What are the local consequences of a continued global warming? And what kind of future climate can you expect for you children? Do we expect more extreme events, and will a global warming affect the statistics of storms? Another question is how the local changes matters for local communities and the ecosystem.
It may be contrary to most people’s impression. We have a clearer picture of future climate changes on a global scale than of the local consequences associated with a global warming. And we know why.
It’s reasonably predictable that the global mean temperature will increase according to the models’ climate sensitivity. But it’s harder to answer the question where the storm tracks be in the future, or what will happen to El Nino Southern Oscillation (ENSO) in a warmer world. And how will the heat be distributed in the oceans?
Climate models, like all models, are designed with some limitations. Their objective is to describe features that are of key interest for a given task, and not reproduce all the details seen in nature. They typically capture the coarse aspects of large-scale weather phenomena, which often implies that they may be somewhat displaced in terms of their real location.
Furthermore, they reproduce much of the natural variability seen in the real world, but also indicate that it is impossible to predict their exact future path beyond the time horizon of weather forecasting (see previous comment on Deser et al. 2012). Nevertheless, we can get some idea of the range of plausible outcomes by making many model predictions (ensemble runs, explained as “Monte-Carlo simulations” in the excellent BBC documentary “Climate Change by Numbers“).
The local climate can be regarded as the same as weather statistics, providing a picture of expected ranges and occurrences of different atmospheric phenomena. A climate change then implies a change in the weather statistics, with changes in frequencies and ranges. Some weather phenomena are dangerous, and hence a change in their occurrence means there will be a change in weather-related risks.
In other words, we know that Earth’s climate is changing, but we do not know exactly what the consequences will be locally where you live. However, we can make some estimate of weather-related risks. The problem is to provide a bridge between the scientific knowledge and information that is directly relevant and tailored for decision-making.
The local dimension is important for climate change adaptation and for many decision-makers, and it is important to figure out how the climate-related risks may change on specific locations in order to be prepared. For this reason, the so-called global framework for climate services (GFCS) was established by the World Meteorological Organisation (WMO).
There are also initiatives that try to enhance our understanding of regional and local climate change, such as the COoRdinated Downscaling EXperiment (CORDEX) under the World Climate Research Programme (WCRP).
Now, the downscaling efforts are getting a renewed vigour within the IPCC, and Brazil’s INPE recently hosted a workshop on regional climate projections and their use in impacts and risk analysis studies (link).
One key question is how to make best use of our knowledge and information in decision making and climate change adaptation. How to make decisions based on climate science? To achieve this objective we need to ask who are using the information. And what do people actually need?
Not surprising, one take-home message from the workshop was that dialogue between decision-makers and scientists is important. And it is important that the scientists and users of the information (such as decision-makers or scientists from other disciplines) understand the limitations of the data and what are the consequences of climate change.
Some of the hottest debated concepts at the IPCC workshop involved “model bias” and “bias correction“, but not all who need climatological data may understand their meaning. Not that they are stupid, but many discussions on this topic are cryptic for those outside the climate research community.
The obstacles associated with mutual understanding across different scientific disciplines also surfaced during a more recent workshop on biodiversity and climate change in Bogota, Colombia (link), organised by Alcue Net and CORDEX and hosted by Colciencias. One conclusion from this meeting was that the mutual understanding across scientific disciplines may improve through working closely together over time. The experts must come out of their comfort zone.
Furthermore, data sharing facilitates better understanding, however, it’s important to document the limitation of model results and distinguish between what is model results and what is observations. Data need to be accompanied with unambiguous and standardised metadata.
In other words, there’s a need for a common description of the data, using standard terms and data structures. The recipient of the data should know exactly what the numbers represent and what is their history.
The discussion during the two workshops also coincided with the publication of a white paper on ethics by an organisation called Climate Service Partnerships (CPS). Many of the ideas from the IPCC workshop, the biodiversity meeting in Bogota, and points made in the CSP white paper all come together: better guidelines, best practices, and collaboration are necessary to avoid mal-adaptation to climate change.
