Climate tipping points are thresholds beyond which changes in a climate subsystem become self-perpetuating — driven by internal feedback loops rather than by continued external forcing. Once a tipping point is crossed, the system transitions to a qualitatively different state, and this transition is effectively irreversible on human timescales (centuries to millennia).
Identified tipping elements include: the Greenland Ice Sheet (committed to irreversible loss above approximately 1.5–2°C of global warming, contributing up to 7 meters of sea level rise over centuries); the West Antarctic Ice Sheet (potentially already in early stages of irreversible retreat, with 3–5 meters of sea level rise committed); the Atlantic Meridional Overturning Circulation (AMOC) (collapse would radically alter weather patterns across Europe, Africa, and the Americas); the Amazon rainforest (drought-driven dieback converting the forest from carbon sink to carbon source); permafrost (thaw releasing carbon that drives further warming); and coral reef systems (functional extinction above 1.5–2°C).
The critical danger of tipping points is their interaction. The crossing of one tipping point can trigger or accelerate others — a “tipping cascade” in which the climate system shifts rapidly between states. Current warming (~1.3°C above pre-industrial) has likely already committed some tipping elements to transition. The analysis in this library that staying under 2°C was never plausible connects directly: if the political and economic structures that produce emissions cannot be reformed fast enough, the question shifts from prevention to response.