Our Changing Climate : a summary review

Sometimes it seems to me that people have been misled by climate modeling computer software and consequently believe that climate change and global warming are problems that will develop over 50 or 100 years (and so you sometimes hear people talking about our ‘responsibility to our grand children' and there are frequently stories going around about how the climate will be different in about one hundred years). What strikes me as conservative, overly cautious computer programming would then be the source of a mythology that allows climate change to rapidly advance while many people remain unaware of the scope of the developing problems.

It is also probably just human nature to want to think that a situation remains hopeful, and if we are fighting to prevent climate change for the sake of our grandchildren, then certainly there is reason to be optimistic, and as well, debunkers have savaged any error made in attempting to make predictions in climatology and for this reason every scientific report on climate change is loaded with caveats, with ifs, buts, or maybes, since debunkers will beat a dead horse to a pulp whenever they can find one...

Another problem with this climate modeling software is that it is linear, rather than exponential, and thus predicts a slow gradual change in the climate, and it might also be insensitive (recent research indicates that more dramatic effects in the climate result from smaller stimuli than has been previously believed to be the case). A study of the history of the climate reveals that Sudden, rapid climate change is the historical norm. Certain dynamic, chaotic systems, such as the climate, have thresholds, below which a stimulus continues to build without much evidence of changes taking place, until the threshold is reached, and then sudden, exponential changes take place, with the entire system destabilizing, and becoming extremely sensitive from that time forward to even small increases in stimulus (certain chemical reactions behave like this, and a study of the past history of the climate reveals the same threshold behavior, with changes taking place suddenly and a new climate settling into place in as little as ten years). Never in the past has the climate ever changed slowly, in a linear fashion, over the course of 50 or 100 years, but given how little is understood about thresholds and the climate, the subject remains a source of controversy when it comes to modeling the climate with software, since it is regarded as speculative at present, rather than science, and thus there is a tendency to model the small changes of the past and then project forward in a linear fashion, thus resulting in projections of gradual change that would be true if it were true that the climate was a linear system (which history indicates, it is not).

Concurrent changes

One argument that can be used to suggest that climate change is taking place much more rapidly than had been anticipated is that in recent years the climate can be seen to be displaying the signs of a dynamic system which has crossed a threshold, and is now responding rapidly to stimulus, rather than showing a dulled response as would have been the case in the past.

Acceleration in the melting of the ice cap and glaciers

The image above shows the shrinkage of the arctic ice cap over the last two decades, as viewed from space. The data can then be entered into a climate modeling software scenario to predict that the ice will disappear in ‘50 to 100 years', which is what you often hear. However, during the latter part of the 1990s, the ice began to recede at a rate 20 times faster than was previously the case. During the beginning of this period there was anomalous warm water measurements of about one half a degree above average in the arctic, but in the last half of the 1990s there were measurements of anomalies of up to 4 to 5 degrees warmer water that appeared concurrent with this increase in the rapidity of the retreat of the ice sheets. As well warmer summers meant that water was also pooling on the ice sheets, which absorbs heat, rather than reflecting it as ice alone would do, and the water also opens and widens cracks in the ice, which also accelerates the process. See the page Arctic ice melting much faster than previously thought. Robins also began nesting in the high arctic for the first time in the late 1990s (the Inuit of the region had no word in their vocabulary for ‘robin', having never seen one before) and at the same time this anecdotal evidence was confirmed by scientific studies which were revealing what Robins somehow also discovered, in the form of higher than expected arctic ocean temperatures.




Warm water anomaly in the arctic for sept. 7th, 2004


At the same time as this accelerated rate of change in the arctic was taking place tropical glaciers were melting with greater speed. South American glaciers in the Andes retreated at a rate 32 times faster at the end of the 1990s than they did in the previous three decades, and if this accelerated rate of melt continues (and if we assume that further acceleration does not take place - linear thinking once again) they will be gone sometime between 2010 and 2020. These glaciers provide the only source of drinking water for millions of South Americans, many of whom are very poor, as well as feeding rivers and streams and lakes that are vital to animal life and the entire ecosystem.

