Monday, April 15, 2013

The Whole Story of Climate: What Science Reveals About the Nature of Endless Change

Book Review: The Whole Story of Climate: What Science Reveals About the Nature of Endless Change by E. Kirsten Peters (Prometheus Books 2012)

Hot off the presses, this very readable book delves into the history and implications of climate science. The potential implications of climatology go way beyond just man-made global warming and this book does an excellent job of presenting much of the developmental picture of climate science as we know it, without being overly biased regarding predictions and policy. The author is a geologist too and provides a wonderful geological history of climate science. Although this book is a great and valuable read it is in no way the “whole” story of climate. It is a great history of climate science from a predominantly geological perspective but it neglects much meteorological and atmospheric data and is not in great detail as some climate studies are. Her conclusions regarding the immediate threat of climate change are a bit more muted than the detailed data suggest in my opinion. Nonetheless she does paint a nice picture of the development of climatology as well as some ideas for the future.

Geological evidence reveals multiple massive climate change events. The author notes that many of these happened very quickly (in geologic time terms) although the pace of anthropogenic climate change seems likely far quicker than any of these.

She suggests that climate scientists rely too much on computer models and should rely more on geological studies of past climate events. This may be true but it does not offer any evidence to the contrary that man-made climate problems could be in a precarious position in danger of feed-backing out of control as evidence suggests. In fact, studies of the geologic past may be supporting the alarmist position. She talks about rapid climate change events (RCCE) such as one that is thought to have occurred in ancient Egypt around 2300 BC where there are records of drought, crop failures, and subsequent famine to the extent that people were said to have eaten their own children. She does point out that we have been remarkably fortunate for the climate stability since the last Ice Age since natural climate change can be extreme, especially on a local scale.

We have a very good geologic picture of the extent and conditions of Pleistocene glaciation that began about 1.8 million years ago (mya) and ended about 10,000 years ago. The general pattern has been about 100,000 years of cold Ice Age conditions followed by about 10,000 years of warm conditions so logically one could assume that we are due for another Ice Age soon. The Holocene Era (dubbed so due to the influence of humans) begins after the last Pleistocene ice recedes and humans very soon make jumps such as agriculture, animal domestication, pottery, cloth-weaving, and eventually writing. The implications of a new Ice Age are potentially as bad or worse than current scenarios of global warming. The world’s foremost grain agricultural regions would be under ice and famine could kill billions. The author notes that such a change could occur rapidly, in the space of a few generations, and indeed this was more of a concern before the data about industrial greenhouse gases was discovered and tracked to show that it was causing climate to warm. There is also the possibility that humans have increased greenhouse gas emissions since the advent of agriculture through such methods as slash and burn. This, along with industrial greenhouse gases may have actually held off the Ice Age that was due in the current solar minimum. Even the foremost climate scientist and global warming alarmist champion Dr. James Hansen has implied that that might be the case.

The author gives a nice history of the development of glacial geology in the early 1800’s in the story of the Swiss scientist Louis Agassiz’s work beginning in the Alps. This is a story of the development of glaciology as a science. He convinced the famed naturalist/geologist Charles Lyell of his theory of Ice Ages and mounting evidence brought it into the mainstream. Geology as a profession led to detailed observations and terrain mapping that further confirmed mechanisms and multiple periods of glaciation. The glacial extents of the various periods are now well mapped. Water wells revealed multiple layers of glacial debris called till, with layers containing wood in between, which indicates changing climatic conditions through time. Reading the vertical record through geologic time became established and thus stratigraphy was born. Beach strands indicated sea level fluctuations through time. In terms of climate, sea level is low when ice is thick and high when temps warm back up. It was also discovered that land surfaces flexed upward, or “rebounded” through time after heavy weights of ice were removed. Such is happening now around the Great Lakes and in Scandinavia. The author gives stories of other early geologists such as Whittlesey, T.C. Chamberlain, and G.K. Gilbert. Gilbert unraveled the mystery of the Lake Bonneville Salt Flats in Utah, the massive lake that was breached and emptied into the Snake River Canyon and on to the Columbia River Gorge to the Pacific. It is now well-known that catastrophic flooding accompanied the retreating and melting of glaciers.

The proliferation of religion and observations of an ordered world led many in the past – such as Thomas Jefferson – to infer an ‘intelligent design-like’ theory of nature where everything has its place, created by God, and so the idea of extinction was rather alien. Examination of fossils in the stratigraphic record confirmed that many species had gone extinct. The connection between climate events and extinction events gradually became clear. Many Ice Age mammals became extinct during or after the Pleistocene ice retreated but many are still around today.

