Category: Featured

Revisiting the Amazon after the fire season

Earlier this year (“Whose Amazon” September 2, 2019), I wrote about the fires in the Amazon at the time when the French and Brazilian heads of state were exchanging personal insults.  G7 leaders attacked the Brazilian president for torching the “lungs of the planet,” and Brazil’s President Bolsonaro told the Europeans to mind their own business, indicating Brazilian natural resources were Brazil’s to exploit, despite protestations from overseas “colonialists.” In a speech to the United Nations, he rejected notions that the “Amazon is a world heritage” (Washington Post, September 24, 2019).  

He has repeatedly asserted that indigenous reserves should “no longer be demarcated” and contain valuable mineral, timber and agricultural resources which need to be developed. (  These reserves represent both human and ecological havens; they are home to the remaining 850,000 indigenous peoples of Brazil and contain largely undisturbed and intact forest ecosystems. They also contain nearly 13% of Brazil’s total land area, occupied by handfuls of indigenous peoples (<1% of Brazil’s population), with weak governance and policing—almost overwhelmingly attractive targets for development. 

When I wrote the earlier blog, fire activity in Brazil as a whole and the Amazon was not remarkably elevated over previous years, relative to the historical record dating to 2001.  This assessment is still true through the year to date, but with some important revisions. 

Overall fire alerts for 2019 (far right) are higher than 2018, but not higher than many previous years.
Source:  Source:
Fire alerts for 2019 are indicated by the curve immediately above 2006
  • Fire activity within the Amazonas region appears to be nearly as high as 2015, making 2019 the third highest fire season from 2001 onwards.  The combined MODIS and VIIRS data (starting in 2012)  posted on the website through October 7, 2019, show that fire detections are not as high as those detected in 2012, nor as high as 2017 (see the Modis alert figure above).  

Absent aggressive pressure from countries that import Brazilian beef and soy (two of the commodities linked to deforestation and land conversion), coupled with widespread opposition to continued development within Brazil, land transformation across many regions of Brazil, particularly the remaining, largely intact areas located in demarcated indigenous reserves, will continue and accelerate.  It is very likely the fundamental character of much of Brazil’s vast undeveloped regions will be decided during the course of the next decade.  

Satellite Image:

The next ten years…

One would think the latest reports documenting the lack of action regarding climate change, the continued and accelerating changes to the oceans and cryosphere, the deteriorating condition of the Great Barrier Reef, and the astonishing decline in avian populations along with the ongoing extinction of numerous other plant and animal species, should serve to focus global attention on planetary change in the Anthropocene.  Unfortunately, it would appear that business as usual will be the most likely outcome of all these reports, despite much wringing of hands, gloomy predictions and opining of pundits, experts and the like. 

A hallmark of the Anthropocene is the observably (much!) higher rate of change in many Earth system processes as compared to “background” rates determined from historical records. This acceleration has been well documented, but very poorly communicated to the general public and largely ignored by decision makers.  Rising concentrations of carbon dioxide, increasing sea and land temperatures, accelerated melt rates of sea ice, permafrost and ice sheets, along with rising sea level, inform us that a critical fork in the road lies ahead.  Ignore these signposts and there will be no opportunity to even make a choice as to which road we take—the decision will have been already made.

With this analogy in mind, I turn to three papers, one written in 1976, one in 2013, and another released this September.  In 2013, James Hansen and 17 other scientists published “Assessing ‘Dangerous Climate Change’:  Required Reduction of Carbon Emissions to Protect Young People, Future Generations and Nature.”( Dangerous climate change) Their paper documented the continued rise in atmospheric carbon dioxide from fossil fuel combustion, along with the various attendant impacts to Earth system processes, the environment and human health and well-being arising from this accumulation.  The authors suggested that the inertia of the climate system causes it to respond “slowly to this man-made forcing,” complicating policy responses, as well as obscuring the potentiality for irreversible climate change due to slow feedbacks.  Although the rapidity and scale of such changes; e.g., irreversible melting of Antarctic and/or Greenland ice sheets remains unclear, continued combustion of fossil fuels threatens to lock us into this future. 

They argued that the implications of future climate change already “in the pipeline” are thus intergenerational, presenting young people of today with a future they will have had no hand in shaping.  The authors suggested that “(a) scenario is conceivable in which growing evidence of climate change and recognition of implications for young people lead to massive public support for action” based on the expectation of “fairness and justice in a matter as essential as the condition of the planet they will inhabit.” This sounds remarkably like the argument underlying today’s campaign by young people for climate justice. The conclusions of the 2013 paper are stark:  the opportunity to avoid climate disruptions and maintain global temperatures below 2oC will require “extraordinarily rapid emission reductions” and choosing an alternative energy pathway, a “fork in the road” from a carbon-rich energy path to one that is carbon-free.   

The choice of a “hard energy path” as opposed to a “soft energy path” was outlined more than forty years ago, in Amory Lovin’s seminal October 1976 Foreign Affairs article “Energy Strategy:  The Road Not Taken?” (Soft Energy Paths) in which he outlined the numerous benefits of shifting from a “hard path” of fossil fuels and nuclear power to a “soft path” of efficiency and renewable energy, focused on matching the quality of energy to its end use.  Lovins’ deeply controversial and influential article showed a way forward to an energy future that today bears a remarkable similarity to his original description.  However, despite rapid efficiency improvements, technological breakthroughs and movement along a soft energy path envisioned by Lovins, a key aspect of the soft energy path, deployment of renewables, lags approximately 25 years behind the 1976 projections.  Deployment of renewables must therefore accelerate even more rapidly if we are to move towards an energy future that will avoid the irreversible climate change outlined by Hansen et al.

