I have previously shown that it is too late to mitigate, by at least fifty years (see my earlier blog post of 18 January 2021). Central to that argument are the facts of self-reinforcing feedback loops, tipping points, and the realization that temperature increases from higher concentrations of Greenhouse Gases (GHGs) in the atmosphere have now led to greater amounts of GHGs being emitted from the planet itself rather than just from human activity.
But now it must be shown that the mitigation of human GHGs emissions can NEVER stabilize, let alone reduce, the greenhouse gas effect. I return to the ‘blanket’ analogy, since this is a helpful way of explaining how greenhouse gases trap heat from escaping into space, thus warming the planet. It is like adding a blanket on a bed that you are sleeping in. As said before, there is a delayed response to the warming effect by adding ‘blankets’. It is not instant… about 10 – 20 years for the planet by adding CO2 into the atmosphere.
Mitigation of human generated GHGs is possible, but we have no control over ‘natural’ GHGs emitted from the planet. But that is not the major problem here. It is that over the last few hundred years there has been a massive accumulation of GHGs in the atmosphere. Every year for the last fifty years or more, humans have added tens of billions of tonnes of CO2e annually. The amount back in 1990 was about 35 billion tonnes annually. Now it is more than 50 billion tonnes annually and showing no signs of becoming less despite political ambitions. In other words, we have been adding larger ‘blankets’ every year. Mitigation of human GHGs means adding smaller ‘blankets’, NOT the removal of blankets. So, here then is another reason why mitigation is futile.
The only solution to return the planet to a stable Holocene climate is to remove from the atmosphere the massive excess of GHGs that have accumulated there, both from human activity and now also the excess from nature itself due to the carbon cycle having been thrown out of equilibrium.
The scale of the challenge for carbon removal using technologies like Direct Air Capture is almost too large to comprehend. Just keeping pace with 1990 global CO2 emissions, 36 gigatonnes per year, would mean building about 30,000 large-scale DAC plants, more than three for every coal-fired power station. Each plant would cost up to US$500m to build – coming in at a cost of about US$15 trillion.
The removal of the excess GHG ‘blankets’ is practically impossible. We have neither the technology at scale, nor the political will and consensus globally, nor the enormous amount of money to invest doing this! We also don’t have the energy resources to use for doing this either.
Then there is the problem of thermal inertia. Warming oceans and lands now contribute to atmospheric warming. The warming oceans are a capacitor of heat, ensuring continued warming for centuries, especially with the disappearance of Arctic sea ice. This is an obstacle to any mitigation effort, and to the effects of removing the accumulated GHGs (if that were possible).
So, where does this leave us? Firstly, it reiterates the observation that it is too late to mitigate, and that mitigation (by reducing emissions) is totally futile. Secondly, the only solution may be the currently impossible task of removing massive quantities of greenhouse gases from the atmosphere. Thirdly, this also is likely to be ineffective against the growing thermal inertia in the system with warming oceans. Besides that, the ever-increasing GHGs being emitted from a warming planet cannot be mitigated other than by cooling the planet.
There are many accelerating and irreversible processes currently in motion. These include self-reinforcing feedback loops and the crossing of tipping points. If you extrapolate from the known facts and the known trajectories of change, you can only arrive at one conclusion. It is not a happy outcome for life on the planet. But the planet itself will survive, at least for another five billion years until consumed by the expanding sun.
We need to adapt to the changing conditions to mitigate suffering, at least until it is also too late to do that.
Addendum: A Brief Response to Professor James Renwick’s recent comments.
James Renwick is a Professor of Physical Geography at Victoria University, New Zealand. He is one of the seven commissioners on the recently formed government Climate Change Commission tasked with implementing ‘The Climate Change Response (Zero Carbon) Amendment Act 2019’. He has recently been quoted as saying…
The latest science paints a stark picture, but also points out that it is not too late. I think it is very important to take this on board because if we think it’s too late then we’ll be less motivated to take the action required.
Yes, there are feedbacks in the climate system that add to the effect humanity is having. However, the best science I am aware of says that those feedbacks do not operate autonomously and will not continue of their own accord IF we cease emitting carbon dioxide.
Some things are indeed irreversible, such as a certain amount of sea level rise. The climate is already changed from last century and will stay changed for centuries into the future. However, we can still avoid catastrophic change by reducing emissions urgently. It is still the case that getting to ZERO GLOBAL EMISSIONS of CO2 by 2050 would stop warming at not much over 1.5 degrees. When we stop emitting, we stop the warming within a few years. There is no long-term feedback that would over-ride this.
In my opinion, the professor needs to become a confessor. One must assume that he knows the science, and that the facts of science reported in many peer reviewed science papers are incongruent with the popular myth of ‘net zero’ and effective mitigation. One must then assume deliberate obscuration so as not to impede the attempts to mitigate, the charter for his current work for the New Zealand government and the Climate Change Commission.
His comments about feedback loops are clearly erroneous. A simple Wikipedia search will show this. In plain English they are defined as ‘self-reinforcing’ and ‘self-accelerating’. The irreversible nature of tipping points is not discussed, other than his comments on sea-level rise. Contrary to Renwick, the science indicates that it is too late to mitigate!
‘Climate scientists: concept of net zero is a dangerous trap’ by James Dyke, Robert Watson, and Wolfgang Knorr, The Conversation, 22 April 2021, https://theconversation.com/climate-scientists-concept-of-net-zero-is-a-dangerous-trap-157368
 Samset, B.H., Fuglestvedt, J.S. & Lund, M.T. ‘Delayed emergence of a global temperature response after emission mitigation’, Nature Communications Journal 11, 3261 (2020). https://doi.org/10.1038/s41467-020-17001-1 Also ‘Maximum warming occurs about one decade after a carbon dioxide emission’ by Katharine Ricke and Ken Caldeira, Environmental Research Letters, Vol 9 No 12, 2 December 2014 https://iopscience.iop.org/article/10.1088/1748-9326/9/12/124002
 David Roberts, ‘Sucking carbon out of the air won’t solve climate change, but it might fill in a few key pieces of the clean energy puzzle’ Vox, 16 July 2018, https://www.vox.com/energy-and-environment/2018/6/14/17445622/direct-air-capture-air-to-fuels-carbon-dioxide-engineering ; ‘The Direct-Air Capture Debate’ Anthropocene Magazine, 25 March 2021, https://www.anthropocenemagazine.org/2021/03/the-direct-air-capture-debate/ ; ‘Emergency deployment of direct air capture as a response to the climate crises’ by Ryan Hanna, Ahmed Abdulla, Yangyang Xu and David G. Victor, Nature Communications volume 12, Article number: 368 (2021) https://www.nature.com/articles/s41467-020-20437-0
 Also, there is virtually no profit to be made by sequestration by this method… burying the carbon back into the ground. It may however be possible to convert this carbon into synthetic fuels by using a massive amount of energy. Perhaps New Zealand, being a 0.17% contributor to the problem, could do this with its large amount of electricity generated by hydro and geothermal electricity production.
 Claudia Tebaldi and Pierre Friedlingstein ‘Delayed detection of climate mitigation benefits due to climate inertia and variability’ PNAS October 22, 2013 110 (43) 17229-17234; https://doi.org/10.1073/pnas.1300005110
 From email correspondence with Lorna Sutherland read at the hearing of submissions on the Whanganui District Council Climate Change Strategy, 20 April 2021.
 A self-reinforcing feedback is an accelerating process that occurs in a feedback loop which exacerbates the effects of a small disturbance. That is, A produces more of B which in turn produces more of A.