Methane and Global Climate Change EAS 1540 -- Oceanography November 6, 2015 Bob Howarth Department of Ecology & Evolutionary Biology
Methane is an important greenhouse gases… it fills in “holes” in the infra red spectrum not filled by water vapor and CO 2 http: //oceanworld. tamu. edu/resources/oceanography-book/radiationbalance. htm
Carbon Dioxide Methane
The climate system responds much more quickly to methane than to carbon dioxide http: //news. discovery. com/earth/alas kas-arctic-tundra-feeling-theheat. html 2. 0 o. C threshold 1. 5 o. C threshold Shindell et al. 2012
The two faces of carbon: Carbon dioxide (CO 2) – climate system responds slowly to changes, but current emissions will influence climate for 1, 000 s of years; human activity has increased CO 2 by 45% Methane (CH 4) – much faster response by climate system, but methane stays in atmosphere for only 12 years; human activity has increased CH 4 by 170% > 200 times as much CO 2 in atmosphere, but CH 4 is > 100 times more powerful as a greenhouse gas
Methane is important…. Where does it come from? Multiple sources, both natural and human-caused. Fluxes often hard to measure, so global sources somewhat uncertain. Two major types of methane in atmosphere: • Methane formed in rock formations over geological time frame • Methane formed by decomposition of organic matter by bacteria in absence of oxygen
Begon et al. 2014, adapted from IPCC 2007
Methane in the atmosphere for most of the last 10, 000 years vs. change since industrial revolution let’s us estimate the natural fluxes vs. human-caused fluxes: Natural = 220 Tg of C per year Human-caused = 350 Tg of C per year
Of the natural flux of 220 Tg C per year: Seeps from geologic formations = ~ 50 Biological sources (decomposition) = ~ 170
Of the natural flux of 220 Tg C per year: Seeps from geologic formations = ~ 50 Biological sources (decomposition) = ~ 170 Mostly from oxygen-free sediments of lakes and wetlands
Of the natural flux of 220 Tg C per year: Seeps from geologic formations = ~ 50 Biological sources (decomposition) = ~ 170 What about oceans, which also have oxygenfree sediments, and cover far more of the Earth than do lakes and freshwater wetlands?
The high level of sulfate in seawater greatly limits the production of methane, since bacteria using sulfate instead of producing methane gain more energy and are more ecologically competitive. Organic C + sulfate Organic C CO 2 + sulfides CH 4 + CO 2
So oceans are not important methane source globally (BUT, may become so due to melting of methane clathrates)
Methane in the atmosphere for most of the last 10, 000 years vs. change since industrial revolution let’s us estimate the natural fluxes vs. human-caused fluxes: Natural = 220 Tg of C per year Human-caused = 350 Tg of C per year Again, two types: geologically ancient methane (released in obtaining fossil fuels), and recently formed from biological decomposition in absence of oxygen.
Fluxes of methane to the atmosphere globally (Tg C of methane per year) _______________________ Natural sources • geological seeps • biological sources 220 53 167 Anthropogenic sources 350 fossil-fuel emissions animal agriculture rice cultivation landfills and sewage biomass burning 115 90 60 55 30 • • • Total 570 Begon et al. 2014
Released from geological formations, Fluxes of methane to the atmosphere globally some from mining coal but much more (Tg C of methane per year) from developing oil and natural gas. _______________________ Natural sources • geological seeps • biological sources 220 53 167 Anthropogenic sources 350 fossil-fuel emissions animal agriculture rice cultivation landfills and sewage biomass burning 115 90 60 55 30 • • • Total 570 Begon et al. 2014
Fluxes of methane to the atmosphere globally (Tg C of methane per year) Produced from decomposition of _______________________ organic matter in oxygen-free Natural sourcesenvironments (cow guts, manure piles, 220 flooded rice paddies), etc. • geological seeps • biological sources 53 167 Anthropogenic sources 350 fossil-fuel emissions animal agriculture rice cultivation landfills and sewage biomass burning 115 90 60 55 30 • • • Total 570 Begon et al. 2014
A lot of uncertainty in individual source estimates. Fluxes of methane to the atmosphere globally But sum of geological seeps and fossil-fuel emissions is well (Tg C of methane per year) known, from the amount of radioactive 14 C in atmospheric _______________________ methane (30%) Natural sources 220 • geological seeps • biological sources 53 167 Anthropogenic sources 350 fossil-fuel emissions animal agriculture rice cultivation landfills and sewage biomass burning 115 90 60 55 30 • • • Total 570 Begon et al. 2014
