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Can animals and plants adapt to global warming?

What the science says...

A large number of ancient mass extinction events have been strongly linked to global climate change. Because current climate change is so rapid, the way species typically adapt (eg - migration) is, in most cases, simply not be possible. Global change is simply too pervasive and occurring too rapidly.

Climate Myth...

Animals and plants can adapt
[C]orals, trees, birds, mammals, and butterflies are adapting well to the routine reality of changing climate." (source: Hudson Institute)

Humans are transforming the global environment. Great swathes of temperate forest in Europe, Asia and North America have been cleared over the past few centuries for agriculture, timber and urban development. Tropical forests are now on the front line. Human-assisted species invasions of pests, competitors and predators are rising exponentially, and over-exploitation of fisheries, and forest animals for bush meat, to the point of collapse, continues to be the rule rather than the exception.

Driving this has been a six-fold expansion of the human population since 1800 and a 50-fold increase in the size of the global economy. The great modern human enterprise was built on exploitation of the natural environment. Today, up to 83% of the Earth’s land area is under direct human influence and we entirely dominate 36% of the bioproductive surface. Up to half the world’s freshwater runoff is now captured for human use. More nitrogen is now converted into reactive forms by industry than all by all the planet’s natural processes and our industrial and agricultural processes are causing a continual build-up of long-lived greenhouse gases to levels unprecedented in at least the last 800,000 years and possibly much longer.

Clearly, this planet-wide domination by human society will have implications for biological diversity. Indeed, a recent review on the topic, the 2005 Millennium Ecosystem Assessment report (an environmental report of similar scale to the Intergovernmental Panel on Climate Change Assessment Reports), drew some bleak conclusions – 60% of the world’s ecosystems are now degraded and the extinction rate is now 100 to 1000 times higher than the “background” rate of long spans of geological time. For instance, a study I conducted in 2003 showed that up to 42% of species in the Southeast Asian region could be consigned to extinction by the year 2100 due to deforestation and habitat fragmentation alone.


Figure 1: Southeast Asian extinctions projected due to habitat loss (source: Sodhi, N. S., Koh, L. P., Brook, B. W. & Ng, P. K. L. 2004)

Given these existing pressures and upheavals, it is a reasonable question to ask whether global warming will make any further meaningful contribution to this mess. Some, such as the sceptics S. Fred Singer and Dennis Avery, see no danger at all, maintaining that a warmer planet will be beneficial for mankind and other species on the planet and that “corals, trees, birds, mammals, and butterflies are adapting well to the routine reality of changing climate”. Also, although climate change is a concern for conservation biologists, it is not the focus for most researchers (at present), largely I think because of the severity and immediacy of the damage caused by other threats.

Global warming to date has certainly affected species’ geographical distributional ranges and the timing of breeding, migration, flowering, and so on. But extrapolating these observed impacts to predictions of future extinction risk is challenging. The most well known study to date, by a team from the UK, estimated that 18 and 35% of plant and animal species will be committed to extinction by 2050 due to climate change. This study, which used a simple approach of estimating changes in species geographical ranges after fitting to current bioclimatic conditions, caused a flurry of debate. Some argued that it was overly optimistic or too uncertain because it left out most ecological detail, while others said it was possibly overly pessimistic, based on what we know from species responses and apparent resilience to previous climate change in the fossil record – see below.

A large number of ancient mass extinction events have indeed been strongly linked to global climate change, including the most sweeping die-off that ended the Palaeozoic Era, 250 million years ago and the somewhat less cataclysmic, but still damaging, Palaeocene–Eocene Thermal Maximum, 55 million years ago. Yet in the more recent past, during the Quaternary glacial cycles spanning the last million years, there were apparently few climate-related extinctions. This curious paradox of few ice age extinctions even has a name – it is called ‘the Quaternary Conundrum’.

Over that time, the globally averaged temperature difference between the depth of an ice age and a warm interglacial period was 4 to 6°C – comparable to that predicted for the coming century due to anthropogenic global warming under the fossil-fuel-intensive, business-as-usual scenario. Most species appear to have persisted across these multiple glacial–interglacial cycles. This can be inferred from the fossil record, and from genetic evidence in modern species. In Europe and North America, populations shifted ranges southwards as the great northern hemisphere ice sheets advanced, and reinvaded northern realms when the glaciers retreated. Some species may have also persisted in locally favourable regions that were otherwise isolated within the tundra and ice-strewn landscapes. In Australia, a recently discovered cave site has shown that large-bodied mammals (‘megafauna’) were able to persist even in the arid landscape of the Nullarbor in conditions similar to now.