I learned from the Bogota meeting that biologists often use a dataset called ‘worldclim‘ to provide a basis for climate information. Climate scientists then need to explain why worldclim often is not appropriate for describing local climatic conditions. The reason is that future projections are derived (interpolated) from coarse global climate models which do not account for local details such as geographical details, that many of the station records used to estimate the baseline may not have been quality checked, and that there are many regions with missing observations.
The concept of scales may also cause some confusion, with different definitions in different disciplines. The climate scientists need to know what exactly is the question and what kind of answers people expect. Also that there is a crucial difference between data and information, and that people often want an answer or some information rather than data. However, those who use climate data for further processing may have to adapt their analysis to the available information.
One example is a person who asks for hourly precipitation in order to figure out how often do we get a flash floods. So it is not really hourly data that is needed, but instead the answer to the question whether flash floods will become more frequent or severe. In other words, we may make sense out of rare events and extremes if we know how to pose a question that can be answered with science or statistics.
In other words, we have both information and knowledge that can be used as guidance in decision-making and climate change adaptation. However, we need to rethink our questions and look for cases where climate science can provide reliable information that have a direct relevance, even if we cannot get a complete answer. At least, we should look for ways to improve the information basis for decision making by looking at the type of information and data that has been used in the past. One way to do that is through a dialogue and co-production of knowledge.
re #45 Kevin:
“Only simulations that include increasing concentrations of long-lived greenhouse gases match the warming observed during the twentieth century.”
Sorry, but I find it difficult to see how a period of almost 40 years (ca. 1941- ca. 1979), during which we see an abrupt decline in temperature, followed by a period of little to no trend in either direction, while CO2 levels continue to climb, could be seen as evidence for the long term influence of CO2 emissions on 20 century global warming, regardless of whatever other forcings might have been in effect during that period.
Even if you’ve managed to convince yourself that this is the correct interpretation of the data (which obviously you have), why is it so difficult to understand that others might not be so easily convinced? Why is it necessary to continually accuse skeptics of ignoring “the science” when your preferred conclusion seems so unlikely, and, indeed, contrived?
> wonder if it’s the SAME 15%
Testable hypothesis; read the linked blog piece for the test used:
http://blogs.agu.org/wildwildscience/2015/10/13/the-vaccine-to-prevent-crazy/
BPL,
Of course drought does not only depend on temperature. If it did, then we would expect a global increase, commensurate with rising temperatures. Drought is much more dependent on precipitation, with a smaller evapotranspiration contribution. Sheffield, et. al. used the Penman-Monteith equation to calculate drought. While more accurate, it does have greater data requirements. Just claiming that you got it right, and that others got it wrong, does not stand up to scrutiny. Any barroom drunk will argue similarly. A little more evidence is required to (dis)prove scientific research.
— Victor
Precisely. You disregard the aerosol component (which increased from WW2 until the Clean Air Act). You find it difficult to add negative numbers and positive numbers.
Think of it as balancing your checkbook. Can you do that?
Three words for Victor @51:
Aerosols, aerosols and aerosols.
How many factory and power plant SO2 and fly ash scrubbers and automobile catalytic converters were in place 1941-1979? How much low sulfur Wyoming coal was being burned in midwestern power plants 1941-1979? And the situation in Western Europe was the same.
Of course this has been pointed out to Victor repeatedly, but he simply refuse to learn. Ignoring the science, not to mention physical reality, is exactly what Victor is doing.
Dan: Just claiming that you got it right, and that others got it wrong, does not stand up to scrutiny. Any barroom drunk will argue similarly. A little more evidence is required to (dis)prove scientific research.
BPL: Then disprove my paper. Show your work.
Victor, sorry but where does anyone claim that GHGs are the sole forcing at work? The theory is that climate responds to net forcing and that is exactly what model runs over 20th show. Try Chpt 10 of the AR5.
Why is it necessary to continually accuse skeptics of ignoring “the science” when your preferred conclusion seems so unlikely, and, indeed, contrived?
Comment by Victor — 14 Oct 2015
Veektor, Your cozening behavior is wearing thin. I hear Trump is looking for some extra campaign staffers. You should apply. While you’re at it you could make meaningful contributions to science by researching that thing on top of his head.
