Climate Change Part 18: Climate is a Social Justice Issue

Note: This program first aired on March 7, 2014. 

This is a science and nature show and we’ve spent nearly 20 weeks looking at the science around climate change, but the dirty secret about climate change is that it is ultimately a social problem. And it’s a problem that doesn’t affect us all equally. Climate change has become as much a social justice issue as it is an issue for scientific research. We’ve said before on this program that life isn’t fair; we all have to die, and suffering is universal. Is it fair to the frog that the snake has to eat?

I don’t know the answer to that question but I do know this: Climate change isn’t fair, and here’s why. The people it will impact the most are the poorest people on earth. The people with the least ability to change their circumstances, and in many cases, the people least responsible for the mechanics of changing the climate in the first place. The Intergovernmental Panel on Climate Change is unequivocal: we suffer from “uneven risk distribution”, which is a fancy way of saying that wealthy nations will be able to insulate their citizens, for a time at least, against some of the extreme weather events, food shortages and security threats that climate change poses, poor nations will not. The intersection of uneven economic development and climate change exposure makes the world’s poor vulnerable to changing conditions in a way that most of us in the industrial world are not. And while we are all at eventual risk of social unrest and even violence if conditions get desperate enough, we already see the unrest and violence that has occurred in regions and nations that are environmentally on the brink.

In the near term, extreme weather events are the way in which most of us will experience climate change directly, in the form of more intense storms, colossally heavy rain fall, coastal flooding and heat waves that exacerbate drought and wild fire conditions. Droughts and floods, too much water coupled with not enough, these are what is on the agenda. Those two problems alone set in motion a cascade of human impacts; decreases in crop production and increases in food insecurity, decreasing freshwater resources for agriculture, industry and direct human consumption, and flooding in coastal zones and marginal recently urbanized land. These problems then compound themselves, as subsistence agriculture becomes more and more difficult in drought prone regions, human populations migrate increasingly to urban areas, colonizing marginal territory on the outskirts of cities, territory with little to no services. These people, driven from their homes by the inability to grow their own food and provide for their families and communities, then confront the other faces of climate change, namely the food insecurity that comes from rising food prices due to decreases in crop productivity, and the domestic insecurity that comes from moving into a rapidly expanding urban shanty town on marginal swampy land or steep hillside. Extreme precipitation events, monsoon rains, and typhoon storms easily flood these areas.

And we haven’t even considered sea level rise in this scenario. As the sea encroaches into coastal human landscapes the consequences are clear. Some low lying areas will be swamped all together, like the Pacific island nations or the Ganges River delta in Bangladesh, home to millions. Sea level rise is an existential threat to the people who live there. Large storm systems cause storm surges to threaten otherwise stable coastlines; low pressure and high winds, when coinciding with high tides can cause the ocean to rise much higher than its normal high water mark, as the people of the Philippines, New Orleans, lower Manhattan  now know. And as freshwater aquifers are rapidly depleted and sea levels continue to rise, in coastal areas seawater seeps into these aquifers, filling the void created as freshwater is drawn out. Wealthy communities can for a time afford to purchase fresh water, poor communities cannot. Humans can survive only a matter of days with out fresh water, and salt water intrusion joins food insecurity and social unrest as yet another driver of human displacement and suffering with significant ties to climate change.

For most listeners of this show, the near future impacts of climate change may be uncomfortable, or economically challenging, but are unlikely to destroy our communities or fundamental way of life. The same cannot be said for the world’s truly poor. As the conversation around climate change pivots increasingly away from mitigation towards adaptation, we need to keep this in mind: it is in our local communities that we focus on adaptation, but it is for the global community that we must continue efforts to mitigate climate impact. We’ll look at how we do that in the coming weeks.

 

References:

http://economix.blogs.nytimes.com/2013/11/12/the-inequality-of-climate-change/

I don’t always agree with the World Bank, but they released a big report on this issue a couple of years ago: http://www.worldbank.org/en/news/feature/2013/06/19/what-climate-change-means-africa-asia-coastal-poor

https://www.nwf.org/pdf/Global-Warming/NWF_ExtremeWeather_pages_sm.pdf

http://cargocollective.com/climatechangestoriesforsocialjustice/Disappearing-Islands-Maldives

Climate Change Part 17: Impacts on the Ocean

Note: This program first aired on February 28, 2014.

