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Other Papers in this Series

  • Tipping Points. The notion that the planet's climate has now reached a tipping point, and has begun to change on its own, is conjecture. But there are reasons to think a tipping point has been reached.
  • Trends in Biodiversity Overall declines in terrestrial, marine, and freshwater animal populations; declines in tropical forests, dryland systems, and grasslands; declines in Neotropical, Afrotropical, and Indo-Pacific regions; declines in birds and mammals. Last revised Wednesday, January 7, 2009.
  • Thawing Permafrost In southern Alaska, the permafrost has gone from 0 days per year above freezing in 1987 to 139 days above freezing in 1993. Last revised Wednesday, January 14, 2009.
  • Trends in Atmospheric Carbon Dioxide There has been a geometric growth in atmospheric carbon dioxide since the Industrial Revolution, whether measured through Ice Cores, at Mauna Loa, or at marine sea surface sites. Last revised Wednesday, January 7, 2009.
  • Trends in Atmospheric Methane The concentration of methane (CH4), the most abundant organic trace gas in the atmosphere, has increased dramatically over the last few centuries, more than doubling its concentration. Atmospheric methane levels of the past 150 years far higher than those of the previous 420,000 years, and are currently 2.5 times as high as any previous level. Last revised Wednesday, January 7, 2009.
  • Trends in Global Temperature: Appendix In this appendix to Trends in Global Temperature, we examine monthly anomalies, seasonal anomalies, and mean global temperature in degrees centigrade. The Northern Hemisphere has generally warmed more than the Southern. This gap emerged in about 1920, disappeared between 1965 and 1990, but has re-emerged. Warming in the Northern Hemisphere has been most severe in the Arctic. Between 1920 and 1960, the Arctic was warmer than normal, and the Antarctic was colder than normal.  Since 1980, both Arctic and Antarctic have been warmer than normal, with the greatest warming occurring in the Arctic. Last revised Sunday, January 11, 2009.
  • Trends in Global Temperature For the 2000 years prior to 1880, the earth was cooler than it now is, and was cooling. However, a growth curve best describes measured global temperatures since 1880. The ten warmest years on record have occurred in the 12-year period 1997-2008, and the pace of warming may be increasing. While mean temperature is now rising rapidly, seasonal variability appears to be decreasing. Last revised Wednesday, January 14, 2009.
  • Trends in Snow and Ice Cover In the Northern Hemisphere, the average snow extent has decreased by 3.75 million square Km in the last 39 years. The greatest loss of snow cover has occurred in the months of June and July.  In the Northern Hemisphere, the average extent of sea ice decreased by 1.5 million square Km during the period 1978-2008, from about 9.9 million square Km to about 8.4. In the Southern Hemisphere in this period, the extent of sea ice did not change significantly. Reduced snow and ice cover changes albedo, increasing the rate of warming. Last revised Friday, January 16, 2009.
  • "Anthropogenic": A Look at Critical Correlates of Human Population Growth abstract Last revised Wednesday, January 14, 2009.

Tipping Points

Humans today have differing views on what we have done to this planet, and what we might do to fix things. A commonly held view, however, is that whatever damage we have done is something that can be corrected by concerted action. Many don't think that global warming is actually occurring, while others think that things are warming, but that humans haven't caused it. Many think that sea level rise is the main unwanted consequence of global warming. And nearly all think that if we cut back on greenhouse gas emissions, we'll cut back on warming. It is this last belief that I want to address here.

The mission of The 2050 Project is to provide accurate, useful, long-range forecasts and information about the future of the planet.  Our favored forecast interval is to 2050 and beyond, because we believe that shorter-range forecasts cannot portray the magnitude of our impending problems, and thus can only guide half-steps toward solution.

