Making the case for net-zero emissions.
Growth is at the core of modern civilization. Population is growing, Global GDP is growing, people want their children to have a better life than they had. We want all people to rise to an acceptable, minimum lifestyle. Growth is at the core of our hopes and dreams and our very being.
But the climatic expression of our growth is obscenely-high GHG emissions into a finite atmosphere. Although we must rapidly reduce our emissions to cap warming at "sustainable" levels, no level of reduction will ever be enough, on its own, to solve the fundamental growth problem.
We need something equally big to counter the GHG emissions we cannot eliminate. And that big "something" will have to grow as our emissions grow.
Life has given each of us about 30,000 days to live, consumed one day at a time. With known capacity and consumption rate, we plan our life with clock-work precision: go to school until age 20, raise a family until 50, work until 65, pass our goods to the next generation before we exit life at age 80. We have a linear, predictable, measured sense of time and lifespan.
But what if we were offered a “better” life? More money, more fame, more of whatever people want. The cost of this Faustian Bargain? The rate at which we consume our 30,000-day lifespan grows each day by 1%: on Day 1 we consume 1 day of our lifespan. On Day 2 we consume 1% more, Day 3 1% more, … By Day 10 we consume our lifespan 10% faster/day than on Day 1. But we’re having a “better” time.
How long will our “better” life last? About 574 days, because at the compounding rate of 1% faster each day, after 574 days we are consuming our lives 300 times faster than on Day 1! The fundamental problem is mixing growth with a limited resource. Unlimited growth of the consumption of a limited resource often ends in collapse when the limited resource is exhausted (think of a growing population of rabbits with a limited food supply). Accelerated growth leads to accelerated collapse.
How does this relate to our discussions of GW/CC? If we accept that we must limit warming to no more than 2°C, there is a finite carbon-capacity of the atmosphere that correlates to 2°C. However, unlike other limits of growth with natural systems, there is nothing in the natural world that will limit atmospheric carbon to the arbitrary 2°C limit we're setting, beyond which it is likely that life will become unbearable for a large part of the world’s population. Nature has no mechanism for limiting the warming to 2°C. If we continue growing inside this limited world, we can easily blow past 2°C and reach 6°C warming or more.
Figure 1. Ice-core CO2 concentration from the recent ice age up to the start of the Industrial Revolution. During the “Unstable, exponential growth” part, historical CO2 growth rates were adjusted down to 0.01% of actual rates and extended forward until atmospheric CO2 increased to about 380 ppm. In a growth scenario, no matter how low the CO2 emission rates start out during the Industrial Revolution, they eventually grow into catastrophic rates that overwhelm any recent, historical precedence.
What if we slowed the growth rate so that starting from the Industrial Revolution CO2 accumulated in the atmosphere at only 1/10,000th of historical rates? The rates would be lower, but just like today, each year CO2 would accumulate in the atmosphere about 1% faster than the previous year. Figure 1 shows the result of such a scenario, and indicates that it would take about 8000 years to reach levels comparable to today. But we’d get there and, more to the point, at some point the annual rate of rise of CO2 would be just as high as it is today. This is the fundamental problem of growth scenarios: no matter how slow they start, they eventually progress into the same, catastrophic rates of increase. If rates start out a little slower, they just take a little longer to get to the level that constitutes a catastrophe.
Figure 1 shows another interesting contrast. During the recent deglaciation CO2 rose at a near constant rate, and then something stopped this slow, steady increase, stabilizing the climate at the level that provided a stable base for the development of modern civilization. By contrast, we know of nothing that will naturally limit the current exponential growth before we suffer potentially catastrophic consequences. Whatever halted the increase during the recent, natural deglaciation will not halt the industry-driven increase. This time around nature has left us on our own to figure out how to stabilize the climate.
The purpose of Fig. 1 is to show that any growth scenario coupled to a finite system (i.e., Earth’s atmosphere), eventually exceeds the allowed limits. We’ve already exceeded the atmospheric concentration corresponding to 1.5°C! Yes, there are optimistic discussions occurring suggesting that if we do this or that, then we might be able to restabilize the climate at 1.5°C. But these are long-shots, and considering the degree to which the Keeling Curve has completely ignored all of efforts so far to encourage it to slow down, the best bet is that we are looking at 1.5°C in the rear-view mirror, and we had better focus hard on stabilizing at 2.0°C before we are looking at it in our rear-view mirror. If there is one lesson we should have learned by now it's that the Keeling Curve is a very tough negotiator.
For any chance of stabilizing at 2.0°C, we must stop net human GHG emissions so that the atmospheric GHG concentrations can stabilize. Although we talk about goals of limiting warming to either 1.5 or 2°C, the real goal is stabilization at any level, because by nature, growth systems don't stabilize. They want to keep growing!
The core problem? Human growth is continuing unabated. Global population is increasing, people are consuming more, more people in the world are raising their standards of living to achieve a better life. Growth happens and regardless of how successful we are deploying renewable-energy technologies, we will not stop human growth, we will not eliminate GHG emissions. Human growth drives growing GHG emissions.
After we've done all that we can to reduce our GHG emissions, the only chance for stabilizing the climate is by actively countering our growth with methods for removing GHG’s from the atmosphere at the same rate we emit them. As GHG emissions grow, so must the systems used to remove them. They are collectively called Negative-Emissions Technologies (NET), and we must deploy them to stabilize the climate.
Some may look at Fig. 1 and proclaim that a “slower” rate would be acceptable, because we should be able to move cities as sea-level rises, build ocean barriers quickly enough, adapt to changing weather patterns, change the locations of our farmlands, etc. But Fig. 1 represents a “what-if?” scenario and nothing more. There is no dial we can turn to adjust the amount of CO2 increase/decrease. We describe human growth in hindsight, but it is nothing that can be precisely controlled, especially in democratic countries. Even though we have some emissions-reduction tools to deploy (e.g., wind turbines, solar panels, proposed new farming methods, proposed new energy-efficiency technologies), as of 2022, push-back in the media and in the voting booths is slowing deployment of the limited resources we have. There is no feasible way to dial down our emissions to the low rate shown in Fig. 1: it merely shows that growth eventually overwhelms a limited resource, regardless of how small the initial rate is.
Some will quickly start quoting “S-curve this” and “limits of growth that” to assure us that all will be OK and that our CO2 growth curve won’t go on forever and that something will limit it. If we wait until the growth of fossil fuels and human population reach their natural limits, however, we will likely blow past any atmospheric GHG limits that provide some guarantee of climate stabilization. Remember that as we warm Earth we risk increasing natural GHG sources and/or reducing natural GHG sinks. This will cause further warming that may be beyond our control.
We must deploy NET systems to limit the negative effects of the growth we cannot limit. There is no other option.
Posted by Evan on Monday, 28 February, 2022
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