California Wildfires, Climate Change, and Lisa Murkowski Message #12

 Synopsis

Alaska Senator Lisa Murkowski and James Hubbard, USDA Undersecretary for Natural Resources and the Environment, recently produced a session of the Senator’s podcast, talking about the extraordinary wildfire season in the Western US.  These public servants failed to acknowledge man-made climate change as the ultimate cause of the fire intensity.  Increased fire size and intensity were clearly forecast in the IPCC (Intergovernmental Panel on Climate Change) Impacts report in 1990, thirty years ago.  The causes of increased fire intensity were clearly identified in that report: higher temperatures and drought, leading to low soil moisture, dry plants and deadwood, increased fuel loading and increased lightning strikes.  Every contributing factor identified in the 1990 report has been realized and today’s wildfires are larger and more intense as predicted.  To neglect the explanation for that intensification is irresponsible.  Murkowski and Hubbard failed to inform the public, not only about what happened in 2020, but to warn the public of future risks as CO2 emissions and climate change continue unchecked.

Murkowski’s Message #12

In September of 2020, California was wracked by some of the largest and most destructive wildfires in its history.  Senator Lisa Murkowski, in her role as chair of the Senate Committee on Energy and Natural Resources, met with James Hubbard, USDA Undersecretary for Natural Resources and the Environment, to discuss the crisis.  Senator Murkowski posted audio of the twenty-minute interview as #12 in her series of Murkowski’s Messages, available here:  https://vimeo.com/459453081. 

I listened to the entire discussion. There is practically no mention of climate change, although Murkowski and Hubbard danced around the topic, with Murkowski making a passing reference to “the changing climate”.  However, they quickly brushed that idea aside and focused instead on overstocked fuel conditions in the forests.

Undersecretary Hubbard noted the persistence of abnormal fire conditions in the western states, with Hubbard saying, “…it has been developing for a long time, and it’s certainly going to be with us for a long time….We can expect this kind of fire behavior for some time to come.”  Hubbard also noted the significance of high heat and low humidity in intensifying the fires, and stated “This is unusual, but I think we will see more of it.” 

For her part, Murkowski dismissed the idea of seeking causes for the intense fires.  The Senator said that others were asking, “Why are we seeing so much?  What can be done?  Who is responsible, and who is to blame?”, but these were not questions she wanted to pursue.  In my view, this is deeply flawed.  On the contrary, these are exactly the questions we must answer if we want to avoid even worse wildfires in the future.

Incredibly, this talk by the Senator and the Undersecretary avoided all mention of human-caused climate change, which is the most significant factor in causing the disastrous Western wildfires.  Let me be clear – the dry and hot weather conditions of recent years in the West are due to the accumulation of greenhouse gases in the atmosphere, principally CO2 from human use of fossil fuels.  Hot and dry weather cause low soil moisture, dry plants, and more deadwood.  Low soil moisture causes excess fuel in the forest, and causes fires to burn hotter and faster.  As Undersecretary Hubbard acknowledged, these conditions are strikingly different from the past and will persist a long time.  In fact, these conditions will persist as long as elevated CO2 in the atmosphere persists.  Levels of atmospheric CO2 will inevitably increase in coming decades, worsening the wildfire problem in the West.  We are not likely to return to the CO2 levels and climate conditions of the 20^th century for another century or more. 

Forecast of Increased Wildfires, 1990 IPPC Impacts Assessment

For thirty years, we’ve been warned repeatedly that human-caused climate change will result in more destructive wildfires.  Beginning in 1990, each report of the ICPP (Intergovernmental Committee on Climate Change, a UN agency) has warned about the increasing danger of wildfires.  The series of National Climate Assessments produced by the United States have also highlighted the danger. 

The 1990 IPCC Impacts Assessment lays out in explicit detail how and why wildfires are becoming worse, depending on geography.  Temperatures are higher, and some areas are subject to drought; these cause a number of second-order changes that intensify wildfires.  Later IPCC reports provide even more area-specific forecasts.  Here are a few quotes from IPCC 1990 Impact Assessment:

• "Losses from wild-fire will be increasingly extensive" (Policy-Makers Summary, p. 2)
• “Fire damage is expected to increase with the susceptibility of forests.  Even if precipitation remains roughly the same, increased temperatures will lead to increased evapotranspiration and thus drier sites.  Warmer drier sites could have a higher incidence of severe fires, especially where stands are in a state of decline because of climatic changes” (p. 2-25).
• “…blocking high pressure patterns, more lightning strikes and increased fuel loadings are a dangerous combination causing more and larger fires" (p. 2-25).
• “Wildfire frequency and severity is expected to increase throughout most of the unmanaged lands because of the projected increases in available fuel as primary productivity increases and because of the increased amount of dead fuel accumulating as a result of increased mortality” (p. 3-19).
• “In those forested areas where there is a decrease in soil moisture, drying of forest fuels will be enhanced, thereby increasing the amount of available fuel”  (p. 3-20).
• Increased fuel loading resulting from climate change was forecast to cause a three-fold increase in the number of fires greater than 1000 hectares in the Sierra Nevada (p. 3-20). 

Temperature, Precipitation and Fires in California, 2000 – 2020

Dr. Robert Rohde of Berkeley Earth compiled temperature and precipitation data for the California fire season from 1895 to 2020.  The animation of the data can be found on Dr. Rohde’s Twitter page, and is quite striking.  The trend of increasing temperatures and decreasing precipitation across the decades is quite evident in his chart, with 19 of the years from 2000 to 2020 occurring above the midpoint in temperature, and 12 of those 20 years occurring in the hot and dry quadrant of the chart.  The last two decades have also seen the largest deviations from normal conditions of the preceding century. 

Dr. Rohde also posted the ten largest fires and ten most damaging fires in California’s history on the chart, by year.  The year with the farthest excursion from normal temperature and precipitation, 2020, also had the worst fire record.  Other years with bad fire records, 2017 & 2018, were among the years with the farthest excursion from normal.  It’s worth noting that all of the large and destructive fires occurred in the hot and dry quadrant of the chart.

