THE PROBLEM
The scientific consensus is that the source of this perfect storm of catastrophic events may be found in an increasing proportion of minute particles of carbon dioxide in the Earth's upper atmosphere causing it to act as an insulating blanket and the planet to warm. Of recent times, this is largely the result of human activities.
Carbon dioxide is produced by the combustion of any substance containing carbon such as coal, oil, petrol and methane gas. Electricity generation is the single biggest contributor, at 33.7 per cent, according to the quarterly update of Australia’s emissions, figures current to September 2018 (source no longer extant) though this percentage has since declined somewhat (e.g. 4.2% or 7.6 Mt CO2-e during the March 2020 quarter) the result of a variety of factors. The sector is still heavily reliant on coal, despite the move towards renewable energy.
The next most polluting sector is other stationary energy – that involving the direct combustion of fuels in mining, manufacturing, and steel and aluminium production – followed very closely by transport emissions from aviation, road, rail and shipping. The list is rounded out by agriculture, by fugitive emissions (those that leak when fossil fuel is processed, moved or stored), industrial processes, the waste sector, land use and forestry.[0]
Over the past 150 years, since the late 19th century, the Earth’s climate has changed dramatically. The planet has warmed 1.5 degrees Fahrenheit on average, and most of the warming has occurred since 1960. When things are operating as they should, the earth will have “an effective temperature”: a balance of solar radiation it receives and radiates back to space, and our atmosphere is an insulating blanket keeping the planet’s surface at about 298 Degrees Kelvin (28 degrees) compared with space’s 3 degrees K, but if you alter (increase) the amount of carbon dioxide in the atmosphere - in the 1980s it was rising at 1.2 ppm (parts per million) a year, less than half the present rate - that insulating heat-trapping blanket will produce a greenhouse effect significantly warming the Earth’s surface[1].
The Earth’s atmosphere is dominated by gases: 78% nitrogen, 21% oxygen, 1% argon, 0.04% carbon dioxide, and a few trace amounts of many others. In addition the variable gas water vapour can make up to 4%[2]. The atmosphere also contains very small amounts of liquids (mostly cloud droplets) and solids such as aerosol particles, considered and defined later. That .04% of carbon dioxide may appear quite small. For this reason, it is in fact known as a trace gas. However, its overall percentage in the atmosphere is not the operative factor. What is critical is that CO2 has the capacity to trap heat and that its overall concentration is increasing.
This process, more fully explained on subsequent pages, has long been understood. The heat-trapping propensity of carbon dioxide and other gases was demonstrated as long ago as the mid-19th century. In the 1860s, physicist John Tyndall recognised the Earth's natural greenhouse effect and suggested that slight changes in the atmospheric composition could bring about climatic variations. In 1896, a seminal paper by Swedish scientist Svante Arrhenius first predicted that changes in the levels of carbon dioxide in the atmosphere could substantially alter the surface temperature[3].
CO2 - the 'stuff of life' and potential mass killer-in-waiting
There are those who refer to CO2 as the stuff of life, which indeed it is, especially where plants are concerned, but it can also be a mass killer. This so-called stuff of life has already been responsible for the greatest mass extinction of life this planet has known at the end of the Permian period when the continent of Pangaea was in the process of formation some 252 million years ago.
The generalities of the story are well known: unrestrained volcanic eruptions in Siberia spewing massive amounts of carbon dioxide causing the oceans to acidify, killing off fish and shellfish, the biggest victims of the extinction, while changing the climate so fast that plants and animals on land also died out, unable to adapt in time, but Peter Brannen [4] has recently fleshed out the details in graphic fashion:
Methane [5] and carbon dioxide exploded out of the ground by the tens of thousands of gigatons. Temperatures spiked by almost 22 degrees Fahrenheit. And in the oceans, where spreading anoxia and acidification wiped out 96 percent of life, it was as hot as a jacuzzi. The oceans “overdosed” on this volcanic CO2. "The seawater acidified as a simple matter of chemistry, and the temperature of the planet soared as a simple matter of physics. This is what CO2 does.
"As it turns out the most frequent mass killer of life on Earth is Earth itself and the most reliable murder weapon is carbon dioxide". (My emphasis) |
When a few species vanish, others can take over their roles, but when nearly 95% disappear, entire ecosystems are destroyed, and new species must evolve from the few survivors. It took 20 to 30 million years for ocean diversity to rebound after the Permian extinction - much longer than other recoveries. Brannen links these events to the world we know today:
At the start of the industrial revolution, long slumbering forests of carbon were resurrected from the ancient Earth and pressed into service in the furnaces of modernity. We know that this artificial fire can’t go on forever without immiserating our world. At 416 parts per million, carbon dioxide is already higher than it has been in millions of years and is perhaps rising even faster than in these greatest calamities of all time.
Meanwhile, centuries, millennia even, of hunting, land clearing and pollution have impoverished the natural world. By one estimate, at the rate at which we are currently driving species extinct, we could match the biological devastation of those towering mass extinctions of the ancient past within 300 to 12,000 years. This might sound like a long time frame, but from a geologic perspective, it is downright subliminal. More worryingly, there may yet exist unseen ecological cliff edges along the way, beyond which the biosphere does not simply suffer the onslaught of attrition but collapses suddenly in cascading failures. In other words, there may be tipping points—points of no return. |
These days the consensus viewpoint of the world’s best climate scientists whose work passes through the Intergovernmental Panel on Climate Change (IPCC)[6] for peer review on an annual basis is unequivocal: that since the advent of the industrial era, the planet is warming well beyond the levels anticipated for normal climate variability such as those caused by the El Niño Southern Oscillation Index (ENSO) and its La Niña counterpart, and that human activities are substantially to blame, relevant factors being the observed rise in greenhouse gas concentrations, and global land and sea warming corroborated by satellite data and modelling studies including the earth’s energy budget.
