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.
Nice article.
One detail is not that well explained to the general public. As long as the rate of energy inflow is faster than the rate of outflow from the planet, the only way this can be corrected is by an increase in surface temperature, and hence outgoing radiation.
Short-term effects like transfers between atmosphere and ocean don’t alter this.
The ultimate equilibrium temperature after a change in composition of the atmosphere depends on feedbacks, but there is no escaping the fact that decreasing the rate of energy outflow has to result in an increased surface temperature.
We need to look for cases where climate science can provide reliable information that have a direct relevance, even if we cannot get a complete answer.
Rasmus, considering climate change is potentially an existential problem, would it not be more productive to look to natural examples of when atmospheric warming 1998-2012 and sea level rise 2011 declined. It seems therein lay the elements of solutions?
Philip 1, “decreasing the rate of energy outflow has to result in an increased surface temperature.”
If you move heat from the ocean surface to the deep to produce energy in a heat engine you are first converting a portion of that heat to work and second you will alter the composition of the atmosphere because this is zero emissions energy.
By the time that heat returns to the surface, 250 years after it has been moved to a depth of 1000 meters, radiative forcing from greenhouse gas concentrations will be declining and if that heat is still a problem it can be recycled back to the abyss.
The zero emissions, constant, base load, alternative being offered is fission or fusion both of which produce about twice the waste heat as energy.
We get 14 terawatts from fossil fuels. Replace this with ocean thermal energy and you convert 14 terawatts of warming heat to productive use and move about 280 terawatts more into the deep.
With any thermal source you add 28 terawatts of waste heat, mostly to the ocean.
One example of a possible local consequences of continued global warming is that provided by the Hansen et al 2015 paper in Atmospheric Chemistry and Physics (of which I have only seen the discussion paper)which provides the following graph (taken from Tamino’s discussion here: https://tamino.wordpress.com/2015/07/28/hansen-et-al/ )
https://tamino.files.wordpress.com/2015/07/tempmap.jpg?w=500&h=405
It shows the surface air temperature (relative to 1880-1920) response to various scenarios involving 10 year doublings of ice melt from Greenland and Antarctica from the present time, which apparently are regarded as at least plausible.
The consequence is a huge purple blob appearing in the North Atlantic by 2065, (second row, Greenland melting only) representing a temperature anomaly in excess of minus 10C, including in the area where I live, the Scottish Highlands. Since the difference between our average summer and winter temperatures is only a little more than that 10C, it would mean summer temperatures here in fifty years time similar to the harsh winters of the end-19th century. That would bring an end to any agriculture and make much of Scotland uninhabitable.
I have not noticed any comment about this scenario in any of the Scottish media.
A quibble: It is true that many times practical decisions have to be made with less than complete data — sometimes with sparse data — but this per se doesn’t make the available data any better. A nit: The Ethics Working Group really addressed quality control — in the first place with the data itself and in second place with the process used in working with the data. This does not strike me as an “ethical” question.
That being said the article is an impressive description of the situation.
> atmospheric warming … and sea level rise … declined.
Move the heat into the oceans? “sweep it under the rug”
Many thanks for this post – an extremely important subject.
In my work (trying to help farmers adapt to CC in the tropics), it’s even difficult to get accurate representations of how the climate has been changing over the past 30 years, especially in regard to variables that affect crop production (e.g. no. days > 30C; extreme values etc.) – let alone the future.
When it comes to the future, we have to cope with an increasing number of papers and reports projecting crop distribution changes, mostly based on some mean of model runs, without any depiction of uncertainties, which I think are huge, especially in regard to precipitation and extreme values, which is what really is affecting farmers. Some papers even now refer to ‘predictions’ rather than projections, which is leading to widespread misconceptions.
At the very least, peer review should be much more stringent to insist on representation of uncertainty levels. The whole area of how met. and climate data for agriculture and other uses is presented needs to be urgently reviewed.
As far as people noticing climate change at the local level, biological changes are probably most persuasive. Especially pests. I’m in central Vermont, and we’ve just received ticks, and the general opinion that is because it is warmer. There are public health warnings about Lyme disease. This is very noticeable because it is a stark change. Weather, in contrast, is variable and climate changes are very gradual. It is hard to “feel” that things are different, and climate changes in and of themselves are not distressing in one’s everyday life.
There are many such discrete biological changes in communities. Poison ivy came here several years ago. Weeds, like cheatgrass, are moving north.
Because of the tragedy-of-the-commons situation, not much can be done about AGW until innumerable local communities suffer through such changes.
