Decarbonization Delusion
(Adapted from The Climate Pandemic: How Climate Disruption Threatens Human Survival)
“Decarbonizing” the economy—reducing or eliminating carbon pollution—has been touted to avoid catastrophic global heating. Decarbonization can involve efforts ranging from increasing solar and wind energy production to capturing CO2 emissions from fossil-fueled power plants.
The realistic outlook for decarbonization, however, reveals it to be a delusion borne of desperation and ignorance.
For one thing, few decarbonization technologies are mature enough to be deployed on a significant scale, according to a report from the International Energy Agency (IEA). Some such technologies include:
Development of energy-related technologies is a long road, the report pointed out. Even the fastest such technologies, like LEDs and lithium-ion batteries, “took 10-30 years to go from the first prototype to the mass market.”
And many of these technologies face insurmountable obstacles to ever being commercially deployed (see Carbon Capture Snake Oil, and “Hydrogen pipe dream” below).
The IEA report charged that there is a “stark disconnect between these high-profile pledges” by governments and companies to reach sustainability goals and “the current state of clean energy technology.”
Still at the prototype and demonstration level are decarbonizing technologies for heavy industry such as chemicals, steel, and cement, found another IEA report.[2] The decarbonization challenges they face include their:
A report by the Energy Transitions Commission—a coalition of corporate leaders—concluded that overall, there is no real acceleration toward decarbonization.[3] The authors analyzed the policies required to jump-start a decarbonizing transition in ten sectors of the economy that account for 80% of the world’s emissions, including steel, cement, plastics, heavy road transport, aviation, and shipping.
“The low carbon transition has barely begun” in most sectors, the report concluded. Decarbonization technologies in a few areas, like power generation, cars, and buildings are only in the “diffusion” stage, beginning to change the technology. None are at the “reconfiguration” stage where they are changing the whole sector.
Fantasy decarbonizing scenarios
Decarbonization computer models are little more than technological fantasies that spin out unrealistic 1.5°C and 2°C scenarios—as detailed in a 2022 report by the UN Intergovernmental Panel on Climate Change (IPCC).[4] All the models depend on massive reductions in fossil fuel production and greenhouse gases. They depend on transitioning to renewable energy (see Renewable Energy Hype). And they depend on unproven and uneconomic carbon capture technology to remove CO2 from the air (see Carbon Capture Snake Oil).
For example, one modeling study found that limiting heating to 1.5 °C by 2050 would mean leaving in the ground nearly 60% of oil and gas and 90% of coal reserves.[5] Another study found that 40% of even existing fossil fuel production must be shut down to give a 50-50 chance of staying below 1.5 °C.[6]
Even a higher 2°C limit requires stranding a third of oil reserves, almost half of gas reserves, and over 80% of coal reserves, found another economists’ analysis.[7]
Such resource stranding would be political suicide for any government seeking to impose such limits. And it would be financially disastrous. One study found that aggressive energy policies to limit warming to 2°C would cause massive financial losses to investors. Tracing the risk of ownership of more than 40,000 oil and gas assets, the researchers calculated that such a move would mean that $1.4 trillion in existing projects would lose their value. Private investors would suffer the most through their pension funds and investments.[8]
Stranding oil, gas, and coal deposits would mean as much as $28 trillion in lost revenue for energy companies over the next two decades, asserted historian Adam Tooze in 2019. Besides impacting investors, decarbonization would damage the companies that depend on those resources—chemical, construction, and industrial companies and power utilities—causing trillions of dollars in lost asset values.[9]
What’s more, attempts at stranding resources will be thwarted by legal claims from investors seeking compensation under international treaties. Countries offer such treaties to encourage foreign investment, and if they are violated, those investors can demand arbitration. One analysis estimated that such arbitration could lead to government liabilities up to $340 billion for oil and gas projects. Risks would be even greater if coal mining and fossil fuel infrastructure were included. What’s more, governments fearing such liabilities could abandon climate commitments and roll back regulations.[10]
Nature won’t help
Some climate models assume that a significant amount of CO2 will be naturally absorbed, which is also unrealistic.[11] As one group of environmental researchers commented:
The resilience of natural carbon sinks is deteriorating, and some key biomes, such as rainforests, may cross tipping points to becoming sources of carbon. Keeping well below 2°C will require creating a new carbon sink on the scale of the natural ocean sink.[12]
Study after study has projected an inexorable march toward disastrous CO2 levels. The curve of increasing CO2 shows that, unless the current growth rate is drastically slowed, levels will reach 500 ppm within 50 years. That level would raise the global temperature increase to more than 3°C—a level that would trigger vast climate disruption. The world would see superstorms, major sea-level rise, famine-level agriculture disruption, and other disasters.[13]
Preposterous decarbonizing plans
Just as decarbonization models are breathtakingly unrealistic, so are decarbonization plans. They are entirely academic, in the sense of being theoretical and impractical. They are technocratic solutions to a societal problem—neglecting the political, economic, and sociological barriers to their implementation.