We are right to believe that greenhouse gases result in warming. Greenhouse gases, such as water vapor, carbon dioxide, and methane, work like a blanket around the planet: They absorb infrared radiation rising from the earth's surface, the air, and the clouds, and radiate some of it back to earth. The average spot on earth would be about 0°F without a greenhouse effect, rather than the 57°F it now averages. Scientists have understood this effect since the 1800's, and today's scientists are unanimous in the view that increases in greenhouse gases will produce increases in the earth's temperature.

We are also right to believe that humans produce greenhouse gases. Every exhaust pipe, power plant, smokestack, fire or farting cow produces greenhouse gases. And so studies of the level of greenhouse gases show that they began to rise slowly when humans entered the scene and began farming; they they rose faster as humans deforested, began raising livestock, and began cities; that they surged at the start of the industrial revolution, and that they are being produced in even greater quantities today.

We are right to think that the planet is warming, as evidenced by our drowning polar bears, our melting glaciers, and snowless winters. But we are also right to believe otherwise, for many good reasons. The actual warming has been slight so far -- about 1.33°F in the last 100 years. This very slight increase over such a long time period (in human terms) is further masked by daily fluctuations and regional variations. For instance, some parts of the world are currently cooling, even though its average temperature overall is rising. So anyone who trusts intuition, experience, or memory more than science is likely to remain skeptical that global warming is taking place.

Even for those who are willing to believe that the earth is warming, the notion that humans are causing this can be difficult, again for many reasons.

We all have a sense that we are puny, compared to the earth, and so how could humans have such a powerful effect? (Anyone flying across this country at night will see that we have lighted empty parking lots and empty ball fields and quiet suburban streets from coast to coast, and keep these lights on all night. They'll see the congestion at rush hour, four lanes wide and stopped, with engines running. Perhaps collectively we are not so puny.)

We know that other forces can affect global temperature, including changes in the brightness of the sun, changes in the earth's orbit, and volcanic eruptions. So it is possible that other factors are to blame, or have stronger effects than humans on what is happening.

We like to think that good people do good things, that good things happen to good people, and that people are good. This Pollyanna Principle makes it hard for us to accept that our species could be a planetary villain.

Those troubled by the notion that humans are causing global warming may draw strength from well-intentioned newspaper accounts. Reporters strive for "fairness", giving "both" sides near-equal space in their stories. Fairness can be judged by column inches, but accuracy is harder to judge. A fair account of the shape of the earth might be to spend a few column inches explaining why some people think it is round (or "an oblate spheroid"), and then a few column inches explaining why others think it is flat. That seems silly, because today nearly everyone thinks it is round... but the typical global warming story falls into the trap, giving thousands of scientists a few column inches, and then a few lobbyists from the energy industries a near equal number. In fact, some 2,500 scientists from over 60 countries have reviewed 20,000 papers in scientific journals and concluded that the balance of evidence suggests a discernible human influence on global climate.

Finally, the skeptical laymen can draw strength from the normally skeptical scientist. Scientists are professionals at equivocation. Careers are built on split hairs. Wisdom is shown in failure to agree. So when climate scientists show any uncertainty about their forecasts, lobbyists can rejoice, finding support for their idea that the earth is flat.

Tipping Point?

But even if our global attitudes toward the problem were to suddenly shift, and in unison we acknowledged that things are changing, and from our own doing, we have one big problem left to address: the notion that we can fix it. If we slow our output of greenhouse gases, we'll slow global warming, and avert tragedy. So goes our wishful thinking.

The notion that we can do anything if we put our minds to it helped get us to the shores of America, the shores of California, and the surface of the moon. But something stands in the way of fixing the planet: what scientists call a "positive feedback loop". Such a loop happens when a system starts affecting itself, and a little perturbation feeds back, causing a bigger and bigger perturbation, and bigger and bigger effect. Such a loop likely exists with global climate, because the history of the earth's climate seems to be one of fluctuating between quite warm and quite chilly, with little time spent in between. So perhaps the earth's climate history has fluctuated when positive or negative feedback loops were triggered.

Positive feedback loops have not been given the attention they deserve by climatologists or the press, considering how potentially powerful they can be. But they are certainly easy for a layman to understand.