Perchance this belongs in Unforced Variations, but tangentially related. Just received my WHOI newsletter including this nice little 6:34 minute video, and have noticed algal blooms are on the rise. Another set of events to factor in? I see this is more about the science of how than the communication of what, but I think the latter is also needed wherever and whenever possible.
http://www.whoi.edu/oceanus/feature/setting-a-watchman-for-harmful-algal-blooms
There may be a better context in which to communicate climate change impacts. Weather related risk management involves insurance rates, construction codes, and investment return analysis. Historically, these have been based on weather statistics gathered over the last century or so, analyzed to reflect regional differences, etc. But now this historical data base is not an effective basis for these essential business functions. So who can help the insurance companies, govt construction standard setters, and investment decision makers get it right in a changing world? TA DA!!! Climate scientists are the ONLY ones with real insight into this process. So I am suggesting that translating climate change insights into the language of business will develop a communication tool that far exceeds your current efforts to engage the general public.
Consider an Insurance company. They are highly motivated to get their rates right. Currently they look at each years experience to estimate how the average has moved to increase the next years rates. But how do they determine the expected shift in the average due to climate change? I suspect there is a nice research project in there somewhere. And ultimately the change in insurance rates is the most direct measure of climate change impacts you will find.
Code standards for construction are a more difficult measure. The code requirements must match the life of the construction (be it buildings, bridges, aircraft, highways, etc etc). For a 40 year life building, the design must be based on the expected weather extremes over that period. A harder problem, but you guys wouldn’t be climate scientists if you shied away from hard problems. And the answer translates to project costs, which we all understand. And believe me, those backing the investments will be very interested in the answer, maybe enough to support some well targeted research projects. Anyway, it is always good to communicate your position in the other persons language. And dollar cost impact is as close to a universal language as we are likely to get. Chuck Preble
This could almost be summed up in a simple mantra:
All climate change is local.
All mitigation is local.
All adaptation is local.
Wish I had thought of this sooner.
But snark aside, I want to agree with t marvell at #8. If you are a gardener or farmer or outdoors-person and you still deny something is going on, you must really be blinded by ideology.
Move the heat into the oceans? “sweep it under the rug”
The alternative is $369 trillion dollars in economic costs over the next 200 years and 250 000 additional deaths every year.
IMHO a little planetary housekeeping is more than justified.
As global temperatures rise, then we can expect all sorts of related effects, from the earlier than normal appearance of deer ticks to rising algal blooms, to an increased rise in sea levels, and increased incidence of heat waves. Also some positive effects, such as longer growing seasons.
The question remains: does most of this warming have an essentially anthropogenic cause? When we examine the record, we see a steep temperature rise from the late 70’s to ca. 1998, followed by a leveling off from that year to now. The extent and significance of this “hiatus” has been disputed, but I don’t think anyone is claiming Earth’s temperatures have risen during the 21st century at anything close to the earlier rate. But as a result of this earlier rise, the Earth is now considerably warmer than it was around 100 years ago.
When we examine the evidence for the 20th century as a whole, we find another equally steep rise taking place between ca. 1910 and ca. 1941 — after that we see a steep decline lasting through most of the 40s, followed by a leveling off until the late 70’s. Was that earlier rise due to the burning of fossil fuels? Since CO2 emissions increased steeply after the 1950s and were relatively modest prior to then, such an explanation seems doubtful. Moreover, if the earlier rise was caused by increasing CO emissions, then why was the trend reversed during the 1940s and for almost 40 years thereafter?
When we examine the evidence from 1910 to the present, we see that the enhanced temperatures we are now experiencing are the product of both the earlier and later 20th century rises, the later one building on the earlier. If we knew what caused both the earlier increase and the decrease following that, then we would be in a better position to assess the possibility of an anthropogenic cause.
It’s a huge leap to go from an increase in deer tick activity and agal blooms to the dire warnings we’ve been getting, both here and elsewhere, projecting catastrophic increases in the rate and intensity of droughts, storms and sea levels. In the September open thread I cited studies from legitimate scientific sources, reporting that neither the incidence nor severity of droughts, hurricanes or tornadoes has increased to any significant degree for any appreciable length of time, despite the significant runup in temperatures during the previous century. (See posts 222, 229-31.)
As for sea level, that’s been increasing for well over a century, long before CO2 emissions exploded, and will continue to increase even if all use of fossil fuels were to cease tomorrow. Thus, sooner or later parts of Florida, California, the Gulf region and many other coastal areas, some now heavily populated, will be under water. This is inevitable, there is no way we can prevent it. If we spend our money wisely, we can take steps to adapt. If, on the other hand, we spend trillions in a futile attempt to roll back the inevitable, we’ll be impoverished and helpless when the tides overwhelm us. You pays your money and you takes your choice.
According to the recently published Hansen et al 2015 study which models of our future using the Eemian period (about 125,000 years ago), due to certain similarities with our period (excluding the fact that the PPM of CO2 was only about 290 back then), the oceans are going to get extremely stormy.
Besides the large increase in sea level, the wave action predicted makes every hull design of modern shipping inadequate. It will be very hard to sustain our level of civilization without the benefits of modern shipping.
Redesigning hulls will not work for the simple reason that the waves, now called “rogue” waves, of those oceans will be routine. 30 to 35 meter tall waves exert forces on a hull of about 100 tons per square meter. No modern hull design exceeds 20 tons per square meter.