Victor: “Sorry, but I find it difficult to see…”
You could have stopped right there. Your personal incredulity is not sufficient to cast doubt on established physics. You probably also find it difficult to see how gravity can be viewed locally as a curvature of spacetime or that the vacuum is full of virtual particles popping in and out of existence. All of these things are more of a comment on your level of understanding, not on the soundness of the physics.
A big part of your problem is that you utterly mischaracterize the trend in temperatures–which is unequivocally upward since 1975. Try looking at the data statistically rather than through the veil of ignorance and self-deception.
Victor, #51:
” Sorry, but I find it difficult to see…”
Yes, I’ve noticed.
And no, I have not ‘convinced myself.’ I’ve listened to folks who really know their stuff, and read as deeply as I can given my level of preparation. Is it really so hard to understand that other forcings can have an effect? The whole point of the modeling is to understand the various competing effects at work, and estimate their combined influence. It’s been a pretty robust finding that by far the best match for OBS is anthropogenic plus natural forcing–not something I made up.
Dan H,
BPL and I had a discussion about this a while ago. I noted that drought didn’t seem to be an issue during hot periods such as the carboniferous. BPL said that one goes through a drought period initially, and then millions of years later everything turns lush. Or maybe you get drought until it gets hot enough to break the drought. The logic was beyond me. (I’m probably misrepresenting BPL’s stance. I’m sure he’ll explain)
My stance is that, barring tectonic reasons, since we know that warmer periods were lush, the odds are slim that warming is the primary cause for the current expanding-or-not of drought. We’re doing plenty more than mere warming to muck up the system.
What do you think, Dan?
Victor says “Sorry, but I find it difficult to see how a period of almost 40 years (ca. 1941- ca. 1979), during which we see an abrupt decline in temperature, followed by a period of little to no trend in either direction, while CO2 levels continue to climb, could be seen as evidence for the long term influence of CO2 emissions on 20 century global warming, regardless of whatever other forcings might have been in effect during that period.”
This is an amazingly irrational statement. Firstly nobody is arguing that this time period is evidence that CO2 would affect temperature. And secondly it’s obviously entirely plausible that the heavy particulate emissions during that period were enough to completely cancel the effect of CO2. The abrupt initial decline was only a tiny fraction of a degree.
You need at least 30 years of data to be able to see beyond short term cycles like el nino and clearly particulates could have a longer effect at times requiring a century of data to see the greenhouse effect. However when you look at the long term over the last 10,000 years you see clear hockey sticks of both CO2 and temperature. I dont know about Victor but the pattern is starkly obvious to me and shorter term anomalies of flat temperature periods seem relatively easily explained.
I think Victor is making a strawman argument, and that immediately makes me suspicious of his motives for commenting. He is being deliberately stubborn, and that is the kindest word for it.
51 victor
I borrowed this from Hotwhopper.
The graph shows GISS temperature anomalies and CO2 concentration. This is the most recent temperature data with the 1940s sea temperature measurement errors corrected for. The correalation looks respectable.
http://marvelclimate.blogspot.com/2015/10/the-whole-sum-and-parts.html
Dan H. talks sciencey and is much more certain than the climatologists.
Check what you see claimed.
If we know the gross climate effects over the Atlantic and the eastern US seaboard, can we then run simulations of hurricane tracks with assumed temperature, humidity, etc., distributions, just as the actual weather forecasts do today, and see if anything significant changes?
It’s been more than a week since these boards were updated. What happened?
RC 61: since we know that warmer periods were lush, the odds are slim that warming is the primary cause for the current expanding-or-not of drought.
BPL: Not all warmer periods were lush. It depends on things like the locations of the continents. And the lush Mesozoic flora was adapted to the Mesozoic climate. Present flora is not. So if you suddenly change from a Holocene to a Mesozoic climate, you will first get a mass extinction before you get adaptation.
Richard Caldwell @61 (and Dan H), you might want to try reading up on Hadley Cell expansion.