We’ve come to the part of the climate change story that really matters. What is going to happen? What will the world look like for your kids and grand kids? How will it be different than it is today?

When we look at the ocean, the impacts of climate change are vast and many. The ocean covers 70% of the surface of the planet, and its’ medium, water has all the unique properties that make this planet hospitable to life. So you should expect anything that affects climate will affect the ocean in a big way, and it does.

Sea level rise is one of the first things people think of when they ponder the impacts of climate change. Some 44% of people world wide live within 150 km of the coastline, here in the US, that number is over 50%. The coastline though is an arbitrary location, relatively stable in the past few hundred years, our time frame for the modern world. The location of the coast is the result of a combination of factors; the amount of water in the ocean, the volume of the water in the ocean,  and the level of the land, and it turns out all of these factors are dynamic. The current climate event is increasing both the mass and volume of the ocean. By melting land based fresh water ice caps (both large and small) the total amount of liquid water in the ocean is increasing, and as we all know, when you over fill a glass, it spills out. A second issue is at play, thermal expansion. As water warms the molecules spread out more, so the same mass of water will take up more space. Not only are we putting more water into the ocean, that water is getting bigger because it is warming up, increasing the volume of the ocean. How high will it go? The IPCC’s last projection was for approximately 0.4 and 0.7 meters of average sea level rise between now and 2100. Currently sea levels are rising at a rate of 3mm a year.

Things in the ocean are responding to changing water temperatures the same way things on land are to changing terrestrial climatic conditions, those that can move to keep up with their water temperature of choice are doing so. This is one of the main reasons we haven’t had a winter shrimp fishery here in the Gulf of Maine for the past couple of years. The commercially harvested Northern Shrimp (Pandalus borealis) are at the southern edge of their range here in Maine. Warming Gulf of Maine water is interfering with their reproduction, and populations have collapsed here as a result.

As ocean waters warm, ocean circulation is affected, particularly the vertical circulation that brings nutrients to the surface, and oxygen rich water to the bottom of the ocean. Increased warming at the surface creates a warm surface layer, effectively putting a cap on top of the ocean that prevents these vertical mixing currents (this is what happens on a small scale on the west coast of South America during an El Nino event). With no nutrients at the surface primary productivity drops dramatically. With no oxygen replenishment at the bottom, the bottom goes hypoxic. There is evidence from the fossil record that this kind of situation has happened before, and let’s just say, it wasn’t good.

The final elephant in the room is of course ocean acidification. This is a chemical phenomenon directly related to the increase in atmospheric carbon dioxide. As levels rise in the atmosphere, they correspondingly rise (by diffusion) in the ocean as well. When carbon dioxide mixes with sea water it forms carbonic acid, and uses up carbonate ions in the process. Carbonate ions are what calcium carbonate are made of, and animals that use calcium carbonate in their shells are very negatively impacted. Unfortunately those organisms happen to be important in the food chain, provide significant ecosystem services and are a significant part of many fishing dependent economies.

So you see, the impacts of climate change on the ocean are numerous and diverse and what happens on land also happens in the sea. There’s no place to hide. We’ll see what this really means for us next week.

References:

UN Coastal Atlas:

http://www.oceansatlas.org/servlet/CDSServlet?status=ND0xODc3JjY9ZW4mMzM9KiYzNz1rb3M~

Sea Level Rise: http://ocean.nationalgeographic.com/ocean/critical-issues-sea-level-rise/

Storm surge: http://toolkit.climate.gov/topics/coastal-flood-risk/storm-surge

IPCC 2013 report on Sea Level Rise: http://www.ipcc.ch/pdf/unfccc/cop19/3_gregory13sbsta.pdf

Island nations in threat: http://www.japantimes.co.jp/life/2013/09/06/environment/pacific-islands-fighting-for-survival-as-sea-levels-rise/#.VOzFv8bhJJM

Northern Shrimp in Maine: http://www.pressherald.com/2014/11/07/shrimp-depletion-in-gulf-of-maine-part-of-a-pattern-across-globe/

Under a Green Sky author Peter Ward (outlines the evidence that ocean stratification was related to mass extinction), on Vimeo https://vimeo.com/64407973

Gulf of Maine Research Institute on ocean acidification: http://www.gmri.org/news/waypoints/ocean-acidification-growing-concern-gulf-maine

NOAA on Gulf of Maine ocean acidification: http://oceanacidification.noaa.gov/WhatsNew/OANews/CurrentNews/TabId/552/ArtMID/1344/ArticleID/9991/Study-shows-Gulf-of-Maine-likely-to-be-more-sensitive-to-ocean-acidification-.aspx

Climate Change Part 16: Future (and present) Impacts

Note: This program first aired on February 2, 2014.