This is a serious issue that should be addressed more by the scientific community. Actuaries of insurance companies are already addressing it: “every year, on average, more than two dozen large ships sink, or otherwise go missing, taking their crews along with them.” http://www.actuarialeye.com/2014/03/30/how-many-ships-disappear-each-year/
I am grateful to Paul Beckwith of the University of Ottawa for alerting me to the threat from violent oceans that mankind faces.
Paul Beckwith is a part time professor at the University of Ottawa and a post graduate studying and researching abrupt climate change, with a focus on the arctic.
Part 4: An Ocean Full of 30 meter Tall Waves by Paul Beckwith
Published on Jul 23, 2015
“Near the end of the previous warm period (Late-Eemian) when the sea level was +5 to +9 meters higher than today, persistent long period long wavelength waves 30 meters high battered the Bahamas coastline. Will we see these massive storm generated waves soon? No ship could survive this…”
https://youtu.be/rq24d3-bIU4
Victor,
Agreed. The ncdc shows a decrease in tornadic activity over the past half century.
https://www.ncdc.noaa.gov/climate-information/extreme-events/us-tornado-climatology/trends
According to Ryan Maue, tropical cyclonic activity shows a better correlation with ENSO activity than global temperatures.
http://weatheradvance.com/home/weather/weatheradvance.com/wp-content/uploads/2014/04/Global-Hurricane-ACE-ENSO-PDO-1024×515.png
Droughts do not appear to have changed appreciably either:
http://www.nature.com/nature/journal/v491/n7424/full/491338a.html
http://www3.epa.gov/climatechange/science/indicators/weather-climate/drought.html
http://onlinelibrary.wiley.com/doi/10.1002/2015EA000100/full
“…neither the incidence nor severity of droughts, hurricanes or tornadoes has increased to any significant degree,,,”
– See more at: https://www.realclimate.org/index.php/archives/2015/10/climate-change-is-coming-to-a-place-near-you/comment-page-1/#comment-636420
Some do say that about drought. Others disagree; AR5 said the picture was uncertain. But note that it’s not ‘haven’t increased’–it’s ‘can’t be shown to have increased.’ And in fact, although the statistics are still muddled,
there are good physical reasons to expect increasing problems with drought: chiefly, hot weather makes everything drought-related worse. (See “California, 2015.”)
As to hurricanes, I think there is a significant exception: the North Atlantic basin shows a long-term increase:
http://www.nhc.noaa.gov/climo/images/Atlantic_Storm_Count.jpg
But it’s early innings for hurricanes yet; the projections I’ve seen are over century time scales (i.e.., keyed to 2100.) Simulation experiments show fewer, but more powerful cyclones. We’ll see. But there is reason for concern–other than the dreaded ‘extrapolation from deer tick data.’
For tornados, there’s never been any claim that they will increase in a warming climate, though research is ongoing–due to the persistent suspicion that even though they are small-scale storms and therefore hard to simulate, tornados should logically get stronger given more ‘thermal fuel.’ Maybe at some point they will get a handle on that.
I really admire the smooth manner in which you tacitly exclude the possibility that we can still have a significant influence on the ultimate amount and rate of sea level rise.
But it’s still meretricious:
To sum that up, even just the mean difference–never mind the total span of the estimates–has serious emissions cuts holding SLR by 2100 to just two-thirds of what it would be under the most drastic emissions scenario. (Which, sadly, is the best match for the current carbon trajectory.)
http://www.carbonbrief.org/blog/2013/10/what-the-new-ipcc-report-says-about-sea-level-rise/
Thanks for this article. Very important subject, but, it seems to me, often not being considered as a real problem. Example: my impression, as a health care worker and researcher in Norway, is that the question “what will the consequences of climate change be for health care in the long run?” is not posed in a serious way. The problem does not really exist. There is no planning for a different future. A report is made, there will be some problem with more ticks and a few other nuisances, but nobody really cares. Everything will go on as before, only a little better. We will have more money to throw at any problem. We will treat more people. The services will be even better. I have struggled with climate change since woken up by James Hansen´s book “Storms of my grandchildren”, but still can´t REALLY wrap my head around the catastrophic things that might happen. And I read about these things every day. Most people don´t. It´s just an unpleasant story, not real. How does it become real? When it hits you. Like the war in Syria – not really a problem until thousands of refugees cross our borders. Then “something must be done”. But with climate change, then it´s too late.
Won’t most localities continue to experience wide fluctuations in the future very much like those documentable over the past 135-200 years? Mean rainfall and mean temp will be higher (or in some cases lower), but won’t the oscillations continue? Lots of places are not even prepared for repetitions of past events, say the California flooding of 1863, or the recurrent Indus Valley floods, or the many ocean storms of the US Eastern Seaboard.
13: Victor, umm, you might like to tell that to the hundreds of cattle farmers in 80% of Queensland Australia which are as we type experiencing their worse ever drought on record. When you’ve finished telling the Queensland farmers that there has been no increase in the number of droughts worldwide, you just might like to pop over to the other side of the pacific and tell the same crap to all the Californians and generally anyone on the western seaboard of the US. Then take a flight to Indonesia..etc etc. Why are you so blind?