Figure 1.  California temperature and precipitation, 1895 – 2020, with the ten largest fires and ten most damaging fires.  Chart created by Robert Rohde, Berkeley Earth, and used by permission.

Low soil moisture is a consequence of high temperature and low precipitation.  Most of the years since 2000 have been marked by persistent drought conditions in the west.  The USDA published nationwide maps of drought conditions, which have been seasonally persistent in the American West since the year 2000.   National Centers for Environmental Prediction (NCEP), a department of NOAA, publishes maps of soil moisture over the lower 48 states.  Relative soil moisture is shown as a percentile map with respect to historical conditions.  Maps of drought conditions and soil moisture show persistent conditions that predispose the West to high fire activity since the year 2000. 

Figure 2.  Drought conditions, week of September 15, 2020, USDA map.

Figure 3.  Soil Moisture Percentile (relative to history) September, 2020, map from NCEP, NOAA.

Of course, California was not the only place on earth to experience severe fires in recent years.  Dr. Rohde also prepared a similar chart of temperature and precipitation for New South Wales, Australia.  Although Dr. Rohde did not include fire statistics on this chart, the decadal shift in temperature and precipitation is clearly apparent on this chart. 

Figure 4.  New South Wales temperature and precipitation, January – October, 1900 – 2019.   Chart created by Robert Rohde, Berkeley Earth, and used by permission.

In Alaska, Senator Murkowski’s home state, wildfires have also been larger and more damaging.  Lightning initiates most of the wildfires in the state.  It follows that increased thunderstorm activity results in more fires.  The location of the state’s largest recent fires, generally north and east of Fairbanks, corresponds with the highest summer temperatures and increased thunderstorm activity.  This information is documented in communications by Rick Thoman, climatologist with the International Arctic Research Center (IARC), Fairbanks. 

Figure 5.  Alaska Wildfire Acreage, Season Total, 1950 – 2019.  Chart by Rick Thoman, IARC.

Figure 6.  Fairbanks Alaska, Annual Days with Thunder, 1952 – 2020.  Chart by Rick Thoman, IARC.

Conclusion

It’s clear that the scientific forecasts of wildfire intensity in 1990 were correct.  The processes causing more intense wildfires are higher temperatures and lower precipitation, which lead to low soil moisture, dry plants and more deadwood.  Higher temperatures and low precipitation in California and Australia are predictable consequences of human emissions of greenhouse gases, which continue to accumulate in the atmosphere.  The conditions which lead to large, fast-moving and destructive wildfires didn’t “just happen”, and will worsen in coming decades. 

Senator Murkowski and Undersecretary Hubbard failed the public by not discussing the actual causes of the wildfires in their public communications.  Explanations matter, and causes matter.  Senator Murkowski’s questions -- “What can be done?  Who is responsible, and who is to blame?” – are pertinent questions.  Human emissions of CO2 are responsible; consumers of energy are to blame.  And the best thing to do is to reduce emissions of greenhouse gases, significantly and quickly.   

The physical processes of climate change are well-established, proven science.  We’ve known how it works for over 120 years.  We’ve had pretty good estimates for how much temperatures would change, depending on how much CO2 was in the air, for almost as long.  The forecasts of more intense wildfires, made 30 years ago, have been entirely accurate.  At this point, in 2020, it is important for our public leaders to acknowledge man-made climate change as the ultimate cause of intense wildfires, and to give a credible warning that the situation will only get worse as temperatures continue to rise.  Senator Murkowkski and Undersecretary Hubbard have done the public a disservice by neglecting to address the cause of 2020’s extraordinary fire season, and to give a warning for the future.  It’s time for them to address the public truthfully.

References

Murkowski's Message #12    https://vimeo.com/459453081

Arrhenius, 1896, On the Influence of Carbonic Acid in the Air upon the Temperature on the Ground  https://www.rsc.org/images/Arrhenius1896_tcm18-173546.pdf

Arrhenius, 1906, The Probable Cause of Climate Fluctuations http://www.friendsofscience.org/assets/documents/Arrhenius%201906,%20final.pdf

Climate Change, The IPCC Impacts Assessment, 1990  https://www.ipcc.ch/site/assets/uploads/2018/03/ipcc_far_wg_II_full_report.pdf

Forest Fuels   

California Department of Forestry and Fire Protection  https://californiasaf.org/policy/forest-fuels-management/

University of California Cooperative Extension  https://ucanr.edu/sites/fire/Prepare/Treatment/

California chapter of the Society of American Foresters   https://californiasaf.org/policy/forest-fuels-management/

Soil Moisture maps

https://www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/US/US_Soil-Moisture-Monthly.php

https://www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/US/Soilmst/Soilmst.shtml#

Drought Maps

https://droughtmonitor.unl.edu/Maps/MapArchive.aspx

Australia's Climate in 2019  

http://www.bom.gov.au/climate/current/annual/aus/

Australia’s climate in 2019

• Australia's warmest year on record, with the annual national mean temperature 1.52 °C above average
• Both mean annual maximum and minimum temperatures above average for all States and the Northern Territory
• Annual national mean maximum temperature warmest on record (2.09 °C above average)
• Widespread warmth throughout the year; January, February, March, April, July, October, and December all amongst the ten warmest on record for Australian mean temperature for their respective months
• Significant heatwaves in January and in December
• Australia's driest year on record
• Nationally-averaged rainfall 40% below average for the year at 277.6 mm
• Rainfall below average for most of Australia
• Rainfall above average for parts of Queensland's northwest and northern tropics
• Much of Australia affected by drought, which was especially severe in New South Wales and southern Queensland
• Widespread severe fire weather throughout the year; national annual accumulated Forest Fire Danger Index highest since 1950, when national records began

Understanding the Source of Rising Atmospheric CO2

For the last time, increasing atmospheric CO2 is coming from fossil fuels, and not from volcanoes.

The concentration of CO2 in the atmosphere is rising rapidly.  Before widespread burning of coal, circa 1750, atmospheric CO2 was about 280 parts per million (ppm).  By 1955, global CO2 concentration had risen to 314 ppm.  Average global CO2 levels are now about 412 ppm, and are still rising at about 3 ppm per year. 