Retreat of the Sahara

Another concurrent change in the global climate which was taking place at the same time as this rapid acceleration in ice melt was the beginning of a remarkable retreat in the Sahara desert. Climate modeling software had been predicting that a rise in the temperature of the North Atlantic would result in a retreat and eventual disappearance of the Sahara desert, and as the warm water anomalies began to strengthen in the Northern Atlantic in the late 1990s, this predicted change began to manifest in the Saharan region.





The images above are vegetation graphics which show the effects of increasing rainfall which has pushing northward from the Sahel since the late nineties, another change that began concurrent with the changes noted above in the arctic and in the mountain glaciers. Blue is the thickest vegetation, while green is ‘fair' and red is desert.





In the image above I have used a red line to show where the boundaries of the desert were in 1990 as compared to where it was in late 2003. (See the page Africa's deserts are in retreat according to New Scientist Magazine.)



Sahara, November 2000, September 2003


Last year exceptionally heavy rains created flooding right into the Sahara itself, soaking the region, following a pattern that emerged in the late 1990s (a year of record breaking rains, and correspondingly good harvests, followed by a stable year, followed by another year of record breaking rains, and so on (an oscillating pattern which I interpreted as a sign of instability in the climate). Last years powerful monsoons created the heat wave in Europe and is also responsible for this years formation of what looks to be a giant plague of locusts (with more locusts reported on the ground during the start of this plague than were present during the peak year of the previous plague in 1988). So far a rain pattern which has pushed storm systems into the Sahara has kept the locusts breeding on the Southern Sahara. And thus this diversion created the situation whereby , they stayed away from farmer's crops during the summer months, but it also allowed them to increase in numbers and now they are headed south to the crop areas of the Sahel just at harvest time.

Flooding in China, Failed Monsoons in India

Another disturbing pattern that has emerged over the last few years, concurrent with the changes above, is year over year increases in the rainfall in China, resulting in increasingly bad flooding, with a corresponding decline of rainfall and monsoon failures in India.





The image above shows the vegetation graphic for India and the deterioration taking place due to repeated monsoon failures. The FAO is instituting a program to help India's drought stricken farmers., since the drought has only increased problems caused by deforestation and bad land use..." inappropriate land use practices and depleted vegetation have made farming increasingly unviable under low and uncertain rainfall conditions". Meanwhile climate modeling software has come under fire as the monsoon fails since the software predicted good rains, and now is being replaced. Indian farmers continue to commit suicide this year a wide spread behavior pattern that is the result of 5 years of successive drought, and failing monsoons.

While this is going on, the opposite problem has been developing over the last few years in China, where the rain keeps increasing every year, bringing worse flooding each time. "Seasonal rains wreak havoc across much of China every summer, and with the amount of rainfall increasing each year the problems are only likely to grow worse, Sparrow said."You cannot build defenses in concrete and steel against flash floods and a changing climate," he said. "We must invest in community level disaster preparedness."

America's worst drought in recorded history

At the same time as the Sahara began its rapid retreat, the monsoons began failing in India, China began flooding, the arctic sea temperature rose and ice melt accelerated, and the glaciers began a rapid melt, the the American west was plunged into the worst drought in recorded history. These drought conditions have been shown to be linked to warming in the North Atlantic, the same warming that has been predicted by climate models to result in such things as the retreat of the Sahara (not to mention the melting of the polar ice caps).