One agreement I must have with you is that much more money should be spend on adaptation rather than mitigation. However this problem is blatantly and unequivocally anthropogenic!. I doubt for a second that this situation can be reversed now it is already so advanced; so adaptation has got to be the only logical way to go.
Kevin Mckinney #17,
This is the problem with continuing to “defend” against claims that “nothing is going on” based on global averages.
1. The statistics are muddled, and drought can’t be shown to have increased.
2. There are good physical reasons to expect increasing problems with drought.
If I, locally, experience increased problems with drought, why is 2 not sufficient for me to rationally, even if not with absolute confidence, attribute the effect to the cause? Are we forgetting Ockham somehow?
In all these interchanges, there is still this strange implication that maybe the physics is wrong. Maybe the system isn’t acquiring excess energy? Maybe the excess energy will not have an effect?
I know that there have been papers demonstrating what you say about temps affecting the severity of e.g. the California drought. So what is left to demonstrate? Why is it necessary to give credence to the kinds of implications contained in comments such as Victor’s?
It has always seemed to me that the bad effects must show up locally before they manifest globally. If anyone would like to correct that perception, I would really like to hear an explanation.
DH 16: Droughts do not appear to have changed appreciably either
BPL: Look again:
http://www.ajournal.co.uk/pdfs/BSvolume13(1)/BSVol.13%20(1)%20Article%202.pdf
Victor, studies repeatedly show that dry areas are getting drier and wet areas are getting wetter, accounting for the increased incidence of extreme flooding events as well as severe drought events.
Yes, if you average the droughts and floods together, you get little average change, but that’s little consolation for the affected regions. Try summing the economic costs of the extreme flood and severe droughts, instead. A more useful metric, isn’t it?
So : How does this bimodal response take place? Why do some regions get wetter, some drier?
A primary global response to increased atmospheric CO2 is an increase in atmospheric water vapor on the order of 6-7% per 1C of warming. In some regions, the result is high precipitation (North Carolina’s flooding was enhanced by atmospheric water vapor fed in from the warming tropics); in others, the result is drier conditions due to changing atmospheric circulation patterns as well as higher land temperatures that reduce soil moisture.
Now, it may appear counterintuitive for increased water vapor to cause droughts as well as floods, but here is where regional conditions become important.
Desert air (30N/S) is actually twice as moist as subpolar air (50N/S), so desert air is not really ‘dry’ – but since the air is too warm for condensation (the saturation vapor pressure is too high), the water vapor over deserts acts only as an invisible greenhouse gas. In contrast, in the southern United States, that water vapor encounters cold subpolar air (lowering the saturation vapor pressure) and thus serves as a source of enhanced precipitation, leading to record-breaking massive flooding.
Hence, drier regions tend to get drier and wetter regions, wetter, with the driving force being the increase in atmospheric water vapor. And this is documented:
#20 Lawrence Coleman.
Lawrence, if you consult this web site (http://www.jaconline.com.au/downloads/sose/2004-11-drought.pdf), you’ll see a diagram (vertical graph on right) illustrating the incidence of major droughts in Australia since 1850. I count 13, and they are fairly evenly spaced. I don’t see any tendency for droughts to have increased in either frequency or length during this period. Much of Australia is desert country anyhow. It’s the driest continent on Earth by a long shot. While it’s easy to understand why Australians would be fed up with the current drought, I think most of the old timers realize that this is nothing new. If the latest has set some sort of record, that might relate to global warming if there were some sort of trend toward more and/or longer droughts over the last 100 years or so, but there is no sign of that, either in Australia or the world at large, as the report I cited indicates. If in fact there has been no trend in the direction of more or longer droughts over the last 100 years then there is no basis for a correlation with either the runup in global warming or the increase in CO2 emissions during that period.
No one is claiming the world isn’t significantly warmer now than it was 100 years ago. And one might expect that the increase in warming would lead to a worsening in drought conditions. But that does not seem to have been the case. And if the warming over the last 100 years hasn’t made things worse, it’s hard to understand how anyone could predict a worsening over the next 100 years.
I posted on this topic a few days ago, but my post seems to have gotten lost, so I’ll give it another try.
First, no one would deny that the world is hotter now than it was 100 years ago. And there is good reason to assume that the increases in temperature could be having an effect on things like animal and insect migrations, polar bear feeding habits, loss of polar sea ice and melting glaciers, to name a few examples. However: animal and insect migration patterns and feeding habits have changed many times in the past, as have sea ice levels and glacier conditions. None of this is really new. The question at the present time is: given that the current runup in warming is causing the changes we now see, then what could be the cause of this runup?
If in fact the runup in temperatures is caused by CO2 emissions, mostly due to the burning of fossil fuels, we would expect, first of all, to see a clear correlation between the increase in atmospheric CO2 and the increase in warming — and second of all, since correlation does not imply causation, we would need to establish that the increased CO2 emissions are the most likely cause of the correlation we see.
