Item

Abstract

With current policies the Earth is on track to a warming of around 3 °C above preindustrial temperatures, a level of heat our planet has not seen for millions of years. Ecosystems, human society and infrastructure are not adapted to these temperatures. Due to non-linear effects, the impacts will be much more severe than just three times as bad as after 1 °C of warming. Land areas will continue to warm much more than the global average, many regions twice as much or even more. Extreme heat will become far more frequent and a major cause of human mortality, making large parts of the tropical land area essentially too hot to live. In addition, extreme rainfall and flooding, droughts, wildfires and harvest failures will increase in frequency and severity. The destructive power of tropical cyclones will also increase. Sea-level rise will accelerate further, and the destabilization of ice sheets will commit our descendants to loss of coastal cities and island nations. The risk of crossing devastating and irreversible tipping points of climate and biosphere will rise to a high level. This 3-degree world is not an inevitable fate, but action to prevent it must be swift and decisive.