However, although the geological record is essential for understanding how species respond to natural climate change, there are a number of reasons why future impacts on biodiversity will be particularly severe:

A) Human-induced warming is already rapid and is expected to further accelerate. The IPCC storyline scenarios such as A1FI and A2 imply a rate of warming of 0.2 to 0.6°C per decade. By comparison, the average change from 15 to 7 thousand years ago was ~0.005°C per decade, although this was occasionally punctuated by short-lived (and possibly regional-scale) abrupt climatic jolts, such as the Younger Dryas, Dansgaard-Oeschger and Heinrich events.

B) A low-range optimistic estimate of 2°C of 21st century warming will shift the Earth’s global mean surface temperature into conditions which have not existed since the middle Pliocene, 3 million years ago. More than 4°C of atmospheric heating will take the planet’s climate back, within a century, to the largely ice-free world that existed prior to about 35 million years ago. The average ‘species’ lifetime’ is only 1 to 3 million years. So it is quite possible that in the comparative geological instant of a century, planetary conditions will be transformed to a state unlike anything that most of the world’s modern species have encountered.

C) As noted above, it is critical to understand that ecosystems in the 21st century start from an already massively ‘shifted baseline’ and so have lost resilience. Most habitats are already degraded and their populations depleted, to a lesser or greater extent, by past human activities. For millennia our impacts have been localised although often severe, but during the last few centuries we have unleashed physical and biological transformations on a global scale. In this context, synergies (positive or self-reinforcing feedbacks) from global warming, ocean acidification, habitat loss, habitat fragmentation, invasive species, chemical pollution (Figure 2) are likely lead to cascading extinctions. For instance, over-harvest, habitat loss and changed fire regimes will likely enhance the direct impacts of climate change and make it difficult for species to move to undamaged areas or to maintain a ‘buffer’ population size. One threat reinforces the other, or multiple impacts play off on each other, which makes the overall impact far greater than if each individual threats occurred in isolation (Brook et al 2008).


Figure 2: Figure from the Millennium Ecosystem Assessment

D) Past adaptation to climate change by species was mainly through shifting their geographic range to higher or lower latitudes (depending on whether the climate was warming or cooling), or up and down mountain slopes. There were also evolutionary responses – individuals that were most tolerant to new conditions survived and so made future generations more intrinsically resilient. Now, because of points A to C described above, this type of adaptation will, in most cases, simply not be possible or will be inadequate to cope. Global change is simply too pervasive and occurring too rapidly. Time’s up and there is nowhere for species to run or hide.

Last updated on 22 December 2011 by Daniel Bailey. View Archives

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Further reading

Acknowledgements

This is a guest post by Professor Barry Brook, an international research leader in global ecology and conservation biology. He holds the Foundation Sir Hubert Wilkins Chair of Climate Change and is Director of the Research Institute for Climate Change and Sustainability at the University of Adelaide. He has published two books and over 120 scientific papers on various aspects of human impacts on the natural environment and biodiversity, including climate change, deforestation and overexploitation of populations. In 2006, he was awarded both the Australian Academy of Science Fenner Medal for distinguished research in biology and the Edgeworth David Medal by the Royal Society of New South Wales, and in 2007, the H.G. Andrewartha Medal by the Royal Society of South Australia and was listed by Cosmos as one of Australia's top 10 young scientists. The principal motivation for his research is to identify ways and means of reducing extinctions and mitigating the worst ravages of global change. Read more at Brave New Climate.

Comments

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Comments 1 to 50 out of 55:

  1. Good article. The only fault I see is "The IPCC storyline scenarios such as A1FI and A2 imply a rate of warming of 0.2 to 0.6°C per decade." which just has not happened but it does not change the message or impact of the article. Kudos to Professor Barry Brook.
  2. England: Little egrets have been observed nesting
    (previously seen but in winter migrated to southern Europe/Africa) and in 2008 cattle egrets ( from Africa) have also been filmed, although not nesting.
    In S.England green lizards and brown rock lizards, both mediterranean species are now resident.
    An illustration of species movement as conditions allow.
    ( and in the case of the lizards, ably assisted by transcontinental traffic)
  3. I would like to invite readers to my blog witsendnj dot blogspot dot com and especially the early post, Effects of Climate Change, where I give an overview of my concerns. I see very prominent and deleterious effects on vegetation around my home in NJ and I would be very interested to learn of other observers who would be willing to compare notes.

    Why is this important? Because many of the prominent and influential policy makers live on the Eastern Seaboard and maybe if they become enlightened enough to recognize the collapse of the ecosystem around their own homes, they might finally realize how urgent it is to eliminate carbon emissions.

    Thank you!
  4. When there is a end, there is always (mostly) a new beginning.
  5. #4. New beginnings? Just look at much of the Middle East. Large areas were once fertile crop producing lands supporting substantial populations in cities. Now the deserts, mostly caused by abandoning age-old water management practices, barely support an assortment of goats and lizards. Not a fruit tree or a grain crop in sight. There are similar places elsewhere in the world. Once lost, always lost.