When we examine the history of global temperatures since 1900, however, a pattern presents itself that is very far from the clear correlation we would expect. Thus, regardless of the argument from physics that CO2 has the potential to significantly warm the atmosphere (given certain feedbacks that are themselves subject to debate), the first, equally important condition does not seem to have been met.
How do I know this? From roughly 1910 through 1941, a period of 31 years, an increase in global temperature occurred that was at least as extreme as the one observed during the last 20 years of that century. Yet the output of fossil fuel generated CO2 during the earlier period was far less than the dramatic runup in CO2 emission during the latter part of the century. Since the burning of fossil fuels is unlikely to have been the cause, what was?
Then, during the 1940’s there was a dramatic downturn in global temperatures, followed by a leveling off until ca. 1979, when another significant runup in temps occurred, lasting till 1998. Thus, from 1941 through 1979, a period of 38 years, we see little to no sign of any significant warming.
So. Even if we disregard the period of the so-called “hiatus,” from 1998 to present, which is admittedly controversial, it is impossible to see much sign of any consistent correlation between CO2 emissions and global warming over the entire period when the Earth heated up to the extent we see today. What we do see is two periods of extreme warming, from 1910 – 1941, and 1979 – 1998, with a 38 year period between them in which temperatures essentially leveled off. It would seem that the reason the world is so much warmer now than it was 100 years ago is therefore not due to a steady increase in CO2 emissions but to two separate and very possibly unrelated periods of warming in which the later built upon the earlier. If the increase in CO2 emissions over the last century were the cause, then we would expect to see a concomitant rise in temperatures during the entire period — but we don’t.
Now I’ve read studies purporting to explain away this discrepancy, usually by examining the effects of various forcings during the period in question. However, the existence of possible ameliorating factors that might appear to save a discredited theory, does not in itself demonstrate the correctness of that theory. The best such studies can do is suggest possible reasons why the theory appears to fail. The claim, therefore, that studies of this kind are sufficient to prove beyond all possible doubt that the theory is correct after all, despite the obvious lack of a clear correlation, seems dubious in the extreme.
“Why is it necessary to give credence to the kinds of implications contained in comments such as Victor’s?”
– See more at: https://www.realclimate.org/index.php/archives/2015/10/climate-change-is-coming-to-a-place-near-you/comment-page-1/#comment-636552
I don’t think that contradicting them, with clear reasons as to why they are wrong, constitutes “giving credence.”
#25–Victor, you’ve said this all before.
And you’ve had the appropriate response before, which is that there has always been natural variability in the system, and adding an anthropogenic signal won’t make that go away. You’ll still have natural ‘ups and downs’, but they will be superimposed upon that anthropogenic trend.
Which would look a whole lot like the observational record:
http://www.ncdc.noaa.gov/cag/time-series/global/globe/land_ocean/12/12/1880-2015
Perhaps you find that ‘difficult to see.’ But that doesn’t mean that the problem is an objective one.
Oh Victor. If you don’t get it yet, you probably never will. But what the hell… one more time for posterity’s sake:
Physics tells us that increasing CO2 concentrations will increase the heat stored in Earth system. There is no dispute here. In addition, physics tells us that other factors also have an impact on the storage of heat in the systems (for instance, compounds in the atmosphere reflecting light back into space) or the distribution of heat within the system (for instance, oceanic-atmospheric interactions causing more heat to be stored in the deeper ocean). Again, this is nothing controversial. At times, those other factors will overwhelm the signal from CO2. As a result, you should not expect to see a monotonic increase of surface temperature with increasing CO2 at all time scales and periods. You could even see a decrease in surface temperature.
This is all well-corroborated by the physical evidence, both current and paleontologic. Your citation of the recent temperature record as a suggestion that the prediction of AGW is “dubious in the extreme” displays either ignorance of the facts or a profound lack of understanding about how physical science works. The facts have been explained to you many times, so I can only conclude that you just can’t or wont understand.
“Now I’ve read studies purporting to explain away this discrepancy, – See more at: https://www.realclimate.org/index.php/archives/2015/10/climate-change-is-coming-to-a-place-near-you/comment-page-1/#comment-636552
Then you have utterly failed to read the peer-reviewed science contained/referenced in the IPCC reports. There is no excuse for such continued scientific intellectual ignorance when it has been clearly demonstrated to you that warming and cooling has occurred over millennia due to natural causes/forcings. The warming since the 1970s can not be explained by natural causes. It can only be explained when the additional forcing from man-made greenhouse gases are considered. This has been known for a long time yet you continue to show you make absolutely no effort at all to learn, but rather lazily regurgitate what you want to believe, to heck with the science. Busted, sport!
V 24: If the latest has set some sort of record, that might relate to global warming if there were some sort of trend toward more and/or longer droughts over the last 100 years or so, but there is no sign of that, either in Australia or the world at large, as the report I cited indicates.