Over the past weeks and months our climate change series has told us quite a tale about Earth’s climate system and how it is changing. We’ve looked at how the green house effect works and what gasses enhance it, what the parts of the climate system are and how they interact in very basic terms, and where the carbon comes from and where it goes. We’ve laid the ground work and now we’re coming to the final chapter of this story, the one in which we find out what happens next. 

And what happens next is a story of degrees. If you have a chance, read through the Intergovernmental Panel on Climate Change’s 2014 Summary for Policy Makers-it’s available freely online. In it scientists clearly lay out the risks of various impacts on natural ecosystems and human societies. The devil is in the details, if global average temperatures increase only 1 to 2 degrees Celsius, the impacts are “considerable”. If temperatures increase 4 degrees or more, the risk become high or very high. The different in temperature increases reflect different emissions scenarios. Two things remain important to understand, first that under all assessed future scenarios some risk of adverse impact remains, and second, risks are substantially reduced under low emissions scenarios. Simply put, no matter what, change is coming, but we still have some say in just how much change it is.

And what can we anticipate in the coming century (and indeed it is a hundred year horizon that these predictions mainly look towards)? Where to start? Risks from climate change are extensions of much of what we see taking place already. As temperatures increase, so do the risks, significantly.  If we look at the pure ecosystem impacts, we can anticipate a continued decline in biodiversity and an increased in extinctions for organisms that can’t adapt and or migrate to follow shifting favorable climate regions fast enough. Weakened ecosystems then become vulnerable to additional problems like diseases vectors and invasive species. These kinds of impacts are what many of us think of when we worry about climate change, as well we should, but we also need to remember that intact ecosystems provide vital services like cleaning water and air, and thus, negative impacts to natural ecosystems also have a negative impact on us. All of the other risks the IPCC report outlines are ones that directly impact the functioning of human society. Fresh water resources are projected to decline due to increased drought, especially in already semi arid areas. At the same time increased precipitation events are expected, which sounds like a good thing, except for when the additional inches of rain all fall at once. Then we have catastrophic flooding, and waste water systems that get overwhelmed, leading to increased pollution of surface water. High latitude areas may see increased freshwater resources, which brings up an important point—there can be effects that have a positive impact. Though, so far the projected negatives have outweighed the projected positives in virtually all areas of assessment.

Food security is another area where climate change is expected to negatively impact the human condition. Wheat, corn, rice and soy are the 4 most widely grown crops world wide, and increasing temperatures are projected in negatively impact the production of three of them (all but possibly soy). Decreased crop yields due to heat and water stress are likely to be the biggest issue, but problems arise with access and distribution as critical infrastructure is weakened by severe weather events. As annual crops, intensive breeding may be able to effect adaptation in a relatively short period of time, and had already yielded some more heat ready, drought tolerant varieties. The question remains, just how hot will it get? How much heat tolerance do we need to breed into these staple crops? These are just a couple of examples of what is coming between now and the end of the 21rst century. We’ll look at others in the coming weeks.

What we find as we dive increasingly deeper into the thought exercise that is “preparing for climate change”, is that while science has identified many negative ecosystem impacts, the things human society needs to pay attention to are the things that enable our “normal” day to day lives, the things that are easy to take for granted. Climate change seems very far away when you hear about a frog in the central American rain forest that has gone extinct, it’s much closer to home when you go to the sink for a glass of water and nothing comes out of the tap, just ask the folks in California. We’ve looked at the science, in this final chapter we’ll be looking at the human part of this story. 