Dangerous tipping points may be only 15 to 35 years into the future. Controlling methane is CRITICAL to the solution! http: //news. discovery. com/earth/alas kas-arctic-tundra-feeling-theheat. html 2. 0 o. C threshold 1. 5 o. C threshold Shindell et al. 2012
Stable to a point, then very rapid and radical change in the Earth’s climate system Leiserowitz et al. (2011)
High potential for massive emissions of ancient CH 4 due to thawing permafrost and release of “frozen” methane (methane hydrates and clathrates). CH 4 Zimov et al. (2006) Science 23
The global area of tundra decreased 18% in just 20 years (Wang et al. 2004) http: //www. arctic. noaa. gov/detect/land-tundra. shtml (downloaded June 9, 2014)
Two photographs from the same location in Alaska, showing the transition from tundra to wetlands over the last twenty years (from Torre Jorgenson). http: //www. arctic. noaa. gov/detect/land-tundra. shtml (downloaded June 9, 2014)
Hansen et al. (2007) suggested critical threshold in climate system, to avoid melting of natural methane clathrates, at ~ 1. 8 o C.
2 -9 Tg CH 4 yr-1 METHANE CLATHRATES - methane frozen in water ice mix under ocean sediments on continental shelves and in permafrost - large potential for destabilization with increasing temp - will it be oxidized to CO 2 within the water column? - HUGE pool (10, 000 times current total annual global flux) http: //www. globalcarbonproject. org/news/Methane. Hydrates. html
2. 0 o. C threshold 1. 5 o. C threshold Danger point for methane clathrate melting, based on geologic past Shindell et al. 2012
Will be reached in ~ 25 years, unless the world starts immediately to control methane and soot pollution 2. 0 o. C threshold 1. 5 o. C threshold Danger point for methane clathrate melting, based on geologic past Shindell et al. 2012
Will be reached in ~ 25 years, unless the world starts immediately to control methane and soot pollution NOT predicting that methane clathrates will all melt on this time frame, but the start of an irreversible process of melting may well occur, with disastrous consequences in the decades to a century afterward. 2. 0 o. C threshold 1. 5 o. C threshold Danger point for methane clathrate melting, based on geologic past Shindell et al. 2012
What can be done to reduce methane emissions? Globally and in the US, the two largest sources are fossil fuels (particularly oil and natural gas) and animal agriculture.
US National Methane Emissions for 2009 (Modified from Howarth et al. 2012, based on EPA 201
Begon et al. 2014, adapted from UNESCO 2012 and UNEP 2014
World Health Organization (2012): Obesity and over-consumption of meat now larger public health issues globally than are starvation and malnutrition.
…. Instead of this This …. .
Fossil fuels? We continue on the wrong track…. Begon et al. 2014, adapted from Hughes 2012
Is natural gas a “bridge fuel? ” For just the release of carbon dioxide during combustion…. . g C of CO 2 MJ-1 of energy Natural gas 15 Diesel oil 20 Coal 25 (Hayhoe et al. 2002)
Methane emissions – the Achilles’ heel of natural gas • Natural gas is mostly methane. • Methane is much more potent greenhouse gas than carbon dioxide, so even small emissions matter.
Methane (natural gas) leaks from tanks, pipelines, compressors, etc. Naked eye Infra-red (42) Methane is not visible to naked eye, but can be “seen” with infra-red cameras. 39
Shale gas is new, the science behind it is new …. . Natural Gas Production in the United States Dept of Energy -- EIA 2015 Outlook data and mean reference projections 35 30 Exajoules 25 20 15 conventional shale 10 5 0 6/2/1905 6/12/1905 6/22/1905 7/12/1905 7/22/1905 8/1/1905 12: 00: 00 12: 00: 00 12: 00 AM AM Howarth 2015
Publication of first peerreviewed paper on any aspect of environmental risk of shale gas (Howarth, 35 Santoro, & Ingraffea 2011) 30 Exajoules 25 20 15 conventional shale 10 5 0 6/2/1905 6/12/1905 6/22/1905 7/12/1905 7/22/1905 8/1/1905 12: 00: 00 12: 00: 00 12: 00 AM AM Howarth 2015
One of our major conclusions in Howarth et al. (2011): pertinent data for shale gas were extremely limited, and poorly documented. Great need for better data on shale gas, conducted by researchers free of industry control and influence.