BPL: As many times as you repeat this, I will repeat THIS:
http://www.ajournal.co.uk/pdfs/BSvolume13(1)/BSVol.13%20(1)%20Article%202.pdf
V 25: If in fact the runup in temperatures is caused by CO2 emissions, mostly due to the burning of fossil fuels, we would expect, first of all, to see a clear correlation between the increase in atmospheric CO2 and the increase in warming — and second of all, since correlation does not imply causation, we would need to establish that the increased CO2 emissions are the most likely cause of the correlation we see.
When we examine the history of global temperatures since 1900, however, a pattern presents itself that is very far from the clear correlation we would expect
BPL: Crap. CO2 accounts for 82% of the variance of Hadley CRU annual temperature anomalies from 1850 to 2014. That is what anyone in their right mind, with some education in statistics, would call “a clear correlation.” p < 10^-40.
And it still works if you correct for autocorrelated residuals.
Victor (25) – you say that there is a lack of correlation between temperature and CO2. You do that by eye-balling the trends, finding short-term anomalies. If you talk about (and demand) correlation, then you should use correlation analysis, and not cherry pick elements of the trends.
In fact, the two series are cointegrated, the strongest evidence possible of a correlation.
Victor basically claims that correlation is only approximate for CO2 and temperature and sea level rise, therefore causation by fossil fuels isn’t proven. This ignores the fact that in a complex system like climate natural variation makes all correlations rough.
By analogy its like lung cancer. We have only got approximate correlation between tobacco smoking and cancer, and a reasonable understanding of causation. However the medical community accept smoking causes cancer. There are many similar examples.
Victor, are you going to deny that a 1C increase in average surface temperature results in a 6-7% increase in atmospheric water vapor content?
Victor: Also some positive effects, such as longer growing seasons.
RC: Wider, but perhaps with a month or two hacked out of the middle as too hot and/or dry. Our geneticists will be very busy.
Victor: I don’t think anyone is claiming Earth’s temperatures have risen during the 21st century at anything close to the earlier rate.
RC: Pretty much everybody in climate science claims that as a whole, the Earth’s warming has continued relentlessly. What they don’t claim is that the teensy part of the Earth we call the bottommost six feet of the atmosphere warmed terribly much between 1998 and 2013. Of course, 2015’s first nine months have been rather hot. Trends trump weather.
Victor: If we knew what caused both the earlier increase and the decrease following that, then we would be in a better position to assess the possibility of an anthropogenic cause.
RC: Dude, that’s “deliberate ignorance”. Not a pretty debating technique. As always there’s more detail to learn, but climate scientists successfully run models through simulations of the 20th century.
https://www.skepticalscience.com/global-cooling-mid-20th-century-advanced.htm
Victor: neither the incidence nor severity of droughts, hurricanes or tornadoes has increased to any significant degree for any appreciable length of time, despite the significant runup in temperatures during the previous century.
DH 16: Droughts do not appear to have changed appreciably either
BPL: Look again:
Kevin McKinney: AR5 said the picture was uncertain. But note that it’s not ‘haven’t increased’–it’s ‘can’t be shown to have increased.’…hot weather makes everything drought-related worse.
RC: I’m with Kevin. I’m particularly bothered by the possibility of widespread spring flooding followed by baked summer ground, which makes next spring’s flood not soak in. The two can feed on each other, so even if the drought index doesn’t increase much, for human utility things could get grim.
Susan Anderson: algal blooms are on the rise.
RC: And the worldwide coral bleaching, which now is a regular part of El Nino. The least-heat-tollerant 10-20% of the world’s corals will probably die in the current one. Hawaii, Great Barrier reef, Caribbean. If we’re lucky, warm-tollerant corals will rebuild.
Lawrence Coleman: I doubt for a second that this situation can be reversed now it is already so advanced; so adaptation has got to be the only logical way to go.
RC: Though the “2degree C limit” makes it sound binary, climate change isn’t a light switch. If you had the choice of either a 220 pound man or a 200 pound man (of equal abilities) hit you, you’d pick lighter. Every ton not emitted drops the damage a tad.
Victor: Much of Australia is desert country anyhow. It’s the driest continent on Earth by a long shot.
RC: Antarctica.
26 Kevin: yeah, good point..move on….
I’ve been conducting an experiment. Whenever the jetstream over the US at around 250mb becomes appreciably rossby-like, no clear path, meandering all over the place, deep excursions from north to south, forming many eddies and fractured troughs etc, I’ve predicted an extreme weather event the next day(it gets reported here by our media 2 days later). Whether it was flash flooding in UTAH or South Carolina etc. I’ve been spot on 4/5 times sequentially. The obvious slowdown in the jetstream seems to greatly affect the incidence and severity of flash flooding events more than anything else. Has anyone else noticed this??
Kevin McKinney #26,
Let me try to frame this in a more concrete way.
