Shock scenarios

There is three additional shock scenarios ("wild cards", hazard driven scenarios). They are artificial experiments, simulating in a model-supported semi-quantitative narrative three singular events with widespread consequences: one environmental (GRAS-CUT, collapse of the thermohaline circulation THC), one economic (BAMBU-SEL, peak oil) and one societal shock (BAMBU-CANE, a pandemia). In IPCC terminology they can be characterised as implausible but based on an inherent logic (we prefer to call them possible, plausible, but improbable).

For GRAS-CUT, since the warming was of limited economic effect, so is the interim cooling (if it materialises after 2050 - nowadays the shock would be significant, but this is not a plausible scenario).

The quadrupling of the oil price in BAMBU-SEL first sounds like a safe receipt for an economic disaster, and so it is (grossly minus a fifth of the GDP) - for less than five years. Then the economic growth bounces back to the old level (or possibly even more), since due to international trade the money that has flown out of the importing countries comes back in form of product orders. As a result, the economic damage is limited in time, but since a high bill has to be paid for imports, the social impact is serious and lasting, resembling the wave of poverty resulting from the East Asian economic crisis a few years ago, and still pertaining. What would be the most plausible policy response? For Europe, most probably a massive investment in biofuels (in this respect, the EU policy has already adopted the scenario, although the oil price increase was still significantly below the BAMBU-SEL figures). The expected result indeed materialised: a massive pressure on agricultural land, leading to significant losses of biodiversity, in Europe and - even more so under a GRAS scenario - internationally. So what looked like an economic crisis turns out to be a social one, and the policies to mitigate it create an environmental disaster (while reducing GHG emissions only to a very limited extent).

The pandemia described by the BAMBU-CANE scenario is either an economic transformation with some sectors loosing and others winning, with an overall reduction of GDP below 10% and an early rebound, or leads to the total collapse of the economy. The latter would be the case if about 20% of the population would drop off the production process - some dead or in sick leave, but more of them trying to escape infection by avoiding to all events where many people meet (as observed in the bird flue epidemic in China).