Understanding tipping points is key to understanding climate change. Most of the ideas on this page come from a book by Fred Pearce called With Speed and Violence: Why Scientists Fear Tipping Points in Climate Change.
This book was written in 2008 but the ideas in it are still very valid today. Some of the things Pearce said in 2008 were a little speculative at the time. However in the eleven years since the book was written all of his ideas about the dangers of tipping points has been proven, in spades.
As in my other articles I have added a lot of my pictures of the earth to remind you that the American Earth is still pretty beautiful. It isn’t gone yet.
The basic idea of Pearce’s book is that climate change is not going to be a 1000 year process as many scientists once thought. Climate change has happened again and again in the earth’s history, and it has never come slowly or gently before, it has always come “With speed and violence.” It happens this way because there are a series of tipping points, which once passed, are often irreversible and which result in extremely rapid climate change.
The idea of tipping points can be illustrated very simply. Paddling a canoe down a river is often simple and easy. The canoe can survive many rough stretches and even rapids. It can take on quite a bit of water and nothing much changes. But canoes can also tip over. And once they do tip, everything changes very, very rapidly. They are upside down, the paddler can go instantly from blissfully enjoying a warm, balmy summer day to freezing to death in very cold water. And recovering from a tip-over in mid stream is very difficult if not impossible. A tipping point changes everything very, very rapidly.
Right now we are living in a world which has not yet radically tipped. It still looks pretty much like it always did; we are still merrily canoeing down that gentle and scenic river. But after we hit the first tipping point, as it looks like we will sometime this century, probably sooner or later, a lot of things in this world are going to look a lot different. Probably the first big tipping point will occur when the arctic and Antarctica melt.
Many scientists agree, they think one of the first tipping points the earth will encounter has to do the the melting of the arctic and antarctic. Both sea ice and ice on the land is in the process of rapidly melting right now. ( I wrote that sentence eight or ten years ago and the present melting is already far more than was expected at that point.)
At first ice melts quite slowly since most of the sun is reflected off of the white ice. But as ice melts, the dark open sea or dark land is left in its place and these darker areas absorb the rays of the sun much more readily than ice, and then the sea or earth warms and the ice begins melts even more rapidly. The more ice that melts, the more dark areas are exposed, the warmer the earth gets and the faster melting progresses. This is called a positive feedback loop and this kind of system results in very rapid change: if the change is graphed it is a curve rather than a straight line; it is an exponential rather than an arithmetic progression. Most tipping points involve positive feedback mechanisms and often cause much faster change than that anticipated by conventional climate modeling.
And this is still true in 2019. Scientists tend to be very conservative with their predictions and most have still not incorporated feedback loops into their projections. If they did our predicament would look a lot more dire than predicted.
I live in New Mexico and another positive feedback loop similar to the melting ice in polar regions has been observed here. The predicted climate change scenario for the Southwest is increasing heat, drought, wind and blowing dust. In the past few years a lot of us in NM have noticed that the increased blowing dust in the spring is beginning to coat snow in the high mountains with a dark brown covering. This dark covering is absorbing the heat faster than pristine white snow and the mountain snow is beginning to melt much faster and much more completely than in previous years. As a result, spring runoff happens much earlier and proceeds faster than it used to and the big rivers like the Rio Grande run at much lower levels later in the summer than previously. All of this causes a late summer shortage of water for agriculture and people in the valleys, and less mid and late summer water in the mountains. By early summer much of the snow has melted, ripped down the mountains and is long gone.
Another polar tipping point discussed by Pearce, involves the melting of entire ice caps. This happens when the surface ice of large ice sheets or glaciers melts and forms lakes on top of the thick ice. It doesn’t take long for this water to find a crack in the ice where it pours in and then refreezes and wedges the crack further open; it then remelts and refreezes and re-wedges again and again. Before long, the crack reaches the bottom of the ice and as the warm surface water pours down into the ice, the crack gets larger and larger until a huge waterfall forms. Often these waterfalls can be 1000 or even 2000 feet deep and they develop tremendous power. Once the water hits the base of the ice sheet or glacier it runs underneath the ice, lifting and breaking the ice above in the process. All of this breaks up massive ice sheets and then lubricates their downhill slide into the sea. When the ice hits the water, big hunks break off into the sea. Or the whole mass can slide out into the warm ocean in huge shelves that gradually get thinner and thinner and more and more extended until they also finally break off and float away into the sea.
All of this is happening big time right now. The Larson B ice shelf, a huge piece of ice the size of the country of Luxembourg broke off from the antarctic ice cap just a few years ago. Previously the Larson B shelf was thought to be a permanent feature of the antarctic. When something like this happens it is like pulling a cork from a bottle and everything upstream begins to move faster and faster toward the ocean. On the other side of the Antarctic, the Western Ice cap is currently in danger of sliding out to sea just like the Larson B did. Except this hunk of ice is the size of Germany and France combined. When this happens, climate change may have progressed to the point where it will be unstoppable.
