Reaching net zero requires climate intervention and aggressive mitigation

Prudent planning and risk management have powered social and economic development for centuries. Those strategies should also be at the heart of the climate fight, write Dr. Michael MacCracken and H. David Tattershall

In the most recent IPCC report, AR6, scientists advised the world that a 1.5C temperature increase risks catastrophic impacts. In any other sphere of human activity, a warning of catastrophic risks from the most august international expert body would undoubtably engender an immediate and effective response. With respect to the warnings of the severity of climate change, this is presently far from the case.

And this grave warning is based on assessments of literature that is limited by a deadline for submission for IPCC reports. A specific example of an event occurring after material was submitted for AR6, and its probable catastrophic consequences, is discussed in this short video, Arctic Rain.

With regard to addressing climate change, the transition to a new renewable energy-based paradigm is the greatest economic opportunity of all time. But, for this to be recognised and put us on a path toward a solution, the problem and an effective response must be defined more clearly than has been the case.


The challenge

To limit global warming to a peak of 1.5C, which the impacts we are experiencing at 1.35°C warming (based on an average of the last 10 years) make clear is a higher than desirable goal. To achieve this the IPCC calculates that annual global emissions of CO2 must be reduced to 45 per cent below their 2010 level by 2030, which was roughly 1.9 gigatons of CO2 annually (GtCO2/year).


Nature is no longer on our side

Observations in 2019 made clear that the Arctic has now become a significant source of CO2 emissions, emitting the equivalent of around 2.3 Gt CO2. The risk is that this is now well occurring every year and the rate could be increasing as amplified polar warming increases. In 2021, observations also indicate that the Amazon Rainforest flipped from a sink to a source, emitting the equivalent of roughly 1.1 Gt CO2 that year. Given the ever-increasing deforestation of the Amazon region, the risk is a year-on-year increase in the associated net emissions.

The above research was published after the assembling of data for AR6 and was therefore not considered in the calculations of required emissions reductions to avoid a 1.5C increase. Including these new findings, the global community must actually reduce emissions by over 6 Gt CO2 per annum, at a minimum, to meet the actual challenge. We would suggest that is arguably impossible, both economically and technologically.


The response

Currently, international emissions reductions are falling well short of even the 1.9 Gt challenge. It has been suggested that the response can be augmented by using various draw-down approaches. At present, the construction of an industrial plant large enough reduce the atmospheric CO2 concentration by one ppm per year (7.81 Gt) is estimated to be near $4tr with an operational cost of as much as $150/tonne (equivalent to almost $1.2tr per year). A key question is who would pay for all of this? With respect to planting more trees, due to associated microbial activity early-stage growth actually emits more CO2 than is taken up and it takes 20-30 years for significant CO2 sequestration to begin for many trees. So, though planting trees is essential for the long-term it will not address the near-term challenge.


The bottom line

In any other sphere of human activity, be that concerning the military and all sectors of commerce, investment (plus many others), thorough due diligence (or its equivalent) would expose the risks and problems associated with not including nature’s responses to human-induced climate change impacts in the analysis. It is abundantly clear that emissions reductions alone, even accounting for the suggested augmentation to presently planned mitigation measures, will not solve the problem within the narrowing window of time for limiting warming to less than 1.5C (or even 2C). Clearly, more must be done, and the only cost-effective additional approach that could keep global warming below levels projected to lead to catastrophic outcomes is climate intervention.

This must be optimally complemented by sharp reductions in the rise in concentrations of short-lived greenhouse gases, in particular methane, which will further slow warming and thereby limit the time and amount of the required intervention.


The choice is ours

There are really only two choices for society: fail to do much more than is being done and suffers the consequences; Or, do much more, both in cutting emissions and intentionally intervening to shave off peak warming until emissions reductions, including short-lived species, and sufficient CO2 drawdown can make that intervention unnecessary.

Currently, society is continuing to subsidise the combustion of fossil fuels at a direct and indirect cost the IMF estimates approximately to have been $5.9tr in 2020. Add to this cost the $4tr per year that ongoing emissions are adding to what will need to be paid to pull today’s emissions back out of the atmosphere; an unfunded liability now totaling $100-$200tr if the climate is to be stable at a CO2 concentration (eg, 350 ppm) that will not cause serious climate disruption, ice sheet destabilization (leading to accelerating rate of sea level rise), and ocean acidification that is endangering the marine food chain which provides significant global protein.

Alternatively, society can progressively repurpose the $10tr per annum to seize the greatest economic opportunity of all time, create millions of jobs, and an economic boom that will sustain for decades and ensure a hospitable climate for our children.

While the youth of the world seem to understand this because it is they who will inherit the consequences of the choice that is made, it is very perplexing that the investment community, whose assets are most at risk, has refused to demand much greater concerted action . We conclude that the type of prudent planning that has underpinned social and economic development over the last few centuries calls for both more aggressive mitigation and climate intervention to moderate the inevitable warming that is developing and all it will lead to.


Dr Michael MacCraken is chief scientist for climate change programs with the Climate Institute. H David Tattershall is a retired business consultant with a specialization in due diligence.

With contributions from: Sir David King, former chief scientific advisor to the UK government and chair of the Climate Crisis Advisory Group; Dr Mark Trexler, CEO and founder of the Climatetographers; and Perses Bilmoria, CEO and Founder of Earthsoul Bio Products and director of The Club of Rome in India.


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