References: 

The Summary for Policy Makers (Summary being code for a document that is still 34 pages long) of the 5^th IPCC report on climate change (2014): http://www.ipcc.ch/pdf/assessment-report/ar5/wg2/ar5_wgII_spm_en.pdf

This document is highly recommended, if still a bit dense. It contains many excellent graphics that accompany the assessment of risk.

http://time.com/3672276/climate-change-oceans/

Portland Press Herald (from the Washington Post) on the new NOAA NASA study: http://www.pressherald.com/2015/01/16/climate-change-milestone-outside-of-maine-2014-sizzled/

From Truthout and Bill Moyers, a shit ton of bad news,: http://billmoyers.com/2015/01/06/climate-disruption-advances-26-percent-mammals-face-extinction/

U S Navy predicts an ice free Arctic in ths summer by next year +/-3 years…

http://www.theguardian.com/environment/earth-insight/2013/dec/09/us-navy-arctic-sea-ice-2016-melt

Climate Change Part 15: Linear and Abrupt Models

Note: This program first aired January 31, 2015.

It may be no surprise to you that anthropogenic climate change is paying dividends to the world already. No longer is this something we can think of as impacting the future. The future, as they say, is now. World wide glaciers, both continental and alpine are in rapid retreat, phenological changes that include earlier dates of ice out on lakes and rivers and earlier timing of spring tree, flower and phytoplankton blooms are being documented everywhere, tropical diseases are spreading, along with their host insects to higher latitudes whose climates can now support them, the intensity and frequency of extreme heat waves are increasing, Arctic sea ice is getting smaller and thinner each summer, and last year was the warmest year on record.

When we think about the consequences of climate change, there are two models that are used to conceptualize what might happen (as well as for comparison with what IS happening). The first model is linear. In this world view, incremental increases in green house gasses yield incremental changes in climate, it’s a y equals mx plus b vision of how the climate system works. The carbon dioxide level and average global temperature have a direct relationship. As carbon dioxide levels increase, average global temperature increases at some set proportion described by the slope of the line, and that relationship remains a constant straight line regardless of how high carbon dioxide levels get. It is a reassuring, predictable relationship, in that the math is simple. If we know the X value, a carbon dioxide level, we can get a Y value, the resulting temperature. Everyone can interpret a straight line graph. It’s worth noting that this is the model that the Intergovernmental Panel on Climate Change, the world’s preeminent climate change research and policy body, uses to makes its predictions, predictions that direct the course of global policy actions.

The problem is that Earth’s climate system is not actually linear. The relationship between carbon dioxide and temperature may appear to have simple causal attributes, but it is just the tip of the iceberg. Climate is defined as the long term average of weather, and weather is acknowledged to be a chaotic system, chaos in this sense as a technical term, meaning distinctly non linear. As we increase atmospheric carbon dioxide and thus increase average temperatures as expected, all kinds of other related processes can get triggered, and lead to rapid and unexpected effects. Take for example, last year’s intensely cold winter in North America, not the kind of thing you would expect if you used the simplistic model of increasing carbon dioxide leading to warmer temperatures. In fact the increasing temperatures have disrupted typical atmospheric pressure arrangements and thus wind patterns, which led to changes in the jet stream. Instead of running primarily west to east last winter, the jet stream (which is simply the boundary between polar and mid latitude air masses) was able to take large north and south running loops, bringing very dry cold polar air to lower latitudes than we are used to. Chaos.

The ultimate expression of this non linear climate system, and the one that keeps climate scientist up at night is the model of abrupt climate change. It’s what many leading climate scientists see on the very near horizon. Essentially X leads to Y, which then leads to A, B, C or any other letter in the alphabet, or perhaps, all of them. A warming average global temperature pushes certain aspects of the climate system past their tipping points, which result in a rapid and more irreversible change in the functioning climate system. Those anticipating abrupt climate change are looking hard at what is happening in the Arctic. Polar amplification has long been recognized, in that the Arctic has seen warming temperatures several degrees higher than the global averages, due largely to feedback loops related to the loss of sea ice and therefore albedo. As less sunlight is reflected (because there is less highly reflective ice around), more light is absorbed, which then warms the Arctic and melts yet more ice. There are suggestions that the Arctic may be more intimately influential in global climate than was previously suspected, and if the Arctic continues its death march towards a tipping point, it may take the whole world with it, quickly. There is precendent for the mechanisms of abrupt climate change in the paleoclimate record, abrupt climate change is in fact what has led the Earth into glacial periods, as well as to rapidly emerge from those same ice ages over a matter of decades.  