"Albedo" refers to the degree to which a substance reflects light. Snow and ice reflect light better than liquid water, and thus absorb less heat. Every bit of ice in the arctic thus helps keep things cool, and every bit of open water helps warm things further. Albedo plays a big role in helping an ice age keep its cool, and in preventing ice from even forming in warm periods, such as the Eocene. Warming an area that is covered in snow or ice does not have much local effect on temperature until that snow or ice begins to melt. But melting triggers a more rapid rise in temperatures, which mean more melting.

"Permafrost" is soil that is frozen year-round. Warming permafrost is no more dangerous than warming ice, but thawing permafrost is just a dangerous for global temperature as melting ice and snow, forming a similar feedback loop. In northern Alaska, the 4-7°F. warming that has occurred in the last century has still not reached a thawing temperature, but south of the Yukon River and on the south side of the Seward Peninsula, permafrost was thawing in 2003.

"Methane" is a greenhouse gas that is 20 times as potent in global warming as an equal amount of carbon dioxide. It is formed when plant matter decomposes without much available oxygen, such as under water or in an animal's intestine. In May 2005, Katey Walter of the University of Alaska Fairbanks told a meeting in Washington of the Arctic Research Consortium of the US that she had found methane hotspots in eastern Siberia, where the gas was bubbling from thawing permafrost so fast it was preventing the surface from freezing, even in the midst of winter. In August 2005, Sergei Kirpotin and Judith Marquand reported that one million square kilometers of a frozen peat bog covering the entire sub-Arctic area of Western Siberia had started to melt in 2001 or 2002. New calculations showed the levels of methane emissions from northern wetlands 10 to 63 percent higher than the previous estimates. Larry Smith of the University of California, Los Angeles, estimates that the west Siberian bog alone contains some 70 billion metric tons of methane, a quarter of all the methane stored on the land surface worldwide. Massive methane release, which will warm the earth further, has been in progress for the past 5-7 years.

Drought and fire form another vicious cycle. When the water table drops and vegetation dries, fire becomes more likely. When vegetation burns, it switches from carbon sink to carbon source, releasing massive amounts of carbon dioxide, further warming the earth, further increasing the chances of drought. Many parts of the world, including Australia, Indonesia, the Amazon, and the American West and South, are experiencing epic droughts, and increasing probability of fire.

Each of these feedbacks push us to a tipping point of irreversible climate change, one from which no human actions can recover. With each, it is looking like the tipping point is not sometime in the near future, but has already occurred, some few years ago. If this is so, then the earth is subject to runaway warming and its effects -- a little unexpected warming at first, and then more and more. The problem will not be a rise in sea level or destruction of habitat, but rather change that we cannot stop, no matter what we do. If the earth warms 10 degrees F as it is expected to, there will be no putting the genie back into the bottle.

One clue that the tipping point has already occurred: we are finding that our prior forecasts of higher greenhouse gas concentrations or warmer temperatures were too low -- some unexpected factors have pushed things beyond what would have been expected from simple human population growth. A related clue: carbon dioxide is now building in the atmosphere faster than the human population has been growing recently. In recent years, atmospheric carbon dioxide has increased about 6.5% per year, compared with a human population increase of about 1.3%.

I hope that no tipping point has been reached. I would like to think that humans can throttle their carbon consumption and turn things around. But all of the evidence suggests otherwise. We need to consider this possibility, and need to report on the facts of global warming accurately, with less concern that we might offend the energy industry and its need for "fairness". Our earth, after all, is not flat.

The notion that the planet's climate has now reached a tipping point, and has begun to change on its own, is conjecture. We do not have first-hand experience with climatic tipping points, and few researchers have focused on them.  But there are reasons to think a tipping point has been reached:

This document will summarize what we know about what is happening to our planet. As an outline of the future, it will be revised bit-by-bit, day after day. Information in it will draw from sources listed in the Bibliography, all of which are highly recommended reading. We start with a look at some basic concepts, to understand the forces that are at work on the future of our climate.