Industrial processes are able to change the composition of the earth’s atmosphere because there really isn’t very much atmosphere, and there isn’t very much CO2.  The atmosphere thins rapidly with altitude, so that about half of the atmosphere is less than 3 miles above the earth, and breathable atmosphere extends only about 6 miles above the earth.  Further, there isn’t very much CO2 in the atmosphere – about 400 ppm, or 0.04%.  Nevertheless, that small amount of CO2 is very effective at blocking thermal infrared radiation, which is why changing the CO2 concentration of the atmosphere has already had a significant impact on global climate. 

Figure 1.  There isn’t very much atmosphere, and there really isn't very much CO2.  The pie-slice of CO2 in the second figure is exaggerated three-fold for visibility.

A common myth that circulates on social media is that rising CO2 in the atmosphere is coming from volcanoes.   It isn't.  I already wrote one blog post about the origin of atmospheric CO2.  (https://dougrobbins.blogspot.com/2017/06/volcanic-co2-emissions.html). 

This blog post will present additional evidence that rising CO2 is of human origin.  The evidence is:

• Declining oxygen concentration of the atmosphere
• The quantity of missing oxygen
• The location of declining oxygen concentration by hemisphere
• Volumetric data for fossil fuel emissions, deforestation, and volcanism, compared to volumes of CO2 appearing in the atmosphere
• The location of rising CO2 by hemisphere
• Changing carbon isotopic composition of the atmosphere
• The location of the declining carbon isotope measure (del C13) by hemisphere
• The steady rise of atmospheric CO2, whereas volcanic eruptions are intermittent (although slow emissions from non-eruptive events, mid-ocean ridges and rifts also occur). 

Atmospheric CO2 is now also monitored by two orbiting carbon observatories (OCO), which directly measure CO2 concentrations in the atmosphere and connect rising atmospheric CO2 with points of origin.

The myth that volcanoes are responsible for human-caused atmospheric disruption has been propagated since the 1990s.  The book “Merchants of Doubt” provides a history of claims that volcanoes were responsible for destruction of stratospheric ozone, or for acid rain in the US and Canada.  Those claims were thoroughly debunked long ago.  Nevertheless, articles attributing rising CO2 to volcanoes still appear on climate-change denying websites, (e.g. James Edward Kamis’ 2018 post on ClimateChangeDispatch).

Let’s look at the evidence.

Fossil-Fuel Combustion

When fossil fuels are burned, atmospheric oxygen is converted to CO2.  Consequently, the oxygen concentration in the atmosphere falls.  If we quantify oxygen depletion in the atmosphere, we find that it validates the volumes of fossil fuel consumption reported by inventory methods (BP Statistical Review, CDIAC, EIA, etc.).  The volumes of CO2 determined by either method are approximately twice what is necessary to account for the observed rise in atmospheric CO2.  The remaining CO2 is dispersed into CO2 reservoirs in the oceans and biosphere.  A full accounting of the CO2 flows on earth can be found in the Global Carbon Project or Berkeley Earth websites. 

Simply stated, the depletion of atmospheric oxygen quantifies CO2 emissions from fossil fuels.  This volume of CO2 emssions more than accounts for the rise in atmospheric CO2.  There isn’t any room for a significant contribution from volcanoes without somehow getting rid of the CO2 from the combustion of fossil fuels in some as-of-yet unidentified carbon sink (which is unlikely to exist). 

Depletion of Atmospheric Oxygen

The amount of oxygen in the atmosphere is falling (although not enough to cause trouble for breathing).   Atmospheric oxygen is falling because oxygen is consumed by burning fossil fuels.  This would not occur if the source of rising CO2 was from volcanoes (Figure 2).  As seen in the bulk CO2 and Del C13 charts, there is a strong seasonal signal in the concentration of atmospheric oxygen, related to the growing season in each hemisphere.  The amplitude of the seasonal cycle is somewhat stronger in the Northern Hemisphere, due to the preponderance of temperate land-mass and agriculture. 

Figure 2.  The concentration of atmospheric oxygen is falling, due to combustion of fossil fuels.  The Per Meg (del O2/N2) can be roughly converted to ppm by multiplying by 0.2095, the fractional concentration of oxygen in the atmosphere.  A discussion of the Per Meg (del O2/N2) measure can be found on the Scripps Institute CO2 website FAQs.  The loss of 700 ppm of oxygen is a relatively small change because of the greater abundance of oxygen in the atmosphere as compared to CO2.  The percentage of oxygen in the atmosphere is about 20.95%; the percentage of CO2 in the atmosphere is about 0.04%.

Oxygen Depletion by Hemisphere

Falling oxygen concentrations in the Northern Hemisphere lead falling oxygen in the Southern Hemisphere (Figure 3).  This is because 90% of fossil fuels are being burned in the Northern Hemisphere, consuming oxygen in the Northern Hemisphere.  Atmospheric mixing works to equilibrate oxygen concentrations, but continuing combustion of fossil fuels in the Northern Hemisphere keeps oxygen lower than in the Southern Hemisphere.

Figure 3.  Atmospheric oxygen recorded by Scripps Institute network of atmospheric observatories.   The seasonal cycle at each station was filtered with a 12-month rolling average.  The Northern Hemisphere leads the Southern Hemisphere in falling oxygen.

Oxygen – Carbon Stoichiometry

The number of molecules of oxygen disappearing from the atmosphere is a very close match to the number of carbon atoms burned in fossil fuels and deforestation (Figure 4).  There is a quantitative match, showing that for each atom of carbon burned, one molecule of oxygen disappears from the atmosphere, as C + 02 -> CO2.  The depletion of atmospheric oxygen, in stochiometric balance with human carbon combustion, validates the volume of CO2 released into the atmosphere by burning fossil fuels.  

Figure 4.  Moles of carbon burned by fossil fuels and deforestation annually, compared to atmospheric oxygen depletion in moles.   The close match confirms that volumes of CO2 released from fossil fuels and deforestation are responsible for rising atmospheric CO2.  

Moles of oxygen depletion can be calculated by converting “per meg” to ppm (oxygen/atmosphere) and assuming an initial volume of the total atmosphere of 1.81E+20 moles (various Internet sources).  Notes on the calculation are given in the Appendix, following References.