We often, in frustration, ask people like Victor “OK, just tell me, what would it take to convince you that CO2 is having an effect?”. Rhetorical, of course, because we know almost certainly nothing will.
But let me turn the tables and ask the various people here trying to communicate with and educate the public:
What would it take to get you to say “this flooding in SC was caused by anthropogenic CO2”? I mean, if it happens two more times in the next ten years, would that be enough? What about an event with say 50% more rainfall than this one?
Is there anything, short of a complete time series into 2115, that will get us past this point? Would even that be enough?
In my universe, if I am convinced that the climate is being changed, then any event is by definition a result of that change. What am I missing?
#16-Dan H wrote:
>Victor,
>Agreed. The ncdc shows a decrease in tornadic activity over the past half century.
>https://www.ncdc.noaa.gov/climate-information/extreme-events/us-tornado->climatology/trends
Attempting to make any conclusions on the trend of tornadic activity in the U.S. using the U.S. tornado database is problematic at best and trying to use it to make any conclusions about the impacts of global warming is beyond ludicrous. First, the U.S. is pretty much the only country were such detailed (if flawed) tornado records are kept. Many parts of the world, e.g. Australia, portions of Europe and Russia, India, South Africa etc., experience significant tornado activity for which records are much less robust. Secondly, even the U.S. database has severe issues with detecting, recording and assessing the strength of tornadoes. A good starting reference for this is:
Brooks, H. E., 2013: Severe thunderstorms and climate change. Atmos. Res., 123, 129-138, doi:10.1016/j.atmosres.2012.04.002
Racetrack and BPL,
The 2004 paper to which you refer shows that the “previously reported increase in global drought is overestimated because the PDSI uses a simplified model of potential evaporation7 that responds only to changes in temperature and thus responds incorrectly to global warming in recent decades.”
and
” More realistic calculations, based on the underlying physical principles8 that take into account changes in available energy, humidity and wind speed, suggest that there has been little change in drought over the past 60 years.”
http://www.nature.com/nature/journal/v491/n7424/full/nature11575.html
Check out the following assessment of the “drier regions tend to get drier and wetter regions, wetter” claim:
http://www.nature.com/ngeo/journal/v7/n10/full/ngeo2247.html
#27 Kevin (et al.)
First I want to express my gratitude for the civil responses I’ve been getting, as opposed to the many ad hominem dismissals in the past.
“Victor, you’ve said this all before.”
What’s new is my effort to clearly separate the three most important factors in this debate: 1. the issue of warming per se, which is unquestionably real, in the sense that it is now considerably hotter now than it was 100 years ago — regardless of the cause; 2. the issue of how serious a problem the warming poses; 3. the question of what is causing it.
Too often these three very different issues are collapsed into one. Just because the increased global temps might (and I must emphasize “might”) have serious consequences in future, that tells us nothing about the ultimate cause of the increase or whether or not we can do anything about it. Yet time and time again such distinctions are ignored, especially in reports we read almost on a daily basis in the popular media.
Now as to the question of natural variability. In my book I examine attempts to offer such an explanation by John Cook, in Skeptical Science (http://www.skepticalscience.com/The-CO2-Temperature-correlation-over-the-20th-Century.html), and James Hansen et al., in a very thorough study published in 2007 (http://pubs.giss.nasa.gov/docs/2007/2007_Hansen_etal_3.pdf). The former is based on the latter, though Cook fails to clearly acknowledge that. What is the difference between the two? Cook confidently asserts that the set of natural forcings identified by him (via the study by Hansen et al.) are sufficient to explain the discrepancy he himself has acknowledged. Turning to his source, however, we see far less certainty. Here’s an excerpt from the abstract of the Hansen paper:
“We carry out climate simulations for 1880– 2003 with GISS modelE driven by ten measured or estimated climate forcings. . . Discrepancies between observations and simulations with all forcings are due to model deficiencies, inaccurate or incomplete forcings, and imperfect observations. Although there are notable discrepancies between model and observations, the fidelity is sufficient to encourage use of the model for simulations of future climate change. . .”
As I state in my book, I have no problem with Hansen et al. “as it appears extremely thorough and the authors readily acknowledge difficulties and deficiencies in the various methods used to gather and also interpret their data. What becomes clear from the abstract alone is that there are indeed a great many difficulties in managing a task of such enormous complexity. While the authors freely acknowledge the many difficulties in both producing and evaluating their data, Cook treats their findings as definitive.”
As I see it, Hansen’s paper is a perfectly valid attempt to thoroughly study and evaluate a complex set of natural forcings that might (or might not) account for puzzling anomalies in the temperature data (assuming the significance of AGW). Nothing wrong with that at all. But the conclusions drawn by Cook, and so many others, are not warranted by Hansens’s study, or by any of the subsequent studies of natural forcings designed to explain the same anomalies, studies which, by the way, tend to weaken one another by focusing on different bodies of data interpreted in a variety of different ways, as though climate science were a kind of smorgasbord.