Over the past many many weeks and months we’ve spent most of our climate change energy focusing on the carbon, because quite simply, this whole thing starts with the carbon, it’s the crux of what is driving the warming of the climate. The parallel story is that while carbon is simple, climate is wildly complex and the system is massively difficult to describe quantitatively in terms of predicting behavior. That is why climate scientists are a strange mix of computer geniuses who build super computing climate models, and field researchers who drill cores in glaciers and ocean sediments trying to reconstruct past climate patterns. We look at the past to predict the future, and the past tells us that it is likely an abrupt shift, rather than a gradual stepwise transition, that we should be looking forward to.

References:

Current effects of climate change from NASA, including several really good graphical representations of various effects: http://climate.nasa.gov/effects/

IPCC home page, read the projections for your self: http://www.ipcc.ch/index.htm

Maine Climate Change Institute on Abrupt Climate Change http://a2c2igert.umaine.edu/sample-page/what-is-abrupt-climate-change/

Thinking about adaptations: http://climatechange.umaine.edu/maine_clas_conference/

Tipping points: http://au.ibtimes.com/climate-change-arctic-could-trigger-domino-effect-around-world-1292935#.UqWaV_R9aSo

Book Review: WTF, Evolution?

Note: This program first aired January 17, 2015.

I read a lot of books, science and nature books mostly, and I am always on the lookout for new work that effectively translates heady science concepts into engaging understandable material for the public. 2005’s fabulously funny “How Animals Have Sex: A guide to the reproductive habits of creatures great and small” by David Strorm is a great example. It’s a small format, full color photographic book that surveys the amusing sex lives of a wide variety of animals. The heady topic in question? That life is incredibly diverse, and evolution has come up with an amazing array of ways for life to go on, that is, for animals to reproduce. It answers questions you’ve always wondered like, how do dolphins and whales mate? What about porcupines? And then titillates the reader with fun facts about animals you may have never heard of like Bean Weevils and Spoon Worms and Argentine Lake Ducks. I consider How Animals Have Sex to have set a high standard for this genre.

So it was with pleasure that I purused Mara Grunbaum’s “WTF, Evolution?! A theory of unintelligible design”, a 2014 release from Workman Publishing. WTF, Evolution?! follows the same small format, full color photographic design, with a sort of scrap book-y layout. The author imagines an ongoing conversation with Evolution, and the book is full of cheeky irreverent dialog, sharp enough to get your attention, smart enough to keep it. The narrator’s skeptical comments and dead pan retorts are contrasted by enthusiasm in the voice of Evolution. Each section is prefaced by a short explanation of some facet of the mechanisms of Evolution, highlighting how adaptations have given the world some very strange solutions to otherwise straightforward biological problems.

The main goal of the book is to showcase the diversity of strange adaptations that have evolved in the animal kingdom over the last 3.8 billion years on this planet. In doing so Grunbaum highlights  key misconceptions about evolution, that it has a goal in mind or some kind of intention, and that humans are the apex of evolutionary adaptation. Evolution is precisely not directional, and has no end goal in mind. As she says in the introduction “Like the rest of us, it’s basically just fumbling in the dark”. Genetic engineering aside, evolution is profoundly limited by its starting material. It can only work with the genes that are in the gene pool. The only source of new material is mutation, which happens with regularity yet doesn’t yield viable new genetic material all that often. Not every mutation is adaptive, but if it doesn’t have a negative effect, it can get taken along for the ride and persist along side genes that increase an individual’s fitness. And that makes the fact of the incredible diversity of animal forms (and they are almost entirely animals in this book) simultaneously bewildering and understandable.

If you are interested in evolution, find animal diversity fascinating, like to laugh and don’t take yourself too seriously, do yourself a favor and pick up a copy WTF, Evolution?! At a bare minimum you will see evolution from a new angle, and regardless of where you are standing, a new perspective is something that benefits us all.

References:

Yes, its real: http://en.wikipedia.org/wiki/Pigbutt_worm

How Animals Have Sex http://www.betterworldbooks.com/how-animals-have-sex-id-1592401910.aspx

WTF Evolution?! http://wtfevolution.tumblr.com/

Climate Change Part 14: Methane 2

Note: This program first aired January 10, 2015.

 

Last week we introduced a key non carbon dioxide green house gas, methane. There are several naturally occurring sources of methane, a gas that is produced by anaerobic bacteria when organic matter decays.