Other changes

Other changes that have been taking place include the decline of the Great Lakes, which have been dropping by a foot or a foot and half a year, this rate of decline also accelerating over the past few years, with barge traffic on the Mississippi carrying only half loads to avoid scraping bottom, just some of the symptoms of what could become a water crisis due to reduced snow pack and shrinking lakes and rivers. Satellite imagery has shown that snow pack on the North American continent has been retreating northward on an annual basis. And it would appear that some particularly nasty hurricane seasons may be upcoming in the future if this year is any indication of what to expect. This month's issue of National Geographic Magazine features global warming. " The devastating impacts of global warming are examined in depth in this issue of National Geographic."Diseases spread, snowpacks decline, precipitation increases, winter loses its bite, lakes shrink, sea levels rise, droughts linger." These are among the alarm bells ringing with increasing intensity.The magazine shows how every part of the world is affected by climate changes – glaciers rapidly melting in Peru, ice retreating in Alaska, coral reefs and other marine life dwindling in all the oceans and a dramatic spread of drought-stricken areas."

Summary conclusion

Given the conservative nature of the science of climatology, and the tendency of scientists to introduce caveats and ‘await further confirmation'. I thought I might introduce this argument from concurrence as an attempt to be ‘scientific' in discussing our changing climate. (When I read about such things as an unexpected rise in the temperature of arctic oceans, the scientists who did the study introduce a caveat, by stating that they do not know if that is just an unusual passing phenomena, and therefore more years of research are required.) This sort of caution and conservatism is just in the nature of science, a discipline in which intuition is taboo, and I think that it does expose a certain weakness in the scientific method, when science is incorporated as a total world view, rather than simply as another tool, an just one way of looking at the world, which can itself be subordinated to other ways of experiencing our world and our environment (rather than being considered supremely pre-eminent). After all, farmers on the Sahel were up planting crops in what were once desert areas unsuitable for planting, a year or two before the scientists described by New Scientist magazine showed up to do a scientific survey on the retreating desert, and similarly, while scientists await more evidence that the arctic is actually warming as much as the unexpected results indicated, Robins decided that the warming was here to stay and moved into the high arctic. (In both these cases, the Sahelian farmer used his intuitive understanding of his environment, which is obviously what the Robin does as well, to make a determination not based exclusively upon the scientific method). This is not intended as a slam against science, but at the same time it seems to me that science is actually lagging behind everyone else on this one, and this episode could be useful in exposing the limitations of this scientific methodology, not in a laboratory, where such methods have their place, but as a totalistic world view, and as the sole guide for public policy to the exclusion of all else.

Nevertheless, even with all this being said, it still seems suitable to me to patch together a quasi- scientific argument (based upon the concurrence of all these events) to suggest that it would seem logical to assume that the climate is in fact a dynamic system, with thresholds, and that the rapid changes we have been seeing in recent years are an indication that some type of rapid climate change is already underway, and that in the future we cannot simply expect linear change of the type I am convinced is wrongly predicted by those climate computers (thus leading to a false sense of complacency and an inappropriate sense of urgency in dealing with the immediately ongoing impacts of a changing climate)

Global Warming and Climate Change Links

Sahara Sunset

Sahara sunset September 9th, 2004




This image from a few days ago is interesting because you can really see just how far up the desert line is now (half way up the upper part of the continent)

Comments on this article

I recieved the following comment from a climatologist...

Ongoing climate change, and the possibility of abrupt change (meaning a change that occurs over a time scale shorter than the characteristic time scale of its forcing) are issues the mainstream climate & paleoclimate research communities take quite seriously. Scientists and activists need to work together on these issues (indeed, I know some scientist-activists). It is encouraging to see this writer's interest in the subject and the science but there apear to be some important misunderstandings.

>The image above shows the shrinkage of the arctic ice cap over the last two decades

No, it does not. It shows the retreat of the annual maximum extent of the Arctic sea ice edge. Floating sea ice and ice sheets and glaciers are very different parts of the climate system. Changes in both are important for myriad reasons but they ocurr on different time scales, have different causes, and different effects on climate and ecosystems. Also, in the case of the Arctic sea ice, the ongoing change in its thickness is as imporant a part of the story as the change in its extent. There are important (and not well-understood) feedbacks here.

