No abstract

Financial markets have historically exhibited sudden and largely unforeseen collapses, at a systemic scale. Such "phase transitions" may in some cases have been triggered by unpredictable stochastic events. More often, however, there have been endogenous underlying processes at work. Analyses of complex systems ranging from the climate to ecosystems reveal that, before a major transition, there is often a gradual and unnoticed loss of resilience. This makes the system brittle: A small disruption can trigger a domino effect that propagates through the system and propels it into a crisis state.

The IPCC's global mean sea-level rise scenarios do not necessarily provide the right information for coastal decision-making and risk management.

No abstract

No abstract

No abstract

We use a coupled climate-carbon cycle model of intermediate complexity to investigate scenarios of stratospheric sulfur injections as a measure to compensate for CO 2 -induced global warming. The baseline scenario includes the burning of 5,000 GtC of fossil fuels. A full compensation of CO 2 -induced warming requires a load of about 13 MtS in the stratosphere at the peak of atmospheric CO 2 concentration. Keeping global warming below 2 • C reduces this load to 9 MtS. Compensation of CO 2 forcing by stratospheric aerosols leads to a global reduction in precipitation, warmer winters in the high northern latitudes and cooler summers over northern hemisphere landmasses. The average surface ocean pH decreases by 0.7, reducing the calcifying ability of marine organisms. Because of the millennial persistence of the fossil fuel CO 2 in the atmosphere, high levels of stratospheric aerosol loading would have to continue for thousands of years until CO 2 was removed from the atmosphere. A termination of stratospheric aerosol loading results in abrupt global warming of up to 5 • C within several decades, a vulnerability of the Earth system to technological failure.V. Brovkin (B) · M. Claussen

No abstract