Fig. 1. Climatic hazards of the Earth’s system affected by the ongoing emission of GHGs.

We considered the following ten climate hazards. GHGs mediate the balance between incoming solar radiation and outgoing infrared radiation; thus, (1) their excess in the atmosphere causes warming. Compounded with an increased capacity of the air to hold water, warming accelerates soil water evaporation, leading to (2) drought in places that are commonly dry; excess drought can lead to (3) heatwaves when heat transfer from water evaporation ceases. Drought and heatwaves ripen the conditions for (4) wildfires. In moist places, the quick replenishment of evaporation strengthens (5) precipitation, which is prone to cause (6) floods as rain falls on moist places/saturated soils. Warming of the oceans enhances evaporation and wind speeds, intensifying downpours and the strength of (7) storms, whose surges can be aggravated by (8) sea level rise, which in turn can aggravate the impacts of floods. Uptake of CO₂ in the oceans causes ocean acidification, whereas changes in ocean circulation and warming reduces oxygen concentration in seawater; these combined ocean physical–chemical changes are referred to as (9) ocean climate change in this paper. We included (10) changes in natural land cover as one of the hazards because it can be a direct emitter of GHGs via deforestation and respiration, modify temperature via albedo and evapotranspiration and because it can be a direct modifier in the transmission of pathogenic diseases^59,84. This figure is intended as a justification for the hazards used and not as a full array of interactions between GHGs and hazards and feedback loops among hazards.