The accurate study of the geologic past (Historical Geology) requires relative timing and dating of events. Fortunately, nature records prevailing conditions through time in various ways. For instance, one can study current rates of erosion and extrapolate back. The study of “varves”, which are alternating thin layers of clay-mud and silt along the shores of what were once bodies of water, indicate annual conditions. Several hundred years of varves are accessible at the bottom parts of glacial lakes that once existed in Sweden and Denmark. The contrast between summer and winter conditions of such northern lakes bounded by glaciers is enough to create these contrasting layers. Gerhard Jakob de Geer and his students surmised that it had taken about 800 years for the Swedish glaciers to melt.

Another method of unraveling the earth’s recent regional climate history year by year is the study of layers of pollen in peat bogs. Pollen is stable and can reveal the local vegetation and thus suggest climatic conditions. The pollen record, later confirmed through coring, has given us a good picture of the climate variation of the late Pleistocene and into historical times so that more detailed knowledge of this climate variation is now available. Much of this evidence has been corroborated through ice core data and even tree ring data. Pollen data has been especially good at mapping regional climate variability so that comparisons of conditions in different parts of the world at the same time could be made.

The author also gives the history of the unraveling of local and regional climate history through tree ring variability and dating. This is called dendrochronology. One could even say that anything that grows or accumulates also records – even if it is just changes in the growth or accumulation rates that are recorded. The author details the development of dendrochronology through the work of Andrew Ellicott Douglass in the American Southwest in the early 1900’s. Douglass was also an astronomer and remarkably discovered the relationships between tree rings (and thus weather variations) and sunspot cycles. During his retirement in the 1930’s and 40’s Douglass worked out that the sunspot cycle was affected by the planetary orbits of the larger planets – Jupiter and  Saturn. Although the relationships between planetary motions and alignments and sunspot cycles and weather patterns are complex and not reliably predictable, the relationship seems likely, even if controversial.

Next she describes the development of radiocarbon dating and the great implications of this more precise form of dating. This has done much to corroborate and date climate evidence from other sources such as tree ring data and the pollen record.

The story of the ice record is next told, beginning with the expedition of Ernst Sorge and Alfred Wegener to Greenland in 1930. Wegener, the first purveyor of the radical “continental drift” theory, died there, but Sorge came back with evidence for the detailed yearly recording of climate variations by the layers in the ice. The annual layers of variable summer and winter snowfall amounts are called “firns” and can be compared to  the seasonally alternating varves. The Greenland ice sheet was eventually found to be close to 2 miles thick which represents quite a time period. After World War II the ability to core the ice sheets was developed. Trapped air bubbles in the ice layers give detailed data about atmospheric composition. Traces of salts, dust, and volcanic ash can also give information such as wind speeds. Temperatures of the ancient past can be deduced from the ice record through analysis of oxygen isotope ratios. The ice record gives the most complete and detailed picture of the climate past from the middle of the Pleistocene glaciation to the present. The ice cores collected in the 1980’s and 1990’s were key to unraveling this detail. The Vostok ice data records the last 420,000 years. These are where our CO2 and temperature graphs of the past come from. Temperature variations up to about 20 deg F occur at the onset of warm periods such as the Eemian period about 125,000 years ago which was warmer than today. Some of this data was suggested from other sources, such as the pollen record, varves, the glacial till record, and fossilized tree ring data. The reason for the 100,000 year cold/10,000 warm general cycles was unknown but in the early 1900’s a Serbian engineer – Milutin Milankovitch built upon the work of Scottish geologist James Croll who suggested that differences through time of the power of sunlight could be a factor. Croll also suspected the earth’s elliptical rather than circular orbit to be a factor in sunlight intensity variation. Croll’s work did not reveal close correlations to the data, however. Milankovitch added to it in various ways, demonstrating several planetary cycles that could affect solar intensity. One was the change in the angle of the earth’s tilt on its axis, its wobble, which also accounts for the apparent phenomena known as the precession of the equinoxes. Another cyclic variation due to earth’s orbit is its distance from the sun in winter relative to summer through time which can either enhance or suppress temperature. Milankovitch calculated the cumulative effect of the three orbital cycles and got a closer match to the geological data but there is still variability due to other factors such as clouds, the amount of open sea, and the amount of ice cover. Since reflection or absorption of solar energy is dependent on color, there can be much variability in the feed-backing mechanisms. The three cycles that make up the overall Milankovitch cycle occur at intervals of 100,000 years, 40,000 years, and 23,000 years. I believe another affect is that of the larger planets whose orbits can also affect the elliptical-ness of the earth’s orbit so it can change through time as well. The author mentions other cycles in the ice record of climate, one a 6000 year cycle, the other a 1500 year cycle, which are covered below. This underscores her theme throughout the book that climate change is complex with many variables and low overall predictability. Many other climate scientists, such as James Hansen, would agree that there is complexity, but they think there is more than enough information to begin mitigating anthropogenic greenhouses gases immediately.