    As for evolution taking care of the problem. Evolution for changed climate consitions takes many generations - maybe centuries, maybe millennia, maybe millions of years. The big difference for substantial impact on species this time round is the lack of places to go. Even where human population is sparse, the lands in question are surrounded by urban or agricultural developments inimical to the free movement and re-establishment of existing or changing species.

    Change *is* natural - when it occurs on natural time-scales. This time we're changing things in the space of a few human generations rather than a few thousand or million years.
  6. Good news,Adelady.
    Snippet from National Geographic:-

    "Desertification, drought, and despair—that's what global warming has in store for much of Africa. Or so we hear.
    Emerging evidence is painting a very different scenario, one in which rising temperatures could benefit millions of Africans in the driest parts of the continent.
    * Ancient Cemetery Found; Brings "Green Sahara" to Life
    * Exodus From Drying Sahara Gave Rise to Pharaohs, Study Says
    Scientists are now seeing signals that the Sahara desert and surrounding regions are greening due to increasing rainfall.
    If sustained, these rains could revitalize drought-ravaged regions, reclaiming them for farming communities.
    This desert-shrinking trend is supported by climate models, which predict a return to conditions that turned the Sahara into a lush savanna some 12,000 years ago"

    More info available at Nat Geographical website. Use their search button and key in"Satellite greening".
    Acacias spreading and thriving in Sudan. Nomads in Western Sahara say "We've never had it so good."

    As for rapidity of evolution. Check out Howard Bloom's website and in the black column on the left, click on"Instant Evolution:the effect of the city on human genes"
    He cites some thought - provoking examples of rapid evolution.
  7. Africans will move to the Sahara? Problem solved? Rather than rely on some quotes from National Geographic Kids, better to delve into the literature and get the big picture, as usual.

    Here's a continental-scale review for Africa, a little long in the tooth but a good starting point:

    African climate change: 1900–2100

    Continental-scale scenario for surface water:

    Changes in Surface Water Supply Across Africa with Predicted Climate Change

    Meanwhile, it's best to take changes on the timescale mentioned in National Geographic w/a grain of salt because of course there's always natural variability in play:

    The impact of decadal-scale Indian Ocean sea surface temperature anomalies on Sahelian rainfall and the North Atlantic Oscillation
  8. Replying to Doug Bostrom,
    Like most folks I generally accepted that a battle against the encroaching sands was being lost, so the evidence of a reversal, especially in a magazine(kiddies?) as pro-AGW as Nat Geographic, came as a surprise.
    I am familiar with the PROJECTIONS and PREDICTIONS, and very plausible they sounded too.
    HOWEVER.....this report as to what is ACTUALLY happening on the ground, is at odds with that which was predicted.
    What would be a reasonable attitude towards people that make predictions, in your opinion, that don't come to pass?
  9. @AWoL: it is common practice here to provide links to your sources. Do you have the link handy, so we can evaluate how accurate the NatGeo Kids article really is?
  10. A reasonable thing to do would be to read articles by researchers rather than a massively compressed synopsis in a kid's magazine, AWoL.

    It's worth noting that climate models have a tough time w/predicting precipitation in N. Africa. If you read the literature, you'd know that. You'd also have some idea of the ease with which decadal natural variation can slew precipitation in the region of the Sahara.

    By the way, are you having some sort of trouble with your caps-lock key?
  11. Sorry ASteel, haven't provided a direct link but if you refer to my earlier post on this subject I do give instructions as to how to reach it. Just checked it.Up and running.Don't go to the kids section for it ain't there.
    Yes it is probably massively compressed, but by a climate researcher who has been working in the region for 20yrs.....which was why I brought the matter to the attention of this forum.
    Google National Geographic, type "satellite greening" in the search box, then select title with "Sahara" in it.
  12. AWoL - Here's the link to the Sahara Desert Greening Due to Climate Change article in National Geographic.

    The article appears to be based on Hickler et al 2005, "Precipitation controls Sahel greening trend". The article also (indirectly) points to Haarsma et al 2005, "Sahel rainfall variability and response to greenhouse warming" indicating increased Sahara rainfall of 1-2mm/day.
  13. @AWoL: I think Doug said it best. Climate models do disagree on N. Africa, and the article acknowledges this:

    "Even so, climate scientists don't agree on how future climate change will affect the Sahel: Some studies simulate a decrease in rainfall.

    "This issue is still rather uncertain," Haarsma said.

    Max Planck's Claussen said North Africa is the area of greatest disagreement among climate change modelers.