So what must we do to avoid the calamity which inevitably awaits? Brannen again:
Set aside swaths of the planet—in the form of marine protected areas, natural reserves and corridors for migration—to allow the living world to recover from the uppercut we have already delivered it.
Then, we must simply stop digging up old life from deep in Earth’s crust and lighting it on fire at the surface. As humanity leans on the very same levers pulled in the very worst things that have ever happened in history, we must consult the ages and listen to the counsel of broken worlds past. |
Wise words indeed! Let’s take a look.
[0] Nicole Hasham, "How do Labor and the Coalition plan to cut emissions:", SMH, 13 May 2019: https://www.smh.com.au/federal-election-2019/how-do-labor-and-the-coalition-plan-to-cut-carbon-emissions-20190429-p51ic8.html
[1] Peter Hannam, “Climate facts can’t be Trumped”, Sydney Morning Herald, 30 March 2017, p 19. See also the Skeptical Science website where the process is comprehensively explained: https://skepticalscience.com/empirical-evidence-for-co2-enhanced-greenhouse-effect.htm
[2] Michael Box’s WEA course “Our Atmospheric Environment” (May-June 2017), 1.1.
[3] https://climate.nasa.gov/evidence/; http://www.defenders.org/sites/default/files/publications/10-things-you-should-know-about-climate-change-and-wildlife.pdf
[4] In his article "The worst times on Earth - Mass extinctions send us a warning about the future of life on this planet - carbon dioxide has done plenty of damage before", Scientific American, 175 years anniversary edition, September 2020, pp 74-81
[5] On methane, a study by researchers at the Massachusetts Institute of Technology in Cambridge, and the Nanjing Institute of Paleontology of the Chinese Academy of Sciences published in the journal Proceedings of the National Academy of Sciences in early April 2014 has suggested that the key culprit in the extinction was a microbe called Methanosarcina that suddenly gained the ability to generate massive amounts of methane and release it into the seas and atmosphere at roughly the time of the mass extinction triggering a runaway greenhouse effect. The methane microbes then experienced an explosive growth spurt fueled by the mineral nickel which they found in sedimentary rocks from those Siberian eruptions.
[6] The IPCC has produced 5 Assessment reports: in 1990, 1995, 2001, 2007 and 2014. The IPCC does no science itself, but as we shall see, analyses all peer-reviewed Science on topics such as changes in gas and aerosol concentrations, temperature data etc. For AR1 in 1990, scientists from 25 countries contributed with a further 200 involved in peer review. For AR4 in 2007, there were 152 lead authors, 500+ contributing authors and 600 involved in peer review. Over 30,000 written review comments had to be processed: Associate Professor Michael Box’s WEA course “Our Atmospheric Environment”, May-June 2017, 5.0. At the time of writing, I do not have the up to date figures for AR5. For an analysis of the consensus between scientists on this issue, see Appendix B.
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[0] Nicole Hasham, "How do Labor and the Coalition plan to cut emissions:", SMH, 13 May 2019: https://www.smh.com.au/federal-election-2019/how-do-labor-and-the-coalition-plan-to-cut-carbon-emissions-20190429-p51ic8.html
[1] Peter Hannam, “Climate facts can’t be Trumped”, Sydney Morning Herald, 30 March 2017, p 19. See also the Skeptical Science website where the process is comprehensively explained: https://skepticalscience.com/empirical-evidence-for-co2-enhanced-greenhouse-effect.htm
[2] Michael Box’s WEA course “Our Atmospheric Environment” (May-June 2017), 1.1.
[3] https://climate.nasa.gov/evidence/; http://www.defenders.org/sites/default/files/publications/10-things-you-should-know-about-climate-change-and-wildlife.pdf
[4] In his article "The worst times on Earth - Mass extinctions send us a warning about the future of life on this planet - carbon dioxide has done plenty of damage before", Scientific American, 175 years anniversary edition, September 2020, pp 74-81
[5] On methane, a study by researchers at the Massachusetts Institute of Technology in Cambridge, and the Nanjing Institute of Paleontology of the Chinese Academy of Sciences published in the journal Proceedings of the National Academy of Sciences in early April 2014 has suggested that the key culprit in the extinction was a microbe called Methanosarcina that suddenly gained the ability to generate massive amounts of methane and release it into the seas and atmosphere at roughly the time of the mass extinction triggering a runaway greenhouse effect. The methane microbes then experienced an explosive growth spurt fueled by the mineral nickel which they found in sedimentary rocks from those Siberian eruptions.
[6] The IPCC has produced 5 Assessment reports: in 1990, 1995, 2001, 2007 and 2014. The IPCC does no science itself, but as we shall see, analyses all peer-reviewed Science on topics such as changes in gas and aerosol concentrations, temperature data etc. For AR1 in 1990, scientists from 25 countries contributed with a further 200 involved in peer review. For AR4 in 2007, there were 152 lead authors, 500+ contributing authors and 600 involved in peer review. Over 30,000 written review comments had to be processed: Associate Professor Michael Box’s WEA course “Our Atmospheric Environment”, May-June 2017, 5.0. At the time of writing, I do not have the up to date figures for AR5. For an analysis of the consensus between scientists on this issue, see Appendix B.
Next