These choices are now before us, laid out in a September 2019 White Paper from the World Economic Forum, “The Speed of the Energy Transition—Gradual or Rapid Change?”  (The speed of the energy transition) The paper poses the question “Will the global energy transition from fossil fuels to sustainable energy be gradual or rapid?”  The authors suggest the choice of paths will be made this decade, that the two paths are mutually exclusive, and that the choice of business as usual “regrettably … means that the goals of the Paris Agreement will become increasingly unachievable.” 

There are three “signposts” along the path to a Rapid global energy transition by 2030 according to the White Paper: 

(1)  solar electricity at $20-$30 per megawatt hour

(2)  carbon taxes implemented on around half of emissions at $20 per tonne

(3)  three peaks to take place in the 2020’s

            a.  peak demand for new internal combustion engine cars

            b.  peak demand for fossil fuels in electricity

            c.  peak demand for all fossil fuels

If we pass these, the Rapid transition is on track; failure to pass these leads to a future whose socioeconomic  and Earth system dimensions will be dictated by processes humanity has set into irreversible motion.  The chart from Hansen, et al hints at the potential long lags in the climate system’s response to fossil fuel emission cuts: it could take centuries before atmospheric carbon dioxide levels return to “safe” levels of 350 ppm.  

Carbon dioxide has a long residence time in the atmosphere; the longer we delay in cutting emissions, the longer it will take for CO2 to return to “safe” levels after we reduce emissions. From Hansen, et al., 2013 (See link in the article)

The chart below from BerkelyEarth shows the path to 1.5oC is only a decade or so distant, if current trends continue.  The chart shows a ten-year moving average of the Earth’s surface temperature, plotted relative to the average temperature from 1850-1900.  At the current rate of increase, 1.5oC above the 1850-1900 average will be reached by 2035. 

Projected temperature increase if current trends continue
Source: BerkeleyEarth

According to Hansen et al., warming will reach 1.5oC and “stay above 1.0oC until 2400 if emissions continue to increase until 2030.”

Perhaps Greta Thunberg said it best in her September 23 address to the United Nations:

“For more than 30 years, the science has been crystal clear. How dare you continue to look away and come here saying that you’re doing enough, when the politics and solutions needed are still nowhere in sight…The popular idea of cutting our emissions in half in 10 years only gives us a 50% chance of staying below 1.5 degrees [Celsius], and the risk of setting off irreversible chain reactions beyond human control…Fifty percent may be acceptable to you. But those numbers do not include tipping points, most feedback loops, additional warming hidden by toxic air pollution or the aspects of equity and climate justice…You are failing us. But the young people are starting to understand your betrayal. The eyes of all future generations are upon you. And if you choose to fail us, I say: We will never forgive you. 

We will not let you get away with this. Right here, right now is where we draw the line. The world is waking up. And change is coming, whether you like it or not.” (Thunberg Transcript)

Image: Jon Tyson on Unsplash

Whose Amazon?

“Our House Is On Fire”

“Our house is on fire,” declared French President Macron, describing the fires burning across Brazil’s vast interior.  Satellite imagery revealed clouds of smoke from the thousands of fires obscuring large portions of South America, including the skies of Sao Paulo on Monday, August 20.  News outlets described the Amazon forests as the “lungs of the planet,” and articles warned of the Amazon “tipping” from its present forested state to one in which only savannah ecosystems could survive.  Blame for the fires was laid at the feet of President Bolsonaro, whose anti-environmental, pro-development policies were encouraging rampant conversion of forests to agriculture, mining, timber, and cattle operations. 

Fires in Brazil, August 11 2019

President Bolsonaro’s position on the use of Brazil’s natural resources has been clear: Brazil, not the international community will determine their best use.   Concern regarding the ongoing Amazon fires was highlighted at the just-concluded G7 meeting in Biarritz, where President Macron had declared them a “global emergency,” and the G7 agreed to provide funding to fight the fires and aid in reforestation.  (The Guardian, August 26, 2019) However, in a tweet, President Bolsonaro appeared to reject the G7 proposal, asserting that the G7 was treating Brazil as a colonial entity.  A further exchange of tweets between the French and Brazilian leaders ensued,  which did little to ease the situation. 

Is This Fire Season Different?

The fire season in the southern Amazon runs from June to December, with peak burning activity in September (Global Fire Data)  This website has a great deal of information regarding global fire activity, so let’s take a look at some of the data for the Amazon Region (“Legal Amazon”).  Since 2012, VIIRS satellite data has been available along with the older, somewhat less accurate MODIS data. (The VIIRS data has a resolution of about 375 meters, as compared to about 1 kilometer for MODIS.)


Here are a few highlights:

1.  As of August 31, the 2019 fire season has the highest count since 2012, when VIIRS data became available. 

Screenshot from Total Legal Amazon August Fire Count 2003-2019 showing Cumulative Monthly Fire Count for August. 2019 is in green.

2.  Fires in 2019 are more intense than in previous years, as measured in terms of radiative power.

3.  There has been a noticeable increase in large, intense, and persistent fires burning along major roads in the central Brazilian Amazon, which is more consistent with land clearing than regional drought.  (NASA Earth Observatory)  As an example, the screenshot below is an enlargement of an unprotected area in Para’ shows the clustering of fires adjacent to existing roads in the middle of the image.   Darker areas are unprotected forests, lighter areas above and below the dark green are National Parks.