Demonstrating the possibility that aerosols could have significantly cooled the atmosphere during the period in question does not in itself demonstrate even a correlation between CO2 emissions and temperature,not to mention a cause-effect relation. No more than demonstrating that Ptolemaic epicycles can be made to account for the planetary orbits can support that particular hypothesis. Just because you can come up with something that looks like an explanation does not make it one. There have been no end of such “explanations,” based on all sorts of forcings and other influences, but all are in violation of Occam’s razor — and for good reason.
And yes, I’ll agree. This looks like deja vu all over again. To add to the feeling of nostalgia, I will once again refer you to the excellent online discussion of Occam’s Razor by F. Heylighen (http://pespmc1.vub.ac.be/OCCAMRAZ.html), which includes the following, of central importance to all science:
“Though the principle may seem rather trivial, it is essential for model building because of what is known as the “underdetermination of theories by data”. For a given set of observations or data, there is always an infinite number of possible models explaining those same data. This is because a model normally represents an infinite number of possible cases, of which the observed cases are only a finite subset.”
Here’s more, from another source, on the same basic principle:
“[F]or each accepted explanation of a phenomenon, there is always an infinite number of possible and more complex alternatives, because one can always burden failing explanations with ad hoc hypotheses to prevent them from being falsified . . . Put another way, any new, and even more complex, theory can still possibly be true. For example, if an individual makes supernatural claims that Leprechauns were responsible for breaking a vase, the simpler explanation would be that he is mistaken, but ongoing ad hoc justifications (e.g. “and that’s not me on the film; they tampered with that, too”) successfully prevent outright falsification. This endless supply of elaborate competing explanations, called saving hypotheses, cannot be ruled out— but by using Occam’s Razor”(https://en.wikipedia.org/wiki/Occam%27s_razor)
I think Victor is making a strawman argument, and that immediately makes me suspicious of his motives for commenting. He is being deliberately stubborn, and that is the kindest word for it.
Comment by nigelj — 17 Oct 2015
Weektor is trolling. That’s all. He wants to eat up time and space and keep meaningful conversations from taking place by continually making ignorant remarks so others will waste their time responding. Gish Gallop, if you will. Ignore. Move on. Quit wasting time. Eventually he’ll shut up and go away…. hopefully.
RC,
Agreed. Temperature rises tend to follow droughts, rather than cause them. Precipitation changes (for whatever reason) is the leading factor. The lack of cloud cover then allows the surface to heat much more than otherwise during the warmer months.
Historically, warmer periods were wetter. The entire water cycle was accelerated, due to the warmer waters. Obviously, the close to the oceans, the more accurate this statement. This occurs today, as the warmest months are the wettest; the Gulf coast states, England, India receive the most rainfall during the summer. Other areas receive the most rainfall in spring or fall. Winter is generally the driest season worldwide.
We do not need to return to the carboniferous for an example of the relationship between temperature and droughts. Africa experienced its wettest periods about 7-8k years bp, when temperatures were warmer than today, and was much drier during the last glacial periods (~20k years bp and 100k years bp).
http://www.esd.ornl.gov/projects/qen/nercAFRICA.html
Granted, this is an oversimplification; using bulk temperature as a determinant. Weather patterns are a bigger cause of droughts. However, a good correlation exists between higher temperatures, increased precipitation, and decreased drought. Check out the following analysis between vegetation growth and temperature. While a negative correlation exists during the summer months, a positive correlation exists during the winter and spring (insignificant during the fall).
http://www.atmos.umd.edu/~sun/Sun_2007GL031485.pdf
During the recent warming, temperatures have risen much faster during the coldest months and higher latitudes, than during the warmest months and lower latitudes. Once again, water was found to be limiting factor affecting vegetative growth, with temperature being a minor player.
> more than a week since these boards were updated. What happened?
My guess? We of the peanut gallery are not being interesting enough. Not asking interesting enough questions based on actually having read the papers to keep the real climate scientists involved; and the obvious, too many trolls, rebunking the same old frequently rebutted nonsense, and (sigh) too many of us replying to stupid distractions.
The climate science conversations are still happening.
Not here so much.
Hope I’ve guessed wrong.
