"System change is now inevitable. Either because we do something about it, or because we will be hit by climate change. '...

"We need to develop economic models that are fit for purpose. The current economic frameworks, the ones that dominate our governments, these frameworks... the current economic frameworks, the neoclassical, the market frameworks, can deal with small changes. It can tell you the difference, if a sock company puts up the price of socks, what the demand for socks will be. It cannot tell you about the sorts of system level changes we are talking about here. We would not use an understanding of laminar flow in fluid dynamics to understand turbulent flow. So why is it we are using marginal economics, small incremental change economics, to understand system level changes?"

Tuesday, February 16, 2016

Should We Stop Breathing?

If CO2 CAUSES climate change, and we EXHALE CO2, what happens if a billion people (like CHINA) stop exhaling for a minute? A measurable effect?

Lung capacity is about 3 L according to Lung Volumes and Capacities
Exhaled air contains about 100 times the concentration of carbon dioxide that inhaled air does, or about 4% CO2 by volume via Carbon dioxide comparison between inhaled and exhaled air

So the amount of CO2 sequestered in the lungs of a billion people is 4 % of 3 billion liters or 120 million liters at roughly 1 atmosphere pressure. At 2 g / L (What is the density of carbon dioxide (CO2) at STP if 1 mole occupies 22.4 L?) we get the lungs of China holding 0.002 * 1.2e8 = 240,000 kg.

The entire atmosphere has 5 x 10^18 kg total, of which 0.04% is CO2 so that amounts to 2 trillion kg.

So the fraction of the earth's CO2 in a billion lungs holding their breath is
240,0002,000,000,000,0o0 = about a tenth of a part per million. If they held it forever, they would be uncomfortable, but the effect on CO2 would be so tiny as to be hard to measure.

As a global warming question this is sort of misguided, because CO2 breathed out balances carbohydrates eaten - there is no new net carbon injected into the system. That is, it seems to confuse fluxes and reservoirs, or as economists call it, stocks and flows. In fact, breathing contributes nothing to global warming at all, if food is produced in a carbon neutral way. It makes more sense to look at the carbon footprint of food production than of breathing, though in practice that is quite substantial, perhaps 10% of the total. This link says 9%: Agriculture Sector Emissions

I am sure you are responding to somebody who snarkily suggested we stop breathing. In fact, this boils down roughly speaking to whether we stop eating. If somehow we could live our lives otherwise the same without eating, we'd reduce our emissions by around 10%, and the accumulation in the atmosphere would be somewhat slowed. It's probably not a promising approach, though. But that's all about agricultural practices, not about agriculture itself. It's probably still possible to feed the earth's population entirely in a carbon neutral way.

No comments: