https://physicsworld.com/a/climate-inte ... t-problem/
This review makes several comments that are absurdly ignorant and unscientific. It is amazing at one level that Physics World can publish such obviously mythological claims, but unsurprising at another level, in view of the popular hold of the myths the review promotes and the emotional comfort they provide to the mass climate movement.
Lets go through them.
No. This is wildly and dangerously wrong in several points. Rapid reduction of emissions is not practical in view of the intense and powerful political and economic opposition to it, and the immense technical challenges in stopping emissions of both carbon dioxide and methane. All the talk of cutting emissions in recent decades has only seen a remorseless rise. Next, even “net zero” would be laughably far from a “way to halt climate change”. Reaching net zero by 2050 would see a CO2 equivalent level well above 600 parts per million. Numerous irreversible tipping points would be crossed before then, unless we move immediately to brighten the planet. Relying on carbon methods alone is like claiming you can stop a thirty foot flood with a ten foot levee. That is not practical. And even if tipping points do not somehow push us into a hothouse, the idea that 600 ppm would not involve further climate change is absurd. It would commit the planet to ongoing change until we reach earth system equilibrium with much higher sea level etc.1. “The rapid reduction of greenhouse-gas emissions to net zero is the only practical way to halt climate change.”
This may seem “obvious” but it is not. It is obvious politically that many (not just some) people do have this worry, which has been aggressively promoted by political opponents using flawed and deceptive moral hazard logic. It is not at all obvious scientifically, which is what should matter to Physics World. There are no good scientific grounds for the ideological worries that have prevented investment in cooling technology. Scientifically, applying known cooling chemistry would cause cooling, if managed under strong technical protocols. This would pull us back from the dangerous precipice of numerous looming unsafe tipping points, with benefits far exceeding risks. Use of charged political rhetoric like “obvious” is unscientific. Cooling chemistry is completely different from the chemistry of emissions.2. One obvious reason for caution is that altering the chemical makeup of the atmosphere is what got us into this climate mess, and some worry that further tinkering could make things worse.
This claim accepts the howling popular error in the meaning of net zero, which means emissions equal removals. It is probable that when net zero is achieved, it will mainly be through removals, not through cutting emissions. That will mean we will have a trajectory of expanding removals. The removal technology will enable the excess CO2 to be removed over the next decades through ongoing removals, and will not at all imply past emissions will endure for centuries. The problem is that this review accepts the popular mythological assumption that net zero mainly requires decarbonisation of the economy when that is not the case at all.3. Even if we do manage to meet the Paris Agreement and get to net-zero emissions shortly after 2050, Smith warns, the excess carbon dioxide that is already in the atmosphere will endure for centuries or even millennia. This means that temperatures will not quickly return to pre-industrial levels.
Claiming biochar would cost trillions seems dubious. Its improvements to soil structure would increase agricultural yields. I suspect greenhouse gas conversion technology will develop other materials-based approaches using photosynthesis that will become profitable, creating large new carbon mining industries to rival the 20th century emergence of aviation, pharmaceutical and chemicals.4. Smith looks at other removal strategies such as making biochar, which involves the partial recovery of elemental carbon from biomass and then using that carbon to enrich soils… we will need to organize the world to pay the trillions of dollars required to deploy them year in and year out for decades to come.”
If this statement were totally reversed it would be true in the short term. Brightening the planet is the only way to “stop or reverse climate change” in this decade, addressing extreme weather, tipping points, biodiversity loss and higher temperatures. Carbon based methods will take decades to have any effect on temperature (ie climate) and might even then be totally swamped by tipping points, absent a main focus on albedo. Stopping climate change requires stopping tipping points, which requires higher albedo. While it is true in the long term that we should bring the GHG level back to the Holocene norm, that is a slow task.5. Unlike cutting emissions or capturing carbon, Stratospheric Aerosol Injection will not stop or reverse climate change
This is from the author not the reviewer. Green movements have a quasi-religious opposition to SAI, based on their historic origins in thinking that is closely related to the communist movements which saw class struggle as a fight between good and evil. Their political war against fossil fuels is a form of class struggle that has morphed in green ideology from a means to stabilise the climate into an end in itself. Converting greens to understand the climate science of direct cooling may well be more difficult than converting denialists. Decisions to cool the planet will likely require implementation without the consent of ideological opponents. Smith is correct this will be a massive challenge, but it is a profound and tragic irony that the people who profess to care the most about climate change are now doing the most to prevent effective investment to reverse it. This is a moral problem that requires much more public conversation to expose the hypocrisy and inconsistency of opponents of geoengineering.6. governance of an SAI programme… ideally would have the consent of all the people on the planet.