Source:  (NASA Fire Information for Resource Management System (FIRMS))

4.  However, if we look at 2019 MODIS Fire Alerts, through August 31 for all of Brazil, 2019 (red line) doesn’t look at all unusual as compared to many other fires seasons.    


5.  Another representation of the historical data reinforces this impression that the 2019 fire season may be well below many other years. 

Source:  Global Forest Watch Fires Brazil

6.  Fire alerts in Intact Forest Landscape Areas appear to include only 6% of the impacted areas.

It’s Too Early To Draw Conclusions

There is no doubt that August 2019 has seen an historically high number of fires in the Amazon,  but we will not have the full picture until the end of the fire season, when satellite imagery can be compared to pre-2019 data to determine the precise location and true extent of the fires.  The degree to which previously intact tropical forest or other threatened biomes have been transformed by fire won’t be known until this type of analysis can be made.  Satellite imagery clearly shows many fires both within and adjacent to Brazilian National Parks.  For example, the screenshot below (NASA Fire Information for Resource Management System (FIRMS)) shows an area of Para’ with numerous fires in the dark greenish black (unprotected) areas as well as in the protected (lighter green) areas. 

Dark green areas denote unprotected lands, lighter green are National Parks. Numerous fire counts are present in both areas

However, cumulative monthly fire counts (January-August 31) for 2019 in Para’ are well below many other years (next figure), a further indication that it is simply too soon to draw conclusions and issue condemnations about the overall extent of fire damage.  

Source:  Global Fire Data Para’ (accessed August 31, 2019)

Global Demand Drives Local Change

To return to President Bolsonaro’s assertion that the disposition of Brazil’s forest resources  are a Brazilian, not international issue, this is a much more complicated issue than the President’s statement would indicate.  Surging global demand for soy has been met by Brazil, Argentina and the United States. As of 2018, it is likely that Brazil will surpass the United States as both the largest producer and exporter of soy.(TRASE Yearbook 2018)  Brazil has produced soy first by converting vast undeveloped subtropical regions in its south, then into tropical areas, into the Cerrado (largest savanna region in South America, largely unprotected) in the mid-1990’s, and now into the agricultural frontier area of Matopiba.  The conversion of undisturbed forests and other biomes in Brazil to the production of soy as well as other agricultural products (e.g., sugarcane, beef, timber) has been well-documented and ongoing for many years. Soybean exports are now valued at over USD 20 billion, making them Brazil’s most valuable export commodity. (TRASE Yearbook 2018)

An estimated 1.8 million ha of soy in the Amazon in 2016 and 3.5 million ha of soy in the Cerrado in 2015 were undeveloped in the year 2000—amounting to about 40% and 20% of the total area of soy in each biome (TRASE Yearbook 2018 Chapter 3)

 A complex network of producers, export and import entities links local land use change across Brazil to global consumers. The screenshots from the website (TRASE) illustrates some of these linkages.  Soy is used as feed for pigs and chickens, and is exported in vast quantities to China, the world’s largest producer and consumer of pork. (Brazil is also the world’s largest exporter of chickens.) The pig population in China is estimated to be nearly 500,000,000 and China doesn’t have the land to supply soy for this plethora of pork.  Instead, it has reduced the amount of land planted to soy and become the world’s largest consumer of soy (around 60% of global exports), primarily from Brazil. 

Soy flows from Brazil’s biomes through a complex network of export/import entities to end users across the globe
Source: TRASE
Soy flows from states across Brazil to many countries, but China is by far the largest end-user
Source: TRASE

This dependence on Brazilian soy will likely increase due to the ongoing and escalating trade war between the United States and China.  Prior to the imposition of tariffs, Chinese soy demand had also been met by the United States, but the tariff war is likely to incentive the Brazilians to increase soy production, as China shifts from America to Brazil to meet its soy needs.  In a grim analysis of the possible deforestation consequences of such a shift, a report in Nature (Trade War Disaster for the Amazon) in March estimated that “soya-bean production in Brazil could increase by up to 39%, to 13 million hectares.”   Following the historical pattern of Brazilian soy production, the ready availability undeveloped land will lead to agricultural extensification, rather than intensification. 

U.S. Farmers Expand Production

Just as their Brazilian counterparts, American farmers respond to global and domestic demands agricultural commodities by expanding production. They have planted more soy for export, and they have planted more corn in response to biofuel mandates by the federal government.  This has come largely at the expense of previously intact grasslands.*  In the 8 year period between 2008 and 2016, 10 million acres (4,047,000 ha) of grassland, shrubland, wetland and forestland were converted to crop production in the United States, more than half of which was planted in corn and soy.    80% of new cropland came from grassland ecosystems, of which 2.2 million acres were intact grasslands, defined as “those which had not been previously planted or plowed and are most likely to contain native species and sod.”  The rate of land conversion has continued at nearly 1 million acres per year. 

The conversion of grassland between 2008-2012 released more than 14 million metric tons of carbon per year—equivalent to yearly emissions from 13 coal-fired power plants.

This extensification of agricultural production has occurred in the Dakotas, Iowa, Missouri, Kansas, Oklahoma, and Texas, Kentucky and Tennessee, as well as areas bordering Canada in the Northern Great Plains.  As in the case of Brazil, extensification has converted previously intact ecosystems, which provide valuable environmental services, including protection of water quality, critical habitat for bird species, pollination, prevention of soil and nutrient loss, and carbon sequestration.  In the case of grassland ecosystems as well as tropical forests, carbon sequestration is particularly important as a means of buffering continued accumulation of anthropogenically sourced carbon dioxide in the atmosphere. 