Volumetric Evidence

CO2 emissions from gas, oil, coal, cement, flaring, and deforestation are now about 40 gt per year, and forecast to go higher.   Estimates and measurements of volcanic CO2 emissions are far smaller than known volumes of CO2 from fossil fuels and deforestation (Figure 5).  Estimated volumes of volcanic CO2 include deep carbon emissions, and passive emissions from continental rifts and mid-ocean ridges.  Volcanic CO2 emissions are only about 1.8% of human CO2 emissions by volume.

Figure 5.  Annual Human CO2 Emissions by type and Volcanic CO2 Emissions, with EIA forecast to 2040.  Estimates of CO2 emissions from volcanic activity have been revised significantly higher since the 1990s, as CO2 emissions from deep volcanic source, continental rifts and mid-ocean ridges have been recognized and quantified.  Still, volcanic CO2 emissions are now estimated at about 700 million tonnes, compared to about 40 gigatonnes of CO2 from fossil fuels and deforestation.

Fraction of CO2 Emissions Which Remain in the Atmosphere

Only about 44% of human CO2 emissions remain in the atmosphere; the rest of the CO2 is absorbed by the oceans or taken up by plants.  Human CO2 emissions are more than twice what is necessary to account for rising atmospheric CO2.  Since volcanic CO2 emissions represent only 1.8% of human CO2 emissions, it is impossible for volcanoes to account for the large volume of CO2 now appearing in the atmosphere.  (Figure 6). 

Figure 6.  If all human CO2 emissions remained in the atmosphere, atmospheric CO2 concentrations would rise about twice as fast as what is observed (red line).  Actual average global CO2 is rising at a rate of about 44% of cumulative human CO2 emissions.  If only volcanic CO2 was entering the atmosphere, atmospheric CO2 would rise only negligibly, offset by the removal of carbon by natural processes.

Difference in CO2 between Northern and Southern Hemispheres, and
Comparison to Net CO2 Emissions from the Northern Hemisphere

About 90% of humans live in the northern hemisphere, and 90% of human CO2 emissions originate in the northern hemisphere.  Atmospheric CO2 concentrations in the northern hemisphere are consistently higher than CO2 concentrations in the southern hemisphere.   The amount of the difference is very close to the net CO2 emissions from fossil fuels in the northern hemisphere (Figure 7).  The close correspondence of net Northern Hemisphere CO2 emissions and the difference between Northern and Southern CO2 concentration is partly a coincidence between the mixing rate between the hemispheres and the reporting period for CO2 emissions.  However, the consistent fit is a clear proof that fossil fuel emissions in the Northern Hemisphere are principally responsible for rising CO2.  The largest volcanic eruptions of the past 60 years have been in the Southern Hemisphere, but these have made no impact on the record of atmospheric CO2.

Figure 7.  Northern and Southern Hemisphere CO2 concentrations, and net fossil-fuel emissions from the Northern Hemisphere.  Major volcanic eruptions, such as Mt. Pinatubo and Mt. Hunter in the Southern Hemisphere in 1991, are not observed as a difference in CO2 observations between the hemispheres. 

Carbon Isotope Ratios in Atmospheric CO2

Natural carbon mostly occurs in two isotopes: C12 and C13.  Plants and all fossil fuels (which derive from plants) are enriched in C12 by biological processes, giving fossil fuel emissions and deforestation a “lighter” isotopic signature (more C12) than the atmosphere.  The measure of carbon isotopic ratios is d C13/C12, typically called “del C13”.  Samples which are relatively enriched in “light” C12 have a negative del C13, while samples that are enriched in “heavy” C13 have a positive del C13.  A technical definition of del C13 is given at the bottom of the article, below the references.

In the 1950s, the atmosphere had a del C13 value of about -7.5, reflecting a higher concentration of C12 than the oceans, which has a del C13 of about zero.  As mentioned above, fossil fuels are enriched in C12 with typical values in the range of -20 to -30.   Biogenic natural gas has been fractionated twice, and may have del C13 values ranging from -40 to -70.  Volcanic emissions have a heavier isotopic signature than the atmosphere, with a del C13 value of about -1 to -4.  

The isotopic composition of the atmosphere is steadily becoming lighter as CO2 concentrations rise.  This is only possible if the additional CO2 is from a source isotopically lighter than the atmosphere, not heavier.  Thus, fossil fuels, and not volcanoes or the oceans, are the source of rising CO2 (Figure 8).

Figure 8.  The Del C13 Carbon Isotopic Record of Atmospheric CO2, recorded by the Scripps Institute.  The record is marked by a strong seasonal cycle in the Northern Hemisphere.  During the Northern Hemisphere growing season C12 is preferentially taken out of the atmosphere by plants, and released back to the atmosphere in winter causing the seasonal cycle in the air.  Overall, the Del C13 index has fallen from -7.5 to -8.5 since 1977, showing an increasing prevalence of light C12 (characteristic of fossil fuels and deforestation) in the atmosphere.

After filtering the seasonal cycle, we see that the Northern Hemisphere leads the Southern Hemisphere in falling Del C13 isotope ratio (Figure 10).  This is because 90% of fossil fuel emissions occur in the Northern Hemisphere. The remaining wavy signal in the Del C13 record correlates to El Nino cycles (Figure 9), with a rapidly falling Del C13 ratio during El Nino events, and a slightly rising Del C13 ratio during La Nina events.  It is unclear whether the El Nino signal in the data is due to fractionation between atmosphere and ocean, changes in the uptake of carbon in the ocean, or related climate events. 

Figure 9.   The Del C13 carbon isotope record in atmospheric CO2, from Scripps Institute atmospheric observatories; the seasonal cycle was filtered with a 12-month rolling average.  Broadly, the Northern Hemisphere leads the Southern Hemisphere in falling Del C13, because 90% of CO2 emissions from fossil fuels occur in the Northern Hemisphere.  The residual long-wavelength signal relates to the El Nino/La Nina cycle. [See an earlier post:
https://dougrobbins.blogspot.com/2013/11/carbon-isotopes-in-atmosphere-part-ii.html ]

Rate of Increase in Global Atmospheric CO2

Atmospheric CO2 is steadily rising around the globe.  Volcanic eruptions are intermittent; the largest eruption (Mt. Pinatubo) and the third-largest eruption (Mt. Hudson) of the past century both occurred in 1991, but there is no perceptible change in the rate of rising atmospheric CO2 (Figure 10).  Likewise, other large volcanic eruptions produced no perceptible impact over the period of detailed CO2 observations [Mount Agung (1963), Mt. St. Helens (1980), El Chichon (1982). Puyehue-Cordón Caulle (2011)].  Slow, *quiet*, emissions of CO2 also occur from non-eruptive events, mid-ocean ridges and onshore rifts, but these have been well quantified over the past 20 years, and do not contribute significant volumes of CO2 to the atmosphere.

Figure 10. Global atmospheric CO2.   This is my version of the Keeling Curve.  Data is from the Scripps Institute network of atmospheric observatories.  Cool colors indicate stations in the Northern Hemisphere. Warm colors show stations in the Southern Hemisphere. Atmospheric CO2 falls in the Northern Hemisphere summer, as carbon is taken up by plants, and rises in winter as the plants decay.  There is a strong seasonal cycle dominated by the Northern Hemisphere due to predominant location of temperate landmass and agriculture in the Northern Hemisphere.  Apart from the seasonal cycle, CO2 has risen steadily from about 314 ppm in 1955 to about 412 ppm today.

Orbiting Carbon Observatories and NASA CO2 Modeling

Two new NASA satellites, OCO2 & OCO3, now provide worldwide continuous CO2 monitoring.  Data gathered by these satellites will provide a detailed identification of the specific sources of CO2 across the entire globe. 

https://www.youtube.com/watch?v=TrQzbXc6LVE

NASA also prepared a supercomputer simulation of atmospheric CO2, based on ground-based and aerial CO2 observations.  A video of the simulation can be seen on YouTube:

https://www.youtube.com/watch?time_continue=33&v=x1SgmFa0r04&feature=emb_logo

The simulation highlights major CO2 sources, in the eastern US, eastern China, industrial centers of central & eastern Europe, oilfields of western Siberia, and wildfires in the Amazon rainforests (Figures 11A and 11B).

Figures 11A and 11B.  Atmospheric CO2 Concentrations from NASA supercomputer simulations for the year 2006.  The location of CO2 sources is apparent from cities, industrial centers, and wildfires.

Conclusion

Rising CO2 concentrations are unquestionably from human sources, as a result of combustion of fossil fuels and deforestation.  There is volumetric, temporal, isotopic, geographic, stoichiometric evidence supporting human sources of rising atmospheric CO2.  There is no evidence that volcanoes make a significant contribution to rising CO2.

References:

Previous Posts on Volcanic and Atmospheric CO2

https://dougrobbins.blogspot.com/2017/06/volcanic-co2-emissions.html

https://dougrobbins.blogspot.com/2016/08/the-keeling-curve-and-global-co2.html

https://dougrobbins.blogspot.com/2013/08/forecast-of-future-carbon-dioxide.html

https://dougrobbins.blogspot.com/2013/05/the-keeling-curve-seasonal-co2-cycles.html

https://dougrobbins.blogspot.com/2012/04/modeling-global-co2-cycles.html

https://dougrobbins.blogspot.com/2012/03/long-term-trends-in-atmospheric-co2.html

https://dougrobbins.blogspot.com/2012/03/seasonal-carbon-isotope-cycles.html

https://dougrobbins.blogspot.com/2012/03/keeling-curve-and-seasonal-carbon.html

Posts on Twitter on Volcanic CO2

https://twitter.com/dougrbbns/status/1128751236012838912

https://twitter.com/dougrbbns/status/1106691152906842117

External References:

Scripps Institute CO2 Home

https://scrippsco2.ucsd.edu/

Scripps Institute O2 Program

http://scrippso2.ucsd.edu/

Boden, et al, 2013, Global and National Fossil-fuel CO2 Emissions, in Global Carbon Atlas

http://www.globalcarbonatlas.org/en/content/fossil-fuel-emissions

http://www.globalcarbonatlas.org/docs/Public_Presentation_of_the_GCA_Paris_EN.pdf

http://www.globalcarbonproject.org/

Burton et al, 2013,  Deep Carbon Emissions from Volcanoes

http://www.minsocam.org/msa/rim/RiMG075/RiMG075_Ch11.pdf

Discussion of CO2 flux from subaerial volcanic eruptions on page 332.

Total CO2 flux from volcanic sources:  637 mT per year, p. 341, table 6.

The eruption of Mt. Pinatubo in 1991 was the largest volcanic eruption since 1912.   That eruption produced ~50 Mt of CO2 (Gerlach et al. 2011).  Individual eruptions are dwarfed by the time-averaged continuous CO2 emissions from global volcanism.  The eruption of Mt. Pinatubo was equivalent to only 5 weeks of global subaerial volcanic emissions. 

The average volume of eruptive CO2 emissions over the past 300 years was only 0.1 cubic kilometers, which suggests an annual rate of about 1 million tonnes of CO2 annually (Crisp, 1984, cited in Burton).

CO2 consumption from continental silicate weathering was 515 Mt/yr, (Gaillardet et al., 1999, cited in Burton).

Metamorphism accounts for the release of about 300 million tonnes of CO2 annually.  (Mörner and Etiope, 2002, Carbon degassing from the lithosphere. Global Planet Change 33:185-203, cited in Burton). 

Lee et al, 2016, Massive and prolonged deep carbon emissions associated with continental rifting,  Nature Geoscience Letters, Jan.18, 2016. 

http://csi.unm.edu/sites/default/files/public/2016_Lee_etal_ngeo.pdf

Paper accounts for additional CO2 emissions from East African Rift, potentially bringing natural world CO2 emissions to 708 mT, an increase of 11% from previous estimates.