Basic Concepts

To talk about the future, most of us need a new vocabulary.

To understand what is happening to our world, it will help to review some important concepts involved in the changes.

acidity, ocean. Under normal conditions, the ocean has a neutral pH. As the carbon dioxide of the air rises, the carbon dioxide dissolves in the ocean, where it joins with water to form carbonic acid. When carbon dioxide is added to the oceans gradually, chalk-forming organisms such as coccolithophorids (a kind of phytoplankton, at the bottom of many food chains) and the foraminifera use it to form calcium carbonate -- chalk -- which settles to the bottom when the organisms die. Added gradually, the ocean buffers excess carbon dioxide: the chalk can buffer the carbonic acid. But when carbon dioxide is added rapidly, the increase in ocean acidity results in grave danger to everything with a calcium-based shell, such as snails, clams, oysters, squid, coral, and coccolithophorids. All of these organisms become part of the buffering system, and their shells dissolve. Because of the sudden surge in carbon dioxide, our oceans are now more acidic than they have been in the past 100 million years. (Our current increase in carbon dioxide is 100 times as fast as it has ever been on the planet.)

albedo. All objects absorb some light, reflect some light. The more light that is reflected, the higher the object's albedo. Snow has a high albedo, liquid water a much lower albedo. When a snowy area is warmed, and the snow melts, the albedo decreases, more sunlight is absorbed and becomes heat, and the temperature rises still further. Every bit of ice in the arctic thus helps keep things cool, and every bit of open water helps warm things further. Albedo plays a big role in helping an ice age keep its cool, and in preventing ice from even forming in warm periods, such as the Eocene.

air pollution.

anoxia. Lacking oxygen. When oxygen levels become too low, aerobic life dies, and may be replaced by anaerobic life. In oxygen-deficient oceans, deep-sea anaerobic bacteria proliferate, and produce hydrogen sulfide.

biodiversity. The number of species, or number of species in an area. Species survive with climate stability, and disappear with climate change. Today's great biodiversity is made possible by a climate that has been stable for the past 8,000 years. Recent climate change accounts for some of the recent extinctions (though most recent extinctions are the result of habitat loss or degradation, or overhunting.)

black shale. A layer of rock with fine lamination and almost no fossils from the ocean floor, made from sediment deposited on an ocean bottom devoid of oxygen. Such shale may contain fossils from plants and animals living at the surface, suggesting that it was created at a time when the deep sea was anoxic, but there was still oxygen at the surface, and the ocean was thus unmixed or stratified. Fossils found in such shale are often well preserved, because of the absence of bacteria to aid in their decomposition after death. The black color of this shale comes from anerobic bacteria that consume sulfur and produced hydrogen sulfide. Black shale forms at the bottom of a Canfield ocean.

blooms. The sudden proliferation of aquatic microbes or algae, often causing a change in water color and usually consuming all of the available oxygen. Blooms are generally toxic, if for no other reason than they produce anoxia. Blooms in the Gulf of Mexico are regular summer-time events, feeding on the fertilizer washing off farmland and carried down the Mississippi, and leaving the Gulf an increasingly large dead zone. A world-wide toxic bloom of microbes that produced hydrogen sulfide occurred at the P-T (Permian-Triassic) boundary, possibly contributing to the mass extinction that occurred.

boundary clay. Dark rock, absent chalky skeletons, that signifies that a mass extinction has occurred and that separates one geological era from the next. Boundary clays may contain high concentrations of fine soot, as in the K-T boundary clay, suggesting that large portions of the earth were simultaneously burning. They may contain iridium, shocked quartz grains, and spherules, suggesting impact from a large boloid. Finally, plants prefer a diet of carbon dioxide built from carbon-12 to that built from carbon-13, and photosynthesis converts this CO2 to carbon and oxygen... so when a high ratio of carbon-13 to carbon-12 is found, it can be assumed that plants were busy using the carbon-12. Boundary clays don't show such high ratios, indicating a disuption to photosynthesis.