*Source: Gibbs Lab

A Telecoupled World

Conversion of intact biomes to agroecosystems is not unique to Brazil or the United States; agriculture occupies about 38% of Earth’s terrestrial surface, making it the largest use of land on the planet (Solutions for A Cultivated Planet).  Flows of energy, resources, information, etc., couple human socioeconomic systems and environmental systems, forming a telecoupled system (Framing Sustainability in a Telecoupled World, one of the hallmarks of the Anthropocene. The relationship between China and Brazil exemplifies this system, driving both extensification and intensification of soy production in Brazil, as vast quantities of soy product flow back to China.  Smaller quantities flow to many other nations, including members of the G7. Through the work of TRASE researchers, the linkages between import/export entities and deforestation have been brought into the open, and it has become clear that a handful of enormous, largely privately held companies dominate these flows.  Land use decisions in Brazil are thus determined by both Brazilian governmental decisions, as well as those of these often vertically integrated transnational agricultural entities. 

In a telecoupled world, it is increasingly difficult to disentangle local land use decisions from global economic forces.  Thus, President Bolsinaro’s claim that Brazilian resources are to be disposed of only by Brazil, is not really that simple. Brazilian resource decisions can be influenced by end-users, mediated by a very complex interplay of actors. Ultimately making a transition to sustainability in the Amazon and elsewhere will be very challenging.  For example, despite the much larger volume of soy exports from Brazil to China, the sourcing of soy from Brazil to Europe actually exposes European nations to higher deforestation risk than China (TRASE 2018 Annual Report)

We Are All Complicit

In a telecoupled world of nearly 8 billion, conversion of vast ecosystems matters in ways that weren’t apparent in earlier eras.  In the plow up of the Great Plains grassland of the United States in the 19th and early 20th century, the near extinction of the buffalo, decimation and relocation of indigenous peoples wasn’t an issue of global concern.  Now, when Brazil is treating its vast frontier regions in much the same fashion as did the United States, it does matter. 

We in the developed world still have our hands dirty; be it grassland conversion in the United States, deforestation of boreal forests in Canada, destruction of the ancient Hambach Forest in Germany for production of lignite—one of the dirtiest of coals.  Why should the Brazilians listen to us? 

Moreover, why should the Brazilians change their behavior?  Perhaps the Chinese should reduce their pork consumption, the Europeans reduce their intake of beef, Americans change their toilet paper purchases from Canadian-sourced pulp to recycled?  In other words, we have outsourced our resource demands from domestic to foreign sources, but want these resources to be extracted on our terms—something we aren’t even doing ourselves.  Can we really have it both ways in a telecoupled world?

President Macron condemns the Brazilians for burning their (“our”) forests.  Who, exactly is lighting the match?

Image of Match: yaoqi-lai-7iatBuqFvY0-unsplash.jpg


Mangrove Deforestation between 2000 and 2012 Source: Section; http://

USGS ecologists produced this map of mangrove deforestation in Burma’s (Myanmar’s) Irrawaddy Delta using an older version of the Global Land Survey dataset. Recent improvements are allowing them to map mangrove deforestation worldwide. (Map adapted by Robert Simmon from Giri et al., 2008.)  NASA Earth Observatory  

Significance:  Mangroves represent a unique ecosystem in coastal area supporting a rich biodiversity and providing a range of nature’s contribution to people including provisioning, regulating and supporting, crucial for the sustenance of local communities.  There ecosystem service benefits have been valued at an average of 4200 US$/hectare/year.*  They provide coastal protection against storms and flooding, are critical nursery habitats for fish, birds and marine mammals, act as effective nutrient filters.* South-East Asian mangroves are among the most species diverse in the world, having 268 plant species including 52 taxa growing exclusively in mangrove habitat. Mangrove forests and forests soils can also store significant amounts of organic carbon.*

Status:  Recent changes in land use primarily for aquaculture has led to transformation of mangroves (up to 75 per cent in the last 3 decades.  Mangroves exist in coastal areas where development demand is high and are being highly threatened by land-use change (see 4.1.2; 4.4.1). An estimated 1,140 km2 of mangroves have been lost between 2000 and 2012 in South-East Asia, with an average rate of 0.7-3.0 per cent per year.

Source: http://

Threats include rapid urbanization (Philippines, Thailand, Vietnam), aquaculture (e.g., shrimp farming), paddy farming (Myanmar), expansion of oil palm (Malaysia and Indonesia, including new development in Papua) (See Figure above and chart below) In Asia, more than 50 per cent of mangroves have been lost to support aquaculture, with 40 per cent of mangroves in the Philippines lost to agriculture.

Indirect anthropogenic changes include those related to climate change—drought (e.g., Gulf of Carpentaria, Australia Nov-Dec 2016); rising sea levels pose a threat to mangroves in Bangladesh, New Zealand, Vietnam and China. Loss of mangrove forests and soils also removes carbon storage; Indonesia, Malaysia and Myanmar contributed 77% of global mangrove organic carbon storage loss between 2000-2015.*

*Source:  Jonathan Sanderman et al 2018 A Global map of mangrove forest soil carbon at 30m resolution. Environ. Res. Lett. 13 055002

Top 20 nation rankings for (a) total mangrove area lost between the years 2000 and 2012, (b0 area loss as a percent of year 2000 mangrove area, (c) total soil organic carbon stocks, (d) carbon loss as a percent loss of year 2000 soil carbon stock. Range in values for (c) and (d) come from 25%-100% loss of carbon in upper meter in pixels identified as being deforested between the years 2000 and 2015.

Water Supply and Sanitation

Binh thanh district, Ho Chi Minh, Vietnam  Photo by Anh Vy on Unsplash
  • The percentage of global population using at least a basic drinking water service rose from 81 to 89% between 2000 and 2015
  • 3 out of 10 (2.1 billion; 29% global population) did not have a safely managed drinking water service in 2015
  • 844 million still lacked even a basic drinking water service
  • Water-related deaths impact thousands and costs billions

Average annual impact from inadequate drinking water and sanitation services, water-related disasters. Adapted from WWAP (UNESCO World Water Assessment Programme). 2019. The United NationsWorld Water Development Report 2019: Leaving No One Behind. Paris, UNESCO

In 2015, an estimated 2.1 billion people lacked access to safely managed drinking water services and 4.5 billion lacked access to safely managed sanitation services. (WWAP)

Almost half of people drinking water from unprotected sources live in Sub-Saharan Africa, where the burden of collecting water lies mainly on women and girls, many of whom spend more than 30 minutes on each trip to collect water. (WWAP)

Proportion of population using at least basic drinking water services, 2015
Source: WWAP (UNESCO World Water Assessment Programme). 2019. The United NationsWorld Water Development Report 2019: Leaving No One Behind. Paris, UNESCO


  • Worldwide, only 2.9 billion people (39% of global population) used safely managed sanitation services in 2015.  40% of these people lived in rural areas.
  • 2.1 billion people had access to “basic” sanitation services.
  • 2.3 billion (one out of every three people) lacked even a basic sanitation service—nearly 1 billion people (892 million) still practiced open defecation.
Photo: SuSanA Secretariat. Creative Commons BY (cropped)

Global and regional sanitation coverage, 2015.  Source:  The United Nations World Water Development Report 2019: Leaving No One Behind. Paris, UNESCO, 2019.

Climate Change: Greenhouse Gases

Carbon Dioxide

Global Temperature Change from 1850-2018. Graphics available for the globe and most countries. Ed Hawkins
Record high 414.71 ppm carbon dioxide reached June 13, 2019
No precedent for this level of carbon dioxide in over 800,000 years of ice core data

Click to access mlo_full_record.pdf

View of Mauna Kea and Mauna Loa from Haleakala
Photo by Ralph Howland on Unsplash
The Keeling Curve–the iconic documentation of carbon dioxide in the Earth’s atmosphere from 1958

The atmospheric abundance of CO2 has increased by an average of 1.83 ppm per year over the past 40 years (1979-2018). The CO2 increase is accelerating — while it averaged about 1.6 ppm per year in the 1980s and 1.5 ppm per year in the 1990s, the growth rate increased to 2.3 ppm per year during the last decade (2009-2018). The annual CO2 increase from 1 Jan 2018 to 1 Jan 2019 was 2.5 ± 0.1 ppm (see, which is slightly higher than the average of the previous decade, and much higher than the two decades before that.

NOAA Carbon Dioxide Radiative Forcing

The relentless rise of carbon  dioxide

Total Global CO2 Emissions

Photo by Martin Adams on Unsplash

Carbon dioxide emissions grew by 2.0% in 2018, the fastest growth for seven years; China (2.2% increase), India (7% increase) and the U.S.(2.6% increase) were responsible for around 69% of global emissions uptick (

Total global carbon dioxide emissions in 2017: 41.2±2.8 GtCO2; 53% increase over 1990 (Source: Global Carbon Project)

  • Carbon dioxide emissions attributable to land-use change are highly uncertain, with no clear trend in the last decade
  • Land-use change was the dominant source of annual CO2 emissions until around 1950. In 1960 land-use change emissions accounted for 43% of emissions; between 2008-2017 they averaged 13%. In total, CO2 from land-use change accounts for 31% of cumulative emissions between 1870-2017.
  • Fossil CO2 emissions now dominate global changes: Coal (32%), Oil (25%), Gas (10%), Others (2%) account for 69% of cumulative emissions between 1870-2017.

Fate of anthropogenic CO2 emissions (2008-2017)

Source: Global Carbon Project Carbon Budget 2018 GCP Presentation
Source :  Figures from the Global Carbon Budget 2018 

Nitrous Oxide (N2O) (EPA N2O)

Shanghai, China  Photo by Holger Link on Unsplash

Radiative Forcing:  298 times that of CO2 over a 100 year period Residence time: 114 years


  • Anthropogenic (40%)
  • Agriculture (soil management—fertilizers, manure, burning of agricultural residues)
  • Fuel Combustion
  • Industry
  • Wastewater treatment

Growth of nitrous oxide

Red line is a linear fit to the global mean data demonstrating a fairly constant annual growth rate greater than 0.75 ppb/year

Global history of nitrous oxide as a function of latitude (y-axis) and time (x-axis).