A big part of your problem is that you utterly mischaracterize the trend in temperatures–which is unequivocally upward since 1975. Try looking at the data statistically rather than through the veil of ignorance and self-deception.
Comment by Ray Ladbury — 16 Oct 2015
It’s a common condition known in “the profession” as ingrown mustache. I heard of a case like this many years ago in Dusseldorf. Very hard to cure once it sets in.
V 69: Demonstrating the possibility that aerosols could have significantly cooled the atmosphere during the period in question does not in itself demonstrate even a correlation between CO2 emissions and temperature,not to mention a cause-effect relation
BPL: What part of “the variance of temperature accounted for by CO2 1850-2014 is 82%” do you not understand? And the link does not depend on demonstrating the correlation; the link is a matter of radiation physics, unless you’re prepared to tell us that quantum theory is wrong–in which case the Sun doesn’t work, let alone your PC. For God’s sake, crack a book. I have some recommendations if you’d like to study up.
Dan H: Temperature rises tend to follow droughts, rather than cause them
BPL: Sims tests for Granger causality show they both cause each other, in a feedback–which you’d know if you’d read the article I kept pointing you to. Here it is again:
http://www.ajournal.co.uk/pdfs/BSvolume13(1)/BSVol.13%20(1)%20Article%202.pdf
READ it this time.
This endless supply of elaborate competing explanations, called saving hypotheses, cannot be ruled out— but by using Occam’s Razor”(https://en.wikipedia.org/wiki/Occam%27s_razor)
Comment by Victor — 19 Oct 2015
The Derp is strong in this one.
Hank Roberts at 72,
At #38, I posed a question that the peanut gallery is invited to answer as well, which is about climate science and related to the topic of this post.
Public opinions about climate are changing, for the better, and one of the reasons given in surveys is perceptions of extreme events.
But still, whenever there is an article where “a climate scientist” is asked to comment, we have the same old hedging about attribution. I would like to see some discussion that can justify this response on a physical basis.
But, if going round and round with Victor’s same old nonsense is more fun, have at it.
Re comments from Victor that are indistinguishable from trolling:
There are sophisticated ways of looking at the temperature record. Those are (obviously!) not at issue here.
For a way of looking at temps that is simple yet legit, I favor looking at the global average by calendar decade (e.g. 1970-79, 1980-89, etc). Everybody can understand it without a PhD, or even a stats course, it’s meaningful, and it gets past a lot of noise, both statistical and conversational.
Since the 1970s, decadal numbers rise at 1-2 degrees per century. When you see a couple decadal deltas less than that (let alone negative), let me know. And not until. (Hint: 2010-19 data are not in yet, and 2020s are not begun.)
Have a prediction for way less than that? I may have a large bet to offer you if you get ridiculous enough.
700,000 lines of computer code is what makes up an average climate stimulation code. Climate modelers spend a lot of time fixing the codes to improve accuracy. On super computers, a single run could take three months, and for longer runs it could take a year. The data from the model is compared to observations from the real world to increase credibility and to see how well the model reproduced things to insure more accuracy in predicting. http://climate.nasa.gov/blog/2295 goes more into it.
Climate change impacts on Alaska threatens villages of natives. US tropical islands will have the sea level rise, threating infrastructure and freshwater supplies. Northeast America is to have increased heatwaves and heavy precipitation. Southeast America will have rise in the sea level and more intense hurricanes. The Midwest will have long periods of dryness, hot summers and mild winters. The Great Plains will have more droughts and more tension on the areas primary water supply. Northwest America will have higher temps. and an increase in disease and pests. Southeast will also have increased temp. and an increase in severe droughts. This site http://www3.epa.gov/climatechange/ gives a nice map in which you highlight an area to see the impacts of climate change. There is also plenty of other information on climate change in there.
#70 Chuck Hughes: “Weektor is trolling. That’s all. He wants to eat up time and space and keep meaningful conversations from taking place by continually making ignorant remarks so others will waste their time responding.”
You’ll be relieved to know that I have nothing to add to what I’ve already written, Chuck. If you feel comfortable ignoring perfectly reasonable objections to your pet theories there’s nothing I can do about it, clearly.
Nor do I see any point in responding to the juvenile ad hominems I’m once again seeing here. I would like, however, to extend a word of gratitude to those who responded in a civil manner.
Comment by Victor — 19 Oct 2015 @ RE:”Occam’s Razor….
Occam’s Razor, when applied to your ongoing, nonsensical commentary concludes that you are a “Simpleton”. Now go away.
> You will first get a mass extinction before you get adaptation.
Thank you very much BPL. Plus: your reminder about the locations of the continents. Many facile pronouncements about complex process on epochal time scales might be prevented by keeping the continental clock on the wall, so to speak, I think.
Victor appears to be sceptical that CO2 is causing recent climate change. He basically claims the correlation between CO2 and temperature since 1920 is only “approximate” and explanations for this are too complicated. Victor claims we should apply “Occams Razor” and look for a “simpler” explanation for climate change.
However the alternatives of solar energy and cosmic rays are much more complicated and troublesome. And the rough correlation between CO2 and temperature is not so rough when you do a statistical analysis.
In fact the simplest explanation for most of the warming since 1920 has to be CO2. “Occams Razor” suggests CO2.
Record hurricane heading to Mexico.
Anything to do with climate change?
“… is this intensification rate an indication of how global warming is altering the characteristics and behavior of nature’s most powerful storms? That’s a harder question to answer at this point …”
http://mashable.com/2015/10/23/hurricane-patricia-global-warming/
Victor, unwilling or unable to understand the science involved, misapplies Occam’s Razor. In fact, the conclusion that carbon is responsible for producing the century-long positive trend in temperature (and, indeed, is responsible for modulating temperatures through history) IS the parsimonious conclusion.
Known physics (green-house gasses, atmospheric particulates, solar radiation and so on) does an excellent job of reproducing observed temperature changes — trend and wiggles included. To say that carbon (the increase of which is unequivocally anthropogenic over the past century) is NOT responsible for the trend (and for many past changes in temperature) requires concluding that our current understanding of physics is wrong AND that there is some physics (or some unknown celestial phenomenon???) of which we are not yet aware.
Yeah, pretty sure which way Occam would rule on this one!
Just wanted to say thanks for previous responses to my question regarding population vs climate. I’m now convinced it’s not a viable way out. The idea of a self-regulating mechanism was attractive, but it seems that such machinery needs to cut off and digest a number of fingers, arms and legs before producing the desired result.
I may have a browser issue, previous post does not display.
Nor do I see any point in responding to the juvenile ad hominems I’m once again seeing here. I would like, however, to extend a word of gratitude to those who responded in a civil manner.
Comment by Victor — 22 Oct 2015 @
V = Victim.
How about your conceited, disdainful and pompous disregard for Climate Science and Scientists? Bringing up Occam’s Razor as if everyone hasn’t already heard of it
check connection
BPL: Not all warmer periods were lush. It depends on things like the locations of the continents. And the lush Mesozoic flora was adapted to the Mesozoic climate. Present flora is not. So if you suddenly change from a Holocene to a Mesozoic climate, you will first get a mass extinction before you get adaptation.
RC: As I mentioned, tectonic events change things, but randomly. You have any evidence that ancient configurations prevented drought better than current ones? And you don’t seem to understand how mass extinctions work. Weedy species take over, especially when it comes to plants. If you wipe out 90% of species, you won’t lose 90% of plant cover. Instead, you just get more monoculture, as well as more human-induced changes. I asked you before to point out any example of what you contend. Of course, you’ve given no evidence at all. So, when was there an increase in temperature, a resulting drought, and then a DNA-induced relief of drought? You’re spouting goop without even the slightest bit of logic or evidence.
Richard, I seem to recall, but I never knew the details, that at the last time we had a supercontinent, that its interior was a huge desert. Very thick layers of sandstone, like the Navaho sandstone that forms much of the Colorado plateau’s magnificent scenery was deposited at that time.
