Who Killed the Liquid Fluoride Thorium Reactor (LFTR)?

[GliderGuider]

63. The impact of aggregate human activity is the problem.

Last edited Thu Dec 29, 2011, 09:38 PM - Edit history (4)

The impact of aggregate human activity is the product of the number of people times the per capita impact. We need to reduce population, the level of activity and the impact of the activities in some combination.

One of the most significant impacts we have on the planet is through agriculture. I don't think we can reduce the wide-ranging ecological impact of agriculture by 85% and still feed 9 or 10 billion people, so reducing the demand for food - i.e. the population - will have to play a major role.

The greater the level of human activity, the greater the demand for raw materials and natural habitat to be converted for human use. Again, efficiency gains seem unlikely to give us the requisite 85% payback, so reduced levels of human activity will be required.

The impact of our activities depends on the extent to which they displace other species and pollute the land, water and air. CO2-induced climate change, eutrophication, urban sprawl, desertification and ocean fish depletion are a few examples of the impact of our activities.

Taking a page from the concept of the IPAT equation, the change in our planetary impact (PI) is the product of the change in each of these three factors: population (P), activity level (AL) and activity impact (AI). So, deltaPI = deltaP * deltaAL * deltaAI.

If we wish to create a specific change in planetary impact we can get some general idea of what changes we would need to make in the other factors given various assumptions about population levels, activity levels and the impact of our activities.

For instance, let's set deltaPI to 0.15 to achieve what I think is necessary for true long-term planetary sustainability. If we assume a future population of 10 billion, then deltaP will be 1.43. If we then assume that on average we can reduce the overall average impact of human activities (in some general sense) by 1/3, then deltaAI will be 0.66. To achieve the stated goal of (deltaPI=0.15), then the level of activity will have to drop to 0.15/(1.43*0.66) or 0.16 - we will need an 84% reduction in our activity levels.

On the other hand, if we could reduce our population by a third to 4.5 billion and also cut the average impact of our activities by a third, we could achieve that same level of sustainability with a "mere" 65% reduction in our activity levels.

A lot depends on what we are prepared to accept as a definition of sustainability, and how much reduction in numbers, activity levels and impacts we can achieve voluntarily.

As always, I'm of the opinion that we will achieve sustainability only as the result of involuntary changes, but the more progress we make between now and whenever Mother Nature finally bites our ass, the better off we will be.

To bring it back on topic, I am quite sure LFTR would make little noticeable difference in the larger picture, as the impact reduction would be quite modest even in the most optimistic case, and it would not promote the reduction of either activity levels or population.