Short-Lived Climate Pollutants

Black Carbon: 6600Gg (2015)

  • Radiative Forcing:    Black Carbon (BC) has a strong influence on radiative forcing, affecting the climate globally and regionally, and is responsible for a significant proportion of the global forcing to date.
    • Bond (2013)*  estimated that black carbon, with a total climate forcing of +1.1 W m-2, is the second most important human emission in terms of its climate-forcing in the present-day atmosphere; only carbon dioxide is estimated to have a greater forcing. For comparison, the radiative forcings including indirect effects from emissions of the two most significant long-lived greenhouse gases, carbon dioxide (CO2) and methane (CH4), in 2005 were +1.56 and +0.86 W m-2, respectively.
    • BC deposited on the cryosphere leads to enhanced melting rates and can affect the intensity and distribution of precipitation. Climate and Clean Air Coalition
    • Residence Time:  4–12 days

! ! Global emission estimates have uncertainties of about a factor of 2 (i.e., -50% to +100%) or even by a factor of 3 (See Climate and Clean Air Coalition)


  • Domestic biomass combustion (especially in traditional cookstoves)
  • Open-burning of municipal solid waste
  • Crop residue open-burning in the field
  • Traditional brick kilns
  • Forest fires and savanna burning
  • Traditional coke ovens
  • Charcoal making
  • Flaring from oil gas extraction and processing
  • Transportation (diesel engines in on-and off-road vehicles, ships, generators)

*Bond, T. C., Doherty, S. J., Fahey, D. W., Forster, P. M., Berntsen, T., DeAngelo, B. J., Flanner, M. G., Ghan, S., Kärcher, B., Koch, D., Kinne, S., Kondo, Y., Quinn, P. K., Sarofim, M. C., Schultz, M. G., Schul, M., Venkataraman, C., Zhang, H., Zhang, S., Bellouin, N., Guttikunda, S. K., Hopke, P. K., Jacobson, M. Z., Kaiser, J. W., Klimont, Z., Lohmann, U., Schwarz, J. P., Shindell, D., Storelvmo, T., Warren, S. G., and Zender, C. S.: Bounding the role of black carbon in the climate system: A scientific assessment, J. Geophys. Res.-Atmos., 118, 5380– 5552,, 2013.

EPA Black Carbon

Global Methane: 1856.2 ppb (February 2018)

Source: NOAA methane trends

  • Radiative Forcing:  84 times stronger than CO2 per unit of mass in a 20 year period; 28 times greater over a 100 year period
  • Residence Time:  12 years
  • Key precursor to tropospheric ozone formation (see “Particulates and Ozone”)
  • Anthropogenic Sources (60% of global total emissions)
  • Livestock enteric fermentation (see note below chart)
  • Livestock manure
  • Rice cultivation
  • Miscellaneous agricultural sources
  • Waste treatment
  • Waste water treatment

Blue Arrow:  After a 7 year near-zero growth, methane emissions surged starting in 2007, and accelerated again in 2014.  Over half of all anthropogenic methane emissions are attributable to agriculture.  The recent surge in methane may be due in part (~50%) to an increase in ruminant emissions as well as a possible spike in tropical wetland emissions (Rising methane:  a new challenge). Rising methane emissions were not accounted for in IPCC projections of atmospheric temperature change; decreasing methane emissions were assumed.

Stratospheric Ozone Depletion

The abundances of the majority of Ozone Depleting Substances (ODSs) that were originally controlled under the Montreal Protocol are now declining, as their emissions are smaller than the rate at which they are destroyed. In contrast, the abundances of most of the replacement compounds, HCFCs and hydrofluorocarbons are increasing. (United Nations Scientific Assessment of Ozone Depletion 2018)

Linkages between stratospheric ozone depletion, UV radiation, and climate change, including environmental effects and potential consequences for human well-being, food and water security, and the sustainability of ecosystems (solid lines), with important feedback effects driven by human action (double-arrow solid lines) and other processes (dashed lines).

Source: Environmental Effects and Interactions of Stratospheric Ozone Depletion


  The ozone hole is not technically a “hole” where no ozone is present, but is actually a region of exceptionally depleted ozone in the stratosphere over the Antarctic that happens at the beginning of Southern Hemisphere spring (August–October). Satellite instruments provide us with daily images of ozone over the Antarctic region. The ozone hole image shows the very low values (blue and purple colored area) centered over Antarctica on 4 October 2004. From the historical record we know that total column ozone values of less than 220 Dobson Units were not observed prior to 1979. From an aircraft field mission over Antarctica we also know that a total column ozone level of less than 220 Dobson Units is a result of catalyzed ozone loss from chlorine and bromine compounds. For these reasons, we use 220 Dobson Units as the boundary of the region representing ozone loss. Using the daily snapshots of total column ozone, we can calculate the area on the Earth that is enclosed by a line with values of 220 Dobson Units (the white line in the figure).                     Source:  NASA Ozone Watch 

Antarctic Situation June 24 2019 Source: UK Met Ozone

  • The 2018 ozone hole:  The polar vortex began to form in early May and reached its maximum area in late September at around 34 million square kilometres.  It was a little larger than the decadal mean in size, and was generally of average or above average stability.  The ozone hole grew rapidly and by its maximum in late September was above the average size for the decade at 24.8 million square kilometres.  The area with ozone hole values had declined to zero by the end of November, later than in the last two years, but sooner than the decadal average.    NASA observations show that a minimum ozone amount of 102 DU was reached on October 11 and 12.  Although this is a low value it is not as low as around 1990 to 2000.  Ozone depletion would have been much worse this year without the protection of the Montreal Protocol.
  • Although the amount of ozone destroying substances in the atmosphere is going down, the inter-annual variation in the size and depth of the ozone hole is largely controlled by the meteorological conditions in the stratosphere. 
  • A simple extrapolation of the trend in minimum values gives the final year with ozone hole levels as 2073, though the error bars on this estimate are very large.  Models suggest that recovery may be more rapid after 2010. 
  • It is still too soon to say that we have had the worst ever ozone hole, particularly as there has been no major volcanic eruption in the Southern Hemisphere since 1992.  There has also been little cooling of the lower stratosphere since the mid 1990s. 