In assessing these barriers, one large-scale analysis concluded that they are, indeed, insurmountable. The Hamburg Climate Futures Outlook study was developed by more than 40 academic researchers in sociology, macroeconomics, and the natural sciences.[14]
The study sought to determine whether “a scenario is not merely feasible, but also that there is enough societal momentum and political will to make that future materialize,” wrote three of the authors. “Our final assessment: even if a partial decarbonisation is currently plausible, deep decarbonisation by the year 2050 is not.”[15]
A notable example of an unrealistic global plan is the IEA’s “Net Zero Emissions by 2050” plan. The plan, in fact, directly contradicts the IEA’s own forecasts, including the IEA’s report on decarbonization technologies, discussed above.
Among the IEA net zero plan’s requirements and implications:
Another such unrealistic plan is Princeton University’s “Net-Zero America” plan. The plan proposes by 2030:
Furthermore, by 2050, the plan proposes having:
One similarly radical scenario, America’s Zero Carbon Action Plan, does address the political realities of decarbonization. However, it notes that “many of the technological solutions are understood but lack the institutional coordination, political support, and market incentives to scale.” The report also noted that some of its proposals “are likely to be controversial and resisted by affected industries, lobbies, and political interests.”
Of the report’s ambitious proposals for electrification of the US economy, the authors admit that “this section has highlighted that the US power sector is characterized by fragmentation in regulation, ownership, financial incentives, and institutions.”[18]
Even plans that aim at less substantial emissions reduction seem wildly unrealistic. One such plan is the International Renewable Energy Agency’s “ambitious, yet realistic” Transforming Energy Scenario.[19] It envisions a decline in energy demand of 75% by 2050, roughly the equivalent of China’s current energy demand. The plan would require coal use to decline by 41% by 2030, and 87% by 2050. Oil use would drop by 31% by 2030 and 87% by 2050. Natural gas use would decline by 41% by 2050. However, the plan does not address the impact of carbon-polluting industries like aviation and shipping.
As detailed in other sections, none of these plans is feasible (e.g., see Renewable Energy Hype, Carbon Capture Snake Oil, and “Hydrogen pipe dream” below).
Other analyses have also concluded that achieving net zero emissions by mid-century would require halting construction of fossil-fueled power plants.[20] Those analyses would also require retiring carbon-emitting power plants, boilers, furnaces, and vehicles before the end of their useful life and replacing them with zero-emission technology.[21] Such construction halts or early retirements would be considered absurd by any electrical utility.
Currently operating generation facilities already commit the world to emissions some 300 billion tons above that compatible with average 1.5-2.0°C reduction scenarios, according to an analysis by economists. What’s more, planned plants would add almost an equal amount to emissions. The researchers concluded that about 20% of global generating capacity would have to be stranded to meet Paris Agreement goals.[22]
Basically, concluded MIT energy researchers, a net-zero-carbon-emitting world is unrealistic. Their analysis that showed that fossil fuels will continue to account for about 78% of global energy by 2050.[23]
Bursting the bubble of overshoot
Many scenarios have conceded an inevitable temperature overshoot above 1.5°C, but claim that carbon capture could bring that temperature back down. However, the idea of overshoot is the equivalent of a soap bubble—alluring, but fatally fragile.
First of all, avoiding overshoot in the first place offers enormous environmental and economic advantages, studies have shown.[24] [25] Secondly, carbon capture is not a viable technology (see Carbon Capture Snake Oil).
