Featured image: Linear clouds in this satellite photo show the path of large ships. Exhaust from the extremely polluting bunker fuel these ships burn acts as a nucleus for condensing water vapor, forming clouds. One container ship releases as much pollution as 50 million cars. Public domain photo.
By Max Wilbert
The Global Climate System
Global climate can be understood as a simple energy balance equation. When climate is stable, energy inputs (sunlight hitting the Earth) matches the amount of energy lost to space through radiation. Industrial civilization has upset this balance by destroying forests, plowing grasslands, damming rivers, and digging up and burning coal, oil, and gas. These processes all release greenhouse gases, which trap additional heat inside the atmosphere. This is called radiative forcing.
This has gradually changed the energy balance of the entire planet. Since 1998, these greenhouse gases have caused an amount of energy equivalent to nearly 2.8 billion Hiroshima-sized atomic bombs to be captured inside the Earth’s atmosphere. Most of this heat has been absorbed by the oceans.
We know the consequences of this: ocean acidification, glaciers melting, droughts, heat waves, floods, stronger hurricanes, crop failures, migration, and so on. The ramifications of global warming are catastrophic and pervasive to essentially every aspect of human and non-human life. But some of the details of global warming are less often discussed.
What Are Aerosols?
One of these rarely-discussed issues is the aerosol masking effect. “Aerosols” in climate science are defined as collections of airborne solid or liquid particles, with a typical size between 0.01 and 10 µm (micrometers) that reside in the atmosphere for at least several hours. Aerosols may be of either natural or anthropogenic origin. Aerosols may influence climate in several ways: directly through scattering and absorbing radiation, and indirectly by acting as cloud condensation nuclei or modifying the optical properties and lifetime of clouds (see Indirect aerosol effect). Examples of aerosols include dust, volcanic ash, pollen, soot, sulphates, even bacteria.
Some of the most common aerosols come from coal, driving cars, and fire for land clearance. When entering the lungs, these particles are extremely hazardous to health of all creatures, and are estimated to kill about 5.5 million people per year. This is one reason that pollution is estimated to be responsible for roughly 40% of all human deaths.
Aerosols also cool the planet by reflecting incoming solar radiation back into space. In the past, researchers have estimated this blocked as much as half of the warming caused to this point. As Dan Bailed wrote online, “It has long been conjectured that an immediate cessation of the burning of fossil fuels would be swiftly accompanied by a spike in surface temperatures (warming rates might spike from 0.2 C per decade to as much as 0.4 to 0.8 C per decade).”
Does Aerosol Masking Make Resistance Counterproductive?
This has been a common question for us here at Deep Green Resistance:
“What’s your take on the aerosol masking effect? Some people believe it is actually protecting the Earth from runaway climate change. If industrial collapse happens, wouldn’t this cause a decrease in aerosols and result in rapid warming? Wouldn’t this mean that life on earth is doomed even faster? Won’t reducing industrial emissions just result in faster warming?”
We have for years regarded this as a false double-bind, or an example of a legitimate concern twisted into an excuse for inaction. Using aerosol masking as an excuse for not shutting down fossil fuel infrastructure is an exercise in cowardice, in holding change hostage, in a sort of blackmail: damned if you do, damned if you don’t.
As you know, the only way out of a double-bind is to smash it.
New Science Reduces Concerns Over Aerosol Masking
But even legitimate concerns may be laid to rest by new science published in Nature this month. In the paper, two researchers Shindell and Smith note that reductions in fossil fuel burning, and thus in aerosols, “do not produce a substantial near-term increase in either the magnitude or the rate of warming.” This warming, they explain, would be negligible “at essentially all decadal to centennial timescales.”
Their conclusion: “We find that any climate penalty associated with the rapid phase-out of fossil-fuel usage… is likely to be at most 0.29 °C.” While climate science is complex and new findings could always change the situation, our conclusion is straightforward as well.