Chlorofluorocarbons (CFC’s)

Observations reported in Nature in May 2018 showed that the rate of decline of CFC-11, an ozone depleting substances in the atmosphere, which is also a greenhouse gas, had become slower than predicted.  This suggested that either something unusual was taking place in the atmosphere or that there were additional man-made emissions.  The paper suggested that the most likely reason was illegal manufacture and release from somewhere in eastern Asia.  Investigation by the EIA has found that production of polyurethene foam in China can explain the observed changes.  They encourage the Chinese government to take immediate action.  This became news again in May 2019 when another paper was published in Nature.

Source:  UK Met Ozone

Hydrofluorocarbons & Hydrochlorofluorocarbons (HCFCs) Source: HFC’s

HCFCs are growing at a rate of 8-15%/year

Radiative ForcingThe most abundant HFC is 1,430 times stronger than carbon dioxide per unit of mass

Source:  UK Met Ozone

            CFC’s—refrigerants; decompose in the upper atmosphere and catalyze the destruction of ozone.  Phased out according to the provisions of the 1990 Montreal Protocols of 1987, 1990.

            HFC’s and HCFC’s—Substitutes for CFC’s.  HCFC to be phased out by 2040 because they destroy ozone.  HFC’s targeted for emission reductions in the  Kyoto Protocol

Residence Time:

            CFC’s—100 years (CFC-12)

            HCFC’s—12 years

            HFC’s –13 years (e.g., HFC-134a); lifetime weighted by usage—15 years

Ozone Depleting Gas Index (ODGI) Source: NOAA ODGI

The ODGI is estimated directly from observations at Earth’s surface of the most abundant long-lived, chlorine and bromine containing gases regulated by the Montreal Protocol (15 individual chemicals). These ongoing, surface-based observations provide a direct measure of the total number of chlorine and bromine atoms in the lower atmosphere, or troposphere, contained in chemicals with lifetimes longer than approximately 0.5 yr. Because the lower atmosphere is quite well-mixed, these observations also provide an accurate estimate of the composition of air entering the stratosphere. The threat to stratospheric ozone from ODSs, however, is derived only after considering additional factors: the time it takes for air to be transported from the troposphere to different regions of the stratosphere, air mixing processes during that transport, and the rate at which ODSs photolytically degrade and liberate reactive forms of chlorine and bromine in the stratosphere.

ODGI “100” is defined as 100 at the peak in ozone depleting halogen abundance as determined by NOAA observations, and zero for the 1980 level, which corresponds to when recovery of the ozone layer might be expected based on observations in the past.
  • 2018 Antarctic ODGI 79; i.e., we have progressed 21% towards the 1980 benchmark
  • 2018 Mid-latitude ODGI 55; i.e., we have progressed 45% towards the 1980 benchmark

Particulates and Ozone

Atmospheric composition is determined by the mixture of emissions to the atmosphere, transport within the atmosphere, and UV-B radiation. The key interactions determining the composition includes (1) transport of ozone from the stratosphere, (2) emission of a wide range of substances from the ground, (3) transformation of material through the action of UV radiation (and particularly UV-B), and (4) mixing of the pollutants in the atmosphere. The resultant O3 and aerosols, in turn, have impacts on human health (5) and plants (6).
Environmental Effects and Interactions of Stratospheric Ozone Depletion (Chapter 6)

Particulate Matter (PM2.5) Air Quality

Mumbai, India            Photo by Abhay Singh on Unsplash

Particulate matter contains microscopic solids or liquid droplets that are so small that they can be inhaled and cause serious health problems. Some particles less than 10 micrometers in diameter can get deep into your lungs and some may even get into your bloodstream. Of these, particles less than 2.5 micrometers in diameter, also known as fine particles or PM2.5, pose the greatest risk to health.( EPA PM2.5) These particles are small enough to work their way deep into the lungs and into the bloodstream, where they trigger heart attack, stroke, lung cancer and asthma (Berkeley Earth Air Pollution)

Get the Airvisual 2018 World Air Quality Report Here

  • Air pollution kills more people worldwide each year than does AIDS, malaria, diabetes or tuberculosis.
  • For the United States and Europe, air pollution is equivalent in detrimental health effects to smoking 0.4 to 1.6 cigarettes per day.
  • In China the numbers are far worse; on bad days the health effects of air pollution are comparable to the harm done smoking three packs per day (60 cigarettes) by every man, woman, and child.
  • Air pollution is arguably the greatest environmental catastrophe in the world today. (Berkeley Earth Air Pollution)
2018 Ten Most Polluted Countries (Airvisual)

Unhealthy: The following groups should avoid prolonged or heavy exertion.

  • People with heart or lung disease
  • Children and older adults

Unhealthy for Sensitive Groups: The following groups should reduce prolonged or heavy exertion

  • People with heart or lung disease
  • Children and older adults

Changes (1990 to 2015) in the aerosol column optical depth at 550 nm, computed as the mean of six global models Environmental Effects and Interactions of Stratospheric Ozone Depletion (Chapter 6)

Carbon Dioxide Radiative Forcing

The annual greenhouse gas index (AGGI) for 2018 was 1.43—a 43% increase in radiative forcing since 1990

Radiative forcing, relative to 1750 due to carbon dioxide alone since 1979. The percent change from January 1, 1990 in this forcing is shown on the right axis.
Source: NOAA Carbon Dioxide Radiative Forcing