The climatic evidence from sea floor sediments is an important subject. The rocks, debris, and silt from glaciers and icebergs end up in the sea when they melt. These layers of glacial sediment were found at 6000-7000 year intervals in tune with climatic cycles. These are called Heinrich events, named after geologist Harmut Heinrich’s work in the 1980’s. The changes are linked to the complexities of ocean circulation which can strongly affect climate. The 1500 year cycles are called Dansgaard/Oeschger events, named after the Danish and Swiss researchers. While Heinrich events lead to colder temperatures, Dansgaard/Oeschger events lead to warmer temps. British geologist Gerald Bond, who studied Cambrian cycles as well, discovered variations in these 6000 and 1500 year cycles. The Bond cycles may mute or enhance the other cycles and all three cycles are thought to have been muted in their intensity in the Holocene. It is not yet clear why this is so. Fortunately (or maybe not) for us this climate stability helped us develop our civilization.

A significant climate event occurred about 8000 years ago (6000 B.C.) that had a negative effect on humans. This is a cooling event not as severe as the Younger Dryas that occurred at the end of the Pleistocene as a millennium of Ice Age relapse. The climate event mentioned earlier, around 2300 BC, may have helped bring about the collapse of the Egyptian Old Kingdom, the Akkadian civilization, and the Harappan civilization. Other extreme climate events are recorded in history as well: the Roman Warming, the Medieval Warming, and the Little Ice Age. The Medieval Warming may have helped the Norse to settle Iceland and Greenland. The so-called Little Age may have led the Norse to abandon their long-held settlements in Greenland as the climate cooled too much. It should be noted that these were overall trends with some variation in successive years – but crop failures and famines are both reported and seen in the archaeological record.

She mentions the possible effects on sunspot cycles in these warmings and coolings, not just the 11-year cycle but other longer-termed cycles. There is much debate about this and some think their increase since about 1850 has had an effect on current global warming. While this may be true, the effect is surely nothing like that of man-made greenhouse gases. Many scientists, however, do not see a correlation between sunspot cycles and climate.

The author gives the Little Ice Age dates from 1300-1850. Incidentally, she says, climate records began to be kept, esp. temperature as thermometers became available, around 1850. However, she notes, most or all of these records were in populated areas with none in the Arctic and remote regions so graphs of avg. global temps from the mid-1800’s. esp. the early ones, have been statistically manipulated, and should not be seen as definitely accurate.

The hypothesis of William Ruddiman, that humans have been affecting climate for millennia, is next examined. I am mot sure how plausible or accepted this is, although Ruddiman is considered to be a distinguished scientist. In examining the ice core record Ruddiman thinks he sees evidence for CO2 and methane increases due to the advent of widespread human agriculture. Ruddiman suggests that this early modest increase of greenhouse gases helped stave off the increase of glaciation here in the Holocene. Ruddiman noticed an anomaly in the regular atmospheric methane cycles (from the ice cores) that began about 5000 years ago. This anomalous rise in methane would have been predicted to be a drop. He looked to the expected sources of increased methane: tropical swamps and peat bogs, but both were known to decline in these periods. Ruddiman noticed that the timing of rice farming in East Asia through the making of rice paddies, ie. man-made swamps, corresponded to the increase in atmospheric methane. Extrapolating back from 1700 CE, the time when hydrocarbons began to be burned and utilizing known population then and suspected population 5000 years ago, Ruddiman determined that the data from methane concentrations could be explained by rice farming. Other farming methods, land clearing, and slash-and-burn agriculture could also contribute to the increased methane concentrations seen in the ice core record. Increased domestication of propagation of livestock in settled agricultural societies with growing populations could also have contributed. The author also emphasizes the complexity and complicated nature of the carbon cycle. The unexpected increase in CO2 beginning about 6000 BC (8000 years ago) also perplexed Ruddiman. He also thought this could be attributable to clearing and burning of land and wood. He also thinks this rise in temperature due to a rise in CO2 and methane could be why the retreating glaciers in North America did not begin to re-grow after the optimum which may have led to a runaway feedback where more light was reflected of the ice cooling things down making more ice, more cooling, more reflection, and on and on. Nowadays with man-made global warming the danger seems to of a runaway feedback in just the opposite way. Ruddiman thinks the overall 1.5 deg F rise in global temperature over the millennia since agriculture began may be attributed to it and may have warded off the scheduled return to increased glaciation. Ruddiman does point out that his theory in no way denies that global warming is occurring at present due to industrial greenhouse gases. The author does acknowledge the uncertainty of Ruddiman’s hypothesis. She also points out that eventually catastrophic climate change of some sort is inevitable:

“… scientists know from a variety of evidence that Earth’s climate changes naturally, rapidly, repeatedly, and drastically.

There is a discussion of early efforts to modify climate, specifically the civil engineering suggestions of Carroll Livingston Riker in 1912 to divert the Gulf Stream in order to warm eastern Canada and Greenland, making them more habitable. Riker worked on the Panama Canal so knew the possibilities of large civil engineering projects. Governments and their militaries also did climate modification experiments such as cloud-seeding. This was also tested to break up hurricanes and to increase rain for crops in dry areas. Results were marginal. In the 1960’s and 1970’s many scientists were concerned about the potential of global cooling and some thought that increased greenhouse gases would be helpful. The 1975 National Academy of Sciences book Understanding Climatic Change mentions both global warming and global cooling. The global cooling effect of particulate pollution was considered but the warming effect of CO2, etc. was thought to be more dangerous over time. It should be noted that as we decrease particulate pollution as is necessary for improving human health, global warming will be somewhat enhanced. The Soviets were particularly worried about global cooling due to their northern latitudes. They developed plans to melt ice by spreading black coal dust over it. There are efforts now to study the effects of forest fires of the American west on enhancing melting of the Greenland ice sheet as ash is deposited by prevailing weather patterns. The concern about global cooling was based on the general cooling trend from the years after WW II till the 1970’s. It was also discovered in the mid-70’s that lichen had disappeared from Baffin Island from about 1600 to about 1900 corresponding roughly to the coldest parts of the Little Ice Age. What the author wants to convey is that fears of both global cooling and global warming echoed from respected scientists and were reasonable assumptions.

Next she conveys the history of global warming and the effects of atmospheric gases on climate. Discoveries were made in the 1800’s regarding the different effects of different gases. Even though the greenhouse effect was understood in the early 1900’s no one predicted the massive increases in world population and subsequent use of fossil fuels. Oceanographer Roger Revelle gave a lecture at Harvard in 1965. A graph of Charles Keeling’s curve of atmospheric CO2 increase was shown. Al Gore was in the audience and often mentions how profoundly this affected him. The graph shows quite obviously, and continues to show up to now, that the rate of CO2 increase is increasing. The ice cores of the 80’s and 90’s showed definitely the relationship between atmospheric CO2 and temperature. The data also show multiple RCCE’s. Apparently, most scientists agree that it is temperature rise that causes greater CO2 and methane in the atmosphere and not the other way around:

“Most Americans who have seen Al Gore Jr.’s documentary An Inconvenient Truth or who have followed public global warming arguments are sure of one thing: they believe the ice core record shows that carbon-dioxide and methane increases create warmer temperature on Earth. But the significant news is that the facts actually run in the reverse direction. On long time scales, increases in temperature, controlled by the Earth’s orbit around the sun, create more methane and carbon dioxide. That’s right: from what most scientists can tell, greenhouse gases are not the primary driver of long-term climate change on Earth – Milankovitch’s orbital variations are. Still, everything about climate is complex, and it’s quite possible that greenhouse gases can help trigger changes at particular times, or they can help exaggerate feedback processes already underway on Earth.”

She further reiterates that it is Milankovitch’s planetary cycles that have initiated the major climate changes of the past seen in the ice cores. Actually, the likelihood that temperature changed before CO2 is probably not good news for mitigating global warming as it suggests that more CO2 will be released from the oceans after it circulates through and out. Hansen refers to this as global warming “in the pipeline” and it may take more than 600 years to cycle through the oceans before it is released to the atmosphere.

