Stoned by Science: Dancing on the Titanic

Prologue

It was reported that many of the passengers who were dancing on the Titanic never felt its collision with the iceberg. With a stopping distance of one-half mile, and a turning radius half again that large, the Titanic was powerless to avoid the iceberg that came into view about 45 seconds earlier. With engines full astern and turning hard to port, the ship's starboard flank scraped along the iceberg, which sliced through the steel plating below the waterline. A 300 foot gash was opened through six of the watertight compartments. A head-on collision which damaged only one or two compartments would have been better, if rougher. The actual damage was far greater than any envisioned by the ship's designers.

Planetary Thermal Physics

The equilibrium temperature of our planet is determined by a single mechanism: thermal radiation balance. The primary source of incoming radiation is the sun, whose output has been quite stable over recent time. Of the incoming solar radiation, earth directly reflects about 30% of it back, and the remainder is absorbed into the atmosphere and surface layers. Because the earth is a warm body (about 60⁰F on average) it also radiates energy back out. Not all of this radiated energy escapes, because there are gases in the atmosphere (greenhouse gases) that selectively reabsorb and retain some of it. The effect is similar to a blanket; it causes earth’s average temperature to be higher than it would be in the absence of greenhouse gases- about 60⁰F higher. The earth’s average temperature is such that the net energies of incoming and outgoing radiation are equal. Earth has remained at or very near this average temperature since the dawn of mankind.

Any change in the earth’s reflectivity or absorptivity affects the average surface temperature. If more radiation is absorbed, then the earth will warm to the point that it radiates enough additional energy to maintain balance. Although simple in concept, the details of how a given change in earth’s properties will ultimately affect temperature are complex. This is because of feedback effects. Temperature changes affect several properties that control absorption and reflection, some of which work to dampen the temperature rise, and others which further accelerate it.

CO2 Balance

One of the greenhouse gases that have made earth’s temperature hospitable is CO₂. Over the past 400,000 years, its atmospheric concentration has varied between 0.02% and 0.03% (200 ppm and 300 ppm). The ice ages occurred during the lower ends of this range. Primary sources of CO₂ production are volcanic eruptions, combustion processes (fires), and respiration of aerobic organisms, e.g. decomposition of organic matter. (Anaerobic decomposition also occurs underground, and in other areas where oxygen is limited, producing methane gas. Methane is an even stronger greenhouse gas than CO₂- more about this later.) Processes that reduce CO₂ include plant photosynthesis and the absorption of the gas into the oceans, where it is used by phytoplankton to form sugars, and marine life to form carbonates which eventually settle out as limestone rocks. Plant matter that is not decomposed, burned, or eaten becomes stored underground, as tundra, coal, or petroleum. Over time periods of a few million years, the processes which produce and absorb CO2 stay in rough balance, acting as a global thermostat which has kept earth's temperature sufficiently stable to maintain an unbroken chain of DNA-based life for over three billion years.

Atmospheric CO₂ levels began rising above their recent historical range about 300 years ago, most likely due to increased burning of the stored carbon (coal and oil) to provide energy. Current production rate of CO₂ via these energy sources is about 30,000 million tonnes per year¹. This is over 130 times greater than the historical, average rate of CO₂ production by volcanoes. Currently, the atmospheric level of CO₂ is about 380 ppm and rising. It is projected to exceed 500 ppm by about 2050- significantly higher than at any time throughout which human civilization has existed. Although 500 ppm is not a large fraction of gases in the atmosphere, CO₂ is a very effective greenhouse gas, because its absorption peak is almost exactly centered at the peak of earth’s radiation back into space, in the 15 micron wavelength region. In contrast, neither nitrogen nor oxygen absorbs at these wavelengths.

Another greenhouse gas that is increasing is methane. Methane also absorbs re-radiation from earth, about 20 times more efficiently than equivalent levels of CO₂. Over the same time period of CO₂ increases, we have also experienced a doubling of methane levels in the atmosphere. The additional methane is almost entirely due to animal agriculture². Along with termites, cows are prolific producers of methane gas, as they decompose cellulose in their anaerobic stomachs. Animal agriculture releases about 100 million tonnes of methane per year, about equivalent to about another 2000 million tonnes of CO₂.

