Methane and Global Climate Change

1. Methane and Global Climate Change Bob Howarth Department of Ecology & Evolutionary Biology EAS 1540 -- Oceanography November 6, 2015

4. Methane is an important greenhouse gases… it fills in “holes” in the infra red spectrum not filled by water vapor and CO2 http://oceanworld.tamu.edu/resources/oceanography-book/radiationbalance.htm

5. Carbon Dioxide Methane

6. The climate system responds much more quickly to methane than to carbon dioxide http://news.discovery.com/earth/alaskas-arctic-tundra-feeling-the-heat.html 2.0 oC threshold 1.5 oC threshold Shindell et al. 2012

7. The two faces of carbon: Carbon dioxide (CO2) – climate system responds slowly to changes, but current emissions will influence climate for 1,000s of years; human activity has increased CO2 by 45% Methane (CH4) – much faster response by climate system, but methane stays in atmosphere for only 12 years; human activity has increased CH4 by 170% > 200 times as much CO2 in atmosphere, but CH4 is > 100 times more powerful as a greenhouse gas

8. 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

9. Begon et al. 2014, adapted from IPCC 2007

10. 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

11. Of the natural flux of 220 Tg C per year: Seeps from geologic formations = ~ 50 Biological sources (decomposition) = ~ 170

12. 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

13. 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 oxygen-free sediments, and cover far more of the Earth than do lakes and freshwater wetlands?

14. 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 CO2 + sulfides Organic C CH4 + CO2

15. So oceans are not important methane source globally (BUT, may become so due to melting of methane clathrates)

16. 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.

17. Fluxes of methane to the atmosphere globally (Tg C of methane per year) ______________________________________________ Natural sources 220 • geological seeps 53 • biological sources 167 Anthropogenic sources 350 • fossil-fuel emissions 115 • animal agriculture 90 • rice cultivation 60 • landfills and sewage 55 • biomass burning 30 Total 570 Begon et al. 2014

18. Released from geological formations, some from mining coal but much more from developing oil and natural gas. Fluxes of methane to the atmosphere globally (Tg C of methane per year) ______________________________________________ Natural sources 220 • geological seeps 53 • biological sources 167 Anthropogenic sources 350 • fossil-fuel emissions 115 • animal agriculture 90 • rice cultivation 60 • landfills and sewage 55 • biomass burning 30 Total 570 Begon et al. 2014

19. Fluxes of methane to the atmosphere globally (Tg C of methane per year) ______________________________________________ Natural sources 220 • geological seeps 53 • biological sources 167 Anthropogenic sources 350 • fossil-fuel emissions 115 • animal agriculture 90 • rice cultivation 60 • landfills and sewage 55 • biomass burning 30 Total 570 Produced from decomposition of organic matter in oxygen-free environments (cow guts, manure piles, flooded rice paddies), etc. Begon et al. 2014

20. A lot of uncertainty in individual source estimates. But sum of geological seeps and fossil-fuel emissions is well known, from the amount of radioactive 14C in atmospheric methane (30%) Fluxes of methane to the atmosphere globally (Tg C of methane per year) ______________________________________________ Natural sources 220 • geological seeps 53 • biological sources 167 Anthropogenic sources 350 • fossil-fuel emissions 115 • animal agriculture 90 • rice cultivation 60 • landfills and sewage 55 • biomass burning 30 Total 570 Begon et al. 2014

21. 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/alaskas-arctic-tundra-feeling-the-heat.html 2.0 oC threshold 1.5 oC threshold Shindell et al. 2012

22. Stable to a point, then very rapid and radical change in the Earth’s climate system Leiserowitz et al. (2011)

23. High potential for massive emissions of ancient CH4 due to thawing permafrost and release of “frozen” methane (methane hydrates and clathrates). CH4 CH4 CH4 Zimov et al. (2006) Science 23

24. 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)

25. 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)

26. Hansen et al. (2007) suggested critical threshold in climate system, to avoid melting of natural methane clathrates, at ~ 1.8o C.

27. 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 CO2 within the water column?- HUGE pool (10,000 times current total annual global flux) 2-9 Tg CH4 yr-1 http://www.globalcarbonproject.org/news/MethaneHydrates.html

28. 2.0 oC threshold 1.5 oC threshold Danger point for methane clathrate melting, based on geologic past Shindell et al. 2012

29. Will be reached in ~ 25 years, unless the world starts immediately to control methane and soot pollution 2.0 oC threshold 1.5 oC threshold Danger point for methane clathrate melting, based on geologic past Shindell et al. 2012

30. 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 oC threshold 1.5 oC threshold Danger point for methane clathrate melting, based on geologic past Shindell et al. 2012

31. 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.

32. US National Methane Emissions for 2009 (Modified from Howarth et al. 2012, based on EPA 2011)

33. Begon et al. 2014, adapted from UNESCO 2012 and UNEP 2014

34. World Health Organization (2012): Obesity and over-consumption of meat now larger public health issues globally than are starvation and malnutrition.

35. …. Instead of this This …..

36. Fossil fuels? We continue on the wrong track…. Begon et al. 2014, adapted from Hughes 2012

37. Is natural gas a “bridge fuel?” For just the release of carbon dioxide during combustion….. g C of CO2 MJ-1 of energy Natural gas 15 Diesel oil 20 Coal 25 (Hayhoe et al. 2002)

38. 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.

39. 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

41. 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 conventional shale Howarth 2015

42. Publication of first peer-reviewed paper on any aspect of environmental risk of shale gas (Howarth, Santoro, & Ingraffea 2011) conventional shale Howarth 2015

44. 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.

45. 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 clean-burning “bridge fuel” to a renewable energy future.

46. 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.

47. 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 McKibben, Herman Cain, Rupert Murdoch, Vladimir Putin, Benjamin Netanyahu…

48. Proceedings of the National Academy of Sciences of the United States of America

49. 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

50. Change in atmospheric methane (polar regions), 1982 - 2013 Torben Christensen (2014) Nature