But the conceptual bubble of overshoot was conclusively burst by the 2022 IPCC report on climate disruption’s impacts. The report concluded that:
Additional warming, e.g., above 1.5°C during an overshoot period this century, will result in irreversible impacts on certain ecosystems with low resilience, such as polar, mountain, and coastal ecosystems, impacted by ice-sheet, glacier melt, or by accelerating and higher committed sea level rise. . . . such impacts are already observed and are projected to increase with every additional increment of global warming, such as increased wildfires, mass mortality of trees, drying of peatlands, and thawing of permafrost, weakening natural land carbon sinks and increasing releases of greenhouse gases.[26]
Hydrogen pipe dream
Hydrogen has been touted as the ultimate carbon-free fuel, given that it produces only water when burned. Advocates have envisioned a “hydrogen economy,” in which hydrogen is generated by renewable energy for home and industry use, for energy storage, and for transportation. However, an investment of more than $11 trillion by 2050 would be required for hydrogen to provide just 24% of the world’s energy needs, according to the research firm BloombergNEF.[27]
A massive hydrogen production, storage, and transportation infrastructure would have to be created from scratch. Existing infrastructure like natural gas pipelines cannot be used for pure hydrogen because it tends to embrittle pipeline steel and welds. Also, as a smaller molecule, hydrogen tends to leak from pipelines more than natural gas.[28] What’s more, the technology for large-scale storage of compressed hydrogen is largely “immature and under development,” found one analysis. The researchers concluded that “Furthermore, the infrastructure and facilities behind some of the technologies are massive, which would require significant resources and costs.”[29]
Natural gas furnaces and other appliances cannot burn hydrogen, so they would have to be modified or replaced.[30] Internal combustion engine vehicles could not be converted to hydrogen in any significant way because hydrogen is far less energy-dense than gasoline or natural gas. To be used in vehicles, it would have to be stored at more than 300 times atmospheric pressure or absorbed as a chemical hydride—requiring complex and expensive equipment.[31] And since hydrogen is lower in energy density than natural gas, more volume would be required to yield the same energy output.
Heavy industry like steel, cement, petrochemicals, glass, and ceramics won’t likely be converted to hydrogen, either. Its use in heavy industry is limited by economic and technological barriers, for example, the cost and engineering challenges of replacing huge inventories of equipment.
As one study of the economics of converting heavy industry to hydrogen concluded, “All approaches have substantial limitations or challenges to commercial deployment.” [32]
Today, almost all hydrogen is “grey hydrogen”—produced from natural gas, releasing large amounts of CO2. Capturing that CO2 —proposed as one pathway to a clean hydrogen economy—is not feasible, as discussed later (see Carbon Capture Snake Oil).
Producing “green hydrogen” from renewable energy using electrolysis is about four-to-six times more expensive than from natural gas, said an IEA report.[33] And investment in hydrogen production by countries and private companies is far short of that required for hydrogen production to play a role in a strategy of net-zero greenhouse gas emissions by 2050, said the report. Nor is hydrogen production technology mature, found the report, concluding that “Hydrogen is a key pillar of decarbonisation for industry, although most of the technologies that can contribute significantly are still nascent.”
Another major drawback to producing green hydrogen is that huge numbers of electrolyzers would be required, found the IRENA analysis cited earlier.[34] The agency’s ambitious Transforming Energy Scenario—which envisions a 75% decline in energy demand by 2050—would require constructing up to 60 gigawatts of electrolyzers per year until then.[35]
Such electrolysis would also require massive amounts of pure water. Each kilogram of hydrogen produced would require 27 gallons of water as a feedstock, found one analysis.[36] Such water would have to be purified at a cost of about $2,400 per ton of hydrogen, calculated journalist Irina Slav—plus the cost of transporting the water.[37] Furthermore, such water demand would arise amid a profound decrease in global water supplies.
Such technological and economic barriers mean that hydrogen could only account for from 1-14% of total US energy demand, according to a Department of Energy analysis. The lower number arises from a “base case” scenario, and the higher from an “ambitious” scenario.[38]
Finally, there is a political barrier in that government policy is inadequate to foster a cost-competitive hydrogen economy, concluded the BloombergNEF study referenced above.
Decarbonization policies won’t work
Successful decarbonization policies would require a drastic improvement in energy intensity—the energy consumption per unit of economic input. However, it is highly unlikely that policies can improve energy intensity enough to spur decarbonization, according to one analysis. [39] The researchers explored 17 decarbonization scenarios aimed at stabilizing CO2 levels or global heating by reducing emissions between 50% and 90% by 2050. Their conclusion: “All of the scenarios examined envision historically unprecedented improvements in the energy intensity of the global economy [emphasis added].”