Methane is a fossil carbon based fuel, and is the main constituent of natural gas, so when we burn it, just like when we burn any carbon based fuel, one of the waste products is carbon dioxide. Carbon dioxide is a major green house gas, meaning as we increase concentrations of it in the atmosphere, we create conditions that prevent the escape of infrared radiation (also known as sensible heat) from Earth’s climate system (that being the atmosphere and the ocean). When more heat is trapped than escapes, then we have a system that is warming. That is the current climate change scenario in a nut shell, and the combustion of methane plays a role.

Methane plays a second, and more significant role in climate change by being a green house gas itself.  The methane molecule, just like the carbon dioxide molecule, the water molecule, the nitrous oxide molecule and various other fluorine containing and halogenated industrial compounds, absorbs specific wavelengths of infrared radiation. Water is by far the most important green house gas, in that it traps the widest range of infrared wavelengths emitted by the Earth back towards space. And remember, the green house effect that results from these various atmospheric gasses is what makes our planet livable, so it’s a good thing. The issue currently is that the proportions of the green house gasses in the atmosphere are changing, resulting in more radiation being trapped down here in the lower atmosphere, so things are heating up on the surface of the earth. I said that water vapor traps the widest range of infrared wavelengths, but it doesn’t absorb all of them. There are gaps, or windows in the water vapor absorption spectrum. In the absence of other green house gasses, it is through these wavelength windows that some heat escapes the atmosphere. Some of these gaps are partially filled by the other greenhouse gasses, including carbon dioxide, and methane.

On a per molecule basis, methane absorbs a large amount of infrared radiation, so you often hear that it is something like 40 times as powerful as carbon dioxide gas in terms of its greenhouse warming potential. Some studies have linked methane releases to major warming events like the PETM (or Paleo Eocene Thermal Maximum) or mass extinctions like the end Permian. Methane is different than most other non water vapor green house gasses in that it breaks down relatively quickly, usually within a decade of emission. In the atmosphere it is oxidized, which essentially does the same thing chemically as combusting it, so when methane goes away, carbon dioxide and water are left, and we already know those are both green house gasses.

In the big scheme of things, methane makes up a very small percentage of green house gasses, and because it oxidizes so quickly, some scientists down play its role in climate change. Others see it as a great place to start mitigation efforts, because the effect of reducing emissions of methane can be felt within a decade, due to its short lifespan. As we have learned, there are many natural sources of methane. However, at this point there are many more anthropogenic sources of methane emissions than natural ones. These sources are industrial and agricultural and are somewhat unavoidable components of modern society. Landfills, the end point for much of our waste stream, are a huge source. When land fills are created and then capped, they become anaerobic environments, full of organic matter—perfect incubators for the creation of methane. Some forward thinking land fill operators actually capture that land fill gas and burn it to create heat or electricity. Methane comes from a variety of agricultural sources, including artificial wetlands where rice is grown, and ruminant livestock as well as manure. The oil, gas and coal industry itself is a large source of methane emissions, coming mainly from leaks in infrastructure, and directly from wells and mines. The anthropogenic effects of methane emissions can be compounded by a positive feedback loop that was recently quantified; Methanogenic bacteria are strongly temperature dependent, so the warmer it gets, the more methane they will make. In other words the warmer climate gets, the more active wetland bacteria are, the more methane is emitted, the warmer it gets. It is this effect that causes some scientists to link methane emissions to specific rapid climate change events in the geologic record.

The consensus in the climate science community seems to be that issue is the carbon dioxide, and that is where we should be directing our energy. At the same time however, methane needs to stay on the table, with a particular eye to all those methane hydrates at the bottom of the ocean. Ocean temperatures are warming, particularly deep ocean temperatures, which means that things could get very weird very fast in the climate system. Methane remains the wild card here, one that bears watching in the years to come.

References:

Science Daily digest here on the study that quantified the “the warmer it gets the more methane we get” positive feedback loop: http://www.sciencedaily.com/releases/2014/03/140327111724.htm

Even high school students preparing for their school exams need to know about combustion chemistry: http://www.gcsescience.com/o30.htm

Old archived science blog, but it has good info: http://www.oocities.org/marie.mitchell@rogers.com/GreenhouseEffect.html

Real Climate Science Blog on Methane: http://www.realclimate.org/index.php/archives/2012/01/much-ado-about-methane/

More about the nitty gritty of the bond chemistry that makes green house gasses work: http://www.windows2universe.org/earth/climate/greenhouse_effect_gases.html

Google “sources of methane” and take a look at the images. You will see a wide variety of pie charts, with huge variation in what they show. Most show anthropogenic sources as nearly ¾ of the methane emissions, the methane hydrates that make up the huge volume of fossil fuels on Earth aren’t being emitted, so they aren’t included on these tallies (except for where they are emitted, in thus far relatively small amounts in coastal oceans and some high latitude lakes).