Houghton, R.A. 2008. Carbon Flux to the Atmosphere from Land-Use Changes: 1850-2005. In TRENDS: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A.

http://cdiac.ornl.gov/trends/landuse/houghton/houghton.html

Marland, G., T.A. Boden, and R.J. Andres. 2008. Global, Regional, and National Fossil Fuel CO2 Emissions. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A.

http://cdiac.ornl.gov/trends/emis/overview

Erik Klemetti, 2015, Volcanic versus Anthropogenic Carbon Dioxide: An Addendum, WIRED website.

https://www.wired.com/2015/04/volcanic-versus-anthropogenic-carbon-dioxide-addendum/

Pre-industrial atmospheric del C13 was about -6.5, and declined following industrialization, in correlation with rising atmospheric CO2.

Individual Volcanic Eruptions

Judy Fierstein, USGS, in Forbes, Ethan Siegel, "How Much CO2 Does a Single Volcano Emit?"

https://www.forbes.com/sites/startswithabang/2017/06/06/how-much-co2-does-a-single-volcano-emit/

Representative del C13 values from volcanism:

https://www.researchgate.net/publication/320194432_Isotopically_delta_C-13_and_delta_O-18_heavy_volcanic_plumes_from_Central_Andean_volcanoes_a_field_study

Del C13 :  -3.2

https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2016GL068499

Del C13: -4.9 to -6.3

https://www.researchgate.net/publication/225535635_First_13C12C_isotopic_characterisation_of_volcanic_plume_CO2

Del C13: Currently  -0.9 to -1.4; 1970s and 1980s ~ -4

http://csi.unm.edu/sites/default/files/public/2016_Lee_etal_ngeo.pdf

Del C13: -6 to -10.  N.B.: These are samples of soil gases in a rift zone with known petroleum generation, and may be contaminated by thermogenic or biogenic CO2 deriving from petroleum sources.  

Faure, 1984, Principles of Isotope Geochemistry
Del C13: -2 to -6. 

Volcanoes and CO2

http://www.volcanocafe.org/volcanoes-and-co2/

http://www.volcanocafe.org/volcanoes-and-co2-continued/

A good discussion of former and current estimates of CO2 emissions from volcanoes and fossil fuels.  Also, a good recap of errors made by certain commentators in creating and propagating the volcanic CO2 myth. 

Naomi Oreskes and Erik Conway, 2010, Merchants of Doubt.

A deeply researched book about right-wing scientists, funded by industry, working outside of their fields of expertise, tried to throw doubt on science that might result in regulations in the interest of public health or environmental protection.  The scientists involved were generally retired, had worked in military science and were given compensation or recognition in return for their efforts.  Among the false narratives they created was the idea that volcanoes were responsible for chlorine damage to stratospheric ozone, and that volcanoes were responsible for acid rain in the US and Canada.  Neither idea is correct.  The idea of blaming volcanoes for man-made atmospheric disruption has now been extended to CO2 and climate change.

Which emits more carbon dioxide: volcanoes or human activities?  Climate.gov.

https://www.climate.gov/news-features/climate-qa/which-emits-more-carbon-dioxide-volcanoes-or-human-activities

The following are examples of deliberately misleading media articles about atmospheric CO2.

Volcano eruption WARNING: Intense volcanic CO2 activity 'drives GLOBAL EXTINCTION'

https://www.express.co.uk/news/science/973192/Volcano-eruption-warning-carbon-dioxide-CO2-extinction-climate-change

Article omits mention of fossil fuels entirely.

J.E. Kamis, 2018, Discovery Of Massive Volcanic CO2 Emissions Puts Damper On Global Warming Theory

https://climatechangedispatch.com/massive-volcano-emissions-warming/

This article contains false claims.  Notably, the article claims that:

“Natural volcanic and man-made CO2 emissions have the exact same and very distinctive carbon isotopic fingerprint.  It is therefore scientifically impossible to distinguish the difference between volcanic CO2 and human-induced CO2 from the burning of fossil fuels (see here).”

The reference provided (https://skepticalscience.com/anthrocarbon-brief.html) directly contradicts the claim!  “In fact the global C13/C12 ratio has declined, which is very strong evidence the source of the CO2 increase has was C12 enriched, ie, derived from photosynthesis.  Therefore it is very strong evidence that it comes from the biosphere or fossil fuels, rather than from volcanoes or oceanic outgassing.”

Appendix

Stoichiometry Calculations
Annual fossil fuel emissions are reported in tonnes of CO2 by CDIAC, the BP Annual Statistical Review of World Energy, and the EIA.  One tonnes of CO2 (1000 kg) contains 22,722 moles of CO2. 

Calculation Notes for atmosphere stoichiometry.  The Scripps pages on units and FAQs are helpful in understanding the use of the “per meg” unit, and conversion to ppm. 

http://scrippso2.ucsd.edu/units-and-terms.html

http://scrippso2.ucsd.edu/faq.html

“Per meg” units of oxygen reported by Scripps can be converted to ppm (oxygen/atmosphere) over small ranges by multiplying by 20.95%, the current oxygen fraction in air.  Parts per million (ppm) of oxygen can then be converted to moles by multiplying by the number of moles in the atmosphere (1.81E+20), from various Internet sources.  https://www.theweatherprediction.com/habyhints3/976/

A Few Words about CO₂ Carbon Isotopes

There are two stable isotopes of carbon, C13 and C12.  C12 is the more abundant isotope; the natural ratio of C12 to C13 is about 99 to 1.  The standard measure of carbon isotopes compares the C12/C13 isotope ratio of the sample in question to the C13/C12 ratio of a standard limestone, according to the expression:

d C13/C12 = ((C13/C12 sample/C13/C12 standard) – 1)*1000.

This expression, commonly termed “del 13”, amplifies small but meaningful differences in the isotopes, which are diagnostic of certain processes and occurrences of carbon.  The standard is a uniform Cretaceous limestone with a d 13 value defined as zero.   Positive values indicate a heavier composition, i.e., a greater concentration of C13 than the standard.  Negative values indicate a lighter composition, i.e., a smaller concentration of C13 than the standard.