The exact temperature rise that 500 ppm CO₂ (and doubling of methane) would produce is difficult to estimate, because of the feedback effects, but it is virtually guaranteed to raise sea levels enough to swamp coastal cities throughout the world. Present estimates project a sea level rise between one foot and five feet by 2100. A three foot rise would require relocation of about half a billion people who live near coastlines. My own state of NC would lose about 2000 square miles of land, putting 30,000 homes at risk. Our problems will be dwarfed by the challenges of moving New York City, Hong Kong, and etc.

Desertification of agricultural land in the mid-latitudes will likely accelerate, further reducing food supplies. Major rivers irrigating Southeast Asia will dwindle as their glacial sources melt away- already these rivers are choking from glacial silt due to recent high rates of melting^16,17. About 20% of the world’s population currently depends on these mountain waters for their agriculture. Somewhat counter-intuitively, northern Europe might become too cold to grow crops, if the large quantities of fresh water from melting Arctic ice disrupt the northerly flowing Gulf Stream, as has happened during previous climate disruptions. It is unlikely that new agricultural regions can be developed quickly enough to avoid worldwide mass starvations.

Questions about the rate of such climate changes, and thus how quickly humanity must adapt, are hard to predict. That is the current goal of climate modeling, but it must be noted that the measured rates of change in such phenomena as sea ice melting, surface temperature increase, northerly movement of tropical species, and length of growing season have been exceeding the predictions of the models. The changes appear to be accelerating.

Feedbacks

Although a number of physical changes could be identified that would trigger an initial increase in temperature, the resulting chain of feedbacks would be similar. Excess CO₂ generation appears to be the main driver of current concern, but the same kinds of changes would also be triggered by increased methane gas, brightening of the sun, or significant loss of vegetation that removes CO₂ from the air. Some of the positive and negative feedbacks are as follows:

The aerobic bacteria that respire CO2 are more active at higher temperatures, so increase their average output as the average temperature increases. This effect is seen daily, with higher CO2 during the day than during the night. The higher average CO2 output leads to higher average temperature which leads to more CO2 generation, and etc. This is a classic positive feedback.

· At higher temperature, earth’s atmosphere retains additional moisture. Because water vapor is also a powerful greenhouse gas- absorbing strongly in the IR- this is a positive feedback, further aggravating the problem. It has been theorized that the additional moisture would increase cloud cover, causing more radiation to be reflected back into space, but measurements have failed to support this speculation. Higher levels of atmospheric moisture would be expected to increase the frequency and strength of violent storms, because water vapor is such a strong player in generating convection currents that power such storms. This means more and stronger snowstorms, as well as more hurricanes, tornadoes, etc.

· Higher temperatures cause a northward migration of the permafrost boundary. This uncovers expanses of frozen, fresh vegetation (tundra). Upon thawing of the vegetation, aerobic and anaerobic decay sets in, releasing more CO₂ and methane. This is a strong, positive feedback. The northward migration of the permafrost line is already under way¹⁸; some Alaskan and Siberian communities are sinking into newly melted ground.

· Large quantities of methane are locked underwater in the form of solid methane hydrates, at depths below about 1000 ft where temperature is low enough to keep them solidified. With warming oceans, these hydrates can rise to the surface and vaporize (similar to dry ice), causing sudden, large releases of methane gas³. This mechanism is thought to be one of the contributors to the Permian extinction about 250 million years ago, when sudden global warming caused the death of most of the species that existed on earth at that time.

· Higher CO₂ levels are thought to contribute to increased growth of vegetation, which should remove more CO₂ from the air- a negative feedback. Experiments have shown that enhanced growth is not guaranteed, however, because other factors such as temperature and nitrogen levels play an even larger role, and the future overall balance is not yet known^4,5. Currently, the net levels of worldwide vegetation are decreasing, due to forest destruction at a rate of about 55 square miles per day. Additionally, more frequent droughts in the Amazon forest have been turning it into a net source for CO2, rather than a net absorber, so this is turning out to be another positive feedback. Unless new, replacement forests can be generated in cooler regions.

· The burning processes that release CO₂ also generate aerosols- small liquid and solid particles that float in the atmosphere. One effect of such particles is light-scattering. This increases the amount of sunlight that is reflected, so reduces the absorbed radiation. This is a negative feedback, and one which can be very powerful⁶. Large volcanic eruptions load the atmosphere with enough particles to cause significant cooling… for a while. Most aerosols have a relatively short lifetime in the atmosphere, relative to the thousands of years that it requires for excess CO₂ to be flushed from the system by natural processes. Atmospheric aerosols have other effects, in addition to scattering, because they can act as sites for chemical reactions. An example is the ozone destruction that was caused by atmospheric chlorofluorocarbons. Aerosols are also known by terms such as haze, smog, and pollution. This is a highly complex topic, and is currently a key area of climate research.

· An effect of deforestation and desertification is to turn the exposed land brighter- to increase its reflectivity. This is a negative feedback, if neither a desirable nor efficient one. But it is not negligible, and must be considered in future climate modeling.

Other Side-Effects

Elevated CO₂ and temperature levels have other consequences that do not alter the climate, but are of significance for those who inhabit it:

· Elevated atmospheric CO₂ causes higher levels of absorbed CO₂ in oceans. This generates more carbonic acid. Currently, the oceans are about 30% more acidic than they were in pre-industrial times¹⁹. The higher acid levels are detrimental to the growth of many of the calcifying (shell-building) organisms and to corals, which provide havens for much of the oceanic food chain. Many coral reefs have already succumbed. About 95% of the coral reefs off Florida are already dead, due to a combination of temperature and pollution. There is valid concern that the marine food supply could be the first major victim of high CO₂.

· Tropical species (plants, animals, insects, and diseases) are currently expanding polewards, as their local environments become hotter^7,8. This brings new inhabitants into the older ecosystems, and they compete for the same resources. This can have drastic implications, with losses of many of the thousands of interdependent species that comprise local environments⁹. One example is the current devastation of white pine trees in the northern Rockies, by pine beetles that are now surviving the warmer winters at the high altitudes²⁰. Currently, world-wide extinction of species is proceeding at a rate about a thousand times faster than during pre-human times- as fast as during some of the past major planetary extinction events¹⁰. Global warming is part of the cause, and extinction rates will increase as warming accelerates in the 21^st century.

What’s One to Do?

Most climate scientists agree that the maximum CO₂ level that would not cause significant (i.e. dangerous) warming is 350 ppm. We have already exceeded that, so some of the above changes will certainly occur. There is a large difference in scale of destruction between 400 ppm and 500 ppm, however, so there are still opportunities to prevent the most appalling scenarios. It will require the concerted actions of governments to force the large changes that are required. Neither individuals nor free-market enterprises could fund them at the scale and speed required.

· The number one greenhouse gas generator is the burning of coal, which produces more CO2than equivalent amounts of oil or natural gas (the “cleanest” fossil fuel). Unfortunately, coal is the cheapest way to generate energy. Most U.S. electrical energy comes from coal, which also produces large amounts of sulfur dioxides and nitrogen oxides. Ironically, these aerosols mask (temporarily) some of the consequent warming effects, although the acid rain also kills vegetation. (So the idea of using rechargeable electric cars is bad, if it means burning coal instead of gasoline to provide their energy.) China also depends on coal to expand its economy, and is currently adding a new plant every month. However, China is also becoming a world leader in the production of clean, high efficiency coal plants¹¹and other green technologies. It seems clear that China's rapid expansion of coal-burning plants is a stopgap measure, and that they fully intend to become the future world leader in green energy. Economic incentives will be the only reliable way to force the rest of the world off its coal-dependency. This might entail taxing emissions, to provide the incentive to develop and expand cleaner sources, e.g. nuclear, wind, biofuels (but not corn-based ethanol), and solar, and better capturing of emissions. Unfortunately, such efforts are typically labeled as “job-killing energy taxes” by our politicians. An alternative is to subsidize greener fuels, until development can make them competitive. The typical political label for this is “wasteful government spending”. Our U.S. politicians offer no alternatives, and ignore the immediacy of the problem.