Radiative forcing, relative to 1750, of all the long-lived greenhouse gases. The NOAA Annual Greenhouse Gas Index (AGGI), which is indexed to 1 for the year 1990, is shown on the right axis.  1990 is the year of the Montreal Protocol, which regulated ozone depleting gases.  The annual greenhouse gas index (AGGI) for 2018 was 1.43—a 43% increase in radiative forcing since 1990
NOAA Annual Greenhouse Gas Index

Pre-1978 changes in the CO2-equivalent abundance and AGGI based on the ongoing measurements of all greenhouse gases
NOAA Annual Greenhouse Gas Index

(Left vertical axis) The heating imbalance in watts per square meter relative to the year 1750 caused by all major human-produced greenhouse gases: carbon dioxide, methane, nitrous oxide, chlorofluorocarbons 11 and 12, and a group of 15 other minor contributors. Source: NOAA graph, based on data from NOAA ESRL.
Today’s atmosphere absorbs about 3 extra watts of incoming solar energy over each square meter of Earth’s surface. According to NOAA’s Annual Greenhouse Gas Index (right axis) the combined heating influence of all major greenhouse gases has increased by 41% relative to 1990.  Annual Greenhouse Gas Index

Uncertainties in Emissions Inventories Source: Climate and Clean Air Coalition

“Studies of emission inventories show that, of the major pollutants, the lowest uncertainties are associated with CO2 and SO2,which depend primarily on the quality of fossil fuel statistical data and fuel properties. Studies estimate globally an 8% uncertainty (90% confidence interval) for emissions of CO2 (Andres et al., 2012; IPCC, 2014) and 8–14% uncertainty for SO2, for a roughly 5–95% confidence interval (Smith et al., 2011). However, uncertainty for certain sectors can be much larger, for example 50% for global estimates of CO2 emissions from the combined Agriculture, Forestry and Other Land Use sector (IPCC, 2014). Similarly, uncertainty can be larger in certain regions (e.g. China) due to uncertainties in the level of coal consumption, emission factor for coal and the actual implementation and efficiency of control technology (Guan et al., 2012; Liu et al., 2015; Olivier et al., 2015; Xu et al., 2009; Zhang et al., 2012). Uncertainties for global inventories of GHGs other than CO2 are much higher, being estimated by IPCC (2014) at ±20% for CH4 and ±60% for N2O (both expressed as the 90% confidence interval). Again, uncertainties for some sectors are much higher, for example, for CH4 emissions from rice paddy fields, livestock enteric fermentation and landfill.

Emissions of PM, including BC and primary OC, are more uncertain, as these pollutants usually form under poor combustion conditions in small, inefficient installations burning poor-quality fuels, which are difficult to account for, resulting in large emission variability (Bond et al., 2004; Klimont et al., 2017; Hoesly et al., 2018). Considering local data and knowledge about emission sources and their emission factors could significantly reduce these uncertainties (Zhang et al., 2009). Inconsistencies in measurements of PM emissions (e.g. in-stack or directly after stack for industry; laboratory versus real- world measurements for cookstoves) in different countries contribute to overall global inventory uncertainties. Uncertainty can also be large for activity data of relevance to PM emissions – such as poor-quality fuels (e.g. biomass) in cook stoves or brick kilns (Klimont et al 2017) or even size and composition of local vehicle fleets.

Bond et al. (2004) estimated total uncertainties of about a factor of 2 (i.e. -50% to +100%) in their global estimates of BC and OC emissions for 1996 from contained combustion (excluding open-burning of vegetation and crop residues). More recent work (Bond et al., 2013) estimated larger uncertainties for a global BC inventory for the year 2000; of around a factor of 3 for energy-related emissions and >3 when open-burning is included. Advances in emission characterization for small residential, industrial, and mobile sources will be required to reduce the scale of these uncertainties. Uncertainties in national scale BC emission estimates are likely to be less than for the global inventories described above. For example, emission uncertainties are considered to be in the order of 1.5 to 2-fold for national BC inventories recently prepared by EU countries for CLRTAP.”   (Emphasis added)

Introduce Yourself (Example Post)

This is an example post, originally published as part of Blogging University. Enroll in one of our ten programs, and start your blog right.

You’re going to publish a post today. Don’t worry about how your blog looks. Don’t worry if you haven’t given it a name yet, or you’re feeling overwhelmed. Just click the “New Post” button, and tell us why you’re here.

Why do this?

  • Because it gives new readers context. What are you about? Why should they read your blog?
  • Because it will help you focus you own ideas about your blog and what you’d like to do with it.

The post can be short or long, a personal intro to your life or a bloggy mission statement, a manifesto for the future or a simple outline of your the types of things you hope to publish.

To help you get started, here are a few questions:

  • Why are you blogging publicly, rather than keeping a personal journal?
  • What topics do you think you’ll write about?
  • Who would you love to connect with via your blog?
  • If you blog successfully throughout the next year, what would you hope to have accomplished?

You’re not locked into any of this; one of the wonderful things about blogs is how they constantly evolve as we learn, grow, and interact with one another — but it’s good to know where and why you started, and articulating your goals may just give you a few other post ideas.

Can’t think how to get started? Just write the first thing that pops into your head. Anne Lamott, author of a book on writing we love, says that you need to give yourself permission to write a “crappy first draft”. Anne makes a great point — just start writing, and worry about editing it later.

When you’re ready to publish, give your post three to five tags that describe your blog’s focus — writing, photography, fiction, parenting, food, cars, movies, sports, whatever. These tags will help others who care about your topics find you in the Reader. Make sure one of the tags is “zerotohero,” so other new bloggers can find you, too.