Plants fractionate carbon, favoring the lighter isotope C12.  Anything derived from plants, including oil, gas, and coal (and algae, animals and people) carries a light (negative) d C13/C12 signature.  Limestone carries a d C13/C12 ratio near zero.  The atmosphere, in 1977, had a d C13/C12 ratio of about -7.5; it is currently about -8.3, reflecting the influence of fossil fuels.  Oceans have a slightly positive d C13/C12 ratio of dissolved inorganic carbon, although Northern Hemisphere waters show a negative ratio due to the greater use of fossil fuels in the Northern Hemisphere.  Fossil fuel CO₂ emissions and CO₂ emissions from deforestation carry a very light d C13/C12, often in the range of -25 to -28 (although biogenic natural gas, which is fractionated twice, can have del 13 value in the range of -40 to -70).  The distinctive isotopic signature of CO₂ from fossil fuels and deforestation is useful in tracking the movement of carbon through the atmosphere and oceans.  

Key References for Understanding Climate Change

Here are key references for understanding the cause and evidence for global warming and climate change. Also included are references for some of the consequences with a focus on Alaska.   Some of the references link to primary data (such as atmospheric data at Scripps); some assembly may be required.

CO2 Emissions

Boden, Marland & Andres, Global and National Fossil Fuel CO2, 2017

https://cdiac.ess-dive.lbl.gov/trends/emis/overview.html

BP Statistical Review of World Energy (annual fossil fuel CO2 emissions, by nation & type)

https://www.bp.com/en/global/corporate/energy-economics/statistical-review-of-world-energy.html

U.S. Energy Information Agency, Data Tables, U.S. Energy Information Agency, Office of Energy Analysis, U.S. Department of Energy, Washington D.C. data tables, 2014

http://www.eia.gov/oiaf/aeo/tablebrowser/

Houghton 2008 (CO2 emissions from land use changes)

https://cdiac.ess-dive.lbl.gov/trends/landuse/houghton/houghton.html

Burton, 2013 (volcanic CO2 emissions)

https://pdfs.semanticscholar.org/4e58/5f447a80c2965cb72c56945e4e9b2306833f.pdf

Lee 2016 (volcanic CO2 emissions)

https://www.researchgate.net/publication/290996133_Massive_and_prolonged_deep_carbon_emissions_associated_with_continental_rifting

EIA World CO2 Emissions Forecast to 2050, International Energy Outlook 2017

Forecast CO2 Emissions by Region

https://www.eia.gov/outlooks/aeo/data/browser/#/?id=10-IEO2017&sourcekey=0

ForecastCO2 Emissions by Fuel Type – select appropriate table.

https://www.eia.gov/outlooks/aeo/data/browser/

Atmospheric CO2

Global CO2 and del C13 isotopes. http://scrippso2.ucsd.edu/cosub2sub-data

Global O2.   http://scrippso2.ucsd.edu/  

Formerly available at CDIAC. https://cdiac.ess-dive.lbl.gov/

Heat Retention by Greenhouse Gases

Tyndall, 1861, 1872, cited in Arrhenius, 1906.

Arrhenius, 1896, On the Influence of Carbonic Acid in the Air upon the Temperature on the Ground

Arrhenius, 1906, The Probable Cause of Climate Fluctuations http://www.friendsofscience.org/assets/documents/Arrhenius%201906,%20final.pdf

NOAA Greenhouse Gas Index.  Page includes formulas for predictive calculation of radiative forcing as function of concentration, and a table for historical annual radiative forcing for major greenhouse gases.

https://www.esrl.noaa.gov/gmd/aggi/aggi.html

IPPC 5th Assessment Report, Anthropogenic Effective Radiative Forcing history, pp 1404 – 1409.

Table includes historical radiative forcing for greenhouse gases, and negative radiative forcing for cooling anthropogenic emissions. 

https://www.ipcc.ch/report/ar5/wg1/

Trenberth, et al, 2009, Earth’s Global Energy Budget. 

http://www.cgd.ucar.edu/staff/trenbert/trenberth.papers/BAMSmarTrenberth.pdf

Ramaswamy, et al 2001, Radiative Forcing of Climate Change.

https://www.ipcc.ch/site/assets/uploads/2018/03/TAR-06.pdf

Ocean Heat Content

https://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/

https://www.climate.gov/news-features/understanding-climate/climate-change-ocean-heat-content

https://cpo.noaa.gov/warmingworld/sea_surface_temperature.html

http://www.argo.ucsd.edu/

https://www.oceanscientists.org/index.php/topics/ocean-warming

Melting Ice

National Snow and Ice Data Center

https://nsidc.org/noaa

NASA Global Ice Viewer

https://climate.nasa.gov/interactives/global-ice-viewer/#/

Global Cryosphere Watch

https://globalcryospherewatch.org/

Antarctic and Greenland

Gravity measure of Antarctic and Greenland Ice Loss

https://climate.nasa.gov/vital-signs/ice-sheets/

IMBIE: Ice Sheet Mass Balance Inter-Comparison Exercise

Antarctic and Greenland Ice-loss data preceding NASA GRACE mission.

http://imbie.org/

NASA Ice-Bridge Project

https://www.nasa.gov/mission_pages/icebridge/index.html

Arctic Sea Ice

Polar Science Center

http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/

Chart with relative volume loss (km3) 1980 – 2018.

http://nsidc.org/soac/sea-ice-age-year.html#seaiceagesequential

Sequential maps of Arctic sea ice extent and thickness.

https://www.ncdc.noaa.gov/snow-and-ice/extent/sea-ice/N/1

Sea Ice Data Portal

https://sites.google.com/site/arcticseaicegraphs/

NOAA Arctic Report Card

https://arctic.noaa.gov/Report-Card/Report-Card-2018/ArtMID/7878/ArticleID/780/SeanbspIce

Continental Glaciers

World Glacier Monitoring Service

https://wgms.ch/

WGMS Global Glacier Change Bulletin 2013

https://wgms.ch/downloads/WGMS_GGCB_01.pdf

Zemp et al, 2019, Global glacier mass changes and their contributions to sea-level rise from 1961 to 2016.

https://www.nature.com/articles/s41586-019-1071-0

Permafrost
Pacific Marine Environment Laboratory, NOAA

https://www.pmel.noaa.gov/arctic-zone/detect/land-permafrost.shtml

UAF Geophysical Institute

https://www.gi.alaska.edu/research/snow-ice-and-permafrost

Jorgenson, 2006, Abrupt Increase in Permafrost Degradation in Arctic Alaska

https://www.researchgate.net/publication/228973531_Abrupt_increase_in_permafrost_degradation_in_Arctic_Alaska