buckminsterfullerenes

buffering systems A buffering system is one which is able to maintain an approximately stable pH by moderating changes that would otherwise make things more acidic or more basic. As carbon dioxide (CO2) dissolves in the ocean, it forms carbonic acid, lowering pH. In buffering, carbonic acid (H2CO3) can lose its hydrogen ions and combine with calcium ions to form calcium carbonate (CaCO3) and reduce the acidity caused by these free hydrogen ions. Calcium carbonate can precipitate and settle on the bottom, or can dissolve in the ocean water. The oceans are important in buffering our CO2 emissions: nearly half of all carbon emitted since the start of the Industrial Revolution has been absorbed by the ocean. [2]

Buffering maintains the pH of the ocean at an average of 8.1 with little variation over time. But buffering is a slow process, and we've been adding CO2 to the atmosphere and ocean rapidly. The slow natural pace of buffering cannot offset the ocean's rapid acidification from carbon dioxide absorption.[1] Since the pre-industrial era, the average pH of the ocean has dropped by 0.1 -- a 30% increase the the average hydrogen ion concentration of the ocean. [3] pH levels might fall by as much as 0.5 units by 2100, which would be equivalent to a three-fold increase in the hydrogen ion concentration since pre-industrial times.[1] The acidification of the oceans reduces the ability of phytoplankton to produce shells and grow, and destroys coral reefs. One recent study concludes that acidification has the potential to trigger a sixth mass extinction event and to do so independently of anthropogenic extinctions that are currently taking place.[4]

calcium carbonate

Canfield ocean

carbon cycle

carbon dioxide. Primary causes of mass extinctions are linked in various ways to the carbon cycle in general and ocean chemistry in particular with clear association with atmospheric carbon dioxide levels[4] We are moving toward higher carbon dioxide levels than the world has seen in the past 60 million years -- which occurred in the greenhouse extinction of the Eocene.

catastrophism

chalk

chlorofluorcarbons

conveyer current. Ocean currents carry warm water up from the Gulf of Mexico, along the east coast of the U.S., across to Europe, and back down toward Africa. Similar currents flow around the entire earth, aided by prevailing winds and by the rotation of the earth. Such ocean currents resemble a convoluted conveyer belt, helping to warm areas that would otherwise be cold, and helping to cool areas that would otherwise be hot.

conveyer disruption hypothesis. The conveyer current is disrupted when there is a massive sudden addition of fresh water to the system, because fresh water is lighter than salt, so the salt water of the conveyer is forced down, below the fresh water, stalling the forward movement of the conveyer current. We don't know for sure what happens next. Two extreme (and extremely different) possibilities are worth considering:

deforestation

Eocene epoch. The Eocene epoch was so hot that there were no polar ice caps. Sea level was about 150 feet higher than it is today. Palms and crocodiles lived throughout the world, including Canada and northern Europe.

extinction, mass. A paper in Nature, 2005, predicted that climate changes caused by our global warming would lead to the extinction of more than a million species by 2050.

greenhouse effect. The warming of the planet that results from the accumulation of greenhouse gasses in the atmosphere. The predicted effects include temperature increases (particularly in midlatitude, temperate, and continental interior regions), decreases in precipitation in these regions, and increases in the severity of storms.

greenhouse gas. Any gas in the atmosphere that absorbs infrared radiation, and radiates it back to earth. Such gases permit sunlight to penetrate and reach the earth, but trap radiated heat, much like the action of a greenhouse. Greenhouse gases include carbon dioxide, methane, chlorofluorocarbons, sulfur dioxide, and nitrogen oxides. The level of greenhouse gases in the atmosphere has increased since the beginnings of human agriculture, dramatically since the start of the industrial revolution, and even more dramatically in recent decades. Most climate models predict that the amount of greenhouse gasses in the atmosphere will double in the coming 100 years.The buildup of greenhouse gases is the leading cause of global warming.