>Another problem with this climate modeling software is that it is linear, rather than exponential

I'm not sure I know what "linear" software is but in any case I wonder if the author means non-linear instead of exponential. A survey of the basic literature would reveal that folks who build computational models used for studying Earth's climate system are quite aware of the vorticity terms in the navier-stokes equations and of the non-linearity of the constitutive relations for the viscous fluids in question. The solution of the momentum balance equations is computationally intensive so we sometimes make simplifications that allow us to study one component of the system or another in an efficient manner. But my point here is that the folks who build numerical models foruse in climate change research are well versed in the fundamental fluid dynamics involved and do their best to embody it in computational models. That said, we are always working on expanding our understanding and mathematical representations of individual components of the climate system and on feedbacks among components. You could spend a lifetime just working toward understanding the role of clouds in climate change (and people do).

The feedbacks among components of the climate system are very important but are often difficult to represent in computational models because of the number of calculations that must be made--it's no good to produce a model that runs too slowly to tell us what we need to know. You may be shocked to learn that some of the supercomputers used in climate modelling are at Los Alamos national labs--the same computers that are used to conduct studies about weapons systems. (At least for a time, the computers are diverted from that sinister use.)

> Never in the past has the climate ever changed slowly

>there is a tendency to model the small changes of the past and then project forward

These two statements are contradictory--are the changes in the past small or aren't they? In any case, the latter is not a helpful representation of how climate models are built and used. The best understanding of the physics is used to write the computational code and then tested using present-day and paleoclimate data. There is no other way to go about this. From this base, we study the system, and indeed, a lot of effort now goes into improving ourunderstanding of how abrupt changes occur and into finding thresholds in the system.

> Sudden, rapid climate change is the historical norm.

This depends on how you define "historical." The possibility of abrupt change is out there and it must be taken seriously but the abrupt changes cited by Dr. Alley in the linked article ocurred 10,000 or more years ago under a far different climate regime than the present regime. The paleoclimate record tells us that over the last 10,000 years (after the Younger Dryas), changes have been relatively gradual--that's just what's allowed our speciesto radiate so succesfully.

But concern over abrupt change, while important, can also be a distraction. The drought responsible for north america's "Dust Bowl" is a minor event in the central US aridity record yet it was economically devestating.

We don't need doomsday scenarios to make the case that climate change matters. Ask anybody on an island nation that's submerging due to ongoing sea level rise. Ask anybody in Alaska who's seen their house collapse into thawing permafrost or their favorite forest killed by insects that emerge earlier and spread farther north each year.

One final idea. If you want a true sense of the state of science research with regard to climatology, please look to the scientific literature, not to popular magazines.


A response to the above comment follows



A graph showing exponential growth

You made the comment that you did not understand what was meant by 'exponential growth' and here you were being a little sarcastic, were you not (but perhaps the term 'non-linear' is considered more appropriate)...but to clear matters up what I was referring to is an exponential growth function where the changes are small in the beginning and then the curve of the graph goes upward dramatically as in the attached graphic.

Now if we assume that response is for the most part linear, and we can therefore expect the same changes in the future as in the past, then we would have a more gradually sloping line, absent the sudden burst you see in an exponential curve

You made the comment that the slow changes of the past and sudden growth in the future are what you called contradictions and you said 'is the change slow or is there rapid climate change' this being the contradiction

now if you look at an exponential graph you will see that the change is slow, at first and then becomes extremely rapid later, and if we were to assume that the same small changes could simply be projected forward we do not get this rapid and sudden change but rather something approaching a more linear and gradually sloping line

you were being disingenous by pretending that you do not know what an exponential function is, and if you really are a scientist then of course you do understand the meaning of 'exponential'

You also insist that we not be 'alarmist' and I feel this is a typical attitude for a climate scientist to take because after all you could get lambasted by the skeptics if you are wrong...however when you consider the potential water crisis in a place such as south america, which is coming quickly, there is good reason to be 'alarmist' and the conservatism of climate change modelling I believe leads people to have an inappropriately apathetic response

I said above that I was making a 'psuedo-scientific' argument when what I really should have said is 'quasi-scientific' argument...what I mean is that the changes taking place in the last few years in a number of different systems has not been linear or gradual but shows rapid acceleration which is characteristic of an exponential curve, and I argued that the number of systems showing that same accelerated rate of change is an argument in favor of the hypothesis put forward by Dr. Alley who may not yet be in the mainstream of climatology, but is it not true that often science resists change, and before a theory becomes accepted it is first fiercely resisted? History tells us this is the case...furthermore although I am not a scientist and I do not read all the scientific literature, as I stated it is possible to understand our world using other methods, for example an intuitive understanding of our environment, and here I come to the conclusion that this accelerating rate of change indicates that the climate is one of those systems with thresholds, where responses are dulled at first and then become rapid when the threshold is reached, resulting in one of those curves of an exponential rate of change...

In general the tone of your comment would indicate that this sort of understanding is quite common place in scientific circles, but this conflicts with what was written in the Climate Change 2001:Working Group II: under the section Impacts, Adaptation and Vulnerability

In the section which disusses thresholds and discontinuous responses they indicate that they can report little given what they refer to as the paucity of research papers published on these subjects in the field of climatology...referring to sudden or rapid climate change they state that "Because of the magnitude of their potential consequences, large-scale discontinuous responses warrant careful consideration in evaluations of climate change dangers. Working Group II points to the potential for such occurrences and their potential consequences for human and natural systems, but it is unable to provide detailed assessments of potential effects, given the paucity of information in the literature."

So if you are suggesting that rapid climate change is in the mainstream this seems not to be the case but rather the gradual climate change model you support is in the mainstream, while there is paucity of research being done on rapid climate changes, according to the report quoted above...

They also state that almost all climatology and thus almost all models are based on the equilibrium model that you seem to be supporting in your comment above...they state "As radiative forcing on the climate builds, the magnitude of adverse impacts would increase, the number and scale of many beneficial effects would decrease (Chapter 19), and the probability that adverse impacts would predominate would increase (high confidence). Transient scenarios are just entering the climate impacts literature, which unfortunately tends to lag the climate effects literature by several years; thus, much of the impacts literature still is based on equilibrium climate change scenarios."

They have some interesting things to say about the potential for rapid climate changes, even if they cannot provide detailed assessments due to lack of research...some quotes follow

The effect of rates of change on impacts is still under active investigation (see Chapter 19). Early results have suggested that rates of change exceeding the ability of ecosystems to migrate would be particularly damaging (see Chapter 5). Adaptation of coastal dwellers to rapid climatic changes or a high background “noise level” of natural variability would be more difficult relative to slowly occurring changes or smoothly varying climates (e.g., West et al., 2001). Finally, as noted by IPCC Working Group I (1996a, p. 7), “nonlinear systems, when rapidly forced, are particularly subject to unexpected behavior.” In other words, the adaptability of various decision agents would be reduced if any change is unexpected; thus, a rapid rate of change is more likely to generate “surprises” that inhibit effective adaptation by natural and managed systems.

By definition, it is difficult to give examples of the surprises that might be created under a changed climate. Such surprises, however, can make even the most careful calculation of impacts extremely inaccurate, as noted previously...where the specific event in question is unexpected but a set of conditions that increases the likelihood of surprises can be assessed; increasing the rate of forcing of the climatic system is one example.

1.4.3.7. Nonlinear, Complex, and Discontinuous Responses .... Investigations into climate change and its potential consequences have begun to highlight the importance of strongly nonlinear, complex, and discontinuous responses. These types of responses, called singularities, can occur at all temporal and spatial scales of systems influenced by climate change (high confidence can be given to the likelihood that some such singularities will occur, but low confidence usually is assigned to any specific example of a possible abrupt event; see Chapter 19). Strongly nonlinear responses are characterized by thresholds—which, if exceeded by a stimulus, result in substantially greater sensitivity to further stimulus or dramatic change, explosive growth, or collapse. Complex responses involve interactions of many intricate elements that yield outcomes that are not easily predicted.