Forgive me, but I’d like to elaborate just a bit on my previous post (assuming Chuck doesn’t mind, natch):-)
CO2 might be the simplest explanation, but it can no longer account for all the evidence without introducing complicating factors which undermine that simplicity. Meaning: you can’t have it both ways. If it can be the simplest explanation only if complicated by additional factors then it’s no longer the simplest explanation. Simple!
RC: I asked you before to point out any example of what you contend. Of course, you’ve given no evidence at all.
BPL: Read the paper. I list all the data in an appendix. Why don’t you do your own analysis and show where I’m wrong?
Hank Roberts #84,
Thanks. This is a perfect example of what I am talking about:
Kerry Emanuel:
“There is no question that this is an exceptionally intense tropical cyclone,” he wrote. “But I wonder whether we really know that prior storms in the region have not been equally intense and we are just lucky to have measured this one.”
I can hear Victor saying much the same thing:
“There were intense hurricanes before CO2 increased, so how can you say this was caused by CO2?”
Sorry, I’m not at all questioning KE’s competence as a scientist, but how is it helpful to support this tired old meme?
A survey says that 55% accept the conclusion “climate is changing and humans are causing it”, while 35% accept “climate is changing but humans are not causing it”. (5% not changing, 5% no opinion)
What exactly is the hedging about? Does the scientific community now have less confidence about the serious effects that have been predicted?
Victor:
Once again, Victor, ad hominem would apply if your arguments were rejected simply because you’re the one making them, rather than because they are incorrect. Unfortunately, you have demonstrated a penchant for re-iterating arguments that have long since been shown to be incorrect. By now there may be commenters who, when they see a comment of yours here, automatically assume it’s the same old nonsense from you. I’m afraid you’ve dug yourself a hole it will be hard to climb out of, the more so when you’re still digging.
Tectonic changes are not random, they are just outside the control of climate. I expect that one reason that the Miocene and earlier was warmer than the Holocene is that there was much more ocean in the tropics, increasing effective solar insolation and increasing average water vapor in the atmosphere.
The stress on an ecosystem depends on the rate of change and whether the change is within the envelope the community has adapted to.
BPL,
I read your report – again. Your calculations are much too simplistic. You mention regional and local variations, but use global average temperatures in your equations. As I referenced earlier, increasing temperatures tend to increase drought during the summer months, but decrease drought during the winter and spring (Fall showing no change). Add to this, the much greater temperature increase during the winter, compared to summer, results in a decrease in drought with increasing temperature. The effect is even greater in the higher latitudes.
Albeit, some crops will suffer if summer becomes too dry. However, the increase in precipitation during the winter and spring will replenish reservoirs and ground water. Deeper rooted vegetation will expand significantly, as satellite imagery have shown. Shallower-rooted grasses, and some crops will not fare as well. Some arid and semi-arid locations may not far as well. However, much of the mid-latitudes are expected to receive higher precipitation, and less frequent droughts. More agriculture occurs in these regions that the arid and semi-arid. Your near-term collapse of civilization is not supported by the data.
http://www.dailytimesgazette.com/persian-gulf-could-be-deadly-by-end-of-century-due-to-global-warming/31643/
leads to
http://www.huffingtonpost.com/entry/parts-of-persian-gulf-could-be-too-hot-for-humans-by-centurys-end_562e8d32e4b00aa54a4ac233
leads to
http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2833.html
Quoted from Huffington:
“If carbon dioxide emissions continue at their current pace, by the end of century parts of the Persian Gulf will sometimes be just too hot for the human body to tolerate, a new study says.
How hot? The heat index — which combines heat and humidity — may hit 165 to 170 degrees (74 to 77 Celsius) for at least six hours, according to numerous computer simulations in the new study.”
Not survivable. Astonishing in spite of having read RealClimate for many years.
V 92: CO2 might be the simplest explanation, but it can no longer account for all the evidence without introducing complicating factors which undermine that simplicity. Meaning: you can’t have it both ways. If it can be the simplest explanation only if complicated by additional factors then it’s no longer the simplest explanation. Simple!
BPL: You’ve never heard of “analysis of variance,” have you?
DH 97: Your near-term collapse of civilization is not supported by the data.
BPL: Show your work. Do the math.