hydrogen sulfide. A poisonous gas emitted by volcanos and produced by anaerobic bacteria. The amount of hydrogen sulfide entering the late Permian atmosphere was likely about 2,000 times greater than the small amount emitted by today's volcanos.

irreversible change

Jurassic-Cretaceous mass extinction

mass extinction. see extinction, mass

melting. The rate at which a glacier melts is not perfectly correlated with rising temperature. Initially, a rise in temperature produces melting that contributes to local climate change, which can increase local rainfall or snowfall, feeding the glacier that has melted and keeping its volume nearly the same. So the edges melt at first, and the center may grow in size. But as this happens, a temperature may be reached where water can remain liquid below the ice. This liquid water speeds the warming of the glacier, and causes it to float... downhill, toward the sea.

methane. One of the most potent of the greenhouse gases. The P-T (Permian-Triassic) event, which had rapid global warming, sudden deforestation, and massive extinctions, may have been marked by large, sudden methane releases.

ocean acidity. see acidity, ocean

Paleocene Thermal Event.

positive feedback loop. A change in a system that causes that system to move in the direction of the change. For instance, if heat is added to ice, it melts, and as liquid water it absorbs more heat -- reflects less heat -- than ice does, so that adding a little heat to a frozen area allows the sun to add more. As a writer in Wikipedia notes, "The end result of a positive feedback is often amplifying and "explosive", i.e. a small perturbation results in big changes. This feedback, in turn, will drive the system further away from its original setpoint, thus amplifying the original perturbation signal, and eventually become explosive because the amplification often grows exponentially (with the first order positive feedback), or even hyperbolically (with the second order positive feedback)... In some cases (if not controlled by negative feedback), a positive feedback loop can run out of control, and can result in the collapse of the system. "[6]

P-T (Permian-Triassic) event. The end of the Permian period 252 million years ago saw the greatest mass extinction in the geological record. It is estimated that 95% of all species of marine animals became extinct. On the land, the impact was so great that no coal was laid down for at least 6 million years afterward.

This "event" is marked by large numbers of fungi spores at the boundary, coal below, and no coal above. The fungi spores suggest that the fungi were feeding on dead, rotting plants, and the lack of coal above this boundary indicates a massive loss of plant life. Ocean sediments suggest massive erosion, which would come with a loss of forests.

Many theories have been advanced as to the cause, including a fall in sea level, severe climate change induced by methane release, intense volcanism, impact by a bolide, overturn of a stratified, sulfidic ocean, or a combination of these. Increasing evidence indicates that the global ocean at this time was anoxic, and likely sulfidic, for a period of time before and through the boundary. Whatever the causes, the extinction event was accompanied by dramatic changes in seawater chemistry including excursions in the isotopic compositions of organic and inorganic carbon. The ratio of carbon-13 to carbon-12 decreases in this boundary, consistent with the catastrophic release of 4 trillion tons of methane from the floor of a stratified ocean.

sea level

tipping point

T-J (Triassic-Jurassic) event

ultraviolet radiation

Climate States

A "stable state" for our climate is one which remains constant, buffering various forces that would change it.  It seems that earth's climate has three stable states:  too hot, too cold, and just right. These states may be characterized as follows:

Mass Extinctions

Exactly what happens in a mass extinction depends a bit on the triggers.

