Bru Pearce Blogs
By Bru Pearce
Human reactions to climate change cause innumerable secondary feedback loops that occur on every scale as the human population comes under pressure for land, food, water and energy resources:
Demand for food and agricultural land causes clearance of forests and drainage of wetlands both of which involve huge releases of carbon. This in turn causes further warming and increased drought, floods and desertification leading to loss of agricultural land.
- Cleared forest is put over to pasture for cattle and sheep farming, both species burp methane
- Rising sea levels force the construction of huge sea defences around the coasts and in many places entire cities have to retreat. Resulting in massive use of concrete and its attendant CO2 emissions
- Over fishing leads to falling catches inshore, requiring larger boats with bigger engines to go further offshore to unexploited fishing grounds, more fuel is burned
- As traditional fish stocks become unavailable fishing moves down the food chain – there are now huge ships fishing for Krill in the arctic.
- Depleted soils lead to reduced crops and additional nitrogen based fertiliser being added and this leads to nitrous oxide emissions; a highly potent green house gas
- As fossil fuel demand continues to increase and easily accessible deposits run out, the energy demands of mining and retrieving the fuel from ever deeper and more difficult to obtain resources increases, adding CO2 not only by energy generation but by the parasitic load of obtaining those fuels
- As the cost of energy goes up, previously marginal fuels become economic to extract such as shale gas and tar sands. Greatly increasing green house gas emissions from the energy burn and, in the case of fracking, by methane release to the atmosphere as the fuel gas is collected.
- Economic collapse and recession, lead to people being unable to pay for fuel – this results in them foraging for fuel and trees are felled. This has happened in Haiti where almost no trees are left. The burned wood has released its CO2 and without the trees the soil has eroded and released its captured carbon.
- As the climate gets hotter so air conditioning is used more, demanding more energy, so more CO2 is released causing more warming and the a/c is turned up again
- An increasingly extreme climate also means that cold spells are more severe requiring more heating of buildings.
- Economic growth in emerging nations particularly China and India generate ever growing demands for energy.
- invasive species such as bark beetle invading the northern forests leads to tree loss and rotting timber releases methane and CO2 and there are many more examples of trees under stress succumbing to diseases all over the world
- Growth and development; as living standards increase, energy usage goes up so CO2 release increases.
- Floods cause erosion and siltation. This can make rivers un-navigable forcing goods on to the roads. So less efficient transportation has to be used as goods are transported by road.
Extreme rain and glacial melt lead to increase siltation of dams which can stop hydropower systems working, energy is then replaced by burning coal or oil leading to increased CO2 emissions.
All of the above, act on each other in a dynamic way, each accelerating the others; it is not the sum of the feedbacks but the multiple. This causes greenhouse gasses emissions to increase ever faster and the heat trapping effect gets exponentially more severe. So expect every year to be worse than the one before for the number and severity of extreme weather events.
General feeling of fear – the basic knowledge that the economics of endless growth on a finite planet does not add up, ensuring that the markets have no confidence. In times of low confidence only short term thinking is promoted. Ongoing recession takes the attention away from climate change and reduces the budget for investment in renewable energies.
Part 5 is just coming....