Extreme Climate Events

The currently developing locust plague in North Africa is another example of a human made disaster, as well as being one of those disasters that history indicates cannot be defeated using technological means...

The plague is first of all directly related to changing climate in North Africa and the retreat northward of the Sahara desert (which climate modelling has suggested would occur with a warming of the SST of the Atlantic Ocean, and what is happening seems to be confirmation of the model predictions, if not the timing, since the models are linear meaning that they would predict that changes would take place over typically a fifty or one hundred year time frame). It is this increase in rains and the subsequent increase in vegetation, in particular along the southern fringes of the Sahara that led to this years plague of locusts. Climate chnage is taking place all over the world, and the changes are becoming exponential as far the pace of change goes (and not linear, thus taking a long time to change with the changes being gradual and evenly paced). The Sahara has retreated northward at a slow gradual pace at first, with rapid changes having taken place over the last few years. At the same time as this rapid change was taking place glaciers in South America began retreating and the Northern Ice caps began melting with an equally exponential rate of change, so that we can see that if these changes were graphed, the graph would be linear for a long time, and then suddenly would begin to curve upward (the typical graph for an exponential rate of change). There have been record number of tornadoes in the United States in recent years, this being directly related to an increase in global humidity by 10 per cent, this extra humidity providing the extra energy for increasing numbers of tornadoes, as well as increasing severity of tornadoes. Once again we can see a graph beginning to form with an upward curve. When you have that many graphs displaying that many upward curves, where exponential rates of change are indicated, this would suggest that the climate is not a linear system, and therefore people should be prepared for sudden and rapid shifts in climates, and not expect to have 50 to 100 hundred years, in particular when the exponential changes have compound effects, which increase the speed of change.

Some interesting quotes from TomDispatch.com ..."For the first time in history, four hurricanes - Charley, Frances, Ivan (the Terrible), and now Jeanne -- have smacked into Florida's long coastline one after another in a single hurricane season (not yet over), and here's the strangest thing of all: Forget that in March Brazil experienced the South Atlantic's first hurricane ever -- Brazilian meteorologists didn't even know what to name it; or that the Atlantic coast of Canada got whacked by Hurricane Juan, "the storm of the century," late last year (and the Canadian government suspects a link to global warming); or that the United States has already experienced a record number of tornados in 2004; or that Japan has had the worst season of typhoons in memory; or that Xtreme weather events have increased in recent years across the planet, including massive flooding in Europe, Bangladesh, and China, and a deathly summer heat wave that struck Europe in 2003."

Some interesting quotes from an article in Wired magazine...

Water vapor or moisture in the air is the high-octane fuel of hurricanes. Oceans need to be 80 degrees Fahrenheit or more to produce enough water vapor for a hurricane to get started. New research by Trenberth's group has found that water-vapor levels are now 15 percent higher on average in the hurricane zone than they were 20 or 30 years ago...global warming is greatly increasing the odds in favor of more intense and more frequent hurricanes and cyclones, Battisti said... while countries that have never experienced them will, he said.Brazil was struck by the first-ever hurricane in the south Atlantic last March, while the Atlantic coast of Canada got smacked by the storm of the century, Hurricane Juan, late last year...Largely unnoticed in the attention focused on hurricanes is the record number of tornadoes the United States has experienced this year...As for thunderstorms, "the evidence is very strong that their frequency and intensity has increased in the U.S.," said Trenberth.The changing ocean and atmospheric conditions due to global warming are also making historical weather cycles or patterns less useful in helping to do long-range climate forecasts, said Battisti. "In 50 years, conditions will be so different they will overwhelm these historical cycles."