Some computer models predict that human-generated greenhouse gases will heat the earth, postponing the next glaciation by as much as 50,000 years. Other computer models predict that such warming will, paradoxically, trigger global cooling and increased glaciation. I think it likely that we are in store for both heating and cooling, in that order. But I don't think any of us will live to see the cooling. Here's what is most likely:

  1. As we release greenhouse gases, the arctic will warm, and the polar ice will melt. This fresh water will block the flow of the Gulf Stream, causing it to come to a stop.
  2. Once the ocean conveyer belt has come to a halt, the impacts on land will vary. The rainforest, western U.S., and Mediterranean will begin to dry, and be consumed by forest fires, releasing vast amounts of CO2 -- These areas will become uninhabitable. The British Isles will lose the moderation of weather that the ocean conveyer delivered, and suffer hot summers and cold winters. Throughout the east coast of the U.S., weather patterns will stall for longer periods, bringing alternations from flood to drought.
  3. The new warmth in the arctic will melt the permafrost, releasing huge amounts of CO2 and methane.
  4. The release of CO2 and methane from forest fires, burning peat swamps in Indonesia, and melting permafrost will act as a positive feedback loop, producing runaway warming.
    • Throughout the world, storms will become unimaginably intense.
    • With all ice melted, our oceans will rise, drowning all coastal cities. Low-lying areas like Bangladesh and Holland and Florida will be gone.
    • Our oceans will become far too acidic for corals or phytoplankton, and the bottom of the ocean's food chain will be gone.
    • Almost equally quickly, our oceans will become anoxic, and nearly all life in them will die.
    • On the land, the heat and fires will reduce most areas to a look now found in parts of central Australia: near lifeless desert.
  5. Unknown, but likely, are three final blows:
    • stored methane in the oceans will be released in giant bubbles, increasing the greenhouse effect.
    • Sulfur-based bacteria, that don't need oxygen, will begin to rule the seas, producing upwellings of poisonous hydrogen sulfide, killing everything in their path, and serving as still another greenhouse gas.
    • The hydrogen sulfide will destroy the ozone layer. Without an ozone layer, only those animals that live in burrows and are active at night will have a chance to survive mutations triggered by the ultraviolet penetrating the atmosphere. As in parts of central Australia, our new life may be rats, snakes, and flies.
  6. Eventually, most of the stored carbon on earth will have been released as CO2, and no further warming will occur. The planet will be stable -- and remarkably unpleasant -- for many million years, until the natural effects of the earth's wobbly orbit finally begin to create seasons again.

Of course, there will be smaller scale events along the way. The polar bears will die. The penguins will die. The sea birds will die. But there will be some more unpleasantness involving humans:

Not Believable

The suggestion that a tipping point has already been reached, and the extreme changes in our climate have already been set in motion -- irreversible motion -- is not acceptable. Not believable. Here are some of the forces working against belief in such a notion:

  1. Humans as Superman.  People believe that when organized and motivated, humans can do anything. Anything broken can be fixed. Any problem can be solved.  So we can feed the planet if we just buckle down and work at it.  And we can reduce carbon emissions and thus stop global warming if we all pull together. And if there is a plausible plan, then things are as good as done.
  2. The Pollyanna Principle. People want good news. They prefer to hear good news. Too much bad news, and they just can't handle news at all.
  3. Gradual change undetectable, unbelievable. If the world is warming, why were Britain's last two summers so mild and damp?, some wonder.  Humans focus so much on day-to-day fluctuations that small shifts in average rainfall or temperature go undetected. And many choose to believe that what they cannot sense does not necessarily exist. Our planet is full of people who do not believe the planet is warming at all.
  4. Good people don't do bad things. Us little humans couldn't change the weather. Many folks want to find evidence of climate cycles or sun spots or anything that could account for observed climate change, in hopes of sustaining their belief that we are not at fault. 
  5. Sudden change is unimaginable. Climate tipping points have been reached perhaps only 10 times in the last 100 million years. Why should we believe that one might happen (or have happened already) in our lifetime?
  6. Humans don't do real math well. Regardless of our mathematical training, we don't have any direct experience on things very big or very small.  One hundred million years doesn't seem much longer than a thousand years, and a degree doesn't seem like much at all. Most everyone has trouble with simple questions such as "what is the average temperature", answering with "it depends...". Too much variability (noise) and we lose the signal. And so a few cool days makes it harder to see a general increase in temperatures.

