1. Methane and Global Climate Change
Bob Howarth
Department of Ecology & Evolutionary Biology
EAS 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

5. Carbon Dioxide
Methane

6. The climate system responds much more quickly to methane than to carbon dioxide
1.5 oC threshold
2.0 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
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. 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
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
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
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. Total 570 Fluxes of methane to the atmosphere globally
(Tg C of methane per year)
______________________________________________
Natural sources
geological seeps
biological sources
Anthropogenic sources 350
fossil-fuel emissions
animal agriculture
rice cultivation
landfills and sewage
biomass burning
Total
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
geological seeps
biological sources
Anthropogenic sources 350
fossil-fuel emissions
animal agriculture
rice cultivation
landfills and sewage
biomass burning
Total
Begon et al. 2014

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

20. Total 570 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
geological seeps
biological sources
Anthropogenic sources 350
fossil-fuel emissions
animal agriculture
rice cultivation
landfills and sewage
biomass burning
Total
Begon et al. 2014

21. Controlling methane is CRITICAL to the solution!
Dangerous tipping points may be only 15 to 35 years into the future.
Controlling methane is CRITICAL to the solution!
1.5 oC threshold
2.0 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
(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).
(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
Released underwater- much oxidised

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

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

30. Danger point for methane clathrate melting, based on geologic past
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.
1.5 oC threshold
2.0 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
Diesel oil
Coal
(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
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. Mark Ruffalo, Anthony Ingraffea, Robert Howarth
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. Other “People who Mattered” in 2011:
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:
United States
global

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

51. Upstream methane emissions unconventional gas5 10 15 20
Peischl et al. (2015)
NE Marcellus
Fayetteville
Western Arkoma
Haynesville
Schneising et al. (2014)
Bakken & Eagle Ford
Caulton et al. (2014)
SW Marcellus
Petron et al. (2014)
Denver-Julesburg
Allen et al. (2013)
US Average
Karion et al. (2013)
Uinta
Petron et al. (2012)
EPA (2013)
EPA (2011)
Howarth et al. (2011)
Methane emissions from unconventional gas operations (upstream only, % of production)
Upstream methane emissions unconventional gas

53. Howarth 2015 Energy Emissions & Control Technologies
Red = methane
Orange = CO2
Howarth 2015 Energy Emissions & Control Technologies

54. Total US Greenhouse Gas Emissions from Fossil Fuel Use
Carbon dioxide only
Total emissions
(with best accounting for methane)
With very optimistic regulation of methane emissions from shale gas
(with EPA accounting)
Howarth 2015

55. Controlling methane is Essential to the solution!
Dangerous tipping points may be only 15 years into the future.
Controlling methane is Essential to the solution!
1.5 oC threshold
2.0 oC threshold
Shindell et al. 2012

56. 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