Poking Holes in a Green Image Tom Zeller April 11, 2011 “The old dogma of natural gas being better than coal in terms of greenhouse gas emissions gets stated over and over without qualification, ” said Robert Howarth, a professor of ecology and environmental biology at Cornell University and the lead author ……… “I don’t think this is the end of the story, ” said Mr. Howarth, who is an opponent of growing gas development in western New York. “I think this is just the beginning of the story, and before governments and the industry push ahead on gas development, at the very least we ought to do a better job of making measurements. ” The findings are certain to stir debate. For much of the last decade, the natural gas industry has carefully cultivated a green reputation, often with the help of environmental groups that embrace the resource as a cleanburning “bridge fuel” to a renewable energy future.
People who Mattered Mark Ruffalo, Anthony Ingraffea, Robert Howarth By Bryan Walsh Wednesday, Dec. 14, 2011 The biggest environmental issue of 2011 — at least in the U. S. — wasn't global warming. It was hydraulic fracturing, and these three men helped represent the determined opposition to what's more commonly known as fracking. Anthony Ingraffea is an engineer at Cornell University who is willing to go anywhere to talk to audiences about the geologic risks of fracking, raising questions about the threats that shale gas drilling could pose to water supplies. Robert Howarth is his colleague at Cornell, an ecologist who produced one of the most controversial scientific studies of the year: a paper arguing that natural gas produced by fracking may actually have a bigger greenhouse gas footprint than coal. That study — strenuously opposed by the gas industry and many of Howarth's fellow scientists — undercut shale gas's major claim as a clean fuel. And while he's best known for his laidback hipster performances in films like The Kids Are All Right, Mark Ruffalo emerged as a tireless, serious activist against fracking — especially in his home state of New York.
People who Mattered Mark Ruffalo, Anthony Ingraffea, Robert Howarth By Bryan Walsh Wednesday, Dec. 14, 2011 Other “People who Mattered” in 2011: Newt Gingrich, Osama bin Laden, Joe Paterno, Adele, Mitt Romney, Muammar Gaddafi, Barack Obama, Bill Mc. Kibben, Herman Cain, Rupert Murdoch, Vladimir Putin, Benjamin Netanyahu…
Proceedings of the National Academy of Sciences of the United States of America
Schneising et al. (2014) – “Remote sensing of fugitive methane emissions from oil and gas production in North American tight geologic formations. ” Earth’s Future 2: 548 -558 United States global
Change in atmospheric methane (polar regions), 1982 - 2013 Torben Christensen (2014) Nature
Upstream methane emissions unconventional gas Howarth et al. (2011) EPA (2013) Petron et al. (2012) Denver-Julesburg Karion et al. (2013) Uinta Allen et al. (2013) US Average Petron et al. (2014) Denver-Julesburg Caulton et al. (2014) SW Marcellus Schneising et al. (2014) Bakken & Eagle Ford Peischl et al. (2015) Haynesville Western Arkoma Fayetteville NE Marcellus 0 5 10 15 20 Methane emissions from unconventional gas operations (upstream only, % of production)
Red = methane Orange = CO 2 Howarth 2015 Energy Emissions & Control Technologies
Total US Greenhouse Gas Emissions from Fossil Fuel Use Total emissions (with best accounting for methane) Total emissions (with EPA accounting) With very optimistic regulation of methane emissions from shale gas Carbon dioxide only Howarth 2015
Dangerous tipping points may be only 15 years into the future. Controlling methane is Essential to the solution! http: //news. discovery. com/earth/alas kas-arctic-tundra-feeling-theheat. html 2. 0 o. C threshold 1. 5 o. C threshold Shindell et al. 2012
Renewable energy is the future, is cost effective and reliable today, and will only become more so Our Energy Plan for New York State Jacobson & Delucchi (2009), Scientific American; and Jacobson et al. (2013, 2014), Energy Policy
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