As I stated earlier, there is a huge difference between demonstrating that a certain set of data could be consistent with an anomaly and proving beyond doubt that the anomaly has been fully accounted for as a result.
The commenters who say they “can’t see” and “fail to see” — tell their truth.
http://blogs.agu.org/wildwildscience/2015/10/13/the-vaccine-to-prevent-crazy/
As I stated earlier, there is a huge difference between demonstrating that a certain set of data could be consistent with an anomaly and proving beyond doubt that the anomaly has been fully accounted for as a result.
Comment by Victor — 13 Oct 2015
You should take up tap dancing or seriously consider a career as a human pretzel. I assume you’re “doubting the cause” of AGW from what I just read.
Let’s see if I have this right: You wish to establish some sort of separation between the warming and what’s causing it and the affect it is already having? …Knowing full well that CO2 is a major force in determining our climate? Knowing that human activity is responsible for the dramatic increase in CO2 since the dawn of the industrial age? Do I have this correct?
If not, please accept my sincere apology for incorrectly characterizing you or your statement.
The facts have been explained to you many times, so I can only conclude that you just can’t or wont understand.
Comment by MartinJB — 12 Oct 2015
No. It’s even more simple than that. Victor is what is known on the internets as a “Concern Troll”. I’ve pointed this out before but it’s a common term applied to people like our friend Victor. The goal is to eat up time and space and create frustration for anyone who attempts to engage him in some sort of debate. I think his commentary should be sent to the bore hole once and for all. It’s tiring and absurd to the extreme and I’m sure he’s getting a cheap thrill from it. That’s the only reason people like Victor continue unabated in their drivel. Move on.
He claims he writes books? Check the “Comedy” section of Barnes and Noble.
“As I stated earlier, there is a huge difference between demonstrating that a certain set of data could be consistent with an anomaly and proving beyond doubt that the anomaly has been fully accounted for as a result.”
– See more at: https://www.realclimate.org/index.php/archives/2015/10/climate-change-is-coming-to-a-place-near-you/comment-page-1/#comment-636629
And there is a huge difference between making necessary policy choices in a timely fashion, and ‘proving beyond doubt’ every detail of one’s understanding is correct. There may be a world where one can always wait for complete understanding to inform one’s decisions, but it sure ain’t this one.
The understanding we do have is incomplete, granted. But it is very far from nugatory. We disregard it at our peril. And I very much fear that your brand of ‘skepticism’ boils down to disregard.
For example, why stop at the state of the climate modeling art ca. 2007? I was trained to follow the chain of citations. A very quick survey finds Hansen et al., 2011:
http://www.atmos-chem-phys.net/11/13421/2011/acp-11-13421-2011.pdf
Or, from 2014, Schmidt et al:
http://onlinelibrary.wiley.com/doi/10.1002/2013MS000266/full
I’m quite sure that someone who really knows the literature could continue in this fashion for quite some time. But in a way, that’s the point: even an amateur like me can easily go beyond the source at which you stopped.
Will you now make my point even more clearly by pointing out that in these studies, too, there remain instances of model-observation discrepancies?
{As a side comment, let me say that I’m a bit bemused by your comparison of the Hansen paper and the Cook blog post. Is it really shocking, or even telling, that a 500-word blog post lacks the caveats found in a “very thorough study?” Especially when the conclusion of the former that other things besides CO2 affect temperature is precisely the point of least disagreement?}
“…tend to weaken one another by focusing on different bodies of data interpreted in a variety of different ways, as though climate science were a kind of smorgasbord.”
– See more at: https://www.realclimate.org/index.php/archives/2015/10/climate-change-is-coming-to-a-place-near-you/comment-page-1/#comment-636629
A very strange comment indeed. Surely you don’t think that the point of view of all studies should somehow be constrained in some a priori way? Where would ‘skeptics’ be then? ;-)
Researchers necessarily look at different bodies of data and necessarily interpret them differently, for two complementary reasons:
1) Any truly holistic study would be unmanageably enormous, and
2) It is not possible to know which bodies of data and which interpretations will be most fruitful in advancing understanding without first actually examining them.
Really, it’s summed up in one simple and darn near ubiquitous word: “scope.”
[Enough. This is not your platform to promote your book]
@Hank R, re 15% think climate change is a hoax, about the same age of the Earth, moon landing, JFK, etc, etc:
I always wonder if it’s the SAME 15% in each case.
Dan H 40: The 2004 paper to which you refer shows that the “previously reported increase in global drought is overestimated because the PDSI uses a simplified model of potential evaporation7 that responds only to changes in temperature and thus responds incorrectly to global warming in recent decades.”
BPL: You are quoting Sheffield et al. which was three years before my study, and which got WRONG the nature of the evapotranspiration equation used in the NOAA data series. It doesn’t only depend on temperature. Here’s a link to the actual equation used:
http://edis.ifas.ufl.edu/ae459
Please note that it does NOT only depend on temperature.
https://tamino.wordpress.com/2012/02/16/wet-is-dry-and-dry-is-wet/