Basically, such obstacles mean that researchers spinning out decarbonization scenarios are hoping for an energy-intensity miracle to bail them out.
In fact, according to a concept called the Green Paradox, decarbonizing policies can actually accelerate fossil fuel extraction. The Green Paradox holds that carbon-reducing policies force fossil fuel producers to face lower future prices as demand drops for oil, gas, and coal. So, to maximize short-term profits, the industry ramps up production.[40]
“In my view, the Green Paradox is not simply a theoretical possibility,” wrote economist Hans-Werner Sinn Sinn, who identified the concept. “I believe it explains why fossil fuel prices have failed to rise since the 1980s, despite decreasing stocks of fossil fuels and the vigorous growth of the world economy.” He wrote that carbon-reduction policies “alarmed resource owners. In fact, while most of us perceived these developments as a breakthrough in the battle against global warming, resource owners viewed them as efforts that threatened to destroy their markets.”
Delayed, inadequate decarbonization effects
Even if decarbonization magically achieved a drop to zero emissions, the effect on global temperature would not occur for decades, found one modeling study. The researchers analyzed the impact of reducing not only CO2, but also CH4, N2O, and carbon soot. They concluded that for all of those substances, even strong mitigation would have such a delayed effect.[41]
In fact, deep cuts in all non-CO2 emissions would be necessary to limit global warming, concluded researchers. They compared the effects of reducing just CO2 with also reducing substances including CH4 and N2O. The role of such emissions has been “underappreciated” by planners, wrote the researchers. They concluded that “Absent deep cuts in non-CO2 emissions, CO2 abatement alone is unable to keep warming below even the 2 °C threshold by 2050.”[42]
Decarbonization might not even slow global heating over future centuries, concluded researchers who modeled how the climate would adjust to zero-CO2 emissions. They found that warmer oceans could overcompensate for the decreasing CO2 levels, driving a centuries-long global temperature increase after an initial century of decrease.[43]
“If our results are correct . . . limiting the warming to 2°C would require keeping future cumulative carbon emissions below 250 billion tons, only half of the already-emitted amount of 500 billion tons,” co-author Thomas Frölicher told the Climate News Network.[44]
In a perverse twist, if governments managed to miraculously decarbonize the world, the reduction in air pollution would actually increase near-term global heating. Atmospheric aerosols such as sulfates have so far helped limit temperature rise by reflecting sunlight back into space. Their disappearance would trigger a global mean surface heating of 0.5-1.1°C, calculated physicists.[45] [46] [47]
“We’ve been polluting ourselves toward a slightly cooler climate,” researcher Bjørn Hallvard Samet told Yale Climate 360. He said that cleaning up air pollution would result in an immediate increase in global temperature, compared with the far slower temperature reduction from reducing greenhouse gases.[48]
The bottom line is that the Earth is carbonizing, not decarbonizing, and it is projected to do so for the rest of the century. The rate of rise in the CO2 level is accelerating, according to data produced by the National Oceanic and Atmospheric Administration (NOAA). Their data for the measurements between 1990 and 2020 come from some 80 air sampling sites around the globe.[49]
Thus, the carbon contagion continues unchecked. Even if the rising emissions curve is turned downward, massive amounts of CO2 will still be pumped into the atmosphere to remain for centuries.
The resulting global heating will trigger positive feedback loops that will add even more CO2 and CH4—generating sea-level rise, drought, superstorms, and lethal temperatures.
The stark reality is that there currently exists neither the global political structure nor the political will to prevent extraction of the vast majority of potential fossil fuel reserves, which will drive a carbonization level that threatens human survival.
[1] International Energy Agency. Energy Technology Perspectives 2020: Special Report on Clean Energy Innovation (2020).
[2] International Energy Agency. “The Challenge of Reaching Zero Emissions in Heavy Industry.” (September 19, 2020).
[3] Victor, David G., Frank W. Geels, and Simon Sharpe. Accelerating the Low Carbon Transition. Energy Transitions Commission (2019).
[4] IPCC. Climate Change 2022: Mitigation of Climate Change, Summary for Policymakers. From Climate Change 2022: Mitigation of Climate Change (April 4, 2022).
[5] Welsby, Dan, James Price, Steve Pye, and Paul Ekins. “Unextractable Fossil Fuels in a 1.5 °C World.” Nature 497 (September 8, 2021).