The author notes the growing influence of science-based journalism, particularly in influencing public opinion and policy suggestions. Groups like the Intergovernmental Panel on Climate Change (IPCC) have been very influential. Climate modeling with supercomputers and statistics are now used extensively to try and predict what will happen as more greenhouse gases enter the atmosphere. The author thinks that statistical modelers need to work more with traditional scientists. She examines the pros and cons of “group think” a bit. She mentions the great details of climate change that came out of the GISP2 ice core data as well as recent sea floor coring. Competition for funding, policy formulation, and agreement on the degree of immediate danger of global warming has been and continues to be confusing and difficult to balance. Many favor the “precautionary principal” which means we should prepare for the worst as best we can while others disagree. Al Gore and many others have described climate change mitigation as a moral imperative. The IPCC is not strictly scientific as it is a hybrid of scientists and government representatives. The author suggests that what comes through as the nature of current climate change is that it is a well-defined ordered change towards a runaway feedback that needs to be stopped as soon as possible. She thinks that the policy suggesters of IPCC fail to acknowledge the chaotic nature of climate change. She then shows the famous “hockey stick” graph of Mann, etal. which depicts temperature climbing abruptly in the early 1900’s and staying there till now. She also describes McIntyre’s partial refutation of it using the same data, suggesting that the temperature was not constant before 1900 as Mann depicted but up and down as much as the increase in the early 1900’s. That is possible – but I think it is a longshot as there seems to be much corroborating evidence for the Industrial Age- linked temperature rise. The U.S. Congress hired a statistical expert to investigate the matter and he came to the conclusion that McIntyre was more correct – that the past temperature fluctuations were more chaotic. The influence of bias and ideology in these matters can be complex as can be the interface between science and policy. Obviously, it is difficult to make decisions that might affect the lives of many people. Robert Muller, an oceanographic researcher, recently changed his position and now agrees that temperature has climbed strictly due to man-made global warming. It seems that is the most reasonable position. I think the real question is, “How bad is it?” She again invokes climate complexity but others lake James Hansen insist that the evidence is more than compelling. Nowadays, we do have ideologically driven “climate change deniers” as well as scientist “climate change skeptics”. As for myself, as a scientist, I think that climate change as depicted in the global warming models is likely, but the exact details and the immediacy of the danger is not fully assessed. Yet, I think the “precautionary principle” should be a guide and we should do everything we can to mitigate catastrophic climate change as soon as possible.

In the last chapter the author actually makes her own plea for a way to mitigate greenhouse gases. She advocates for worldwide efforts to extinguish the many long-burning coal fires throughout the globe – many of which are in places like China and India and are having negative health effects on local populations. Though she does not give numbers, she notes that these unintentional coal fires “create a meaningful fraction of total global greenhouse gas production.” These fires can burn for decades, even centuries. The Centralia, PA fire has been burning for over 50 years, has caused the town to be abandoned, and even though eight attempts have been made in the past to extinguish it – it still burns the equivalent of 400 acres of land space. Many coal fires were started by humans but some occur naturally as wildfires encounter burnable coal seams. Open mines often allow a supply of oxygen to keep the fires going. Some estimations say that coal fires in China alone put out the annual CO2 emissions of all cars in the US combined. Forest-clearing in Indonesia by burning is estimated to have started around 3000 coal fires. This clearing might be due to palm oil plantations used for food as well as bio-fuels – though I am not sure how much for food and how much for biofuel. The author thinks there should be way more effort and money spent on trying to extinguish these fires and that it would ultimately be a cheaper way to mitigate a significant amount of CO2 and particulates than other means – as well as improving the health of poor local people living near the blazes.

The IPCC global warming predictions note greater warming for arctic regions, less for the tropics, warmer winters, warmer nights, and species ranges will change (which has already been happening). She suggests that the media fail to report that there are some actual benefits of global warming as noted by the IPCC reports – such as less deaths since there are more deaths due to excessive cold than excessive heat, better crop yields in some areas, and lower heating costs. Of course, the predicted downside dwarfs the predicted upside, since many people living near coasts could be inundated and weather patterns could become drastic as recent superstorms have indicated. The author does generally express the opinion that global warming is not the only climate change possibility and that it could be over-hyped and policy could lead to over-preparation for it which could be detrimental to societies. I am not sure if I agree but I think we do need to keep an open mind while sticking as much as possible to the facts, timely data, and pre-caution.

Overall, this is a good book with some great background on climate science but I think the view here about the dangers of man-made climate change is overly muted somewhat.

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