· Climate “engineering” is cautiously being examined in the technical community, as a way to live with high atmospheric CO₂ levels_. Typically, these schemes involve large-scale changes to the oceans or atmosphere, to alleviate some of the effects¹². Examples of this include “iron fertilization” of oceans, to encourage additional plankton growth that removes CO₂ from the air. Also seriously being considered is injection of sulfur aerosols at high altitudes, to scatter more of the incoming radiation. Banks of orbiting mirrors have even been proposed, to redirect radiation. Clearly, some of these are ideas born of desperation, and it is not obvious who would have the authority to implement such risky global experiments. The side-effects of such interventions are largely unknown.

Reflections

The International Panel on Climate Change (IPCC) has provided periodic updates on the scientific consensus on the topic since 1988¹³. Prior to this, there was no organized effort to assemble the data into a form amenable to government action. At every IPCC update, the case for global warming has been strengthened, and the current consensus is that there is a 90% probability that we will experience warming between 3⁰ and 8⁰F by mid-century¹⁴. This represents a higher average temperature than at any time during which homo sapiens has lived. Over 50 international science organizations have publically supported the IPCC conclusions and recommendations, including the American Geophysical Union which represents 20,000 climate scientists. Among climate scientists, over 95% agree that global warming is occurring, and is caused largely by human activities. No scientific organization on record has opposed the IPCC conclusions. There is a small minority of scientists who publically disagree, and many of these are handsomely funded by energy companies. There is always money to be made in climate change denial, especially if backed by plausible research.

In setting up the vast machinery of Homeland Security and two ground wars, VP Dick Cheney famously declared that it was worth the cost and effort, even if there was only a 1% chance of another terrorist attack on the scale of 9/11. In fact, if there was an equivalent of 9/11 attack every year, the lifetime chance for an average American to be affected is about 1 in 1300¹⁵. The chances of ending your life in a plane crash are twice as high, at 1:625. Cars are yet more dangerous, with a 1:83 chance of death. With a 90% probability of major climate impacts, the vast majority of which are negative, and a credible chance of catastrophic consequences for millions of people, it is dispiriting to see the lack of government focus. One is tempted to believe that many politicians are in it only for the next election.

At present, four of the five hottest years on record have occurred since 2003. The recent year 2010 was tied with 2005 as the the hottest ever recorded. Despite yearly fluctuations caused by events such as El Niños and La Niñas, the average baseline temperature is steadily creeping upwards at a rate of about 0.35⁰C per decade²¹. This rate is expected to increase as feedback effects from atmospheric CO2, methane, and water vapor levels continue to strengthen.

Epilogue

After the contact between the Titanic and the iceberg, there were no evacuation plans that could stop the ensuing disaster. It could have been prevented only by being foreseen and avoided. It took a little over two hours for the ship- still carrying most of its passengers- to sink below the surface, and about five more minutes to fall two miles to the ocean floor. Those who survived in the few available lifeboats reported that the screams of the passengers left stranded on the surface took about another hour to subside.

GPR: Jan, 2011

1. http://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth's_atmosphere

2. http://www.earthsave.org/globalwarming.htm

3. http://www.realclimate.org/index.php/archives/2005/12/methane-hydrates-and-global-warming/

4. http://www.newscientist.com/article/dn11655-climate-myths-higher-cosub2sub-levels-will-boost-plant-growth-and-food-production.html

5. http://www.sciencedaily.com/releases/2002/12/021206075233.htm

6. http://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html

7. http://ddr.nal.usda.gov/bitstream/10113/2942/1/IND43945433.pdf

8. http://www.co2science.org/subject/r/summaries/rangeexpbirds.php

9. http://www.hup.harvard.edu/catalog.php?isbn=9780674058170

10. http://www.pbs.org/wgbh/evolution/library/03/2/l_032_04.html

11. http://www.nytimes.com/2009/05/11/world/asia/11coal.html