Bibliography

Footnotes

  1. Caldeira K. and Wickett M. J. (2003) "Anthropogenic carbon and ocean pH ." Nature 425 Page 365
  2. Doney, S.C. 2006. "The dangers of ocean acidification." Scientific American: 58 – 65.
  3. Brewer, P.G. 1997. Ocean chemistry of the fossil fuel CO2 signal: the haline signal of “business as usual”. Geophys. Res. Lett. 24: 1367 – 1369.
  4. Veron, J.E.N. "Mass extinctions and ocean acidification: biological constraints on geological dilemmas" Coral Reefs. Volume 27, Number 3 / September, 2008
  5. Cowen, Richard. The Permo-Triassic (P-T) Extinction. March, 2002. Online.
  6. Positive feedback. Wikipedia. October 22, 2008.

Other Papers in this Series

  • Tipping Points. The notion that the planet's climate has now reached a tipping point, and has begun to change on its own, is conjecture. But there are reasons to think a tipping point has been reached.
  • Trends in Biodiversity Overall declines in terrestrial, marine, and freshwater animal populations; declines in tropical forests, dryland systems, and grasslands; declines in Neotropical, Afrotropical, and Indo-Pacific regions; declines in birds and mammals. Last revised Wednesday, January 7, 2009.
  • Thawing Permafrost In southern Alaska, the permafrost has gone from 0 days per year above freezing in 1987 to 139 days above freezing in 1993. Last revised Wednesday, January 14, 2009.
  • Trends in Atmospheric Carbon Dioxide There has been a geometric growth in atmospheric carbon dioxide since the Industrial Revolution, whether measured through Ice Cores, at Mauna Loa, or at marine sea surface sites. Last revised Wednesday, January 7, 2009.
  • Trends in Atmospheric Methane The concentration of methane (CH4), the most abundant organic trace gas in the atmosphere, has increased dramatically over the last few centuries, more than doubling its concentration. Atmospheric methane levels of the past 150 years far higher than those of the previous 420,000 years, and are currently 2.5 times as high as any previous level. Last revised Wednesday, January 7, 2009.
  • Trends in Global Temperature: Appendix In this appendix to Trends in Global Temperature, we examine monthly anomalies, seasonal anomalies, and mean global temperature in degrees centigrade. The Northern Hemisphere has generally warmed more than the Southern. This gap emerged in about 1920, disappeared between 1965 and 1990, but has re-emerged. Warming in the Northern Hemisphere has been most severe in the Arctic. Between 1920 and 1960, the Arctic was warmer than normal, and the Antarctic was colder than normal.  Since 1980, both Arctic and Antarctic have been warmer than normal, with the greatest warming occurring in the Arctic. Last revised Sunday, January 11, 2009.
  • Trends in Global Temperature For the 2000 years prior to 1880, the earth was cooler than it now is, and was cooling. However, a growth curve best describes measured global temperatures since 1880. The ten warmest years on record have occurred in the 12-year period 1997-2008, and the pace of warming may be increasing. While mean temperature is now rising rapidly, seasonal variability appears to be decreasing. Last revised Wednesday, January 14, 2009.
  • Trends in Snow and Ice Cover In the Northern Hemisphere, the average snow extent has decreased by 3.75 million square Km in the last 39 years. The greatest loss of snow cover has occurred in the months of June and July.  In the Northern Hemisphere, the average extent of sea ice decreased by 1.5 million square Km during the period 1978-2008, from about 9.9 million square Km to about 8.4. In the Southern Hemisphere in this period, the extent of sea ice did not change significantly. Reduced snow and ice cover changes albedo, increasing the rate of warming. Last revised Friday, January 16, 2009.
  • "Anthropogenic": A Look at Critical Correlates of Human Population Growth abstract Last revised Wednesday, January 14, 2009.

© 2009 David Stang. All rights reserved.

Dr. Stang is available for presentations on this topic. Contact him by email.