USGS, Alaska’s Thawing Permafrost

https://landsat.gsfc.nasa.gov/pdf_archive/cape_halkett_4web.pdf

Warming Surface Temperature

https://data.giss.nasa.gov/gistemp/

https://climate.nasa.gov/vital-signs/global-temperature/

https://www.esrl.noaa.gov/psd/data/gridded/data.noaaglobaltemp.html

https://www.ncdc.noaa.gov/data-access/marineocean-data/noaa-global-surface-temperature-noaaglobaltemp

General Climate Change

Climate Dashboard, Climate.gov

https://www.climate.gov/maps-data#global-climate-dashboard

IPCC Fifth Climate Assessment, 2013

https://www.ipcc.ch/report/ar5/wg1/

IPCC Fifth Climate Assessment 2013, Executive Summary, 2013

https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_SPM_FINAL.pdf

Fourth National Climate Assessment, Vol. I and II, 2014

https://www.globalchange.gov/nca4

https://www.globalchange.gov/climate-change

Key findings of the 4th National Climate assessment, organized by topic and by region. https://nca2014.globalchange.gov/highlights#section-5683

NASA Climate Change

https://climate.nasa.gov/

JPL Satellite Data & Climate Models, Earth’s Energy Balance, Oceans & Ice, Carbon & Water

https://climatesciences.jpl.nasa.gov/

NOAA Climate Change

https://www.noaa.gov/climate

https://www.noaa.gov/education/resource-collections/climate-education-resources/climate-change-impacts

https://www.noaa.gov/categories/climate-change

National Climate Data Center/NOAA

https://www.ncdc.noaa.gov/monitoring-references/faq/indicators.php

NOAA Sea Level Rise Viewer

https://coast.noaa.gov/slr/

USGS

https://www.usgs.gov/faqs/what-are-some-signs-climate-change-1?qt-news_science_products=0#qt-news_science_products

https://www.sciencemag.org/news/2019/07/trump-officials-deleting-mentions-climate-change-us-geological-survey-press-releases

European Space Agency Climate Work

https://www.esa.int/Our_Activities/Observing_the_Earth/Space_for_our_climate/ESA_s_Climate_Change_Initiative/(print)

http://cci.esa.int/

World Meteorological Organization, Global Climate Observing System

https://public.wmo.int/en/programmes/global-climate-observing-system

Sea Level

Lambeck et al, 2014, Sea level and global ice volumes from the Last Glacial Maximum to the Holocene

https://www.pnas.org/content/111/43/15296

R. Rohde, K. Fleming, Post-Glacial Sea Level

https://twitter.com/RARohde/status/1107919079699087360

NASA Sea Level

https://climate.nasa.gov/vital-signs/sea-level/

Zemp et al, 2019, Global glacier mass changes and their contributions to sea-level rise from 1961 to 2016.

https://www.nature.com/articles/s41586-019-1071-0

University of South Florida Satellite Oceanography Laboratory

http://xena.marine.usf.edu/~chambers/SatLab/Home.html

Sea-Level Rise for the Coasts of California, Oregon, and Washington

https://www.nap.edu/read/13389/chapter/4

https://www.nap.edu/read/13389/chapter/5

Chambers et al, 2016, Evaluation of the Global Mean Sea Level Budget

between 1993 and 2014

http://cerfacs.fr/wp-content/uploads/2016/10/GLOBC-Article-Chambers_etal_2016-1.pdf

French Space Agency, Satellite Altimetry Data website

https://www.aviso.altimetry.fr/en/data/products/ocean-indicators-products/mean-sea-level/msl-science-issues.html

NASA, New study finds sea level rise accelerating

https://climate.nasa.gov/news/2680/new-study-finds-sea-level-rise-accelerating/

Alaska and Arctic Climate Change

UAF Research

https://www.uaf.edu/research/

UAF International Arctic Research Center

https://uaf-iarc.org/

Alaska Oceans Observing System

http://www.aoos.org/

Arctic Research Consortium of the United States

https://www.arcus.org/

Rick Thoman, at 2019 Weather and Climate Summit, (time marker 1:58 to 3:12)

https://www.youtube.com/watch?v=GHxQ2E7yYs8&feature=youtu.be

Rick Thoman, A Century of Alaska Weather and Climate, Science for Alaska Lecture Series

https://www.youtube.com/watch?v=Yk8gCCzPbNg

Climatologists on Twitter:

Rick Thoman, IARC, https://twitter.com/AlaskaWx

Brian Brettschneider, UAF, https://twitter.com/Climatologist49

Zach Labe, UC Irvine, Cornell, https://twitter.com/ZLabe

Robert Rohde, Berkeley Earth, https://twitter.com/RARohde

Ocean and Food-Chain Stress

Seabird Die-off

https://www.nps.gov/subjects/aknatureandscience/commonmurrewreck.htm

https://www.adn.com/alaska-news/wildlife/2017/09/11/hundreds-of-dead-birds-found-on-bering-sea-shores/

https://www.adn.com/alaska-news/wildlife/2018/08/10/alaska-seabird-die-off-continues-for-another-summer/

Whale Deaths

https://www.adn.com/alaska-news/wildlife/2019/05/31/spike-in-gray-whale-deaths-triggers-federal-investigation-into-unusual-mortality-event/

Declining Humpback Migration and Calving

https://www.pacificwhale.org/research/citizen-science/great-whale-count/

Seal Die-off

https://www.adn.com/alaska-news/wildlife/2019/06/12/noaa-investigating-unusually-large-numbers-of-dead-ice-seals-along-alaskas-coast/

Krill and Mussel Die-off

https://www.adn.com/alaska-news/rural-alaska/2019/07/07/add-krill-and-mussels-to-the-list-of-unusual-marine-deaths-in-northwest-alaska/

Pink Salmon Die-off

https://www.adn.com/alaska-news/rural-alaska/2019/07/12/warmer-waters-investigated-as-cause-of-pink-salmon-die-off-in-norton-sound-region/