Land fill gas: http://www.epa.gov/lmop/faq/landfill-gas.html

Climate Change Part 13: Methane 1

Note: This program first aired on January 3, 2015.

 

We left off last time with the biogeochemical mechanisms by which oil is made. Briefly, oil and gas result from primary productivity at the ocean surface. Photosynthesis happens in the bodies of tiny phytoplankton. Those plankton die without being eaten, and then sink to the bottom, where they accumulate. Over a geologically relevant amount of time, they turn into oil.

Today we talk about the gas part of “oil and gas”. There are several simple hydrocarbons that can form from dead marine organic matter, and the shortest of these chains of carbon are gaseous. The shortest chain of all isn’t a chain at all, it’s a single carbon atom surrounded by hydrogen atoms, CH4, methane. Methane gets special attention in climate change circles because it isn’t just a fossil fuel (it’s the primary component of “natural gas” when it wears that hat), it is also a green house gas in its own right.

Methane forms when organic matter is decomposed anaerobically, meaning without oxygen. This form of decomposition is slow, and yields less energy than aerobic metabolism, but allows microbes exist in anoxic environments where other things can not live. Methane occurs naturally on earth anywhere we have anoxic conditions and organic matter. Wetlands are a major terrestrial source, where waterlogged soils quickly become anoxic, and methanogenic bacteria have plenty of raw material. Swamp gas is the result. Animals are another surprising source of methane, some more so than others. Our guts are anaerobic environments that house billions of bacteria, these bacteria do much of the heavy lifting of digestion for us, but depending on the raw material we provide these bacteria, they sometimes make methane as a byproduct, a phenomenon I am sure you are all familiar with. Animals that make a living eating difficult to digest food, like cellulose and related compounds make methane regularly. Domestic cattle and other ruminants eat hard to digest grasses, and as a result, give methanogenic bacteria plenty of feed stock. Termites make a living eating wood and other high cellulose organic material, and again, rely on gut microbes that can break down the difficult to digest cellulose. As a result, termites are another natural source of atmospheric methane.

Much methane resides in the permafrost areas of the high arctic and subarctic. Productivity is slow in those regions, but the organic matter that does form breaks down very slowly due to the cold conditions, thus the soils there are quite peaty, and high in partially decomposed organic matter. They also suffer poor drainage due to underlying impermeable frozen substrate, and tend to be waterlogged as a result. These conditions lead to a slow but steady production of soil bound methane, typically locked into permafrost.

The largest store of methane on Earth is at the bottom of the ocean. As a simple hydrocarbon methane forms relatively quickly from organic matter that makes its way to the ocean floor. Over the long term these deposits can be buried and become the oil and gas deposits we now search continental shelves for, but in the short term the methane gas can also be trapped in near ocean bottom sediments, held in place by the extreme pressure on the sea floor. These deposits are called methane hydrates, because due to the pressure, the methane molecules get trapped in a crystalline matrix of water molecules, and form solid that looks something like ice.  This methane is not only the largest store of the gas on Earth, it is also constitutes over half of all fossil fuels on Earth, which is why so many people are trying to figure out how to commercially access this this odd source of natural gas, for better or for worse. Next time we will look at methane’s role in climate change, and why it might be our best hope for mitigating the most severe potential impacts.

References:

From the University of California San Diego: http://earthguide.ucsd.edu/virtualmuseum/climatechange1/03_3.shtml

Online text book from the University of Oxford (UK) Environmental Change Institute: http://www.eci.ox.ac.uk/research/energy/downloads/methaneuk/chapter02.pdf

Interesting info from NOAA on non carbondioxide Green House Gasses http://www.esrl.noaa.gov/research/themes/forcing/

Data, including details on sources and proportions from the EPA: http://epa.gov/climatechange/ghgemissions/gases/ch4.html

About termites from the Arizona Sonora Desert Museum (be sure to read the bit about the baby termites eating the feces of their older siblings…) http://www.desertmuseum.org/books/nhsd_termites.html

Department of Energy take on methane hydrates: http://energy.gov/fe/science-innovation/oil-gas-research/methane-hydrate