    Forecasting how global warming will affect the region is complicated by its vast size and the unpredictable influence of high-altitude winds that disperse monsoon rains, Claussen added.

    "Half the models follow a wetter trend, and half a drier trend."


    Whether it is increased desertification or a greening of some of its regions due to increased hydrological activity, however, it's hard no to see the effects of AGW at work.

    Obviously, the best outcome would be sustained greening, as this would introduce a vast new carbon sink, however it's unwise to count on this happening.

    Here is the direct link, if anyone is interested.
  14. Replying to ASteel
    Yes I take your points.
    Nevertheless that which has taken place,whilst not condemning outright AGW and its proponents, is however at odds with mass media output.
    ie we haven't had any glowing reports of this (benign) change in the Sahel.
    When brought to the attention of Joe Public, invariably his first utterance is "Why haven't we heard of this?"(because he still depends for the most part, but increasingly suspiciously, on the mass media for his information)
    I think you may have problems like this in the future. Time is wearing on, after all.Time was always a bit of a problem for soothsayers and fortune-tellers.
  15. AWOL I'm absolutely certain that there's some good news for some species aroung the place. I notice some of the things you refer to involve plants and animals moving to more congenial circumstances.

    Your example of an "exodus" leading to a good outcome is great for a historical example. But there are 2 problems for me there. One, such movements are now highly constrained by the hugs human population, and the effects of habitation and agriculture on grasslands and forests.

    Two, where I live the only way for existing animals to move is south - not many plants and animals will migrate inland to even more inhospitable conditions. Unfortunately, there's not a lot of south to move to. Unless someone's come up with a few generations evolution schema for land animals to imitate seals and penguins.
  16. I wonder how any of our European readers feel about being so near the tip of the spear:

    From MacKenzie and Schiedek 2007:
    ... trends in surface temperatures in the North and Baltic Seas now exceed those at any time since instrumented measurements began in 1861 and 1880. Temperatures in summer since 1985 have increased at nearly triple the global warming rate which is expected to occur during the 21st century and summer temperatures have risen 2-5 times faster than those in other seasons. These warm temperatures and rates of change are due partly to an increase in the frequency of extremely warm years. The recent warming event is exceeding the ability of local species to adapt and is consequently leading to major changes in the structure, function and services of these ecosystems. [emphasis added]

    From Devictor et al. 2008:
    ... a 91 km northward shift in bird community composition, which is much higher than previous estimates based on changes in species range edges. During the same period, temperature increase corresponds to a 273 km northward shift in temperature. Change in community composition was thus insufficient to keep up with temperature increase: birds are lagging approximately 182 km behind climate warming.
  17. AWoL, situations such as you have illustrated in the Sahara will (have?) allow the more astute observers to bring together the rapidly accumulating knowledge of drought tolerant plant species suitable for agricultural exploitation, and the cyclic changes as they occur in various locations.
    Establishing deep rooted perennials that can tap into water reserves well below the surface, that also bring essential nutrients to the surface, will help re-establish ground cover leading to a rebuilding of the top soil and then to the expansion of the cropping or grazing into new areas.

    One of the limiting factors to plant growth in arid areas is the cold night temperatures, but with increased rain comes increased cloud cover that should see some improvement there.

    Much may be happening now, there are many enterprising advances happening that fly below the radar with research often trailing practice by a considerable margin due to the tendency to think laterally by those who have to contend in practice with the vagaries of nature and take whatever opportunities as they present themselves, even if it has not been peer reviewed.
  18. @AWoL: I'm sorry, I have a hard time understanding your point. The fact that AGW is apparently causing some greening of the Sahara desert due to increased rainfall is *not* an argument against AGW theory. I'm also unaware that the Sahara is often cited in Mass Media stories about AGW.

    Furthermore, this is another piece of evidence showing that AGW is real. I don't see how this could "cause problems" for AGW proponents. To the contrary, it goes to show that we are, in fact, having a serious impact on our environment through CO2 emmissions.

    I also don't get your comment about soothsayers and fortune-tellers. I suggest you stick to the science and not try to divine how public opinion will react to an observed greening of the Sahel.
  19. "Nevertheless that which has taken place,whilst not condemning outright AGW and its proponents, is however at odds with mass media output."

    As others have pointed out in different ways, Sahel greening will never "condemn" AGW outright or implicitly. You need to work on larger processes if you want to try to find evidence against a warming planet. If you want to be taken seriously, point to single instances, but do so by looking at the single instances within the context of the whole.

    "ie we haven't had any glowing reports of this (benign) change in the Sahel. When brought to the attention of Joe Public, invariably his first utterance is "Why haven't we heard of this?"(because he still depends for the most part, but increasingly suspiciously, on the mass media for his information)"

    Invariably? Where is your evidence for this response? And if you think mass media news is in collusion with climate science, you aren't paying attention.

    "I think you may have problems like this in the future. Time is wearing on, after all. Time was always a bit of a problem for soothsayers and fortune-tellers."

    Ahhh, the old "modeling a complex system is impossible" game. You do note that you're playing the game, too, yes? You make the implicit claim that the planet is not warming--and certainly not because of humans--because the Sahel is greening. And yet you make this claim without any sort of evidence. Soothsaying indeed!

    Don't be so provincial. The Sahel may be greening, but the oceans are dying and pine mountain beetles are munching my bloody pine trees.
  20. I think one of the points being made by the article goes back in part to what was quoted by archiesteel at 06:35 AM, that being
    "Half the models follow a wetter trend, and half a drier trend."

    Whilst some may feel that this greening is not causing problems for AGW, however it certainly must be causing some problems for some of the modelers.

    If anyone now accepts that the trend of increasing rainfall validates those half of all models that are predicting a wetter trend, then they must also be accepting that it also invalidates those other half of the models predicting a drier trend which obviously have been built around some rather incorrect assumptions.
    If those assumptions are now being found to be incorrect, which one must now be willing to accept in this particular case, then wherever the same assumptions have been inputted into other modeling makes those outcomes produced perhaps somewhat similarly suspect also.
  21. @johnd: in order to invalidate *any* model, we'll need to have sustained greening over a significant area of the desert. It's a bit early to start calling out specific models.

    Your last paragraph is simply an attempt to invalidate climate models in general by introducing a bit of FUD about their precision. However, as the article clearly spells out, it is *North Africa* that is difficult to model. Models tend to agree a lot more about other regions, and there's no reason to believe that the models that eventually get it wrong on North African impact are any less accurate in the rest of their predictions.

    It seems to me you're fishing for a pretty convoluted argument, here.
  22. The article starts quite factual with stating that biodiversity is under constant thread from direct human interference, Most prominently by destroying (slowly but surely) land for industrial use (food industry) with the latest addition of biological fuels as well as destroying the oceans by depleting them of marine live and using them as trash bins at the same time.

    In my opinion that needs to be stopped and as far as possible reversed. Reducing CO2 emissions (unless they stem from deforestation) will not help a bit.

    Besides, if I am not mistaken it is still the tropical rain forests that boast the richest biodiversity which happen to occur where this world counts the highest temperatures. Therefore I completely fail to see how rising temperatures may cause general losses in biodiversity.
  23. h-j-m wrote: "Reducing CO2 emissions (unless they stem from deforestation) will not help a bit."

    CO2 emissions are causing global warming, which is causing habit loss for species all over the planet. Thus, reducing CO2 emissions definitely would help, and more than 'a bit'.

    Also: "Therefore I completely fail to see how rising temperatures may cause general losses in biodiversity."

    Which is happening faster, climate change or the evolution of new species?

    That is, unless you think that evolution happens over the course of a few decades, it should be entirely obvious that 'warmer = more biodiversity' is an invalid assumption. Species which cannot adapt to the warmer conditions will become extinct and new species will not evolve at the same rate... ergo declining biodiversity.
  24. CBDunkerson, if you can tell me how reducing CO2 emissions can help reforesting the destroyed rainforests all over the world and help to regain the lost top soils (destroyed due to monoculture farming) and regain the lost wildlife habitats destroyed in the process I would like to believe you.
  25. h-j-m, setting aside the primary point that CO2 emissions ALSO causes loss of biodiversity and thus is every bit as worth addressing on that front as the other problems you list... there are also several studies showing that rising CO2 levels may further threaten the rainforests by increasing evaporation and decreasing precipitation in the region. Thus, addressing CO2 emissions can also help prevent further rainforest loss. That would also cause rainforest recovery, but only if the land were allowed to revert.
  26. CBDunkerson, I just wanted to point out that at the current time loss of biodiversity is due to direct human intervention by far outranking that what can be attributed to global warming. Chances that tropical rainforests are threatened by it are rather slim as studies show that in the tropics forestation is the main factor governing local weather patterns(i. e. they show that deforestation leads to major changes in weather patterns). Some small scale endeavours on the other hand show that rainforest farming (using the biological productivity of rainforests to support the local population) is a viable and sustainable alternative - capable not only to fight poverty but even to allow for modest prosperity -, but they are not getting a chance due to the profits that biological fuels are promising. So far I can only see that in result the global warming theory has led to nothing but an increasing pace of destroying the ability of this globe to support human life.
  27. h-j-m,

    A problem is not rendered inconsequential if an implementation of a proposed (partial) solution may cause more harm in a given area than it aleviates. Arguing against biofuel farming practices is in no way a valid argument against the effects of global warming.
  28. Hydrogen sulfide is thought to have been a major player in the Permian mass extinction 250 million years ago, because CO2 emissions from the Siberian Traps warmed the atmosphere and oceans, causing the oceans to lose oxygen. With less oxygen, the anaerobic bacteria produce hydrogen sulfide that spreads through the ocean and into the atmosphere and poisons most of the animals on the planet. When we hear about the potentially dire consequences of global warming, why don't we ever hear about hydrogen sulfide emissions from the warming oceans as a result of decreasing oxygen?
  29. The link to "a study I conducted in 2003" doesn't work (http://www.skepticalscience.com/docs/Brook_2003_Extinctions.pdf).