[6] Trout, Kelly, Greg Muttitt, Dimitri Lafleur, Thijs Van de Graaf, Roman Mendelevitch, Lan Mei and Malte Meinshausen. “Existing Fossil Fuel Extraction Would Warm the World beyond 1.5 °C.” Environmental Research Letters 16, no. 6 (May 17, 2022).
[7] McGlade, Christophe, and Paul Ekins. “The Geographical Distribution of Fossil Fuels Unused When Limiting Global Warming to 2°C.” Nature 517, no. 7533 (January 7, 2015).
[8] Semieniuk, Gregor, Philip B. Holden, Jean-Francois Mercure, Pablo Salas, Hector Pollitt, Katharine Jobson, Pim Vercoulen, Unnada Chewpreecha, Neil R. Edwards, and Jorge E. Viñuales. “Stranded Fossil-Fuel Assets Translate to Major Losses for Investors in Advanced Economies.” Nature Climate Change (May 26, 2022).
[9] Tooze, Adam. “Why Central Banks Need to Step up on Global Warming.” Foreign Policy (July 20, 2019).
[10] Tienhaara, Kyla, Rachel Thrasherb, Alexander Simmons, and Kevin P. Gallagher. “Investor-State Disputes Threaten the Global Green Energy Transition.” Science 376, no. 6594 (May 5, 2022).
[11] Walsh, Brian, Philippe Ciais, Ivan A. Janssens, Josep Peñuelas, Keywan Riahi, Felicjan Rydzak, Detlef P. van Vuuren, and Michael Obersteiner. “Pathways for Balancing CO2 Emissions and Sinks.” Nature Communications 8 (April 13, 2017).
[12] Rockström, Johan, Hans Joachim Schellnhuber, Brian Hoskins, Veerabhadran Ramanathan, Peter Schlosser, Guy Pierre Brasseur, Owen Gaffney, Carlos Nobre, Malte Meinshausen, Joeri Rogelj, and Wolfgang Lucht. “The World’s Biggest Gamble.” Earth’s Future 4, no. 10 (October 27, 2016).
[13] Jones, Nicola. “How the World Passed a Carbon Threshold and Why It Matters.” Yale Environment 360 (January 26, 2017).
[14] University of Hamburg Climate. Hamburg Climate Futures Outlook. (June 10, 2021).
[15] Hedemann, Christopher, Eduardo Gresse, and Jan Petzold. “Global Warming Below 1.7°C Is ‘Not Plausible’, Reveals Our Study of the Social Drivers of Decarbonization.” The Conversation (June 24, 2021).
[16] International Energy Agency. “Achieving Net-Zero Emissions by 2050.” World Energy Outlook 2020 (October 2020).
[17] Princeton University. Net-Zero America: Potential Pathways, Infrastructure, and Impacts (December 15, 2020).
[18] Sustainable Development Solutions Network. America's Zero Carbon Action Plan (2020).
[19] International Renewable Energy Agency. Global Renewables Outlook: Energy Transformation 2050 (April 2020).
[20] Tong, Dan, Qiang Zhang, Yixuan Zheng, Ken Caldeira, Christine Shearer, Chaopeng Hong, Yue Qin, and Steven J. Davis. “Committed Emissions from Existing Energy Infrastructure Jeopardize 1.5 °C Climate Target.” Nature 572 (July 1, 2019).
[21] UC Irvine. “‘Committed’ CO2 Emissions Jeopardize International Climate Goals, UCI-Led Study Finds.” news release (July 1, 2019).
[22] Pfeiffer, Alexander, Cameron Hepburn, Adrien Vogt-Schilb, and Ben Caldecott. “Committed Emissions from Existing and Planned Power Plants and Asset Stranding Required to Meet the Paris Agreement.” Environmental Research Letters 13 (May 4, 2018).
[23] MIT Joint Program on the Science and Policy of Global Change. 2018 Food, Water, Energy & Climate Outlook (2018).
[24] Drouet, Laurent, Valentina Bosetti, Simone A. Padoan, Lara Aleluia Reis, Christoph Bertram, Francesco Dalla Longa, Jacques Després et al. “Net Zero-Emission Pathways Reduce the Physical and Economic Risks of Climate Change.” Nature Climate Change 11 (November 29, 2021).