Another tipping point after which climate change may be unstoppable, is the point at which the earth’s carbon balance reverses itself. Normally all the living plants, trees, vegetation and the earth itself both take in and emit carbon dioxide. They take-up CO2 during normal photosynthesis and they give it back when they die and rot or burn. The earth both inhales and exhales CO2. Right now the system is still in balance, barely; the earth still inhales slightly more CO2 than it exhales. But higher temperatures are beginning to change that balance. As the earth grows hotter and drier in the continental interiors, there are more forest fires, more man-made fires, more burning of whole tropical forest systems like the Amazon and more burning of tropical peat bogs the size of many European nation states like the massive peat bogs of Borneo. At some point fairly soon the earth will begin to exhale more CO2 than it inhales and at that point climate change may go irreversibly into high gear. It would probably be too late for humans or anything else to reverse climate change at that point.
A third tipping point that terrifies all climate scientists is the thawing of the permafrost in Siberia and in Alaska. For millions of years the earth in hundreds of thousands of square miles of the far north has been frozen solid. For millenniums, tundra plants and grasses in the arctic have grown, died after the brief arctic summer and quickly frozen before they can rot. This has gone on year after year for millions of years and the frozen organic life builds up into masses of permafrost hundreds of feet deep.
Today, in a world that is warmer than it has been in a long, long time, all of this frozen organic matter in the far north is beginning to thaw as is all the snow and ice around it. The melt water from the surface snow and ice has created huge shallow lakes and bogs which cover the thawing permafrost. This underwater permafrost doesn’t just give off CO2 when it rots like dry grasses and trees do; organic matter that rots underwater gives off methane, a greenhouse gas that is 100 times more potent than CO2 as a greenhouse gas. This underwater thawing of the permafrost has been going on since about 2006 or 2007 and is progressing at breakneck speed in Siberia and the Arctic right now. Methane is bubbling out of arctic marshes and lakes at a rate so fast it sometimes prevents the lakes from freezing in winter.
This melting of arctic permafrost is another positive feedback mechanism: methane is released into the atmosphere, average temperatures rise, more permafrost melts and more methane is released, and temperatures get higher and higher very rapidly. This rapidly escalating scenario has most climate scientists absolutely terrified.
A forth tipping point that is looming more and more importantly in the minds of climate scientists is the release of methane clathrates (sometimes called methane hydrates) from the bottom of the sea. Methane clathrates are a honeycomb of frozen methane and various sediments that contain enormous amounts of methane. Scientists estimate that up to ten trillion tons of methane are stored in and beneath undersea clathrate beds worldwide. There is probably between two and three times as much carbon stored in clathrates as there is in all the oil, coal, wood and other deposits of carbon in the world. And yes, the big oil and other energy companies are very interested in taping into this energy source.
Methane clathrates have been responsible for some of the most serious environmental catastrophes in past eons. 255 million years ago, what is called the Permian Extinction came closer to wiping all life off the earth than at any other time of our globe’s history. The definitive explanation for what caused the Permian Extinction is not yet know exactly, however, most scientist now believe it was a combination of tremendous volcanic explosions, eruptions of lava and massive burps of methane hydrate from undersea deposits. By the end of the Permian extinction, 90 to 95% of all species had been wiped off the face of the earth, everything from microbes to insects to mammals. The earth came very close to turning into an uninhabited hunk of rock. Life did reassert itself but it took some ten million years and the life that returned was very different from the living organisms before the great extinction.
Then, fifty-five million years ago another extinction event called the Palaeocene-Eocene Thermal Maximus (PETM) occurred. Again methane hydrate seems to have played an import part in the sequence of events. An enormous undersea cliff collapsed after a long warming period and exposed immense beds of clathrates and billions of tons of methane were belched out into the atmosphere. The result was an extremely rapid warming of the world and the extinction of many species both in the sea and on land. In fact, this extinction was so large that it eventually helped trigger the rise of mammals and finally the human species.
There are certainly some lessons from the PETM that can be applied to our contemporary world. For example, James Lovelock, a controversial but very rational and readable climate scientist, says that the geological accident that kicked off the PETM released a terraton (a million million tons) of carbon into the atmosphere 55 million years ago. As a consequence, the temperature in the arctic and temperate zones rose 8 degrees Celsius and it took millions of years for the earth to again return to a condition that would support human life. As Lovelock says, man has already added more than half that amount of carbon to the atmosphere in the last century and we are now so far down the climate change track that it is irreversible. As a consequence, Lovelock says that it is now inevitable that billions of people will die in this century and that human civilization will come to an end as we now know it, even if we radically decrease carbon emissions right now.