    It may be this one?:
    http://www.dbs.nus.edu.sg/lab/cons-lab/documents/Brook_etal_Nature_2003.pdf
  30. Another link that doesn't work is in "it left out most ecological detail" (http://www.mncn.csic.es/pdf_web/maraujo/Thuiller_et_al_2004Nature.pdf).

    It may be this one:
    http://stephenschneider.stanford.edu/Publications/PDF_Papers/ThuillerEtAl2004.pdf
  31. Continuing from here.

    "the 10k bp mark"

    From Wikipedia:

    Identifying the exact origin of agriculture remains problematic...

    ... grains of rye with domestic traits have been recovered from Epi-Palaeolithic (10,000+ BC) contexts at Abu Hureyra in Syria, but this appears to be a localised phenomenon resulting from cultivation of stands of wild rye, rather than a definitive step towards domestication.

    ... By 7000 BC, sowing and harvesting reached Mesopotamia, and there, in the fertile soil just north of the Persian Gulf, Sumerians systematized it and scaled it up. By 8000 BC farming was entrenched on the banks of the Nile River.


    So, yes, the last glacial retreat was a good thing for the development of agriculture. But your contention that this development took place during a time of rapidly rising temperatures and sea levels is not well supported -- and really makes no difference.

    However, there is a clear difference in conditions described by Bettinger et al 2009:


    Ice age climates varied at very short timescales (Richerson, Boyd, and Bettinger 2001). Ice core data show that last glacial climate was highly variable on timescales of centuries to millenia ...

    In comparison, the Holocene after 11,600 BP has been a period of comparatively very stable climate.


    So it appears to have been stability that gave birth to civilization. What we have provoked is rapid change and instability: deeper droughts, worse flooding, wilder extremes from winter to summer.

    Anecdotally, from a recent trip west: it is clear that the only people who will get a crop this year are those who can afford to buy lots of water. Poor farmers have abandoned their fields; buildings and other infrastructure are in decay. Everywhere you go, creekbeds and streams are dry and people are saying 'it's never been this bad.'

  32. What may be of conversely great concern to this topic is plants and animals that adapt exceptionally well but are pests - most insects, rodents, and weeds will and are adapting to warming trends exceptionally well, in some cases becoming invasive species on entire continents due to the change of climate allowing new habitation.

    In the same light, the change in climate is putting pressure on "friendly" and "neutral" species, as well as a strong increase is invasive and pest species, which does not bode well for our species even in the short term. It certainly doesn't bode well in terms of comfort - longer term, it won't sit well for meeting the basic needs of all of society as species relied upon for necessities are pushed out by species regarded as pests.
  33. The link to Univ of Texas climate change impact article (marked by the text "timing of breeding, migration, flowering, and so on") is broken. It looks like they've moved the article. I think the link was to this article http://web5.cns.utexas.edu/news/2004/11/global-warming-2/
  34. The author claims in item (B) that a 4 degree or so increase in global temperature will make things hotter than anytime in the past 35 million years. WRONG, at least according to graphs I see of Tertiary temperatures at Google "Tertiary Temperatures" (Images), which show temperatures up to 20 degrees hotter at about that time, even more earlier. So why should I believe anything else you tell me if you so egregioulsy misrepresent such easily available "facts"?

  35. Scott, can you provide a link?  See the "insert" tab above the commenting box.

  36. Regardless of what your link says, Scott, you're not reading carefully:

    "A low-range optimistic estimate of 2°C of 21st century warming will shift the Earth’s global mean surface temperature into conditions which have not existed since the middle Pliocene, 3 million years ago. More than 4°C of atmospheric heating will take the planet’s climate back, within a century, to the largely ice-free world that existed prior to about 35 million years ago."

    It doesn't make the claim you say it makes.  It compares a potential 2100 with the "largely ice-free world" of about 35mya.

  37. Scott...before you simply presume that the post is "egregiously misrepresenting" facts, you should read the paper its referencing, which, lo and behold, has a reconstruction of temperatures through the Cenozoic! It may even be the one you are referring to!  

    That reconstruction indeed shows that there are deep ocean temps in the Eocene era that were substantially greater than today, but those were 55 million years ago. It also shows that the last time temps were consistently 4C higher than current was just prior to the Antarctic glaciation 34 mya. There may have some periods that were a touch more than 4C warmer in the following 10 million years, but that was still 24 million years ago. The point of this post is that we are likely to recapitule tens of millions of years of climate history in the span of a century or two.  

    If you have a reconstruction that says otherwise, link to it. Otherwise we have no idea what you're specifically talking about, and it is therefore impossible to clarify things.

    Then again, maybe you really aren't interested  in actually discussing the evidence.

  38. Following Scott Sinnock's (@34) advice, I searched Google Images for "tertiary temperature".  The most relevant, prominent image was this one (originally from wikipedia):

     

    The data is from dO18 from foraminafora shells on the ocean floor.  dO18 records both the ratio of fresh to salt water, and water temperature.  Consequently dO18 records do not linearly equate to temperature records between different periods with very different ratios of fresh to salt water, as when large quantities of ice are locked up in ice sheets.  Hence the two different temperature scales.

    As Stephen Baines mentions, the paper cited in the OP shows a temperature record for the tertiary.  Indeed, it shows the data in the image above, first in an unmodified form and then adjusted for the size of ice sheets to give a direct temperature measurement (Fig 3(b)):

    As you can see, temperatures did not consistently exceed 4 C above mid-twentieth century values until 35 million years ago.

    Finally, I did see two images that showed temperatures in the 20 degree range.  One showed central european temperatures only, and hence was not representative of global temperatures.  The second was the crude graph by Scotese which is (in its original form), not proxy based, but merely assigns a warm temperature for periods without glaciation, and a cool temperature for periods with extensive glaciation.  It also showed global average temperatures rather than the global temperature anomaly, and therefore showed at most a 7 C increase over modern temperatures at any time in the tertiary.  I do not know what figure Scott Sinnock was basing his claims on, but they are not warranted by the limited evidence he provides.

  39. From clarification in #36, A global warming of 2 deg C is a low range optimistic value and > 4 deg C of global warming by 2100 is a high range estimate. >4 is ~1 deg per 20 years. We are 14 years into the 21st century. What is the global temp increase from 2000 till now?

    We are not on track 14 years into the 21st century. I question that the Earth's crust, atmosphere, and oceans as a heat sink could allow that much change in 100 years. I tried to see the annual fluctuation in Lake superior water temps but they only record surface temps, when avg depth is 183.2 meters.

    Adapting has so far been to .7F in 60 years from 1942 to 2012. What animal, plant or human can't adapt to: NOAA sea level trends: Naples Fla shows 2.4 mm/yr; Daytona shows 2.32 mm/yr. A house in Jupiter, Fla at 14.5 feet above sea level is also 4419 mm above sea level. The recent trend along Fla coast will bring sea water to the Jupiter Fla house doorstep in 1841 years, assuming no changes in continental plate rise or fall over 1841 years. Sounding so many alarms and raising electric rates 50% in 6 years to fight this seems a bit overdone.

  40. At least Polar Bear adaptation is being relieved so far this year. On 2014 being a meltdown year in the Arctic year, there is now 93% as much ice area (May 21st) as record cold year 1979 ice area level. 2014 Peak March to late May melted area is substantially less than in same period of 1979. source: Charctic ISI.

    Response:

    [JH] Your "look squirrel" bloging style is very tiresome and impreses no one reading this comment thread. Please cease and desist posting coments of this nature. 

  41. Not being minded to examine a source used to spread nonsense, I will but point out that the freezy season of 2013/4 left Arctic SIA at 13.5Mkm^2, which is 89.5% of the equivilant 1978/9 figure. The latest SIA is 10.8Mkm^2, which is 89.2% of the equivilant 1979 figure.

    Also, unlike Yogi Bear, the term polar bear is neither capitalised nor the subject of fictional commentary; at least, not on this website.

    Response:

    [JH] I belive that you have directed this coment to jetfuel.

    In the future, please identify the comenter (by name) and coment (by number) that you are respo ding to.

  42. MA Rodger @41, the current (day 142) sea ice extent according to Charctic is 12.592 million km^2.  That is 92.69% (or 93% after rounding) of the 1979 figure of 13.585 million km^2, but only 90.714% of 13.881 million km^2 on day 142 of 1985, ie, he actual record year for day 142 values.  1979 was the record year for maximum ice extent, but not for maximum May extent.

    Jetfuel is very careful to not tell us that the current sea ice extent is only 97.794% of the equivalent 2007 sea ice extent (12.876 million km^2), and 97.794% of the equivalent 2012 extent (12.876 million km^2).  That there is currently less ice than in the former, and current record September minimum ice years, and that the former record minimim extent ice had more ice in day 142 than did the current record shows how pointless are the statistics jetfuel is quoting.