[25] Rahi, Keywan, Christoph Bertram, Daniel Huppmann, Joeri Rogelj, Valentina Bosetti, Anique-Marie Cabardos, Andre Deppermann et al. “Cost and Attainability of Meeting Stringent Climate Targets without Overshoot.” Nature Climate Change 11 (November 29, 2021).
[26] IPCC, Climate Change 2022: Impacts, Adaptation and Vulnerability: Summary for Policymakers. From: IPCC Sixth Assessment Report: Impacts, Adaptation and Vulnerability. (February 27, 2022).
[27] BloombergNEF. Hydrogen Economy Outlook, Key Messages (March 30, 2020).
[28] Office of Energy Efficiency & Renewable Energy. Hydrogen Pipelines.
[29] Elberry, Ahmed M., Jagruti Thakur, Annukka Santasalo-Aarnio, and Martti Larmia. “Large-Scale Compressed Hydrogen Storage as Part of Renewable Electricity Storage System.” International Journal of Hydrogen Energy 46, no. 29 (April26, 2021).
[30] Livermore, Stephen. “Exploring the Potential for Domestic Hydrogen Appliances.” The Engineer (May 2018).
[31] World Nuclear Association. Hydrogen Production and Uses (May 1, 2024).
[32] Friedmann, Julio, Zhiyuan Fan, and Ke Tang. “Low-Carbon Heat Solutions for Heavy Industry: Sources, Options, and Costs Today.” Columbia University Center on Global Energy Policy (October 7, 2019.)
[33] International Energy Agency. Global Hydrogen Review 2021 (October 2021).
[34] International Renewable Energy Agency. Global Renewables Outlook: Energy Transformation 2050 (April 2020).
[35] International Renewable Energy Agency. Global Renewables Outlook: Energy Transformation 2050 (April 2020).
[36] Webber, Michael, E., “The Water Intensity of the Transitional Hydrogen Economy,” Environmental Research Letters (September 6, 2007).
[37] Slav, Irina. “The Green Hydrogen Problem That No One Is Talking About.” OilPrice.com (October 28, 2020).
[38] US Department of Energy. Department of Energy Hydrogen Program Plan (November 2020).
[39] Loftus, Peter J., Armond M. Cohen, Jane C. S. Long, and Jesse D. Jenkins. “A Critical Review of Global Decarbonization Scenarios: What do they Tell Us About Feasibility?” WIREs Climate Change 6 (January/February 2015).
[40] Sinn, Hans-Werner. “The Green Paradox: A Supply-side View of the Climate Problem.” Review of Environmental Economics and Policy 9, no. 2 (July 2015).
[41] Samset, B. H., J. S Fuglestvedt, and M. T. Lund. “Delayed Emergence of a Global Temperature Response after Emission Mitigation.” Nature Communications 11 (July 7, 2020).
[42] Dreyfus, Gabrielle B., Yangyang Xu, Drew T. Shindell, Durwood Zaelke, and Veerabhadran Ramanathan. “Mitigating Climate Disruption in Time: A Self-Consistent Approach for Avoiding both Near-Term and Long-Term Global Warming.” Proceedings of the National Academy of Sciences 119, no 22 (May 23, 2022).
[43] Frölicher, Thomas Lukas, Michael Winton, and Jorge Louis Sarmiento. “Continued Global Warming After CO2 Emissions Stoppage.” Nature Climate Change 4 (November 24, 2013).
[44] Radford, Tim. “Global Warming ‘Hard to Reverse’ Say Scientists.” Climate News Network (November 28, 2013).
[45] Samset, B. H., M. Sand, C. J. Smith, S. E. Bauer, P. M. Forster, J. S. Fuglestvedt, S. Osprey, C.-F. Schleussner. “Climate Impacts from a Removal of Anthropogenic Aerosol Emissions.” Geophysical Research Letters 45, no. 2 (January 8, 2018).
[46] Samset, Bjørn Hallvard. “How Cleaner Air Changes the Climate,” Science 360, no. 6385 (April 13, 2018).
[47] Takemura, Toshihiko. “Return To Different Climate States by Reducing Sulphate Aerosols under Future CO2 Concentrations.” Scientific Reports 10 (December 10, 2020).
[48] Schiffman, Richard. “How Air Pollution Has Put a Brake on Global Warming.” Yale Environment 360 (March 8, 2018).
[49] NOAA. The NOAA Annual Greenhouse Gas Index (2020).