing out it can be done. Four years ago I gave up my job, we moved to a milder climate, in a "cheap" (housing) rural area.  We are off the grid for power and water, stoped consuming gee gaws from China (cutting their emissions for them), stoped flying etc.  I live off a small stipend from invesments, not welfare.

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