Most scientists are not quite as pessimistic as Lovelock, but most agree that some very grim times are ahead for humanity. I would have to agree with these scientists. I think there are still too many unknowns ahead to write off humanity at this point. I think there is still hope, but like the vast majority of scientists and journalists and all people who have looked into climate change closely and seriously, I don’t think there is a minute to waste.
Anyway, back to my discussion of methane hydrates.
After another period of warming, a third, smaller methane hydrate event happened about 8000 years ago off the east coast of Scotland. This time, a 250 mile long sub-oceanic cliff collapsed onto the ocean floor releasing four to eight billon tons of methane, enough to heat the atmosphere by several degrees. Again, the results were disastrous changes to the global environment and extinctions of many forms of life..
In the contemporary world, scientists have to begun to find more and more evidence of many smaller releases of methane from the ocean bottom. The fear is that with warmer global temperatures very similar to those at the time of the catastrophic eruptions of the past, sooner or later we will be in for another gigantic undersea methane eruption , or perhaps many smaller eruptions, that would push global temperatures beyond the point of return in a very short period of time.
Since methane is 100 times more powerful than CO2 as a climate change agent, several billion tons of methane could easily raise average global temperatures the two or three degrees Celsius that it would take to propel the world into a temperature spiral that could mean another mass extinction.
And, all this is on top of another threat of species extinction that is coming from several totally different directions. General environmental degradation from oil spoils, nuclear accidents, overfishing, chemical pollution, out of control economic proliferation, a rapidly increasing world population and many other factors are bringing about the extremely rapid extinction of many species right now.
Many scientists are now referring to the geologic period we now live in as the Anthropocene era, i.e. that period in which human beings are driving change and the direction in which the earth is headed. And many scientists are now talking about the Antropocene extinction which is currently under way, an extinction that is being caused by the general trashing of nature and the ecological web that supports life. Al Gore estimated that about 100 species are going extinct every day in his book, “An Inconvenient Truth: The Planetary Emergency of climate change and What We Can Do About It.”
This current Anthropocene extinction is also the subject of most of the books of EO Wilson. All of Wilson’s books are stimulating and easy reading; he is a serious scientist, but he writes like a novelist. In fact he recently wrote a novel about ants and people and ecosystems and biodiversity called “Anthill: A Novel” that is OK, but not great.
Many, many biologists are deeply worried about what the current destruction of the earth’s biodiversity will mean for our children and grandchildren. The basic problem is that life on earth has evolved into a complex web of ecological dependencies where each organism has an important role in maintaining the thousands of life systems on the earth. When we begin loosing too many species, the bio-systems on which the earth and human life depend, then the earth itself begins to fail and the future of the human species becomes uncertain. Since man has evolved as a part of this complex bio-system, and since human survival is dependant on the health of all these systems, the future for man does not look good. Already human beings are involved in a losing struggle to find enough clean air and water and food to survive. What will happen when the oceans are completely dead, when all the fertile land has tuned into dust bowls and unlivable deserts, and when the rising heat has pushed us further and further north into lands not suitable for agriculture? Certainly resource wars and energy wars and living-space wars and massive migrations resulting in increasingly widespread, man-made destruction are part of our future. And this future does not bode well for human life on earth.
On a less pessimistic note, in a brand new book by Fred Pearce, “The Coming Population Crash: and Our Planet’s Surprising Future,” Pearce points out that human fertility rates all over the world are suddenly falling.
In this new book Pearce says that world population growth is still increasing, but as soon as the baby boomer’s children are done having kids, world population will begin dropping. Demographic experts all over the world agree with him and attribute this phenomena basically to the fact the more and more women, world wide, have gotten tired of being baby machines; they are suddenly becoming aware that life can hold infinitely more possibilities for them. Now-a-days, many more children, instead of dying in childbirth or infancy, are surviving to adulthood and with birth control easily accessible, women all over the world, even in places like India and all over Asia, have opted for having one or two or even no babies. Nowadays, women world wide are more and more going to college (right now women greatly outnumber men at almost all universities), opting for careers in all kinds of fields from law to medicine to politics to executive positions in large corporations and if they happen to live in the third world, even athletic shoe and clothing factories are offering routes out of traditional lives centered around childbearing..
Pearce says that this will result in stable or even falling world populations and that this will eventually bring an end to the current population boom. He says this is almost certain to help reduce our current devastation of the earth. He says that if we can just make it through the next twenty or thirty or forty years without some sort of irreversible ecological disaster, and if we can begin cutting down on our CO2 emissions, humans may still have a chance for survival.