    As jetfuel well knows if he has perused charctic, in May sea ice extent variability is at a minimum.  At this time of year, there is the least difference between all years so that current values of sea ice extent provide almost no predictive value in predicing eventual September minimums.  It also means that at this time of year there is a maximum ice melt for years with the maximum March extent relative to other years - and it means nothing in terms of determining how low the summer sea ice extent will be.

    This repeat and greatly extended series of such posts by jetfuel were he takes data out of context and milks "skeptical" conclusions from them regardless of their actual import (or lack of import).  He does it so consistently, and persistently in the face of correction that he is (IMO) not entitled to the presumption of honest mistakes, and I am astonished that his record of misinformation, sloganeering and repetition has not yet resulted in his loosing the privilege of posting at SkS.

    Returning to the topic, polar bears are adapted to hunting on ice packs.  That makes them poor hunters on land, so that summer months are lean month with many polar bears near starvation by the end of summer.  The most immediate threat from global warming to polar bears is from the extended duration before they can return to the ice after summer due to the more extensive summer sea ice melts.  The slightly reduced sea ice extents in March are of almost no consequence for polar bears, and also have no bearing on the critical summer sea ice extent values. 

    Response:

    Please do not respond to any future comments by jetfuel until a Moderator has had a chance to ascertain whether or not it is in full compliance with the SkS Comments Policy. From here on out, jetfuel is on a very short leash. His/her shennanigans will be stopped one way or another.  

  43. Ahhh, but Tom, jetfuel said "area." 

    CT SIA for the current date is 88.23% of 1979's value and 103.15% of the satellite period record minimum for the date (2011). 

    And just to be complete, jetfuel, PIOMAS volume for the last day in April (PIOMAS comes out monthly) was 69.65% of its value for 1979 and 100.5% of the record minimum (2011), after having spent much of March and April 2014 as the record minimum.

  44. Tom, Per my source Charctic, considerably less melting for this most recent 8 days (251,000 sq km) vs the same ~week in 1979 (415,000 sq km) could cause ponderance to some. Thus, in warmer Arctic Ocean water, from a thinner ice pack, and with 401 ppm CO2, ice is dissapearing slower than way back when everything had warmed less. I was just noting that the ice area @time lines were converging over that short time. Yes, that is a general trend for most years. At least that part is behaving normal this year.

    Unfortunately, yes, there is 7% less ice than in 1979. Actually 2014 = 2010 amt this day.

    Response:

    [PS] This is a/ offtopic, b/ cherry-picking - and suspiciously like trolling. If you wish to discuss science then do so in scientific way. If you are here to amuse yourself with outrageous arguments and trolling, then please find somewhere else for your entertainment. Further offtopic comments will be deleted. 

  45. jetfuel, are you aware of the model projections for Arctic sea ice loss?

    Take your answer here.

  46. DSL, it seems ice loss outpaces most projections. Is only getting down to 4.6-5.3 in 2014 unreasonable at this point? Multiyear ice is up from 2013, but ice area trails 2013 for this day.

     

  47. "Tom, Per my source Charctic, considerably less melting for this most recent 8 days (251,000 sq km) vs the same ~week in 1979 (415,000 sq km) could cause ponderance to some."

    That really is the most ridiculous cherry pick I have ever seen on a climate blog.  A whole eight days, wow that can't possibly be just weather noise!!!

  48. jetfuel:

    As stated above, your future posts will be carefully scrutinized by Moderators to make sure they are in full compliance with the SkS comments Policy. If they are not, they will be dealt with as appropriate by a Moderator.

    Your propensity to post "look squirrel" comments tells us that you are not here to engage in meaningful discussions of climate science. Our Moderators and regular commenters have more important uses of their time and energy than tracking and  responding to your shennanigans.  In other words, you are on the cusp of losing your privilege to post comments on this website. 

  49. Tom Curtic @42.

    Thanks for the pointer to the SIE data source. Sadly there are those who cannot understand (or probably refuse to understand="shenanigans") the simplest use of scientific terms - in this case Area and Extent. The same apprarent ignorance seems true for the effects of Arctic topology on the rate of ice loss - it slows up as it retreats through the Bering Straits. Of course, there comes a point when accumulative shenanigans become statistically irrefutable.

  50. Speaking of migrations, over the past few years, there has been a increase of Canadian Geese who have taken up permanent residence in the San Francisco South Bay Area. The strange part about it is that the weather here is actually warm, not cold. The birds used to be seen here for the winter months, now they are here all year round, hanging at public parks, golf courses, and school fields.

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